Home The optimization of Carreau model and rheological behavior of alumina/linear low-density polyethylene composites with different alumina content and diameter
Article Open Access

The optimization of Carreau model and rheological behavior of alumina/linear low-density polyethylene composites with different alumina content and diameter

  • Guo Li , Mitao Zhang , Huajian Ji , Yulu Ma , Tao Chen and Linsheng Xie EMAIL logo
Published/Copyright: October 4, 2021
Become an author with De Gruyter Brill

Abstract

The influence of alumina (Al2O3) content and diameter on the viscosity characteristics of the alumina/linear low-density polyethylene (Al2O3/LLDPE) composites was discussed. The composites were fabricated by melt mixing with the two-rotor continuous mixer. The equivalent surface average particle diameter ( d ¯ A ) of Al2O3 was calculated by the scanning electron microscopic (SEM) images of samples. The steady-state and dynamic rheological measurements were used to study the evolution of viscosity parameters. With the Carreau model fitting to the steady-rate rheological data, zero-shear viscosity η 0, time constant λ, and power law index n of composites were obtained. On this basis, an optimized Carreau model was established by studying the changes of these parameter values. The rheological result presented that the parameter values (η 0, λ, and n) were linearly proportional to the filling content of Al2O3 particles for nano-Al2O3/LLDPE composites. However, these parameters were, respectively, related to d ¯ A , d ¯ A 2 , and d ¯ A 3 for micron-Al2O3/LLDPE composites.

1 Introduction

Adding fillers and additives is an important method for modifying the physical and rheological properties of polymers. Most advanced polymers are modified by adding inorganic or organic fillers to get better functionality, such as electrical conductivity, thermal conductivity, optical properties, and biological functions (1,2,3). The particle diameter and the content of the filler can affect not only the modification effect of the composites but also the rheological properties. Rheological behavior can be an indicator of the composites microstructure, which is an important factor affecting the final performance. Meanwhile, the addition of fillers will have a direct effect on the rheological behavior of the composites and affect the process. Therefore, the study of fillers’ influence on the rheological behavior of the composites can optimize the processing technology and improve the properties of composites. It is of great significance for the intelligent control and online monitoring of the composite products preparation.

The rheological behavior of the composites reflects the molecular chain structure of the material. A series of studies (4,5,6,7,8) demonstrated that the rheological behavior of composites is mainly determined by the interaction between filler particles and polymer matrix and the interaction among filler particles. The surface tension between filler particles and polymer matrix is one of the main factors in forming the filler’s network structure. Meanwhile, the relative distance between particles was also an important factor (9). The rheological behavior is not only related to the characteristics of the polymer matrix but also related to the physical and chemical properties of the filler particles. Many detailed influence factors on rheological behavior have been studied before, such as the content of particle filler (10,11,12,13,14,15,16), shape (17,18,19), particle diameter (20,21,22,23,24), surface treatment (25,26,27,28,29,30), and dispersion state in the composites (22). As a kind of rigid spherical particles, Al2O3 particles are widely used as fillers in functional composite materials because of their resistance to agglomeration and excellent thermal conductivity. However, most of the researches have focused on the performance of products (3134). There were some researches that focus on the rheological behavior of the Al2O3/polymer matrix composites (3537).

In this article, a series of Al2O3/LLDPE composites were prepared with different Al2O3 contents and particle diameters. Steady-state and dynamic rheological tests were used to reveal changes in the molecular chain internal structure of the composites. Then, influences of the particle diameter and the content of Al2O3 particles on the rheological behavior of the composites were analyzed. The content parameters and average surface particle diameter parameters were proposed to optimize the Carreau model, and the optimized model was verified. With the optimized Carreau model, the viscosity of the Al2O3 filled composites could be predicted. This article provides a research method for studying the rheological behavior of filled polymers, which can evaluate the processing properties of composites and provide guidance for the design of composite material formulations for new applications.

2 Experiment and characterization

2.1 Materials

Spherical Al2O3 (the diameters of Al2O3 particle are 1, 5, 10, 20, 40, and 70 μm, respectively) are supplied from Zhengzhou Sanhe New Material Co., Ltd. Linear low-density polyethylene (LLDPE), of 1,002 kW, density of 0.918 g·cm−3, and melting index of 2 g·10 min−1, is supplied by Suzhou Renfa Plastic Chemical Co., Ltd. Antioxidant 1010 (1,178 g·mol−1) is purchased from BASF (China) Co., Ltd.

2.2 Experiment and characterization

Al2O3 and LLDPE were vacuum dried at 80°C for 8 h. The Al2O3/LLDPE composites were prepared by two-rotor continuous mixer (rotor diameter is 30 mm). The rotor speed was 600 rpm, the orifice setting was 50%, and the feed rate was 4,000 g·h−1. The barrel temperature of the solid conveying section and the melt mixing section were 55°C and 145°C, respectively. The samples for the measurement were made by a plate vulcanizer at 160°C.

SEM was used to characterize the dispersion and distribution of Al2O3 particles in the composites. The samples were cryo-fractured in liquid nitrogen and etched in concentrated hydrochloric acid. The etched surfaces of the samples were coated with gold before SEM observation. The surface morphologies under different magnifications were obtained by vacuum SEM (JSM-6300LV).

Eq. 1 is used to calculate the equivalent average surface diameter ( d ¯ A ) of Al2O3 particles. The Al2O3 particle diameter was obtained by the statistical analysis of the SEM images through the Image Pro Plus software. Then, d ¯ A of the particles was obtained through Gaussian distribution fitting.

(1) d ¯ A = n i d i 3 n i d i 2

To eliminate the statistical error and obtain the particle diameter accurately, five samples were prepared for each kind of the composites, and eight different regions were recorded for each sample. A comparison table of the original particle diameter d and d ¯ A is presented in Table 1.

Table 1

A comparison of the original particle diameter and equivalent average surface diameter of Al2O3

d ( μm ) 1 5 10 20 40 70
d ¯ A   ( μm ) 0.4 6.5 10.2 26.7 37.8 48.6

The viscosity tests versus the shear rate among shear rate of 0.01–10 s−1 were measured by Malvern plate rheometer (Bohlin Gemini&CVO), and the viscosity versus shear rate among shear rate of 10–1,000 s−1 was measured by capillary rheometer (Rosand RH10-D). The dynamic viscosity was conducted with frequency scanning by Malvern plate rheometer, and the strain amplitude was 5% (the composites in this strain amplitude range were always in the linear viscoelastic region).

3 Results and discussion

3.1 Micro morphology analysis

The fracture surface SEM morphologies of the Al2O3/LLDPE composites are illustrated in Figure 1. The spherical Al2O3 particles were indicated with white circles, and the holes where the Al2O3 particles were pulled out were indicated with red circles. It could be seen that spherical Al2O3 was uniformly dispersed in the composites, and Al2O3 particles with different particle diameters still maintained rigid spheres. Many Al2O3 particles were embedded in the LLDPE matrix, as shown in Figure 1a. When d ¯ A of Al2O3 increased from 6.5 to 48.6 μm (Figure 1b–f), more voids spreading in the cross section of the matrix could be found. The reason for this phenomenon was that the interaction between the particles and the composites decreased with the increasing of the spherical Al2O3 diameter. Larger Al2O3 particles would lead to the reduction of specific surface area and the deterioration of the interfacial bonding between the particles and the composites. Therefore, the adhesion between the Al2O3 particles and the LLDPE matrix was weak, and the Al2O3 particles would be pulled out when preparing the sample for SEM testing. In Figure 1g and h, there was an apparent gap between the sphere particle and the matrix, and the particles were almost peeled off from the matrix.

Figure 1 
                  SEM micrographs of composite fracture surfaces with different 
                        
                           
                           
                              
                                 
                                    
                                       d
                                       ¯
                                    
                                 
                                 
                                    A
                                 
                              
                           
                           {\bar{d}}_{\text{A}}
                        
                     : (a) 400 nm, (b) 6.5 μm, (c) 10.2 μm, (d) 26.7 μm, (e) 37.8 μm, (f) 48.6 μm, and enlarged view of 6.5 μm (g) and 48.6 μm (h).
Figure 1

SEM micrographs of composite fracture surfaces with different d ¯ A : (a) 400 nm, (b) 6.5 μm, (c) 10.2 μm, (d) 26.7 μm, (e) 37.8 μm, (f) 48.6 μm, and enlarged view of 6.5 μm (g) and 48.6 μm (h).

3.2 Effect of Al2O3 content on rheological behavior of nano-Al2O3/LLDPE composites

A series of steady-state viscosity and dynamic viscosity measurements were conducted for the composites with different Al2O3 contents, which varied from 4 to 20 wt% with a fixed particle diameter of Al2O3 ( d ¯ A is 400 nm). The steady-state rheological behavior of nano-Al2O3/LLDPE composites is shown in Figure 2. The steady-state viscosity of the composites showed a Newtonian plateau in the curve when the shear rate was below 10 s−1, while the non-Newtonian properties became more obvious with the increasing content of Al2O3 particles. The addition of Al2O3 particles could cause the slip between molecular chains, and the slip effect was enhanced when the Al2O3 content was increased. At the same time, the zero-shear viscosity η 0 was increased with the increase in the Al2O3 content. The addition of Al2O3 increased the shear viscosity of the LLDPE as Al2O3 particles hindered the free motion of LLDPE molecular chains. With the increasing filling content, the number of Al2O3 particles increased, and the hindrance effect was enhanced, which led to the increase of viscosity at low shear rates (10 s−1). When the shear rate exceeded 10 s−1, the viscosity curves of the composites almost overlapped and exhibited a typical shear thinning phenomenon. In addition, when the filling content of nano-Al2O3 particles increased from 8 to 12 wt%, the steady-state viscosity of the composites increased significantly. When the filling content of Al2O3 increased to 16 and 20 wt%, the steady-state viscosity continued to increase.

Figure 2 
                  Shear viscosity versus shear rate of the nano Al2O3/LLDPE composites with different Al2O3 contents.
Figure 2

Shear viscosity versus shear rate of the nano Al2O3/LLDPE composites with different Al2O3 contents.

The dynamic frequency scanning test of nano-Al2O3/LLDPE composites with different contents is presented in Figure 3. As shown in Figure 3a, the complex viscosity of the pure LLDPE sample showed a plateau around 104 Pa‧s when the frequency was less than 10−1 rad·s−1. Besides, the complex viscosity of the composites increased with the addition of Al2O3 particles, and the platform disappeared gradually. Meanwhile, the complex viscosity of the composites gradually increased with the increasing of the filling content. Similar to Figure 2, the complex viscosity curves of the composites had a significant upward shift when the nano-Al2O3 particles filling content increased from 8 to 12 wt%. When the filling content was lower, the blocking effect of Al2O3 particles on polymer melt mainly dominated the hindrance effect of Al2O3 particles on the movement of the polymer molecular chain. This blocking effect increased with the increasing filling content. When the content of Al2O3 particles increased to 12%, the distance among particles would be closer, and the particles no longer distributed individually in the composites. The interaction force among particles was strengthened, and the particle network structure began to form in the composites. Thus, the viscosity of the composites was affected by both the interaction force among particles and the interaction force between particles and polymer molecular chain. As a result, the viscosity increased obviously at this stage.

Figure 3 
                  Dynamic rheological properties of the nano Al2O3/LLDPE composites with different Al2O3 contents: (a) complex viscosity, (b) storage modulus G′, (c) loss modulus G″, and (d) Han plots.
Figure 3

Dynamic rheological properties of the nano Al2O3/LLDPE composites with different Al2O3 contents: (a) complex viscosity, (b) storage modulus G′, (c) loss modulus G″, and (d) Han plots.

Figure 3b and c show that the storage modulus (G′) and loss modulus (G″) of the composites changed with the varying nano-Al2O3 filling content. The pure LLDPE exhibited typical end effect of linear high molecular polymers in the low-frequency range (10−1 rad·s−1) because the ratio of lg G′ to lg ω was close to 2, and the ratio of lg G″ to lg ω was close to 1. When the Al2O3 filling content increased from 8 to 12 wt%, the storage modulus G′ and loss modulus G″ showed an obvious increase in the low-frequency range. The ratio of lg G′ to lg ω and the ratio of lg G″ to lg ω were similar when the Al2O3 content increased to 12 wt%. In the low-frequency range, the ratio of lg G′ to lg ω gradually decreased with the increasing filling content, implying that the particle network structure started to form in the composites. When the content of Al2O3 increased to 20 wt%, the ratio of lg G′ to lg ω was less than 0.5, and the storage modulus G′ of the composites was almost independent of the frequency in the low-frequency range. At the same time, the storage modulus curve appeared at an approximate platform region. Such response characteristic of storage modulus to the frequency indicated that the more complete internal particle network structure was formed, and the elastic characteristics were more obvious.

Figure 3d shows that the Han curves of the composites were significantly higher than that of pure LLDPE. The Han values became higher with the increase in the filling content, which meant that the composites would undergo a longer relaxation process. Meanwhile, an approximate platform region appeared in the low-frequency range when the Al2O3 content exceeded 12 wt%. This phenomenon revealed that the terminal effect was restrained in the composites. The longer relaxation process of the composites and the appearance of nonterminal effects proved that the Al2O3/LLDPE composites transformed from the quasi-liquid state to the quasi-solid state, and the particle network structure was generated in the composites.

3.3 Effect of Al2O3 diameter on rheological behavior of micron-Al2O3/LLDPE composites

A series of steady-state viscosity and dynamic viscosity measurements were conducted, and the d ¯ A of Al2O3 particles varied from 6.5 to 48.6 μm with a fixed Al2O3 content (12 wt%). Figure 4 shows the steady-state rheological curves of the composites with different d ¯ A of Al2O3. It presented that the addition of micron-Al2O3 particles also contributed to the increasing steady-state viscosity of the Al2O3/LLDPE composites, but the degree of increase was lower than that of nano-Al2O3 particles shown in Figure 2. With the same filling content, the number of micron-Al2O3 particles was less than that of nanoparticles, and the specific surface area was also smaller. Thus, the interaction between filler particles and polymer molecular chain was weak, meaning that the hindrance to the melted polymer was inferior. It should be noted that the shear viscosity curves of the composites moved upward in the low shear rate range (10 s−1) when the d ¯ A increased from 6.5 to 26.7 μm. On the contrary, the shear viscosity curve shifted downward when the d ¯ A continued to increase to 37.8 μm. When the d ¯ A of Al2O3 particles reached 48.6 μm, the curve changed little and almost overlapped with the viscosity curve of 37.8 μm. In general, the steady-state viscosity curve increased at first and then decreased to a stable region with the increasing d ¯ A in the lower shear range.

Figure 4 
                  Shear viscosity versus shear rate of the Al2O3/LLDPE composites with different Al2O3 diameters.
Figure 4

Shear viscosity versus shear rate of the Al2O3/LLDPE composites with different Al2O3 diameters.

The dynamic frequency scanning rheological tests of Al2O3/LLDPE composites with different d ¯ A are presented in Figure 5. It could be seen that the evolution trend of complex viscosity in Figure 5a was the same as that of steady viscosity in Figure 4. In the low-frequency range (below 10−1 rad·s−1), the complex viscosity of the composites increased at first and then decreased when the d ¯ A varied from 6.5 to 37.8 μm and finally tended to be stable at 48.6 μm. However, the change of d ¯ A had little effect on the complex viscosity of the composites in the high-frequency range (above 1 rad·s−1), and all the curves almost overlapped. Here, the viscosity of the composites reached the maximum when the d ¯ A of Al2O3 particles was 26.7 μm. The movement of molecular chains could be affected by the size and the number of rigid particles (38). When the content of particles was constant, the amount and the specific surface area would decrease with the increase of d ¯ A of spherical particles. The increasing particle size would hinder the movement of molecular chains, while the corresponding decrease in the number and specific surface area would weaken the hindrance and reduce the viscosity accordingly (19,20). The previous data showed that when d ¯ A varied from 6.5 to 26.7 μm, the viscosity of the composites increased. That was because the effect of particle size played a leading role in overall factors, highlighting the resistance to the movement of molecular chains. However, when the d ¯ A varied from 26.7 to 48.6 μm, the number of Al2O3 particles decreased sharply. The factor of particle size was no longer dominated and had a limited effect on the movement of LLDPE molecular chains, which made the steady-state viscosity of the composites decrease. A balancing effect of the mentioned factors led to the final stable trend of the viscosity.

Figure 5 
                  Dynamic rheological properties of the Al2O3/LLDPE composites with different Al2O3 particles diameters: (a) complex viscosity, (b) storage modulus G′, (c) loss modulus G″, and (d) Han plots.
Figure 5

Dynamic rheological properties of the Al2O3/LLDPE composites with different Al2O3 particles diameters: (a) complex viscosity, (b) storage modulus G′, (c) loss modulus G″, and (d) Han plots.

In Figure 5b and c, the storage modulus (G′) and loss modulus (G″) of the composites showed an increasing trend at first and then decreased in the low-frequency range (below 10−1 rad·s−1). When d ¯ A was 26.7 μm, both the G′ and G″ of the Al2O3/LLDPE composites had the maximum value. When d ¯ A continuously increased to 37.8 and 48.6 μm, the curves of both G′ and G″ moved downward and overlapped. It was worth noting that there was no “platform effect” for the micron-Al2O3 particles, which was not similar to the G′ curves for nanoparticles in the low-frequency range. It revealed that the various micron-Al2O3/LLDPE composites with the same filling content (12 wt%) did not illustrate solid-state behavior in the low-frequency range. In the high-frequency range, all the curves of G′ and G″ tended to overlap, indicating that the effect of oscillating shear on the entangled polymer molecular chains was much greater than that of the Al2O3 particles.

Figure 5d shows that the Han curves of the composites with micron-Al2O3 particles were significantly higher than that of pure LLDPE. However, the change of d ¯ A did not have an obvious effect on the Han curves. The Han curves of the composites with various d ¯ A were overlapped, and the slope of the curves were almost the same. In addition, the Han curves did not illustrate the approximate platform area. It showed that the change of d ¯ A did not affect the molecular chain internal structure of the composites when the filling content of micron Al2O3 was 12 wt%. This was mainly due to the large particle diameter and large specific surface area of micron Al2O3 particles, which mainly affected the movement of the polymer molecular chain in the composites. Due to the large particle diameter, the number of particles was much less than that of nanoparticles, and the distance between the particles was larger. Thus, there was almost no interaction effect among particles in the composites.

3.4 The optimization rheological model of Al2O3/LLDPE composites

To analyze the influence of the nano Al2O3 content and the d ¯ A of micron Al2O3 particles on the rheological behavior of the composites quantitatively, the Carreau model was applied to perform the nonlinear fitting for the steady-state viscosity curves of the Al2O3/LLDPE composites. The fitting parameters including zero-shear viscosity η 0, time constant λ, and power law exponent n are presented in Tables 2 and 3. The η 0 determined the height of the Newtonian platform region in the low shear rate range (below 10 s−1), and the λ indicated the length of the relaxation time. The larger η 0 and the longer λ proved that the Al2O3 particles had a greater hindrance effect on the melt flow behavior for the composites. The formula of the Carreau viscosity model is presented in Eq. 2:

(2) η = η 0 ( 1 + λ 2 γ 2 ) 1 n 2

where η 0 is the zero-shear viscosity, Pa·s; λ is the time constant, s; γ is the shear rate, s−1; n is the power law index; and η is the shear viscosity, Pa·s.

Table 2

Fitting results for the Al2O3/LLDPE composites with different filling contents via the Carreau model

Material η 0   ( Pa s ) λ ( s ) n R 2
Pure LLDPE 9,572 0.86 0.54 0.99
400 nm–4 wt% 31,790 10.85 0.52 0.98
400 nm–8 wt% 44,655 11.31 0.49 0.98
400 nm–12 wt% 75,306 14.53 0.43 0.98
400 nm–16 wt% 88,184 14.72 0.42 0.98
400 nm–20 wt% 98,743 15.48 0.39 0.98
Table 3

Fitting results for the Al2O3/LLDPE composites with different particle diameters via the Carreau model

Material η 0   ( Pa s ) λ ( s ) n R 2
Pure LLDPE 9,572 0.86 0.54 0.99
6.5 μm–12 wt% 32607.51 11.37 0.57 0.98
10.2 μm–12 wt% 41021.37 12.38 0.51 0.99
26.7 μm–12 wt% 62577.27 14.63 0.44 0.98
37.8 μm–12 wt% 40726.74 12.43 0.53 0.98
48.6 μm–12 wt% 40974.63 12.94 0.53 0.98

Under the same pressure and the temperature condition, the main factors affecting the rheological behavior of the filler composites were surface modification, diameter, shape, and content of fillers. It was assumed that there was a certain relationship between the viscosity model of the composites and the viscosity model of the polymer matrix. The relationship is defined in Eqs. 35:

(3) η 0 = f ( s c ) f ( φ c ) f ( ϕ ) f ( ω ) η pure

(4) λ = f ( s c ) f ( φ c ) f ( ϕ ) f ( ω ) λ pure

(5) n = f ( s c ) f ( φ c ) f ( ϕ ) f ( ω ) n pure

where f(s c), f(φ c), f(ϕ), and f(ω) represented the adhesion coefficient, particle shape coefficient, filler particle diameter coefficient, and filler content coefficient, respectively. η 0, λ, n, η pure, λ pure, and n pure represented the zero-shear viscosity, time constant, and power law exponent in the Carreau model parameters of the composites and the polymer matrix under the same pressure and temperature, respectively.

In the previous section, the effects of Al2O3 content and particle diameter on the viscosity of composites were studied. The Al2O3 particles had a spherical structure and hence, the effects of the adhesion coefficient and the particle shape coefficient on the rheological properties of the composites could be simplified in Eqs. 68:

(6) η 0 = f 1 ( ω ) f 1 ( ϕ ) η pure

(7) λ = f 2 ( ω ) f 2 ( ϕ ) λ pure

(8) n = f 3 ( ω ) f 3 ( ϕ ) n pure

where f (1;2;3)(ω) and f (1;2;3)(ϕ) represent the coefficients related to the filler content and the d ¯ A of filler particles, respectively.

The Carreau viscosity model formula of Al2O3/LLDPE composites with different contents and particle diameters could be optimized as presented in Eq. 9:

(9) η = f 1 ( ω ) f 1 ( ϕ ) η pure   ( 1 + f 2 ( ω ) f 2 ( ϕ ) 2 λ pure 2 γ 2 ) 1 f 3 ( ω ) f 3 ( ϕ ) n pure 2

where f (1;2;3)(ω) and f (1;2;3)(ϕ) represent the coefficient of zero-shear viscosity, time constant, and power law index when the effect of the filling content and the diameter of the filler particle were considered. η pure, λ pure, and n pure represent the zero-shear viscosity, time constant, and power law exponent of the matrix material, respectively; γ was the shear rate, s−1; η was the shear viscosity, Pa·s.

As shown in Figure 6, the number of Al2O3 particles in the composites was proportional to the filling content with the same d ¯ A in Al2O3/LLDPE composites, and the distance among particles was inversely proportional to the filling content. When the filling content of Al2O3 particles was consistent, the number of Al2O3 particles decreased with the increase of d ¯ A and the distance between particles increased.

Figure 6 
                  Diagrams of Al2O3 morphology with difference particle diameters and contents in the composites.
Figure 6

Diagrams of Al2O3 morphology with difference particle diameters and contents in the composites.

Combined with the aforementioned analysis, there were three kinds of interactions mainly affecting the rheological behavior (39). The first kind was the hydrodynamic effect of fillers. When the particle diameter of the filler and the content of filler increased, the hydrodynamic effect would be enhanced, as well as the viscosity of the composites. Therefore, the hydrodynamic effect was positively related to the number and content of Al2O3 particles. The second kind was the interaction between filler particles and polymer molecular chain, which mainly depended on the spherical surface area of Al2O3 particles. In another word, the interaction between filler particles and polymer molecular chain was related to the square of d ¯ A . Under the same content, this kind of interaction increased with the decreasing particle diameter. The third kind was the interaction among the particles, which occurred only when the network was formed in the composites.

For nano-Al2O3 composites with the same d ¯ A , it was assumed that the particles were uniformly dispersed in the composites, and the interaction among the particles could be ignored. Besides, the amount, the content, and the surface area of Al2O3 particles were proportional to the filling content. According to the aforementioned assumptions, f (1;2;3)(ω) could be expressed as a linear relationship related to the filling content of Al2O3, as shown in Eqs. 1012:

(10) f 1 ( ω ) = a 1 + b 1 ω

(11) f 2 ( ω ) = a 2 + b 2 ω

(12) f 3 ( ω ) = a 3 + b 3 ω

where a (1;2;3) and b (1;2;3) represented the undetermined coefficients related to the filling content.

The black square points in Figure 7 represented the function values fitted by the Carreau viscosity model for the composites with different filling contents (Table 2). The straight lines in the figure were the curves fitted according to Eqs. 1012. The fitting data and the R 2 are shown in Figure 7. It could be seen that three parameters exhibited excellent fitting accuracy (R 2 > 0.99). With the increase of the nano-Al2O3 content, the zero-shear viscosity η 0 and time constant λ increased proportionally, and the slope of the straight line was positive. While the power law index n decreased and the slope of the straight line was negative. This was due to the increase in the number of particles in the composites, leading to the interaction between particles and the formation of the filler network structure. It was worth noting that the three functions deviated most from the fitting curves when the filling content of nano-Al2O3 particles was 12 wt%.

Figure 7 
                  Carreau model parameters of the Al2O3/LLDPE composites as a function of nano Al2O3 content: (a) 
                        
                           
                           
                              
                              
                                 
                                    f
                                 
                                 
                                    1
                                 
                              
                              
                                 
                                    (
                                    
                                       ω
                                    
                                    )
                                 
                              
                           
                           \hspace{.25em}{f}_{1}(\omega )
                        
                     , (b) 
                        
                           
                           
                              
                                 
                                    f
                                 
                                 
                                    2
                                 
                              
                              
                                 
                                    (
                                    
                                       ω
                                    
                                    )
                                 
                              
                           
                           {f}_{2}(\omega )
                        
                     , and (c) 
                        
                           
                           
                              
                                 
                                    f
                                 
                                 
                                    3
                                 
                              
                              
                                 
                                    (
                                    
                                       ω
                                    
                                    )
                                 
                              
                           
                           {f}_{3}(\omega )
                        
                     .
Figure 7

Carreau model parameters of the Al2O3/LLDPE composites as a function of nano Al2O3 content: (a) f 1 ( ω ) , (b) f 2 ( ω ) , and (c) f 3 ( ω ) .

To verify the reliability of the equations, the steady-state rheological properties of nano-Al2O3/LLDPE composites with 2 and 10 wt% filling contents were used. The three parameters were fitted according to the Carreau viscosity model, and the results are presented in Figure 7, with the red solid triangle. It could be seen that the five verification points were near the fitting line, and the error was acceptable. The fitting equations could reflect the evolution law of the three parameters of Carreau. At the same time, there was an error as Figure 7 illustrated when the filling content of Al2O3 was 10 wt%. Such variation might be due to the interaction between particles and the formation of the network structure.

According to the analysis for Figure 6, the effect of micron Al2O3 particles on the rheology of the composites mainly depended on the diameter of Al2O3 particles, the surface area of the spherical particle, and the number of particles. The relationship between the number of Al2O3 particles and the equivalent average surface diameter ( d ¯ A ) is shown in Eq. 13:

(13) z 1 d ¯ A 3

where z is the number of filler particles in the composites and d ¯ A is the equivalent average surface diameter, μm.

Therefore, the function f(ϕ) of the particle diameter coefficient could be expressed as Eqs. 1416:

(14) f 1 ( ϕ ) = c 1 ϕ + d 1 ϕ 2 + e 1 ϕ 3

(15) f 2 ( ϕ ) = c 2 ϕ + d 2 ϕ 2 + e 2 ϕ 3

(16) f 3 ( ϕ ) = c 3 ϕ + d 3 ϕ 2 + e 3 ϕ 3

where c (1;2;3), d (1;2;3), and e (1;2;3) represent the undetermined coefficients of the function, respectively.

The black square points in Figure 8 represent the values fitted by the Carreau viscosity model for the composites with different d ¯ A (Table 3). In Figure 8, the zero-shear viscosity η 0 and time constant λ would increase and then decrease with the increasing Al2O3 particle diameter. While the evolution of power law index n decreased first and then increased. When d ¯ A of the particles increased from 37.8 to 48.6 μm, the three parameters in the model tended to be unchanged. Therefore, the fitted values for the d ¯ A = 48.6 μm was ignored, thus, just fitting the parameter values with the rest particle diameter according to Eqs. 1416. The obtained fitting curves and equations are shown in Figure 8. The fitted curves for zero shear viscosity and time constant in Figure 8 illustrated an increasing trend at first and then decreased with the increase in Al2O3 particle diameter. The change of the power law index was decreased. Besides, the fitted curve was very smooth as shown in Figure 8, and the data points were just on the curves, proving that the equations proposed for fitting were very accurate and reliable.

Figure 8 
                  Carreau model parameters of the Al2O3/LLDPE composites as a function of mic-Al2O3 particle diameter: (a) 
                        
                           
                           
                              
                              
                                 
                                    f
                                 
                                 
                                    1
                                 
                              
                              
                                 
                                    (
                                    
                                       ϕ
                                    
                                    )
                                 
                              
                           
                           \hspace{.25em}{f}_{1}(\phi )
                        
                     , (b) 
                        
                           
                           
                              
                                 
                                    f
                                 
                                 
                                    2
                                 
                              
                              
                                 
                                    (
                                    
                                       ϕ
                                    
                                    )
                                 
                              
                           
                           {f}_{2}(\phi )
                        
                     , and (c) 
                        
                           
                           
                              
                                 
                                    f
                                 
                                 
                                    3
                                 
                              
                              
                                 
                                    (
                                    
                                       ϕ
                                    
                                    )
                                 
                              
                           
                           {f}_{3}(\phi )
                        
                     .
Figure 8

Carreau model parameters of the Al2O3/LLDPE composites as a function of mic-Al2O3 particle diameter: (a) f 1 ( ϕ ) , (b) f 2 ( ϕ ) , and (c) f 3 ( ϕ ) .

4 Conclusion

The influences of the particle diameter and the filling content of spherical Al2O3 particles on the steady-state and dynamic rheological behavior of Al2O3/LLDPE composites were studied. For the nano-Al2O3/LLDPE composites, the viscosity of the composites increased greatly at the low shear rate range because of its large specific surface area and the interaction among filler particles. Meanwhile, the viscosity increased gradually with the increase in the filling content of Al2O3, and the filling content was proportional to the viscosity of the composites. For the micron-Al2O3/LLDPE composites, the effect of micron Al2O3 particle diameter on the rheological behavior of the composites mainly depended on the equivalent average surface diameter of the particles. Finally, the optimized Carreau viscosity model considering the two factors was established, and the model of nano-Al2O3/LLDPE composites with different filling contents was preliminarily verified. With the help of the optimized rheological model, the viscosity of Al2O3/LLDPE composites could be predicted quantitatively when the content of spherical Al2O3 particles was less than 20% and d ¯ A of Al2O3 particles was less than 38.6 μm.


tel: +86-021-6425-2363

  1. Funding information: The authors state no funding involved.

  2. Author contributions: Guo Li performed the experiments, analyzed the data, and wrote the paper; Mitao Zhang, Huajian Ji, and Tao Chen analyzed some of the data; Yulu Ma and Linsheng Xie designed the experiments and revised the paper.

  3. Conflict of interest: The authors state no conflict of interest.

References

(1) Tapas K, Sambhu B. Recent advances in graphene based polymer composites. Prog Polym Sci. 2010;35(11):1351–2.10.1016/j.progpolymsci.2010.07.005Search in Google Scholar

(2) Ting W, Yan D. Polypropylene/polystyrene/clay blends prepared by an innovative eccentric rotor extruder based on continuous elongational flow: analysis of morphology, rheology property, and crystallization behavior. Polym Test. 2017;63:73–83.10.1016/j.polymertesting.2017.07.012Search in Google Scholar

(3) Li F, Yang S, Yang MT, Li J, Guo SY. Exfoliation of organic montmorillonite in iPP Free of compatibilizer through the multistage stretching extrusion. Polym Bull. 2014;71(12):3261–3.10.1007/s00289-014-1254-7Search in Google Scholar

(4) Sarvestani AS, Picu CR. Network model for the viscoelastic behavior of polymer nanocomposites. Polymer. 2004;45(22):7779–90.10.1016/j.polymer.2004.08.060Search in Google Scholar

(5) Hajir K, Mehrzad M, Mohammad HNF. Prediction of the viscoelastic response of filler network in highly nano filled polymer composites. J Compos Mater. 2015;49(30):12–8.10.1177/0021998314568800Search in Google Scholar

(6) Zhao L, Yang H, Song Y, Tan Y, Hu G, Zheng Q. The role of filler network in nonlinear viscoelastic behavior of vapor grown carbon nanofiber filled polystyrene: a strain dependent rheological behavior and electrical conductivity study. Polym Eng Sci. 2012;52(3):643–8.10.1002/pen.22129Search in Google Scholar

(7) El-Tonsy MM, Fouda IM, Oraby AH, Felfel RM, El-Henawey MI. Dependence of physical properties of linear low-density polyethylene on the silicon dioxide filler size. Thermoplast Compos Mater. 2016;29(6):754–67.10.1177/0892705714533376Search in Google Scholar

(8) Jancar J, Douglas JF, Starr FW, Kumar SK, Cassagnau P, Sternstein SS, et al. Current issues in research on structure–property relationships in polymer nanocomposites. Polymer. 2010;51(15):3321–43.10.1016/j.polymer.2010.04.074Search in Google Scholar

(9) Shao Z, Negi AS, Osuji CO. Role of interparticle attraction in the yielding response of microgel suspensions. Soft Matter. 2013;9(22):5492–500.10.1039/c3sm50209kSearch in Google Scholar

(10) Mackay ME, Dao TT, Tuteja A, Ho DL, Horn BV, Kim HC, et al. Nanoscale effects leading to non-einstein-like decrease in viscosity. Nat Mater. 2003;2(11):762–6.10.1038/nmat999Search in Google Scholar PubMed

(11) Wu D, Wu L, Wu L, Zhang M. Rheology and thermal stability of polylactide/clay nanocomposites. Polym Degrad Stab. 2006;91(12):3149–55.10.1016/j.polymdegradstab.2006.07.021Search in Google Scholar

(12) Gan M, Satapathy BK, Thunga M, Weidisch R, Pötschke P, Jehnichen D. Structural interpretations of deformation and fracture behavior of polypropylene/multi-walled carbon nanotube composites. Acta Mater. 2008;56(10):2247–61.10.1016/j.actamat.2008.01.010Search in Google Scholar

(13) Abdel-Goad M, Pötschke P. Rheological characterization of melt processed polycarbonate multiwalled carbon nanotube composites. J Non-Newtonian Fluid Mech. 2005;128(1):2–6.10.1016/j.jnnfm.2005.01.008Search in Google Scholar

(14) Song YS. Rheological characterization of carbon nanotubes/poly(ethylene oxide) composites. Rheolog Acta. 2006;46(2):231–8.10.1007/s00397-006-0137-8Search in Google Scholar

(15) Hu G, Zhao C, Zhang S, Yang M, Wang Z. Low percolation thresholds of electrical conductivity and rheology in poly(ethylene terephthalate) through the networks of multi-walled carbon nanotubes. Polymer. 2006;47(1):480–8.10.1016/j.polymer.2005.11.028Search in Google Scholar

(16) Zhang Q, Archer LA. Poly(ethylene oxide)/silica nanocomposites: Structure and rheology. Langmuir. 2002;18(26):10435–42.10.1021/la026338jSearch in Google Scholar

(17) Bikiaris D. Can nanoparticles really enhance thermal stability of polymers? Part B: an overview on thermal decomposition of polycondensation polymers. Thermochim Acta. 2011;523(1):25–45.10.1016/j.tca.2011.06.012Search in Google Scholar

(18) Liang JZ. Reinforcement and quantitative description of inorganic particulate-filled polymer composites. Compos Part B: Eng. 2013;51(4):224–32.10.1016/j.compositesb.2013.03.019Search in Google Scholar

(19) Marini J, Bretas RES. Influence of shape and surface modification of nanoparticle on the rheological and dynamic-mechanical properties of polyamide 6 nanocom-posites. Polym Eng Sci. 2013;53(7):1512–28.10.1002/pen.23405Search in Google Scholar

(20) Kourki H, Mortezaei M, Famili MHN. Filler networking in the highly nanofilled systems. J Thermoplast Compos Mater. 2014;29(8):1047–63.10.1177/0892705714556830Search in Google Scholar

(21) Osman MA, Atallah A. Effect of the particle size on the viscoelastic properties of filled polyethylene. Polymer. 2006;47(7):2357–68.10.1016/j.polymer.2006.01.085Search in Google Scholar

(22) Nolte H, Schilde C, Kwade A. Determination of particle size distributions and the degree of dispersion in nanocomposites. Compos Sci Technol. 2012;72(9):948–58.10.1016/j.compscitech.2012.03.010Search in Google Scholar

(23) Cassagnau P, Melis F. Non-linear viscoelastic behaviour and modulus recovery in silica filled polymers. Polymer. 2003;44(21):6607–15.10.1016/S0032-3861(03)00689-XSearch in Google Scholar

(24) Osman MA, Atallah A, Schweizer T, Ottinger HC. Particle-particle and particle-matrix interactions in calcite filled high-density polyethylene-steady shear. J Rheology. 2004;48(5):1167–84.10.1122/1.1784782Search in Google Scholar

(25) Mortezaei M, Famili MHN, Kokabi M. The role of interfacial interactions on the glass transition and viscoelastic properties of silica/polystyrene nanocomposite. Compos Sci Technol. 2011;71(8):1039–45.10.1016/j.compscitech.2011.02.012Search in Google Scholar

(26) Blum FD, Krisaang Kura P. Comparison of differential scanning calorimetry, FTIR, and NMR to measurements of adsorbed polymers. Thermochim Acta. 2009;492(1-2):55–60.10.1016/j.tca.2009.03.011Search in Google Scholar

(27) Zheng X, Sauer BB, Van AJG, Schwarz SA, Rafailovich MH, Sokolov J, et al. Reptation dynamics of a polymer melt near an attractive solid interface. Phys Rev Lett. 1995;74(3):407–10.10.1103/PhysRevLett.74.407Search in Google Scholar PubMed

(28) Prashantha K, Soulestin J, Lacrampe MF, Claes M, Dupin G, Krawczak P. Multi-walled carbon nanotube filled polypropylene nanocomposites based on masterbatch route: improvement of dispersion and mechanical properties through PP-g-MA addition. Exp Polym Lett. 2010;2(10):735–45.10.3144/expresspolymlett.2008.87Search in Google Scholar

(29) Prashantha K, Soulestin J, Lacrampe MF, Krawczak P, Dupin G, Claes M. Masterbatch-based multi-walled carbon nanotube filled polypropylene nanocomposites: assessment of rheological and mechanical properties. Compos Sci Technol. 2009;69(11–12):1756–63.10.1016/j.compscitech.2008.10.005Search in Google Scholar

(30) Bartholome C, Beyou E, Bourgeat-Lami E, Cassagnau P, Chaumont P, David L, et al. Viscoelastic properties and morphological characterization of silica/polystyrene nanocomposites synthesized by nitroxide-mediated polymerization. Polymer. 2005;46(23):9965–73.10.1016/j.polymer.2005.07.057Search in Google Scholar

(31) Mirjalili F, Chuah L, Dayang AB, Hasmaliza M, Aghababazadeh R, Ahmadun F. Mechanical properties of α- Al2O3/PP nano composite. J Appl Sci. 2009;9(17):3199–201.10.3923/jas.2009.3199.3201Search in Google Scholar

(32) Agrawal A, Satapathy A. Effects of aluminum nitride inclusions on thermal and electrical properties of epoxy and polypropylene: an experimental investigation. Compos Part A: Appl Sci Manuf. 2014;63:51–8.10.1016/j.compositesa.2014.04.001Search in Google Scholar

(33) Hu Y, Du GP, Chen N. A novel approach for Al2O3/epoxy composites with high strength and thermal conductivity. Compos Sci Technol. 2016;124:36–43.10.1016/j.compscitech.2016.01.010Search in Google Scholar

(34) Vakhshouri AR, Azizov A. Synthesis, structure, and thermo-physical properties of Fe2O3.Al2O3 and polyethylene nanocomposites. J Appl Polym Sci. 2012;124(6):5106–12.10.1002/app.35661Search in Google Scholar

(35) Chen X, Sha J, Ma Y. Effect of ionomer interfacial compatibilization on highly filled HDPE/Al2O3/ionomer composites: morphology and rheological behavior. Compos Sci Technol. 2019;170:7–14.10.1016/j.compscitech.2018.11.007Search in Google Scholar

(36) Esfe MH, Esfandeh S, Alirezaie A. A novel experimental investigation on the effect of nanoparticles composition on the rheological behavior of nano-hybrids. J Mol Liq. 2018;269:933–9.10.1016/j.molliq.2017.11.147Search in Google Scholar

(37) Jianjun W, Xiang X. Effects of solid loading on the rheological behaviors and mechanical properties of injection-molded alumina ceramics. J Alloy Compd. 2018;768:503–9.10.1016/j.jallcom.2018.07.036Search in Google Scholar

(38) Nourbakhsh A, Karegarfard A, Ashori A, Nourbakhsh A. Effects of particle size and coupling agent concentration on mechanical properties of particulate-filled polymer composites. J Thermoplast Compos Mater. 2010;23(2):169–74.10.1177/0892705709340962Search in Google Scholar

(39) Hajir K, Mehrzad M, Mohammad HNF. Filler networking in the highly nano filled systems. J Thermoplast Compos Mater. 2016;29(8):1047–53.10.1177/0892705714556830Search in Google Scholar

Received: 2021-08-04
Revised: 2021-09-01
Accepted: 2021-09-06
Published Online: 2021-10-04

© 2021 Guo Li et al., published by De Gruyter

This work is licensed under the Creative Commons Attribution 4.0 International License.

Articles in the same Issue

  1. Research Articles
  2. Research on the mechanism of gel accelerator on gel transition of PAN solution by rheology and dynamic light scattering
  3. Gel point determination of gellan biopolymer gel from DC electrical conductivity
  4. Composite of polylactic acid and microcellulose from kombucha membranes
  5. Synthesis of highly branched water-soluble polyester and its surface sizing agent strengthening mechanism
  6. Fabrication and characterization of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) modified with nano-montmorillonite biocomposite
  7. Fabrication of N-halamine polyurethane films with excellent antibacterial properties
  8. Formulation and optimization of gastroretentive bilayer tablets of calcium carbonate using D-optimal mixture design
  9. Sustainable nanocomposite films based on SiO2 and biodegradable poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH) for food packaging
  10. Evaluation of physicochemical properties of film-based alginate for food packing applications
  11. Electrically conductive and light-weight branched polylactic acid-based carbon nanotube foams
  12. Structuring of hydroxy-terminated polydimethylsiloxane filled by fumed silica
  13. Surface functionalization of nanostructured Cu/Ag-deposited polypropylene fiber by magnetron sputtering
  14. Influence of composite structure design on the ablation performance of ethylene propylene diene monomer composites
  15. MOFs/PVA hybrid membranes with enhanced mechanical and ion-conductive properties
  16. Improvement of the electromechanical properties of thermoplastic polyurethane composite by ionic liquid modified multiwall carbon nanotubes
  17. Natural rubber latex/MXene foam with robust and multifunctional properties
  18. Rheological properties of two high polymers suspended in an abrasive slurry jet
  19. Two-step polyaniline loading in polyelectrolyte complex membranes for improved pseudo-capacitor electrodes
  20. Preparation and application of carbon and hollow TiO2 microspheres by microwave heating at a low temperature
  21. Properties of a bovine collagen type I membrane for guided bone regeneration applications
  22. Fabrication and characterization of thermoresponsive composite carriers: PNIPAAm-grafted glass spheres
  23. Effect of talc and diatomite on compatible, morphological, and mechanical behavior of PLA/PBAT blends
  24. Multifunctional graphene nanofiller in flame retarded polybutadiene/chloroprene/carbon black composites
  25. Strain-dependent wicking behavior of cotton/lycra elastic woven fabric for sportswear
  26. Enhanced dielectric properties and breakdown strength of polymer/carbon nanotube composites by coating an SrTiO3 layer
  27. Analysis of effect of modification of silica and carbon black co-filled rubber composite on mechanical properties
  28. Polytriazole resins toughened by an azide-terminated polyhedral oligomeric silsesquioxane (OADTP)
  29. Phosphine oxide for reducing flammability of ethylene-vinyl-acetate copolymer
  30. Study on preparation and properties of bentonite-modified epoxy sheet molding compound
  31. Polyhedral oligomeric silsesquioxane (POSS)-modified phenolic resin: Synthesis and anti-oxidation properties
  32. Study on structure and properties of natural indigo spun-dyed viscose fiber
  33. Biodegradable thermoplastic copolyester elastomers: Methyl branched PBAmT
  34. Investigations of polyethylene of raised temperature resistance service performance using autoclave test under sour medium conditions
  35. Investigation of corrosion and thermal behavior of PU–PDMS-coated AISI 316L
  36. Modification of sodium bicarbonate and its effect on foaming behavior of polypropylene
  37. Effect of coupling agents on the olive pomace-filled polypropylene composite
  38. High strength and conductive hydrogel with fully interpenetrated structure from alginate and acrylamide
  39. Removal of methylene blue in water by electrospun PAN/β-CD nanofibre membrane
  40. Theoretical and experimental studies on the fabrication of cylindrical-electrode-assisted solution blowing spinning nanofibers
  41. Influence of l-quebrachitol on the properties of centrifuged natural rubber
  42. Ultrasonic-modified montmorillonite uniting ethylene glycol diglycidyl ether to reinforce protein-based composite films
  43. Experimental study on the dissolution of supercritical CO2 in PS under different agitators
  44. Experimental research on the performance of the thermal-reflective coatings with liquid silicone rubber for pavement applications
  45. Study on controlling nicotine release from snus by the SIPN membranes
  46. Catalase biosensor based on the PAni/cMWCNT support for peroxide sensing
  47. Synthesis and characterization of different soybean oil-based polyols with fatty alcohol and aromatic alcohol
  48. Molecularly imprinted electrospun fiber membrane for colorimetric detection of hexanoic acid
  49. Poly(propylene carbonate) networks with excellent properties: Terpolymerization of carbon dioxide, propylene oxide, and 4,4ʹ-(hexafluoroisopropylidene) diphthalic anhydride
  50. Polypropylene/graphene nanoplatelets nanocomposites with high conductivity via solid-state shear mixing
  51. Mechanical properties of fiber-reinforced asphalt concrete: Finite element simulation and experimental study
  52. Applying design of experiments (DoE) on the properties of buccal film for nicotine delivery
  53. Preparation and characterizations of antibacterial–antioxidant film from soy protein isolate incorporated with mangosteen peel extract
  54. Preparation and adsorption properties of Ni(ii) ion-imprinted polymers based on synthesized novel functional monomer
  55. Rare-earth doped radioluminescent hydrogel as a potential phantom material for 3D gel dosimeter
  56. Effects of cryogenic treatment and interface modifications of basalt fibre on the mechanical properties of hybrid fibre-reinforced composites
  57. Stable super-hydrophobic and comfort PDMS-coated polyester fabric
  58. Impact of a nanomixture of carbon black and clay on the mechanical properties of a series of irradiated natural rubber/butyl rubber blend
  59. Preparation and characterization of a novel composite membrane of natural silk fiber/nano-hydroxyapatite/chitosan for guided bone tissue regeneration
  60. Study on the thermal properties and insulation resistance of epoxy resin modified by hexagonal boron nitride
  61. A new method for plugging the dominant seepage channel after polymer flooding and its mechanism: Fracturing–seepage–plugging
  62. Analysis of the rheological property and crystallization behavior of polylactic acid (Ingeo™ Biopolymer 4032D) at different process temperatures
  63. Hybrid green organic/inorganic filler polypropylene composites: Morphological study and mechanical performance investigations
  64. In situ polymerization of PEDOT:PSS films based on EMI-TFSI and the analysis of electrochromic performance
  65. Effect of laser irradiation on morphology and dielectric properties of quartz fiber reinforced epoxy resin composite
  66. The optimization of Carreau model and rheological behavior of alumina/linear low-density polyethylene composites with different alumina content and diameter
  67. Properties of polyurethane foam with fourth-generation blowing agent
  68. Hydrophobicity and corrosion resistance of waterborne fluorinated acrylate/silica nanocomposite coatings
  69. Investigation on in situ silica dispersed in natural rubber latex matrix combined with spray sputtering technology
  70. The degradable time evaluation of degradable polymer film in agriculture based on polyethylene film experiments
  71. Improving mechanical and water vapor barrier properties of the parylene C film by UV-curable polyurethane acrylate coating
  72. Thermal conductivity of silicone elastomer with a porous alumina continuum
  73. Copolymerization of CO2, propylene oxide, and itaconic anhydride with double metal cyanide complex catalyst to form crosslinked polypropylene carbonate
  74. Combining good dispersion with tailored charge trapping in nanodielectrics by hybrid functionalization of silica
  75. Thermosensitive hydrogel for in situ-controlled methotrexate delivery
  76. Analysis of the aging mechanism and life evaluation of elastomers in simulated proton exchange membrane fuel cell environments
  77. The crystallization and mechanical properties of poly(4-methyl-1-pentene) hard elastic film with different melt draw ratios
  78. Review Articles
  79. Aromatic polyamide nonporous membranes for gas separation application
  80. Optical elements from 3D printed polymers
  81. Evidence for bicomponent fibers: A review
  82. Mapping the scientific research on the ionizing radiation impacts on polymers (1975–2019)
  83. Recent advances in compatibility and toughness of poly(lactic acid)/poly(butylene succinate) blends
  84. Topical Issue: (Micro)plastics pollution - Knowns and unknows (Guest Editor: João Pinto da Costa)
  85. Simple pyrolysis of polystyrene into valuable chemicals
  86. Topical Issue: Recent advances of chitosan- and cellulose-based materials: From production to application (Guest Editor: Marc Delgado-Aguilar)
  87. In situ photo-crosslinking hydrogel with rapid healing, antibacterial, and hemostatic activities
  88. A novel CT contrast agent for intestinal-targeted imaging through rectal administration
  89. Properties and applications of cellulose regenerated from cellulose/imidazolium-based ionic liquid/co-solvent solutions: A short review
  90. Towards the use of acrylic acid graft-copolymerized plant biofiber in sustainable fortified composites: Manufacturing and characterization
Downloaded on 15.9.2025 from https://www.degruyterbrill.com/document/doi/10.1515/epoly-2021-0077/html
Scroll to top button