Volume 45, Issue 4

This study investigates the nonisothermal crystallization and compatibility behavior of poly( d -lactide) (PDLA) and poly( l -lactide) (PLLA) blends modified with varying amounts of poly(butylene succinate) (PBS), ranging from 0 wt% to 50 wt%. When the PBS content reaches 30 %, the PDLA/PLLA and PBS composites exhibit partial miscibility, as confirmed by differential scanning calorimetry (DSC), X-ray diffraction (XRD), and tensile tests. The addition of PBS significantly influences crystallization kinetics, promoting the formation of stereocomplex (SC) crystals in the PDLA/PLLA blends. DSC analysis at various cooling rates reveals that PBS facilitates SC crystal formation and enhances nucleation, particularly at 30 % PBS content, although the growth rate of SC crystallization slows beyond this point. The nonisothermal crystallization behavior also indicates that slower cooling rates reduced homocrystal (HC) formation and increased SC crystallization, demonstrating that cooling rate played a crucial role in crystallization kinetics. Mechanical property testing indicates that the addition of PBS increased the elongation at break of PDLA/PLLA blends. These effects were most pronounced at 30 % PBS content, suggesting that both PBS content and cooling rate could be optimized to enhance the thermal and mechanical properties of PDLA/PLLA blends for advanced applications.

Bio-based polyamide 56 (PA56), as an emerging green and environmentally friendly material, has garnered significant attention across various industries, including textiles, automotive, and electronics, due to its excellent mechanical properties, thermal resistance, and renewability. Despite these advantages, polyamide 56 faces challenges related to processability, impact resistance, flame retardancy, and other functional properties. To expand its application scope and enhance the added value of polyamide 56 products, improving its performance through various modification techniques has become a focal point of research. This paper provides a comprehensive review of recent advances in modification strategies for polyamide 56, including reinforcement, flame retardancy, toughening, and antibacterial treatments. Additionally, this paper discusses the future application prospects of polyamide 56 and offers valuable insights to guide ongoing research in this field.

This study presents a quantitative assessment of cross-linked polyvinyl alcohol (PVA) granules as sensing elements for detecting aliphatic carboxylic acids and their sodium salts in aqueous solutions. Swelling kinetics were measured across solute concentrations ranging from 0.2 N to 1.0 N, with the granule radius varying between 0.31- and 0.43-mm. Results indicated that both carbon chain length and the presence of additional carboxyl groups exert a pronounced effect on the equilibrium swelling degree, thereby highlighting the interplay between hydrophobic interactions and hydrogen-bond formation. To interpret these observations, a heterophase physicomathematical model was employed, yielding three main kinetic coefficients (K 1 , K 2 , and K 3 ) that capture solvent flux, polymer network elasticity, and solute transport. The model fits exhibited root-mean-square deviations below 1 %, attesting to its reliability in describing complex swelling - deswelling processes. Additionally, three-dimensional kinetic surfaces were constructed to illustrate how swelling evolves over time and concentration, revealing that initial swelling curves can serve as a rapid indicator of solute concentration. By leveraging the reversible nature of polymer swelling, this method offers a non-invasive, cost-effective approach suitable for monitoring organic acids in diverse fields such as environmental analysis, pharmaceutical processes, and chemical engineering.

Bilirubin is an endogenous toxin in the human body. Elevated levels of bilirubin in the blood can cause irreversible damage to the nervous system and the brain. Therefore, we present the development of a novel polysulfone (PSF) dual-functional blood purification membrane for bilirubin removal. Initially, a PSF hollow fiber membrane with excellent biocompatibility was prepared using a non-solvent induced phase separation method, then graft β-cyclodextrin (β-CD) onto the outer surface, establishing a bilirubin adsorption functional layer. In the “filtration-adsorption” mode, the external surface of the membrane demonstrated pronounced bilirubin adsorption capacity, reaching 12.68 mg/g, accompanied by a bilirubin competitive adsorption coefficient (t N ) of 8.74. Furthermore, the inner surface of the PSF hollow fiber membranes with β-CD onto their external surfaces (EβH) exhibited favorable blood compatibility. Notably, the designed PSF dual-functional membrane overcame the trade-off effects between biocompatibility and bilirubin removal in traditional blood perfusion. In conclusion, this membrane demonstrates efficient toxin removal and enhanced biocompatibility, offering substantial potential for advancing blood purification technologies and improving therapeutic outcomes.

A novel radiochromic polymeric film dosimeter based on povidone-iodine was prepared. The spectrophotometric properties of unirradiated and gamma-irradiated films were investigated using a UV–Vis spectrophotometer. This study proved that the polymeric films of PVP-I/PVA can be used as gamma radiation dosimeters in the dose range from 1 to 25 kGy as their color appears and intensity increases with increasing gamma radiation absorbed dose peaking at λ max  = 295 nm and 365 nm. The stability of the color of the polymeric films, effects of temperature and relative humidity were measured. These film dosimeters can be applied in many fields as they have many advantages.

Blade coating is a technique where the fluid is applied to a surface using a fixed blade, providing economic advantages compared to other coating technologies. It is widely used in producing paper, preserving information, manufacturing photographic films and magnetic storage devices. This article examines the blade coating process using hyperbolic tangent model. With the help of mass and momentum conservation laws, the mathematical equations are obtained and then simplified using lubrication approximation theory (LAT). A well-known perturbation method is used to solve the resulting equation. The graphical results are produced for various values of blade height ratio ( k ) and Weissenberg number ( We ) on velocity, pressure and pressure gradient while the blade load is given in tabulated form. It is observed that both parameters k and We are responsible to increase velocity in plane and exponential coaters. It is also interesting to note that hyperbolic tangent model ( We  = 0.8) predicts 26.92 % lower pressure in comparison to Newtonian model at ( x  = 0.6706) in plane coater. Further, by increasing the value of k and We , the blade load declines in plane and exponential coaters.

A series of magnetorheological shear stiffening gels (MRSSGs) were produced by incorporating varying amounts of carbonyl iron powder (CIP) into a shear stiffening gel (SSG) matrix. The dynamic excellence of MRSSG was evaluated using a rheometer. MRSSGs possess magnetic-sensitive properties and can autonomously respond to external stimuli because of B–O cross-linked bonds. In examining the effect of angular frequency on the magneto-induced shear modulus, an initial angle was introduced, leading to the establishment of a diagonal and distributional particle chain model. This model serves to indirectly illustrate the relationship between the magneto-induced modulus and the shear angular frequency. Theoretical results of magneto-induced modulus, derived from modeling calculations and analyses, align well with experimental findings as magnetic induction intensity varies across different excitation angular frequencies. Additionally, the magneto-induced modulus exhibits an increase that gradually approaches saturation with rising magnetic induction intensity.