Volume 41, Issue 8

MCM-41 and SBA-15 mesoporous silica materials with different pore sizes (3.08 nm for small pore size MCM-41 ( P 1 ), 5.89 nm for medium pore size SBA-15 ( P 2 ), and 7.81 nm for large pore size SBA-15 ( P 3 )) were synthesized by the hydrothermal method and then functionalized with 3-aminopropyltrietoxysilane by postsynthesis treatments. Next, polysulfone-mesoporous silica mixed matrix membranes (MMMs) were prepared by the solution casting method. The obtained materials and MMMs were characterized by various techniques including X-ray diffraction, scanning electron microscopy, and N 2 adsorption-desorption, and Brunauer-Emmett-Teller method to examine the crystallinity, morphology, and particle size, pore volume, specific surface area, and pore size distribution, respectively. Finally, the gas permeation rates of prepared MMMs were measured in 8 bar and 25 °C and the effect of pore size of modified and unmodified mesoporous silica on the gas separation performance of these MMMs were investigated. The experimental results indicate that the carbon dioxide (CO 2 ) and methane (CH 4 ) permeability and CO 2 /CH 4 selectivity were increased with an enhancement in the particle pore size.

In this work, a series of bimodal polymethyl methacrylate (BPMMA) was fabricated via solution-blending two neat PMMA resins. Rheology, DMTA, thermal infrared imager measurements were used in an attempt to probe the internal structure of the as-prepared BPMMA. It was demonstrated that the thermorheological behavior of the BPMMA was heavily dependent on shear rate, temperature as well as blending ratio. In addition, a typical “ V -shaped” response, namely, a dip in storage modulus ( G ′) followed by an upturn in the plot of G ′ versus measuring temperature for D4 (with lower weight-average molecular weight) was observed, characteristic of occurrence of thermorheological complexity. Our experimental results of physical–mechanical testings suggested that the BPMMA had better comprehensive properties than those of their neat PMMA counterparts.

Clay is widely used in numerous industrial activities; however, its application as an efficient catalyst for the decomposition of plastic waste on a commercial scale is scanty. Therefore, in this study, we have made efforts to use natural clay as the catalyst for the thermal decomposition of polypropylene in a pyrolysis setup. The pyrolysis oil obtained was found rich in hydrocarbons ranging from C 8 –C 35 . Kinetics of the pyrolysis reaction was determined utilizing thermogravimetric data and the activation energy ( E ) and A -factor were observed as 70.33–94.80 kJ/mol and 6 × 10 5 –2.3 × 10 8  min −1 using the Ozawa-Flynn-Wall method and 58.19–74.82 kJ/mol and 4.1 × 10 2 –4.2 × 10 3  min −1 applying Tang Wanjun equation. The activation energy was found to increase with enhancement in conversion presenting a complex decomposition reaction. Comparing the activation energy determined in this work with previous studies confirmed that natural clay has reduced E of decomposition reaction at high fraction conversion. The pyrolysis results supported with the kinetic investigation in this work would have potential applications in disposing of plastic waste on an industrial scale and a step forward in the field of waste management.

The aim of this research work is to examine the modification of structure, morphology and conductivity properties of PMMA: PEO blend hybrid polymer electrolyte system complexed with NaClO 4 salt. Solution-cast procedure was adopted in preparation of these films. These films were characterized with XRD, SEM, DSC, and DC conductivity for the evaluation of modified properties. Peaks have disappeared and broadened in the XRD pattern of PMMA for higher concentration of PEO polymer and salt presented films, which indicated that attaining of higher amorphous phase in these polymer electrolyte films. Almost smooth surface morphology with fewer pores was observed in 20 wt. % of PEO and NaClO 4 salt present PMMA films of SEM image. This establishes a dominant presence of amorphous content in these NaClO 4 complexed PMMA:PEO hybrid electrolyte films when compared to pure PMMA and PEO. Disappearance of melting temperature was observed in all concentrations of NaClO 4 salt and PEO polymer added PMMA polymer films, which suggests a decrease of crystalline and an increase of amorphous nature. Enhancing of DC conductivity with temperature was observed in all the films but higher conductivity was exhibited at higher concentration of NaClO 4 salt present films.

Poly(acrylic acid) and poly(2-(dimethylamino)ethyl acrylate) chains were grafted to polyurethane (PU) using the graft-polymerization method in order to enhance the water compatibility of PU. The grafted chains were ionized into cationic or anionic form depending on the addition of strong acid or base. The grafted polymer chains did not affect the melting, crystallization, and glass transition of the soft segment of PU due to the softness of the chain. The cross-link density and solution viscosity increased due to the linking between the grafted chains, but the slight cross-linking did not disturb the solvation of PU. The slight cross-linking notably enhanced the maximum tensile stress and shape recovery capability, and the water compatibility of PU could be notably enhanced by the grafted ionized chains. Overall, the grafting of ionized polymeric chains onto PU could enhance the hydrophilicity of PU surface, tensile strength, and shape recovery capability.

Making cryogels, which are among today’s accepted adsorbents, more functional with different methods, has been one of the subjects spent overtime. In this study, water-soluble poly(maleic anhydride- alt -acrylic acid) polymer embedded in poly(2-hydroxyethyl methacrylate) cryogels. Copper ions were then immobilised to this structure, and this polymer was used for adsorption of haemoglobin from aqueous systems. Adsorption interaction was carried out on an electrostatic basis, and approximately 448.62 mg haemoglobin/g polymer adsorption capacity value was obtained. It was found that the same material has managed to maintain its adsorption ability by 90.3% even after the use of it five times in the adsorption/desorption cycle. The adsorption interaction was determined to be appropriate for the Langmuir model by isotherm studies. The change in Gibbs free energy value was calculated as −2.168 kJ/mol.

Marine mussel-inspired polydopamine (PDA) coatings show excellent hydrophilicity and substrate-independent adhesion ability, but low stability, especially in a harsh environment such as strong acid or strong base, significantly restricts their applications. In this work, we prepare a novel superhydrophilic and underwater superoleophobic coating based on a modified PDA. Diglycidyl resorcinol ether (DGRE) polyethyleneimine (PEI) and iron ions were incorporated into PDA to strengthen the cross-linking and coating durability. By using three chemically inert hydrophobic membranes, polytetrafluoroethylene (PTFE), poly(vinylidene fluoride), and polypropylene, as substrates, we showed that PDA/PEI/DGRE-coated membranes had a water contact angle (CA) of 0° and underwater oil CA above 157°, and their underwater oil SAs were <7°. The coating is durable against both physical and chemical damages including ultrasound and heat treatments, as well as acid/alkaline etching. After ultrasound treatment in water for 60 min, and heating treatment for 3 h, or acid/alkaline etching for 3 h, the coated PTFE membrane still showed water CAs of ∼0° in air and underwater oil CAs of ∼150°. The coated membranes can efficiently separate oil-in-water emulsions, even in strong acid and base environments. The water flux was above 1500 L m −2  h −1 , and the oil rejection was above 99%.

Polymeric hydrogels with excellent biocompatibility, high hydrophilicity, and water-holding capacity have attracted considerable concerns in widely fields. However, most hydrogels exhibit poor mechanical property, which largely limited their applications. Herein, a novel dual-crosslinking polymeric hydrogel crosslinked by covalent bonds and metal coordination interactions between Fe 3+ and –COO - was fabricated through accessible method. The metal coordination interactions within the hydrogel were established through dipping in the FeCl 3 solution to reinforce the backbones of the hydrogel. The obtained polymeric hydrogel exhibits enhanced tensile strength (∼4.92 MPa), stiffness (∼6.168 MPa), and toughness (∼2.835 MJ m −3 ).

In this work, zwitterionic polyacrylonitrile (PAN)-based membranes were synthesized via surface grafting strategy for improving the antifouling properties. The copolymer membrane consisting of PAN and poly(hydroxyethyl methacrylate) segments, was cast via nonsolvent induced phase separation, and then treated with acryloyl chloride to tether with carbon-carbon double bonds. Zwitterionic poly(sulfobetaine methacrylate) (PSBMA) layers were grafted onto membrane surface via concerted reactions of radical grafting copolymerization and quaternization with 2-(dimethylamino)ethyl methacrylate) and 1, 3-propanesultone (1, 3-PS) as the monomers. The grafting degree ( GD ) of PSBMA layers increases with the incremental content of monomers, leading to the enhancement in membranes surface hydrophilicity. The permeation experiments show that the flux of the zwitterionic membrane increases and then decreases with the increasing GD value, because of the surface coverage of PSBMA layers. The zwitterionic membrane has excellent separation efficiency for oil-in-water emulsion, with the rejection of a higher value than 99%. The irreversible membrane fouling caused by oil adsorption has been suppressed, as proved by the cycle-filtration tests. These outcomes confirm that oil-fouling resistances of membranes are improved obviously by the surface grafting of zwitterionic PSBMA layers.

Blade coating process is studied in a nonisothermal analysis of viscous fluid with temperature-dependent viscosity by employing both plane and exponential coaters. The governing expressions are nondimensionalized and simplified under the assumption of lubrication approximation theory. Then, perturbative technique is used to find the solution for velocity, pressure, temperature distribution, and coating thickness. The influence of dimensionless parameter ε , Graetz number Gz , and normalized coating thickness γ on the velocity, maximum pressure, temperature distribution, and pressure gradient is portrayed through graphs, whereas load and coating thickness variations reported in a tabular manner. It is found that maximum pressure, coating thickness, and blade load decreases for temperature variations in viscosity, which leads to improved efficiency of blade coating process and life of the moving substrate.

Integration of function in structure is troublesome for structural/functional devices. A novel method of in-mold integrating for structural/functional devices was proposed and studied. In this method, a functional film was prepared by printing and surface mounting to achieve electrical functions, and then the film was formed and back molded into a final product. Owing to the complex electronic film, new problems are raised in the in-mold integrating process. The process was modeled, and was designed with the genetic algorithm. The interaction between the melt and the mounted film was analyzed by two-way fluid-structure coupling. Heat dissipation with anisotropic thermal conductivity was examined. Accordingly, a control panel was manufactured and tested. From the study, the functional film, causing asymmetrical cooling issue, results in concave warpage, which can be effectively controlled by comprehensive processing optimization. Film deformation is significant at button area because of tiny hollow structure. The deformation can be decreased by the epoxy encapsulation. The anisotropic thermal conductivity and injection layer cause heat dissipation problem, and thermal effect should be checked and designed by full thermal analysis. With the designed scheme, manufactured panels can perform all control functions, satisfy appearance requirements, and achieve lightweight performance.