ABSTRACTWaterborne polyurethane coatings made from castor oil as polyol resource, replacing oil from fossil fuels are attracting lot of recognition during recent decades. In this review, castor oil and its modifications to synthesize various biobased waterborne polyurethane and their nanocomposite systems have been addressed. Various synthesis procedures for waterborne polyurethane dispersions and their applications as a coating material have been described. This review will be helpful to the green research community for selection of monomer and further development of biobased waterborne polyurethane utilizing advanced technology.

ABSTRACTCavitation (void formation) in high-density polyethylene cast films, having a stacked lamellar morphology, subsequent to tensile stretching of both nonirradiated and irradiated films was investigated. With nonirradiated films, the cavitation was not observed in the nonannealed films with lower draw ratios, while a limited number of voids was detected in the films of higher draw ratios. Annealing caused an intensive cavitation, and uniform distribution of cavities was noticed in highly oriented films. It was shown that cross-linking exerted a suppressive influence on cavitation in the annealed and oriented films; and with increasing the irradiation dose, the cavitation was completely eliminated.

ABSTRACTThe isothermal and nonisothermal crystallization behaviors of poly(ε-caprolactone) and poly(caprolactone-co-cyclohexene carbonate) were investigated utilizing differential scanning calorimeter and polarized optical microscope. The kinetic of isothermal crystallization could be well defined by Avrami equation, while Mo model was successful to describe the nonisothermal crystallization. Based on the obtained kinetic parameters, poly(cyclohexene carbonate) segments not only act as a nucleating agent accelerating nucleating rate but also restrict the transport of poly(ε-caprolactone) segments decelerating growth rate. The mechanical properties of polymers were investigated using DMA and nanoindentation. It shows that the insertion of hard poly(cyclohexene carbonate) segments improves Young’s modulus and heat resistance but reduces hardness of copolymers.

ABSTRACTNylon-6-b-polydimethylsiloxane copolymer was synthesized with macroinitiator through in situ polymerization. The macroinitiator with two chain-growing centers per molecule is based on hydroxyl terminated polydimethylsiloxane (PDMS) functionalized with diisocyanate. The influence of PDMS contents on the properties of copolymers was studied. Differential scanning calorimetry and X-ray diffraction were used to investigate the melting temperature, crystallization temperature and crystal form of samples, and the results showed that the crystallinity of polymers decreased. The mechanical properties of samples were studied by notched-impact testing and tension test. The notched impact strength was improved by 200% with PDMS concentration up to 4 wt%. The form of scaly was seen by scanning electron microscope proved the improvements of the impact strength of the copolymer. The water contact angles test showed that the surface tension of copolymers decreased with the PDMS content increasing and the surface of copolymer changed from hydrophilic to hydrophobic.

ABSTRACTEthylene vinyl acetate (EVA)/thermoplastic polyurethane (TPU) blend at various blend ratios has been modified via reactive processing with 4,4′-methylene diphenyl diisocyanate (MDI). Modification of the blends with even small amount of MDI shows significant improvement in physico-mechanical properties for EVA/TPU 50/50 and 30/70 blends, and it is also supported by the superior melt rheological behavior and dramatic improvement in oil resistance property. After the treatment of electron beam (dose range: 50–150 kGy), radiation crosslinked EVA/TPU (30:70) blend reveals further improvement in various properties. This particular material can find potential application as cable sheathing component.

ABSTRACTThe bismuth(III)neodecanoate (Bi(Ne)3) was synthesized via the method of co-reaction of bismuth oxide, neodecanoic acid, and acetic anhydride and then characterized by Fourier transform infrared spectroscopy (FTIR) and elemental analysis (EA). The effect of Bi(Ne)3 as a thermal stabilizer on poly(vinyl chloride) (PVC) was assessed by thermal aging test, Congo red test, conductivity measurement, and thermogravimetric analysis, respectively. The results showed that Bi(Ne)3 significantly provided PVC with a good initial color and long-term stability. Bi(Ne)3 played a role in improving the stabilizing efficiency of PVC through absorbing hydrogen chloride (HCl) and displacing labile chlorine atoms in PVC molecular chains.

ABSTRACTRecently, nanocellulosic materials have been received significant research interest as potential nanofiller for the reinforcements in the polymer matrices due to its renewable in nature, readily availability, biocompatibility, inexpensive, excellent physical properties, tailorable surface properties, etc. In this review, author attempted to provide an overview of various methods for nanocellulose reinforced polymer nanocomposites fabrications, properties of nanocellulose-based nanocomposites, and their applications. The review has been emphasized for the reinforcement of nanocellulose in various polymer matrices viz. hydrophilic, hydrophobic matrices. Nanocellulose reinforced polymer nanocomposites have huge potential in diverse applications which ranges from biomedical, packaging, electronic to environmental, water treatment fields etc.

ABSTRACTA ladder-type poly(3,4-ethylenedioxythiophene)-poly (ethylene glycol)-polyurethane (PEDOT-PEG-PU) supramolecular network was successfully synthesized using graft copolymerization of hydroxymethyl-EDOT with isocyanate-terminated PEG-PU prepolymer. PEDOT functionalized as the frame for a ladder-type supramolecular structure and PEG-PU as the rung. The successful formation of supramolecular network was confirmed by analyzing the Fourier transform infrared spectroscopy (FTIR). A series of PEDOT-PEG-PU gel polymer electrolyte by linking the LiClO4 were prepared as a function of [O/Li+] ratios. The pH effect of their electrical capacitances was investigated using cyclic voltammetry. Ionic conductivities of different PEDOT-PEG-PU/Li+ complexes at a fixed pH were also evaluated through impedance analysis.

ABSTRACTPoly(lactic acid) (PLA) was melt blended with thermoplastic elastomer, maleic anhydride grafted poly[styrene-b-(ethylene-co-butylene)-b-styrene] (SEBS-g-MA) copolymer with varied concentration (10–40 wt%) using twin screw extruder. Dynamic rheological behavior of PLA/SEBS-g-MA blends investigated a transition from liquid-like behavior to solid-like behavior in the composition range of 10–20 wt% of SEBS-g-MA. The capillary rheometer analysis showed enhanced shear viscosity with increase in SEBS-g-MA content. At 10 wt% of SEBS-g-MA, a maximum in the non-essential work of fracture was observed which reflects resistance to crack propagation. Scanning electron microscopy revealed a transition in deformation mechanisms from voids, to fibrillation and cavitation.

ABSTRACTA multilayer microcapsule [melamine-formaldehyde resin/aluminum hydroxide/zinc stannate] with unique core–shell structure was prepared. Fourier transform infrared, X-ray photoelectron spectroscopy, thermogravimetric analysis, and transmission electron microscope were used to investigate the chemical structure of the microcapsules, fire retardancy, and thermal stability of polyvinyl chloride with these materials as additives were also investigated. Remarkably, addition of certain amount of melamine-formaldehyde/aluminum hydroxide/zinc stannate microcapsules could evidently increase limiting oxygen index values. The smoke density results showed that polyvinyl chloride containing melamine-formaldehyde/aluminum hydroxide/zinc stannate microcapsules produced less smoke than pure polyvinyl chloride. The morphologies of the residues were revealed by scanning electron microscope, ascertained that the formed char layers on the composites were denser than that of the pure polyvinyl chloride and polyvinyl chloride/aluminum hydroxide/zinc stannate microcapsule composites. Furthermore, the mechanical properties of polyvinyl chloride/melamine-formaldehyde/aluminum hydroxide/zinc stannate microcapsule composites were observably improved, highlighting its promising potential in industrial applications.