Graphene oxide was deposited in a base solution to form base-deposited graphene oxide (bd-GO) particles. The structure and properties of the bd-GO particles were evaluated using transmission electron microscopy, powder X-ray diffraction and X-ray photoelectron, Fourier transform infrared, UV-visible and fluorescence spectroscopies. The effect of the bd-GO particles on the thermal stabilization of poly(vinyl chloride) (PVC) was investigated using the Congo red test and thermogravimetric analysis. The results showed that the thermal stability of PVC was greatly improved by the bd-GO particles. Furthermore, this stabilization mechanism was investigated using UV-visible spectroscopy and nitrogen adsorption–desorption isotherm analysis. It was found that the improvement of thermal stability was mainly related to the deactivation of thermally labile structural defects in the PVC chains by the carboxylate and alkoxide moieties of the basic groups in the bd-GO particles, and the highly efficient adsorption of the bd-GO particles with hydrogen chloride produced during PVC degradation. © 2015 Society of Chemical Industry

Three semicrystalline polymers with different molecular structure and crystallinity were investigated to analyze the Mullins effect therein. The polymers exhibited time-dependent stress resistance and stress softening. Recoverable network alteration in both crystalline and amorphous domains was proposed to explain the cyclic loading deformation and relaxation. The crystallites and the entanglements acted as the joints in the network where stress was transferred. The maximum stress first rapidly decreased and the balance stress was reached after ca 50 cycles. The balance stress was higher than the quasi-static stress obtained by normal stress relaxation. However, the balance stress could be eliminated by the following stress relaxation and the residual stress was very close to the quasi-static stress. The different network strength between the strain before and after yielding is also discussed by comparing the balance stress and the quasi-static stress. The stress resistance of the network before yielding was stronger than that after yielding mainly due to crystallite slip. © 2014 Society of Chemical Industry

In this study, zinc maleate (ZnMA) and zinc oxide (ZnO) complex (ZnMA/ZnO) was prepared by two methods, namely, by the reaction of maleic acid (MAH) with excess ZnO in aqueous solution and by direct mixing of ZnMA and ZnO at 180°C. The chemical structure of the complex was analyzed by X-ray diffraction, thermogravimetric analysis (TGA), and Fourier transform infrared (FTIR) spectroscopy. The thermal stabilizing effect of the complex on poly(vinyl chloride) (PVC) was evaluated through static and dynamic stability methods. Compared to calcium and zinc soaps and ZnMA alone, the complex exhibited better thermal stabilizing effect on PVC. The stabilization mechanism was also investigated by ultraviolet–visible spectrometer, FTIR, TGA, and gel content analysis. The results indicated that the complex which involved the replacement of labile chlorine atoms hindered the formation of conjugated double bonds in PVC chains via Diels–Alder reaction, and ZnMA/ZnO complex also exhibited the ability to absorb hydrogen chloride. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41464.

The hierarchically crystallographic morphologies were fabricated in isotactic polypropylene (iPP) by controlling the stratified distribution of the nucleating agents. The α- and β-nucleating agents were chosen for preparing the different crystalline modifications. The transcrystals and spherulites were found in the stratified distribution samples by polar optical microscopy (POM) and scanning electron microscope (SEM). The transcrystals grew from the surfaces of the nucleating agents filled layers and occupied most space of the pure iPP layers. The crystalline modifications and crystallinity were analyzed by X-ray diffraction (XRD) and differential scanning calorimeter (DSC) analysis. The mechanical and thermal degradation properties of these samples with hierarchically crystallographic morphologies were investigated by tensile testing machine and thermogravimetric analysis (TGA) respectively, and showed better than that of the samples with single crystallographic morphology (spherulites). © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42703.

Isotactic polypropylene (iPP)/calcium carbonate (CaCO₃) nanocomposites with a stratified distribution of CaCO₃ were prepared by two-step molding. The iPP and CaCO₃ nanoparticles were first mixed by a batch mixer and then compressed into thin layers. Thin iPP/CaCO₃ layers alternating with thin neat iPP layers were finally compressed together to form the stratified samples. The transcrystals were observed in the stratified samples by polarized optical microscopy and scanning electron microscopy. The transcrystals grew from the surfaces of the filled layers and occupied most of the space in the neat iPP layers. The β-form crystals were found in the stratified samples with thick transcrystalline layers, whereas the thickness of the transcrystalline layer was dependent on the content of CaCO₃ nanoparticles and the cooling rate of the processing. The relative crystallinity index of the conventional samples first increased and then decreased with the content of CaCO₃ nanoparticles. However, the relative crystallinity index of the stratified samples deceased slightly with the content of CaCO₃ nanoparticles because of the stratified distribution of the CaCO₃ nanoparticles. The stratified samples, except for the samples with high β-form contents, became more brittle than the conventional samples because of the transcrystal formation in the iPP layers. The stratified samples with high β-form contents showed much better mechanical properties than the conventional samples. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39632.