Two kinds of different size distribution calcium carbonate (CaCO₃) particles were blended and filled into ultra-high molecular weight polyethylene (UHMWPE). The torque of UHMWPE/CaCO₃ samples was measured with Haake torque rheometer. The results showed that the process torque of UHMWPE/CaCO₃ samples was decreased by filling two different size CaCO₃ particles (600 and 2500 mesh) into UHMWPE, compared with the samples filled with single size CaCO₃ particles (600 or 2500 mesh). When the content of CaCO₃ in the sample reaches 30 wt%, UHMWPE filled with different size distribution CaCO₃ particles showed the largest decrease in torque compared with the samples filled with single size CaCO₃ particles. We also studied the torque of UHMWPE samples at different temperatures. The results showed that flow activation energy and flow activation entropy of UHMWPE samples filled with different size distribution CaCO₃ particles increase significantly. The result where flow activation entropy increased was used to explain the phenomenon that the process torque decreases when UHMWPE filled with different size distribution CaCO₃ particles. POLYM. COMPOS., 36:1807–1812, 2015. © 2014 Society of Plastics Engineers

In our previous study, we have prepared a novel antibacterial ultra-high molecular weight polyethylene/chlorhexidine acetate-montmorillonoid (UHMWPE/CA-MMT) composites and examined its crystallization process and kinetics [1]. In this work, the rheological behaviors of pure UHMWPE, UHMWPE/MMT, UHMWPE/CA, and UHMWPE/CA-MMT were characterized. The results showed that MMT can increase the viscosity of the polymer composites and CA can act as a plasticizer in the composites. Compared with UHMWPE/CA, UHMWPE/CA-MMT had lower η*, G′, and G″. The TGA result indicated that CA-MMT has higher thermostability than CA. Hence, CA-MMT has the lower thermal decomposition ratio at high temperature than CA when it is blended with polymer. The TGA result could be used to explain that UHMWPE/CA-MMT composites had better plasticizer effect than UHMWPE/CA composites. POLYM. COMPOS., 36:47–50, 2015. © 2014 The Authors Polymer Composites published by Wiley Periodicals, Inc.

In this study, a series of the PMVS/SiO2/GO-C12-hep (polymethylvinyl siloxane, PMVS) nanocomposites of varying fillers concentration were fabricated employing blending technique. Retained tensile tests showed that tensile strength of PMVS/SiO2/GO-C12-hep nanocomposites improved with increasing of GO-C12-hep content from 0 to 0.5 wt %, but it decreased when the GO-C12-hep content was up to 0.8 wt %. SEM results showed that GO/C12-hep had been dispersed into PMVS matrix, and the interfacial consistency property was very well between GO-C12-hep and PMVS. The degradation mechanism was also analyzed. The thermal stability and the degradation kinetics of nanocomposites had been evaluated using thermo-gravimetric analysis (TGA) at different heating rates in flowing nitrogen. TGA curves revealed that PMVS/SiO2/GO-C12-hep exhibited relatively better thermal stability than PMVS/SiO2, and the degradation temperatures of PMVS/SiO2/GO-C12-hep increased with GO-C12-hep increase. The apparent activation energies (Ea) were estimated with the Flynn–Wall–Ozawa method (FWO method). The Ea of PMVS/SiO2/GO-C12-hep nanocomposites had relevance to their content of GO-C12-hep. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

The subject of this study was the crystallization behavior and thermal properties of polypropylene (PP)/maleic anhydride (MAH) modified nano calcium carbonate (nano-CaCO₃) composites. In this study, 5 wt % nano-CaCO₃ modified with different contents of MAH was filled into a PP matrix. X-ray diffraction and differential scanning calorimetry were used to characterize the crystal morphology and crystallization kinetics of a series of composites. The results demonstrate that the nano-CaCO₃ modified with MAH had an important effect on the thermal and morphological properties of the nanocomposites. The Avrami exponent of the pure PP was an integer, but those of the composites were not integers, but the crystallization rate constant decreased as the content of MAH in the nano-CaCO₃ filler increased in isothermal crystallization. In nonisothermal crystallization, the kinetic parameter F(T) and the degree of crystallinity of pure PP were compared with those of the PP composites filled with nano-CaCO₃. We suggest that heterogeneous nucleation existed in the PP composites and that the transformation and retention of the β-form crystal into the α-form crystal took place in the composite system and the β-form crystal had a higher nucleation rate and growth process than the α-form crystal in the PP composites. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011