Eighty/twenty polypropylene (PP)/styreneethylene-butylene-styrene (SEBS) and 80/20 PP/maleated styrene-ethylene-butylene-styrene (SEBS-g-MA) blends reinforced with 30 wt % short glass fibers (SGFs) were prepared by extrusion and subsequent injection molding. The influence of the maleic anhydride (MA) functional group grafted to SEBS on the properties of SGF/SEBS/PP hybrid composites was studied. Tensile and impact tests showed that the SEBS-g-MA copolymer improved the yield strength and impact toughness of the hybrid composites. Extensive plastic deformation occurred at the matrix interface layer next to the fibers of the SGF/SEBS-g-MA/PP composites during impact testing. This was attributed to the MA functional group, which enhanced the adhesion between SEBS and SGF. Differential scanning calorimetry measurements indicated that SEBS promoted the crystallization of PP spherulites by acting as active nucleation sites. However, the MA functional group grafted to SEBS retarded the crystallization of PP. Finally, polarized optical microscopy observations confirmed the absence of transcrystallinity at the glass-fiber surfaces of both SGF/SEBS/PP and SGF/SEBS-g-MA/PP hybrid composites.
A novel functional graphene with high ion exchange capacity (IEC) was prepared by grafting reaction induced by 60 Co g-ray irradiation using graphene oxide. Then, polybenzimidazole/radiation grafting graphene oxide (PBI/RGO) composite membranes were prepared by the solution-casting method and doped with phosphoric acid (PA) to improve their proton conductivity. The properties of PBI/GO/PA and PBI/RGO/PA membranes including the PA doping level, chemical stability, proton conductivity and mechanical properties were evaluated and compared. The tensile strength of PBI/RGO/PA membranes (ranging from 27.3 to 38.5 MPa) increases at first and then decreases with the increase of the RGO content, and is significantly higher than that of other PA doped PBI-based membranes. The proton conductivity of PBI/RGO-3/PA membrane is 28.0 mS cm 21 at 170 8C without humidity, with an increase of 72.0% compared with that of PBI/PA membrane. These results suggest that PBI/RGO/PA membranes have the potential to be used as high-temperature proton exchange membranes.
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