Polyolefin is the most widely used and versatile commodity polymer. In this work, three types of polyolefin-based elastomers (PBEs) were adopted to toughen a high-flow polypropylene to improve its overall performance. The chain microstructures of these PBEs, including ethylene/1-octene (E/O) random copolymer from Dow Chemical s polyolefin elastomer (POE), olefin block copolymers (OBCs) of E/O from Dow, and ethylene/propylene random copolymer from ExxonMobil's propylene-based elastomer, were elucidated by GPC, 13 C NMR, TREF, and DSC techniques. The mechanical, thermal and optical properties, and morphology analysis of the PP/PBE blends were also studied to investigate the toughening mechanism of these PBEs. The results showed that all three types of PBEs can effectively improve the Izod impact strength of the PP/PBE blends by the addition of the rubber compositions, at the cost of the stiffness. PBE-1 and PBE-2 were found to have a great stiffness-toughness balance with about 1700 MPa of flexural modulus, about 110 • C of HDT and 3.6 kJ/m 2 of impact strength on the prepared PP/PBE blends by forming separated rubber phase and refined spherulite crystals. As a result, the OBC with alternating hard and soft segments could achieve a similar toughening effect as the E/P random copolymer. Surprisingly, no obvious rubber phase separation was observed in the PP/PBE-4 blend, which might be due to the good compatibility of the E/P random chains with the isotactic PP; therefore, the PP/PBE blend obtains great toughness performance and optical transparency with the highest Izod impact strength of 4.2 kJ/m 2 and excellent transparency. 22 million tons. Due to rapid market expansion of takeout for dining box and automobile industries in China, the high-flow homo polypropylene market has also witnessed a dramatic increase to about above 600 kilotons annually in the recent few years.Although the high-flow homo polypropylene with high melting index (typically above 50 g/10 min) and good processability possesses high flexural modulus, the impact strength is relatively low compared to the ethylene/propylene copolymer and easily suffers from brittle fracture [22]. In order to solve this problem, two approaches are typically adopted to improve the overall performance of the polymer. One alternative is to introduce an extra operation line for the incorporation of a small amount of ethylene into the isotactic chain in the PP production facility, and the other method is to make post-modifications of the high-flow polypropylene by blending elastomer with PP, and glass fibers for automobiles [23][24][25].The Polyolefin-based elastomers (PBEs) have received considerable attention because of their low density, recycling potential, better chemical resistance, processing advantages, and good resilience without permanent deformation. Unlike rubber, they do not require vulcanization. In addition, the low cost together with the wide availability of ethylene, propylene and α-olefin monomers makes the polyolefin-based elastomers more desirable. T...
Nanodielectric elastomer films consisting of a silicone rubber as the matrix and conductive polyaniline nanorods (PANI-NR) as the filler were fabricated and their electro-mechanical actuation performance was investigated. The nanodielectric elastomers displayed a typical insulator-to-conductor transition as the content of PANI-NR increased. The percolation threshold was observed to show a relatively low value of 5.2 vol. %, which should be mainly ascribed to the one-dimensional structure of the nanorods. As the concentration of PANI-NR approached to the percolation threshold, the electro-mechanical actuation strain of the elastomer films was significantly enhanced. The actuation coefficient of nanodielectric elastomer films with only 4.0 vol. % PANI-NR loading was about 5 times higher than that of pure silicone rubber matrix.
Polypropylene grafted with maleic anhydride (PP-g-MA) was prepared and then was used as compatibilizer in the alloy of r-PET/PP to improve the compatibility of different phases. The influences of grafting ratio of MA, the additive amount of PP-g-MA, and the ratio of r-PET and PP to the flowability and the mechanical properties of r-PET/PP were researched. The results obtained show that PP-g-MA can improve the compatibility of different phases; the favorite grafting ratio of MA on PP mainchains is 1.4%; when the additive amount of PP-g-MA is 12%, melt index of r-PET/PP indicates that not only the flowability of r-PET/PP becomes better but also the tensile strengthen is higher; the ratio of r-PET and PP should be designed at 20/80 in order to obtain satisfied results.
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