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...

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Summary: Facile and effective immobilization of late‐transition metal catalysts, 2,3‐bis‐(2,6‐diisopropylphenyl)butane diimine nickel(ii) dibromide (A) and 2,6‐bis‐[1‐(2,4,6‐trimethylphenylimino)ethyl]pyridine iron(ii) dichloride (B), for ethylene polymerization has been achieved, using spherical MgCl2 supports obtained by thermal dealcoholization of MgCl2 · 2.56C2H5OH instead of using supports of type MgCl2/AlRn(OEt)3−n. BET, XRD, IR, SEM, GPC, and DSC analyses indicate that the composition and structure of the supports, the activities of the supported catalysts, and the properties of the resultant polymers are strongly dependent on the dealcoholization temperature. The support SP‐3 obtained by treating MgCl2 · 2.56C2H5OH at 170 °C for 4 h is very effective for immobilizing late‐transition metal FeII and NiII catalysts. Compared with the corresponding unsupported homogeneous catalysts, a significant increase in activity is observed for the SP‐3 supported catalysts in ethylene polymerization, and the kinetics of polymerization is stable during the reaction process. In addition, replication of the support morphology is found in final polymers.Kinetic profiles of ethylene polymerization using SPC‐4, SPC‐5, and SPC‐6 under 1.0 MPa and at 70 °C.imageKinetic profiles of ethylene polymerization using SPC‐4, SPC‐5, and SPC‐6 under 1.0 MPa and at 70 °C.

Porous organic polymers (POPs) have received much attention in adsorption, separation, and catalysis. In this paper, porous organic polymers with different pore structure were used as metallocene catalyst supports, and ethylene/1-hexene copolymerizations were conducted using the POPs-supported metallocene catalyst. The pore structure of the prepared POPs and the supported metallocene catalyst were characterized by nitrogen sorption porosimetry and non-local density functional theory simulation, and the molecular chain structure of the produced ethylene/1-hexene copolymers were investigated through gel permeation chromatography (GPC), IR analysis, differential scanning calorimetry (DSC), and temperature rising elution fractionation (TREF). The results show that the loading amount of active sites varied with different pore structures of the POP supports, and the active species scattered in different pore sizes had a moderate impact on the molecular chain growth and the molecular weight distribution. The IR, DSC, and TREF analysis revealedthat different branching degree, double bond content, and chemical composition distributions were detected from the molecular chain structure of the ethylene/α-olefin copolymers from different POPs and silica-supported metallocene catalysts, despite their similar IR, DSC, and TREF curves due to the same active species. Scanning electron microscopy (SEM) showed that porous ethylene/α-olefin copolymers with varied surface morphology were obtained from the POPs-supported metallocene catalysts with different pore structure.

Porous functional P(HEMA-co-DVB) particles with controllable pore structure and morphology were prepared using metal oxide as particle-forming template.

Porous P(HEMA-co-DVB) particles with tunable pore structure and morphology were prepared by a dispersion polymerization strategy.

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The effect of Joncryl ADR®-4368 (abbreviated ADR) and dicumyl peroxide (DCP) on poly(butylene adipate-co-terephthalate) (PBAT)/poly(lactic acid) (PLA) blend was investigated. Two different blending procedures were adopted: (1) one-step blending of all components for 8 min; (2) premixing of PBAT and ADR (or DCP) for 4 min followed by addition of PLA blending for 4 min. ADR and DCP were effective compatibilizers for the PBAT/PLA blend by one-step blending which were confirmed by improving the phase interface between PBAT and PLA, decreasing the dispersed phase size, increasing the elasticity, viscosity and tensile strength. Moreover, the addition of ADR into PBAT/PLA blend by two-step blending was more efficient than the one-step blending based on refined morphology and further increased tensile properties. The two-step blending was beneficial to produce a larger amount of PBAT-graft-PLA (PBAT-g-PLA) copolymers at the phase interface. However, DCP was added to the PBAT/PLA blend by the two-step blending which showed lower properties than one-step blending. DCP triggered free branching reactions in a fast way. Based on the character of compatibilizers, choosing properly blending procedures can enlarge the tensile properties. These results would be interesting for industrial polymer materials, and may be importance to the wider practical application of PBAT/PLA blends.