Impact copolymer rubber content

Products The process can produce a broad range of propylene-based polymers, including mono- and bimodal (medium/wide/very wide molecular weight distribution) homopolymer PP, high stiffness homopolymers, random copolymers and terpolymers, high-clarity random copolymers as well as two compositions (homopolymer/random copolymer, twin-random or random/heterophasic copolymer). Conventional hetero-phasic impact copolymers (with improved stiffness/impact balance) can be produced with the second additional gas phase reactor, with ethyl-ene/propylene rubber content up to 40%. 

We used a matrix copolymer system consisting of methyl methacrylate (MMA) and styrene (St) grafted on polybutadiene rubber. The variables investigated were latex particle size (360, 2000, and 5000 A), degree of grafting, rubber content, and the degree of particle dispersion. The following variables must be considered when a transparent impact polymer is prepared. 

Based on the tensile impact data in Table IX, we used Run 46 with Aerosol A-196 surfactant to scale up in the pilot plant. We took the 70/30 rubber to copolymer material and diluted it with copolymer to lower the final rubber content to 15% of the polymer this was done during milling. 

Figure 20.10 Impact strength vs content of SEBS for sPS/EPR blends compatibi-lized with LMW-SEBS (circles) and HMW-SEBS (squares). Reprinted from Polymer, vol. 41, Hong, B. K., Jo, W. H., Effects of molecular weight of SEBS triblock copolymer on the morphology, impact strength, and rheological properties of sPS/EPR-rubber blends p. 2069, Copyright 2000, with permission from Elsevier Science...

Impact-modified polypropylenes are produced by combining the homopolymer with an ethylene-propylene copolymer rubber. Ziegler-Natta processes yield such products in cascaded reactors. The first reactor in the sequence produces a rigid polymer with a high propylene content and feeds the second reactor, where the ethylene-propylene elastomer is polymerized in intimate mixture with the first material. 

Products The process can produce a wide variety of homopolymers, random copolymers including terpolymers and pentene copolymers, and impact copolymers with up to 50% rubber content. Product range also includes metallocene PP based on a simple drop-in technology. 

ICP = blends of isotactic propylene homopolymer with ethylene-propylene rubber. These materials are commonly called "impact copolymers," "heterophasic copolymers," or, incorrectly, "block copolymers." These are typically prepared during the polymerization process using a series of reactors. L = low rubber (less than about 15% rubber by weight typically witli an ethylene content of less than about 10%). H = high rubber content blends (greater than about 15% rubber by weight typically with an ethylene content of at least 7%). 

To design a resin with the property enhancements of AN without the cross-linking problem, it was found that SMA copolymers and terpolymers could be blended with ABS resins to form miscible blends with properties of HHABS. A fundamental look at the miscibility of SMA copolymers with SAN copolymers indicated that the optimum thermodynamic interaction occurs when the AN content of the SAN is nearly equal to the MA content of the SMA [72]. Kim et al. also found low impact strengths at all modifier levels when blending SMA with SAN-g-polybutadiene (GRC = grafted rubber concentrate) [73]. Blends of SMA with SAN and GRC (SAN + GRC = emulsion ABS) exhibited ductility behavior similar to HHABS. The impact strengths of the polymers were 2-5 ft-lb/in, in a notched Izod test at ambient temperature. 

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