Polypropylene resins high crystalline

In the two-step process, polypropylene resin of typically MFR = 35 g/min and isotacticity above 90% is spun at 280°C at a low speed of 200 m/min. The spun fiber, which has a structure of low-oriented hexagonal crystallinity, is drawn at a low temperature of 60°C over seven rolls. The drawn fiber, still having a paracrystalline structure, is drawn again at a higher temperature of 110°C 140°C to change the paracrystallinity into a highly oriented... 

The two TPO systems examined in this study, TPOl and TP02, had virtually the same balance of physical properties. Both materials were comprised of a polypropylene (PP) matrix with an elastomer, and other traditional TPO additives, such as colorant and slip agent. The difference between the two was in the type of PP resin used. For TPOl an impact copolymer (ICP) PP was used, while in the TP02 formulation a high crystalline PP homopolymer was utilized. 

ABA ABS ABS-PC ABS-PVC ACM ACS AES AMMA AN APET APP ASA BR BS CA CAB CAP CN CP CPE CPET CPP CPVC CR CTA DAM DAP DMT ECTFE EEA EMA EMAA EMAC EMPP EnBA EP EPM ESI EVA(C) EVOH FEP HDI HDPE HIPS HMDI IPI LDPE LLDPE MBS Acrylonitrile-butadiene-acrylate Acrylonitrile-butadiene-styrene copolymer Acrylonitrile-butadiene-styrene-polycarbonate alloy Acrylonitrile-butadiene-styrene-poly(vinyl chloride) alloy Acrylic acid ester rubber Acrylonitrile-chlorinated pe-styrene Acrylonitrile-ethylene-propylene-styrene Acrylonitrile-methyl methacrylate Acrylonitrile Amorphous polyethylene terephthalate Atactic polypropylene Acrylic-styrene-acrylonitrile Butadiene rubber Butadiene styrene rubber Cellulose acetate Cellulose acetate-butyrate Cellulose acetate-propionate Cellulose nitrate Cellulose propionate Chlorinated polyethylene Crystalline polyethylene terephthalate Cast polypropylene Chlorinated polyvinyl chloride Chloroprene rubber Cellulose triacetate Diallyl maleate Diallyl phthalate Terephthalic acid, dimethyl ester Ethylene-chlorotrifluoroethylene copolymer Ethylene-ethyl acrylate Ethylene-methyl acrylate Ethylene methacrylic acid Ethylene-methyl acrylate copolymer Elastomer modified polypropylene Ethylene normal butyl acrylate Epoxy resin, also ethylene-propylene Ethylene-propylene rubber Ethylene-styrene copolymers Polyethylene-vinyl acetate Polyethylene-vinyl alcohol copolymers Fluorinated ethylene-propylene copolymers Hexamethylene diisocyanate High-density polyethylene High-impact polystyrene Diisocyanato dicyclohexylmethane Isophorone diisocyanate Low-density polyethylene Linear low-density polyethylene Methacrylate-butadiene-styrene... 

Furthermore, monomers from which crystalline homopolymer can be produced, such as high-density polyethylene and polypropylene, can be copolymerized to produce resins with controllably reduced crystallinity and thus greater transparency. The ethylene/propylene copolymers may range from partially crystalline plastics to amorphous elastomers. 

The oldest example of this procedure is the manufacture of high-impact polypropylene, as already described (see Section 8.1.2). Other applications have become more popular lately, especially for the production of bimodal resins. Figure 8.36 illustrates a tandem process using two gas-phase vertical stirred-tank reactors. Several other reactor combinations are used industrially [65]. For heterogeneous processes, the first reactor(s) in the series can be either slurry or gas-phase, but commonly the second reactor (or set of reactors) is a gas-phase reactor. This is especially important when the production of polymers with lower crystallinity... 

Specific Heat Capacity. Representative values of specific heat capacity are shown in Tables 3 and 6. The range of values is only about 850 to 2400 J/(kgK) or barely a factor of three. As a general rule, differences are usually associated with the molecular composition of the polymer and less with molecular architecture, although crystallinity may be important. For example, a comparison of three forms of polyethylene (Table 6) reveals little difference in heat capacity the high density, and hence more crystalline, form has a somewhat lower value. Similarly, no differences are observed between two grades of phenol-formaldehyde resin, or between them and phenol-furfural resin. However, in comparing isotactic and atactic (amorphous) polypropylene shown in Table 3 with values of 1790 and 2350 J/(kg K), respectively, a fairly substantial difference is observed the more ordered, denser isotactic form has the lower heat capacity, as is to be expected. However, comparable values of isotactic and atactic polystyrene have been reported to be 1264 and 1227 J/(kg-K), respectively (65) here the difference is small. 

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