Copolymers processing

Union Carbide Corp. also uses a siUca-supported chromium catalyst in their extremely low cost Unipol gas-phase linear low density ethylene copolymer process, which revolutionized the industry when it was introduced in 1977 (86—88). The productivity of this catalyst is 10 —10 kg polymer/kg transition metal contained in the catalyst. By 1990, the capacity of Unipol linear low density polyethylene reactors was sufficient to supply 25% of the world s total demand for polyethylene. 

Poly(amIc ethyl ester) block copolymer Processable/soluble Intermediate... 

The first patent on HIPS, a blend of synthetic rubber and transparent polystyrene, was granted in Great Britain as early as 1912. The first graft copolymerization of styrene in the presence of rubber was carried out by Ostromislensky [5]. The decline in the demand for styrene monomer and styrene-butadiene rubber and the simultaneous availability of natural rubber on the world market in the late 1940s drove the development of styrene copolymer processes. 

As discussed in eariler, PPE is fabricated from a wide variety of polymeric materials by many processes. Glove materials, for example, are multicomponent formulations containing one or more polymers and copolymers, processing aids, stabilizers, fillers and so forth. Gloves are typically sold under the generic name of the principal polymer in the formulation (e.g., nitrile, butyl, etc.). However, the formulations for the products sold under one generic name will vary from manufacturer to manufacturer and, in some cases, within one manufacturer. 

Two PPE s with polyetherimide-silane copolymer processability, flame retardant properties and impact strength Haaf, 1992... 

Similar experiments can also be performed with the HB-HV copolymers and, because of their lower melting points (Fig. 7), we do not have to resort to the above complication to obtain TJ, data below 170°C. Typical results for the homopolymer and two copolymers are summarized in Fig. 10 as a plot of log against melt temperature. Clearly low-melting HB-HV copolymers processed at or below 165°C meet the industrial rule of thumb on melt stability and should be regarded as commercially mouldable. 

The role of nucleating agents in PHB has already been described in great detail but, as they are potentially the most useful additives in both homopolymer and copolymer processing, attention is once again drawn to the results in Fig. 14. 

Fig. 47. Dow in situ block copolymer process for making HIPS/ABS toughened (256).

Granular polymers Polypropylene Ethylene-vinyl acetate copolymers process residues, ethylene, vinyl acetate, acetic acid... 

Ronkin, G. M. Investigation of chloring ethylene-propylene-diene copolymers process and properties of obtained modifications. Ronkin, G. M. et al. Manufacturer of SC. 1981,5,8-11. 

Woodward, A. E., Atlas of Polymer Morphology , Hanser, New York, 1989. Useful book for the practising morphologist. It discusses crystallization from the melt, block copolymers, processing effects, blends, fracture and effects of chemicals and other agents. 

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