Poly process technology

With lower-molecular-weight polymers unit cell parameters may also vary with the molecular mass distribution. For poly(ethylene terephthalate) the history of reported unit cell parameters reflects the progress of chemical processing technology [105]. 

World-wide consumption of PVC [poly(vinyl chloride)] has increased dramatically in the past few years. It has now exceeded 8 billion lbs annually. The production of VCM (vinyl chloride monomer) has also been expanded to meet the PVC demand. Future trends for VCM and PVC pro-ductions for the next five years can be forecast on the basis of the raw materials sources, the different process techniques in manufacturing VCM and PVC, and their relative economics, technical merits, and limitations. VCM will be produced principally through the ethylene route by fluid-bed oxyhydrochlorination of ethylene and thermal cracking of ethylene dichloride. PVC will be produced by various processes resulting in more specialized PVC varieties tailored for specific end markets and new processing technologies. 

Novolac and resol cold hardening oligomers habe been used 19-75-99). In the case of resol foams the process technology is not different from that used for epoxy foams. Glass, phenolic resins, carbon, polystyrene, polyacrylonitrile and poly(vinylidene chloride) microspheres have been used as fillers ... 

Lim, L.-T., Auras, R. and Rubino, M. (2008) Processing technologies for poly(lactic acid). Progress in Polymer Science, 33, 820-852. 

Abstract This chapter describes the production of cis-3,5-cyclohexadiene-l,2-diol (DHCD) from aromatic compounds, their polymerization into poly(p-phenyelene) (or PPP), and the properties and applications of the polymer. Large-scale synthesis of DHCD has been demonstrated, and DHCD is widely used in the pharmaceutical industry, as well as in chemical industries for polymer productions. Recent study including different types of dioxygenases, strain development by recombination, and genetical modification were done to develop the process technology for commercialization of this new polymer and chemical intermediates. 

Wong W, Ghana K,Yeunga K W,Tsanga Y M and Lau K S (2000), Surface structuring of poly(ethylene terephthalate) fibres with a UV excimer laser and low temperature plasma. . Journal of Materials Processing Technology, 103,225-229. 

Considering fibres based on poly(hydroxybutyrate) or higher PHAs, no successful process was reported for preparation of PHB fibres by conventional fibre processing technology, i.e. melt or gel spinning with subsequent hot drawing. Therefore, more sophisticated procedures have to be developed to achieve reasonable draw ratios, resulting in production of anisotropic material with important improvement of properties. 

Membrane Sep r tion. The separation of components ofhquid milk products can be accompHshed with semipermeable membranes by either ultrafiltration (qv) or hyperfiltration, also called reverse osmosis (qv) (30). With ultrafiltration (UF) the membrane selectively prevents the passage of large molecules such as protein. In reverse osmosis (RO) different small, low molecular weight molecules are separated. Both procedures require that pressure be maintained and that the energy needed is a cost item. The materials from which the membranes are made are similar for both processes and include cellulose acetate, poly(vinyl chloride), poly(vinyHdene diduoride), nylon, and polyamide (see AFembrane technology). Membranes are commonly used for the concentration of whey and milk for cheesemaking (31). For example, membranes with 100 and 200 p.m are used to obtain a 4 1 reduction of skimmed milk. 

Almost all synthetic binders are prepared by an emulsion polymerization process and are suppHed as latexes which consist of 48—52 wt % polymer dispersed in water (101). The largest-volume binder is styrene—butadiene copolymer [9003-55-8] (SBR) latex. Most SBRlatexes are carboxylated, ie, they contain copolymerized acidic monomers. Other latex binders are based on poly(vinyl acetate) [9003-20-7] and on polymers of acrylate esters. Poly(vinyl alcohol) is a water-soluble, synthetic biader which is prepared by the hydrolysis of poly(viayl acetate) (see Latex technology Vinyl polymers). 

The most innovative photohalogenation technology developed in the latter twentieth century is that for purposes of photochlorination of poly(vinyl chloride) (PVC). More highly chlorinated products of improved thermal stabiUty, fire resistance, and rigidity are obtained. In production, the stepwise chlorination may be effected in Hquid chlorine which serves both as solvent for the polymer and reagent (46). A soHd-state process has also been devised in which a bed of microparticulate PVC is fluidized with CI2 gas and simultaneously irradiated (47). In both cases the reaction proceeds, counterintuitively, to introduce Cl exclusively at unchlorinated carbon atoms on the polymer backbone. 

---