Polystyrene manufacture

For many applications polystyrene might be considered to be too brittle a polymer. Because of this, polystyrene manufacturers have made a number of attempts to modify their products. 

Uses Solvent blowing agent for polystyrene manufacturing chlorinated derivatives. 

Solvent, blowing agent for polystyrene, manufacture of chlorinated derivatives. 

Commercial polystyrene manufacturing techniques are based either on a suspension process if the material is to be foamed or on a bulk polymerization process for GPPS and IPS. ABS-type polymers can also be produced via emulsion polymerization. Figure 2.5 shows the differences in emulsion and mass polymerization processes and the resulting morphology. Typically,... 

Another type of initiator that has been evaluated for increasing polystyrene production rates are the multifunctional peroxides. Examples include 2,2-bis [4,4-bis(tert-butylperoxy)cyclohexyl]propane (I) [9], peroxyfumaric acid, 0,0-te/Y-butyl O-butyl ester (II) [10], ter t-butyl peritaconate (III) [11], and poly (monopercarbonates) (IV) (Figure 7.4) [12]. Although all of these initiators indeed show extremely fast production rates of high MW polystyrene, they all suffer from a flaw, i.e. the polystyrene produced is branched and special precautions must be taken to keep the continuous bulk polymerization reactors from fouling [13]. This is likely why none are currently used commercially for polystyrene manufacture. 

Adsorption. An important factor in adsorption to a surface is its chemical nature and, in particular, wettabihty. Polystyrene manufactured into vessels does not have a good chemical structure in this regard and requires treatment to produce a negatively charged surface suitable for electrostatic attachment and cell adhesion (Maroudas, 1993). The first stage of adsorption requires the presence of... 

The dimer of a-methylstyrene is useful in controlling molecular weight in polystyrene manufacture.467468 The control of molecular weight with... 

A polystyrene manufacturing facility has the following streams that are currently heated (cold streams) using high-pressure steam (450 psi) and cooled (hot streams) using cooling water (20 °C). These utilities are available at 14.50/1000 kg and 0.02/m, respectively. 

World polystyrene manufacturing capacity was reported to be approximately 20.4 million tons in 2004 with consumption running at around 17.3 million tons. China, already amongst the largest PS consumers with consumption in 2004 of 3.8 million tons, is increasing its manufacturing capability to reduce imports which were reported to be 1.563 million tons in 2004. 

H. Honl. Polystyrene. Manufacture, properties, market, range. BASF April 1990. 

Radical polymerization of styrene is the predominant method of polystyrene manufacture, but styrene can be polymerized by other means. Styrene can be polymerized by an anionic mechanism, for example by treatment with a minor amount of butyl lithium to initiate the reaction. 

All the non-polymerisable volatile impurities which occur in styrene monomer used in polystyrene manufacture will also be present in the finished polymer. Analysis of the monomer is therefore important. Gas chromatographic methods, for determining up to 40 impurities in styrene monomer are discussed in methods 28 to 30. 

Low pressure polyethylene might contain minute traces of oxygen or nitrogen or sulfur chain transfer catalyst residues. These are usually labile and can be ignored from the foodstuff contamination point of view. Polymers such as polyethylene, polypropylene and polystyrene manufactured by a catalysed low pressure route will however, usually contain appreciable catalyst residues usually appearing in the form of aluminium, chromium, magnesium and titanium, also possibly lithium and sodium. As the example quoted in Table 3.1 indicates these impurities can occur in the polymer at levels approaching 100 ppm. 

Only one grade of polystyrene manufactured by DOW Chemicals USA was investigated throughout the study. This pol5mier has also been thoroughly investigated and optimized in related studies [3,4]. Selected physical and mechanical properties are depicted in Table 1. 

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