Styrene-based Copolymers

Wang and Smith [60] applied Py-GC to determine the composition and microstructure of styrene-MMA copolymers. The composition of these copolymers was quantified by monomer peak intensities obtained from pyrolysis. Becanse of the poor stability of MMA oligomers, neither MMA dimers nor trimers were detected nnder normal pyrolysis conditions. The number average sequence length for styrene was determined from pure and hybrid styrene trimer peak intensities. The number average sequence 

Chloromethyl-substituted polystyrene gels usnally crosslinked with divinylbenzene (DVB) are widely used as key intermediates for ion-exchange resins, supports for solid- 

Methods for obtaining structural information on those chloromethyl substituted polystyrenes are discussed next. 

Past work has been limited to infrared and NMR spectroscopy. Ford and Yacoub [64] characterised styrene - DVB (ST-DVB) and styrene - chloromethylstyrene - DVB copolymers by high resolution C-NMR. These copolymers were differentiated by the line widths of the backbone methine and chloromethyl carbon peaks [64]. Dependence of the line widths and detected peak areas on DVB content and isomeric distribution of the chloromethyl groups has been discussed [65, 66]. 

Various workers have shown that shown that Py-GC and Py-MS methodologies are both capable of obtaining information on the chemical structure of insoluble PS networks [67-70]. In particular, high resolution Py-MS is a powerful technique for the characteriastion of copolymers with crosslinked structures [71, 49], and have provided information on structural differences between anionically and radically prepared styrene-DVB copolymers [70]. 

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Styrene-based copolymers, 10 171 orientation of, 23 399 Styrene-based plastics. See also Styrene plastics... 

However, such alternative polymers are often too expensive or they have too superior properties, e.g., other than less brittleness that are not needed for the particular application. For these reasons, a good solution is to start with styrene-based copolymers, and to modify them accordingly (2). 

Table 1. Miscibility doors of PPO blended with styrene-based copolymers...

Morphology evolution during solution casting of polymer blends has been studied to some extent in recent years [93-96]. More than 10 blend solutions comprising immiscible polymers and random copolymers such as poly(methyl methacrylate) and different styren-based copolymers were studied in Ref. [93]. The results can be summarized as follows ... 

Orientation of styrene-based copolymers is usually carried out at temperatures just above T. BiaxiaUy oriented films and sheet are of particular interest. Such orientation increases tensile properties, flexibility, toughness, and shrinkability. PS produces particularly clear and sparkling film after being oriented biaxiaHy for envelope windows, decoration tapes, etc. Oriented films and sheet of styrene-based polymers are made by the bubble process and by the flat-sheet or tentering process. Eibers and films can be produced by uniaxial orientation (237) (see Eilmand SHEETING materials). 

In contrast, the foams derived from the a-methylstyrene and styrene-based copolymers showed pore sizes ranging from 200 to -1800 A, values which are considerably larger than the size of the microdomains of the initial copolymer (Fig. 13). Furthermore, the pores in these samples appear to be more interconnected than those obtained from the fully imidized copolymers. Finally, the... 

CleapacL PainipponInk Chem.] Styrene-based copolymer transparent high intact thermoptotic for inj. molding and extrusion of business machine parts, pkg. materials for electronics or food. 

PS is one of the most versatile packaging resins. The amorphous grade, crystal PS, is used to make bottles for pills, tablets, and capsules. High impact PS (HIPS) is commonly used as thermoformed containers for dairy products. PS foam has good shock absorbing and heat insulation characteristics. Applications in food packaging include egg cartons and meat trays. Varieties of styrene-based copolymers have also been developed to exhibit special combinations of properties. Typical PS properties are shown in Table 4.10. 

Because strong Bronsted (proton) acids and Lewis acids can initiate styrene polymerization, other cationically polymerizable monomers can be added to the styrene-based copolymer list. Due to the facile occurrence of chain transfer processes of polymer chains with impurities, cationically prepared polystyrene-based polymers are low molecular weight materials. Nevertheless, low molecular weight polystyrenes still find important applications as additives, as tackifiers for pressure sensitive adhesives, and in hot melt adhesives. However, the market for low molecular weight polystyrene is small. 

What are the industrial production processes for making polystyrenes and other styrene-based copolymers What are the advantages and disadvantages for each of those processes ... 

Blends of styrenic pol5m ers (PS, high impact poly (styrene)) and biodegradable polymers (PLA) can be extruded and thermo-formed to produce very low density food service and consumer foam articles (29,31). The blends are compatibilized with styrene-based copolymers a styrene-maleic anhydride copol5mier, or a styrene methyl methacrylate copolymer. As blowing agent for foaming the compositions z-pentane is used. 

In aprotic solvents and for CO/a -olefin- and CO/styrene-based copolymers, formation of vinyl-ketone [R R C=C(R )C(0)—] and butenyl-ketone end groups has been reported (2,72,114). 

Figure 14.6 AFM tapping mode, phase images of amphiphilic, fluorinated/PECylated styrene-based copolymers. The left hand column shows morphologies of dry films after annealing at 120°. The right hand column shows the same coatings after immersion for 7 days in artificial seawater. The two coatings (A) and (B) differ in the degree of polymerization of the polystyrene (S ) and the relative lengths of...

Kotani Y, Kamigaito M, Sawamoto, M. Living radical polymerization of para-substituted styrenes and synthesis of styrene-based copolymers with rhenium and iron complex catalysts. Macromolecules 2000 33 6746-6751. 

Figure 5.6 Compositional distribution for styrene-based copolymers. Reproduced with permission from M.S. Montaudo, Polymer, 2002, 43, 1587. 2002, Elsevier...

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