Polystyrene-co-acrylonitrile

Galdamez, J.R., Kernion, S.J., Duda, J.L., and Danner, R.P. (2008) Determination of thermodynamic and transport properties of a polystyrene-co-acrylonitrile copolymer by infinite and finite concentration IGC. Polymer, 49 (12), 2873-2879. 

E4 polystyrene-Z)/ocA -[l,4-polybutadiene-grq/Z -poly(styrene-co-acrylonitrile)] (copolymer from styrene and acrylonitrile grafted to a 1,4-polybutadiene-polystyrene two-block copolymer at unspecified sites of some of the but-2-ene-... 

Plastomers. The production of resins (polyfvinyl chloride], polystyrene, and poly [styrene-co-acrylonitrile]) with relatively high toughness has been one of the most important aims of industry. This can be achieved by modifying a rigid chain with small amounts of elastomers. The best results have been obtained by the use of block and graft copolymers. 

Beginning in the late forties, copolymers were fractionated by adsorption chromatography poly (butadiene-co-styrene)32 34), poly(butadiene-co-acrylonitrile)32), polystyrene- -vinyl acetate)35), poly(styrene-h-ethylene oxide)36) and poly(styrene-co-acrylonitrile) 37). HPLC adsorption chromatography was first applied to copolymer analysis by Teramachi et al. in 1979 38>. 

The concept of PO macroinitiators centers on the introduction of an initiation moiety into an olefinic polymer chain for polymerization. The most effective route for preparing PO macroinitiators is by employing functional polyolefins containing hydroxyl groups or other reactive groups. These functional POs are prepared by copolymerization of olefins with functional monomers and post-polymerization reaction, as mentioned above. In the case where an initiation moiety was at the chain-end of the polyolefins, a block type copolymer is produced. It has been reported that thiol-terminated PP was used as polymeric chain transfer agent in styrene and styrene/acrylonitrile polymerization to form polypropylene-b/odc-polystyrene (PP-b-PS) and polypropylene-btock-poly(styrene-co-acrylonitrile) (PP-b-SAN) block copolymer [19]. On the other hand, polymer hybrids with block and graft structures can be produced if initiation moieties are in the polymer chain. 

On the other hand, some mechanically compatible blends as well as some dispersed two-phase systems have made respectable inroads into the commercial scene. Many of these are blends of low-impact resins with high-impact elastomeric polymers examples are polystyrene/rubber, poly (styrene-co-acrylonitrile) /rubber, poly (methyl methacrylate) /rubber, poly (ethylene propylene)/propylene rubber, and bis-A polycarbonate/ ABS as well as blends of polyvinyl chloride with ABS or PMMA or chlorinated polyethylene. 

This chapter discusses the dynamic mechanical properties of polystyrene, styrene copolymers, rubber-modified polystyrene and rubber-modified styrene copolymers. In polystyrene, the experimental relaxation spectrum and its probable molecular origins are reviewed further the effects on the relaxations caused by polymer structure (e.g. tacticity, molecular weight, substituents and crosslinking) and additives (e.g. plasticizers, antioxidants, UV stabilizers, flame retardants and colorants) are assessed. The main relaxation behaviour of styrene copolymers is presented and some of the effects of random copolymerization on secondary mechanical relaxation processes are illustrated on styrene-co-acrylonitrile and styrene-co-methacrylic acid. Finally, in rubber-modified polystyrene and styrene copolymers, it is shown how dynamic mechanical spectroscopy can help in the characterization of rubber phase morphology through the analysis of its main relaxation loss peak. 

Commercially, suspension polymerizations have been limited to the free radical polymerization of water-insoluble liquid monomers to prepare a number of granular polymers, including polystyrene, poly(vinyl acetate), poly(methyl methacrylate), polytetrafluoroethylene, extrusion and injection-molding grades of poly(vinyl chloride), poly(styrene-co-acrylonitrile) (SAN), and extrusion-grade poly(vinylidene chloride-covinyl chloride). It is possible, however, to perform inverse suspension polymerizations, where water-soluble monomer (e.g., acrylamide) is dispersed in a continuous hydrophobic organic solvent. 

Fig. 15. Oxygen permeability versus 1/specific free volume at 25 °C (30). 1. Polybutadiene 2. polyethylene (density 0.922) 3. polycarbonate 4. polystyrene 5. styrene-co acrylonitrile 6. polyethylene terephthalate) 7. acrylonitrile barrier polymer 8. poly(methyl methacrylate) 9. poly(vinyl chloride) 10. acrylonitrile barrier polymer 11. vinylidene chloride copolymer 12. polymethacrylonitrile and 13. polyacrylonitrile. See Table 1 for unit conversions.

Examples of such compatibilized systems that have been studied include EPDM/PMMA blends compatibilized with EPDM- -MMA, polypropylene/polyethylene blends with EPM or EPDM, polystyrene/nylon-6 blends with polystyrene/nylon-6 block copolymer, and poly(styrene-co-acrylonitrile)/poly(styrene-co-butadiene) blends with butadiene rubber/PMMA block copolymer. 

Poly (styrene-co-acrylonitrile). See Styrene/acrylonitrile copolymer Poly (styrene-co-allyl alcohol). See Styrene/allyl alcohol copolymer Poly (styrene-co-butadiene). See Styrene/butadiene polymer Poly (styrene-co-divinylbenzene). See Styrene/DVB copolymer Poly (styrene-co-maleic anhydride). See Styrene/MA copolymer Poly (styrene-co-methyl methacrylate). See Styrene/methyl methacrylate copolymer Poly (styrene-co-a-methylstyrene). See Styrene/a-methyl styrene resin Poly (styrene-divinylbenzene). See Styrene/DVB copolymer Polystyrene, expandable Synonyms EPS Expandable polystyrene Expanded polystyrene XPS Definition Amorphous PS beads contg. pentane as a blowing agent and coated with a lubricant the polymer is converted to foamed articles with a closed cell structure by applic. of steam Properties Beads (0.4-1.5 mm diam.)... 

Synonyms Polystyrene/acrylonitrile Poly (styrene-co-acrylonitrile) 2-Propenenitrile polymer with ethenylbenzene SAN SAN copolymer... 

NMP is based on the concept of a dynamic equilibration between dormant alkoxyamines and propagating radicals as shown in eqn [55].The choice of the persistent radical is cmcial for controlled polymerization. While styrene can be easily moderated by 2,2,6,6-tetramethyl-l-piperidinyloxy (TEMPO), other monomers required the development of nitroxides that contain hydrogen atoms at the a-C. There are two different initiation methods for NMP. Conventional radical initiators (i.e., AIBN, BPO) in conjunction with a persistent radical were initially used to prepare polymers by NMP, but these systems were limited in the choice of monomer. Functionality could be incorporated via a functionalized initiator or a functionalized persistent radical. For example, Baumert and Mulhaupt prepared carboxylic acid-terminated polystyrene, poly(styrene-co-acrylonitrile), and polystyrene-b-poly (styrene-co-acrylonitrile) by the use of the functionalized initiator 4,4 -azobis(4-cyanopentanecarboxylic acid). The polymerization was controlled by the addition of 2,2,6,6-tetramethyl-l-piperidyloxyl radical, and polymers with... 

Figures 3.1 and 3.2 compare the dCp/dT versus temperature data from experiments with theoretical data (using the above equations) and a Gaussian function for, respectively, polystyrene and a (50/50 by weight) miscible blend of poly(methyl methacrylate) andpoly(styrene-co-acrylonitrile) [30]. Clearly, the experimental data can be described by both the theory, and also by a Gaussian function, G, of the glass transition temperature, the width...

The effect of a simple shear flow on the phase behavior and morphology was investigated with the use of a parallel-plate apparatus (Fig. 8.4, Madbouly et al. 1999a) for some polymer mixtures poly(methyl methacrylate) (PMMA)/ poly(styrene-co-acrylonitrile) (SAN-29.5) and polystyrene (PS)/poly(vinyl methyl ether) (PVME), which have an LCST-type phase diagram PS/PMMA, which has a UCST-type phase diagram and polycarbonate (PC)/SAN and nylon4, 6(PA4,6)/ poly(phenylene sulfide) (PPS), which are immiscible in the whole measurable region under the quiescent state. 

Of critical importance, analysis of poly(methyl methacrylate) (PMMA) showed that at a saturation temperature, T, of 40°C, a saturation pressure, P%, of 1,500 psig (at these conditions, carbon dioxide is considered a supercritical fluid), and a saturation time, ts, of 24 h, a 1 mm thick disk absorbed 16.4 wt% carbon dioxide. Additionally, at a foaming temperature, Tf, of 120°C and a foaming time, tf, of 1 min, PMMA had a stable volumetric expansion ratio of 20. Other polymers also absorbed significant quantities of carbon dioxide, such as polystyrene (PS) and poly(vinylidene chloride-co-acrylonitrile) (P(VDC-AN)), which absorbed 8.9 and 2 wt% carbon dioxide, respectively, yet the stable foams that were formed had expansion ratios of less than 2 at the same conditions used to form the PMMA samples. Another polymer poly(vinyl methyl ketone) (PVMK) achieved an expansion ratio of 20. However, the foams were unstable, readily collapsed, and exhibited large voids ( 5 mm diameter), which are inconsistent with microcellular foams. The fact that PVMK readily collapsed after the foaming process made it difficult to determine the concentration of carbon dioxide in the sample. These results led to the eventual incorporation of the MMA monomer into the polymer formulation from the standpoint of carbon dioxide-induced microcellular foamability. 

In spite of its availability and the clarity of this brittle polymer, styrene monomer remained a laboratory curiosity for over a century. However, after Tschunker produced styrene-butadiene elastomeric copolymers (Buna-S), chemists at IG Farbenindustrie reinvestigated styrene homopoljrmers and several copolymers including st3n-ene-co-acrylonitrile. Polystyrene was produced commercially in Germany in 1925. 

Polystyrene PS, Poly(styrene-co-butadiene) SB, Poly(styrene-co-acrylonitrile) SAN Vinylpolymers II... 

Table3.3-7 Polystyrene, PS poly(styrene-co-butadiene), SB poly(styrene-co-acrylonitrile), SAN...

Vollmert presented 31 examples of multipolymer compositions, some of which were IPNs, (see Table 8.1). In example 20, a crosslinked poly(n-butyl acrylate) makes up network I. Poly(n-butyl acrylate-co-acrylonitrile) crosslinked with 1,4-butane-diol diacrylate makes up network II on a separate latex. A linear poly(styrene-co-acrylonitrile) latex makes up polymer III for a third latex. The three latexes are blended to form an impact-resistant polystyrene. This particular product, however, is not an IPN, because the two crosslinked latexes were polymerized and crosslinked separately and then mechanically blended together. 

Shapras and Claver [38] have described a gas chromatographic method for the determination of various volatiles in polystyrene, styrene-acrylonitrile copolymers, styrene-butadiene, styrene-acrylonitrile-butadiene terpolymers and other co-polymers. In this procedure, the polymer is dissolved in dimethyl formamide containing a known amount of toluene as internal standard. A portion of this solution is injected into two columns in series comprising 20% Tween 81 on Chromosorb W, followed by 10% Resoflex-446 on Chromosorb W. Using a hydrogen flame ionisation detector, less than 10 ppm of various monomers and other volatile impurities can be determined in the polymer by this procedure. Shapras and Claver state that the polymer present in the solution injected into the gas chromatographic column deposits on the injection block and is removed by reaming after every 50 sample injections. 

In practice, the existence of both UCST and LCST has been established for polymer-solvent systems. About 10 years ago, Schmitt discussed UCST, LCST and combined UCST and LCST behavior in blends of poly(methyl methacrylate) with poly(styrene-co-acrylonitrile) (PMMA-PSAN), Ueda and Karasz reported the existence of UCST in chlorinated polyethylene (CPE) blends using DSC, Inoue found that elastomer blends of cis-l,4-polybutadiene and poly(styrene-co-butadiene) exhibit both UCST and LCST behavior and Cong et al. (72) observed that blends of polystyrene and carboxylated poly(2,6-dimethyl-l,4-phenylene oxide) copolymers with a degree of carboxylation between molar fraction 8% and 10% exhibit both UCST and LCST behavior. They used DSC to establish the phase diagram. 

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