Polystyrene, anhydride-modified

More recently, Biswas and Chatteijee have prepared polystyrene electro-philically substituted with phthalic anhydride pyromellitic diianhydride tri-mellitic anhydride and 1,2,3,4-tetrahydrophthalic anhydride by Friedel-Crafts reaction. These anhydride-modified polystyrenes have further been converted into sulfonic acid resins by conventional sulfonation reaction. The thermal stabilities of these modified polymers are comparatively better than that of unmodified polystyrene. Ion-exchange capacities also compare favourably with the polystyrene-based commercial resins. 

Engineering resins can be combined with either other engineering resins or commodity resins. Some commercially successhil blends of engineering resins with other engineering resins include poly(butylene terephthalate)—poly(ethylene terephthalate), polycarbonate—poly(butylene terephthalate), polycarbonate—poly(ethylene terephthalate), polysulfone—poly (ethylene terephthalate), and poly(phenylene oxide)—nylon. Commercial blends of engineering resins with other resins include modified poly(butylene terephthalate), polycarbonate—ABS, polycarbonate—styrene maleic anhydride, poly(phenylene oxide)—polystyrene, and nylon—polyethylene. 

Other polymers like polypropylene or polystyrene modified by maleic anhydride or maleamide, with the add groups converted to amide, ester or ester chloride and then reacted on Nylon fibers, have been claimed in a Japanese patent (101). Two patents report grafting of olefinic polymers on polycaprolactam (102,103). Grafting of polysiloxanes on polyamides can be induced by X-rays (104). 

Fig. 13.3. Modified polystyrene beads for covalent binding of proteins. Proteins can be linked to hydrazide beads (a) with glutaraldehyde or to beads derivatized with alkylamine using succinic anhydride and carbodiimide or Sanger s reagent (Pierce Chemical Co. Technical Information).

Esterified polystyrene-co-maleic anhydride Polyethylene-co-propylene Poly(ethylene-co-propylene diene-modified) Poly(ethylene-co-propylene-co-olefin diene-modified) Hydrogenated polystyrene-co-butadiene Hydrogenated polystyrene-co-isoprene Hydrogenated polyisoprene. 

Pinishes are applied to the PAN fiber to improve handling and include silicones (modified polysiloxanes) [132] and trimethylol propane-ethylene oxide adduct [133-135]. These finishes are burned off in the latter stages of stabilization, or in the initial stages of the low temperature carbonization furnace and the breakdown products should be volatile to permit removal. At one time, it was common practice to use adventitious sizes applied prior to the stabilization stage to protect the cosmetics of the oxidized fiber during oxidation. These sizes should preferably break down into gaseous components at about 200° C and typical sizes are the ammonium salt of polystyrene maleic anhydride copolymer, ethyl acrylate, ethyl acrylate/methyl methacrylate and polyacrylic acid. 

X. Zheng, D. D. Jiang, and C. A. Wilkie, Polystyrene nanocomposites based on an oligomerically-modified clay containing maleic anhydride. Polymer Degradation and Stability, 91 (2006), 108-13. 

Until 2003, Chen s [28], Qu s [29-31], and Hu s [32] groups independently reported nanocomposites with polymeric matrices for the first time the. In Hsueh and Chen s work, exfoUated polyimide/LDH was prepared by in situ polymerization of a mixture of aminobenzoate-modified Mg-Al LDH and polyamic acid (polyimide precursor) in N,N-dimethylactamide [28]. In other work, Chen and Qu successfully synthesized exfoliated polyethylene-g-maleic anhydride (PE-g-MA)/LDH nanocomposites by refluxing in a nonpolar xylene solution of PE-g-MA [29,30]. Then, Li et al. prepared polyfmethyl methacrylate) (PMMA)/MgAl LDH by exfoliation/adsorption with acetone as cosolvent [32]. Since then, polymer/LDH nanocomposites have attracted extensive interest. The wide variety of polymers used for nanocomposite preparation include polyethylene (PE) [29, 30, 33 9], polystyrene (PS) [48, 50-58], poly(propylene carbonate) [59], poly(3-hydroxybutyrate) [60-62], poly(vinyl chloride) [63], syndiotactic polystyrene [64], polyurethane [65], poly[(3-hydroxybutyrate)-co-(3-hydroxyvalerate)] [66], polypropylene (PP) [48, 67-70], nylon 6 [9,71,72], ethylene vinyl acetate copolymer (EVA) [73-77], poly(L-lactide) [78], poly(ethylene terephthalate) [79, 80], poly(caprolactone) [81], poly(p-dioxanone) [82], poly(vinyl alcohol) [83], PMMA [32,47, 48, 57, 84-93], poly(2-hydroxyethyl methacrylate) [94], poly(styrene-co-methyl methacrylate) [95], polyimide [28], and epoxy [96-98]. These nanocomposites often exhibit enhanced mechanical, thermal, optical, and electrical properties and flame retardancy. Among them, the thermal properties and flame retardancy are the most interesting and will be discussed in the following sections. 

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