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Copolymerization and copolymers od styrene with dodecyl methacrylate and octadecyl methacrylate

Styrene (St) was copolymerized with dodecyl methacrylate (DDMA) or octadecyl methacrylate (ODMA) in toluene using AIBN as free radical iinitiator over a wide composition and conversion ranges. The copolymer composition was determined from H-NMP spectra. The copolymerization reactivity ratios were determined. The Q and E values were also calculated. The initial polymerization rate, Rp, was found to be in an order ODMA > DDMA >> St and for both copolymerization system sharply decreases as the content of st in the monomer mixture increases. Similar behaviour has also been established for the molecular weights and intrinsic viscosity as their values significantly decrease with increasing the St fraction in copolymer. the polymers viscosity in toluene solution established at 30 to 90 C, slightly increases with the temperature for the poly(alkyl methacrylate) and reach the local maximum value at higher temperature shows a constant values for the polystyrene whereas the copolymers fall intermediate between those of homopolymers. Also the copolymers show an increase of thermal stability with increasing St content.

styrene; dodecyl methacrylate; octadecyl methacrylate; copolymerization; copolymers; viscosity improvers

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