High molecular weight star-shaped polystyrenes were prepared via the coupling of 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) terminated polystyrene oligomers with divinylbenzene (DVB) in m-xylene at 138°C. The optimum ratio of the coupling solvent (m-xylene) to divinylbenzene was determined to be 9 to 1 based on volume. Linear polystyrene oligomers (Mn = 19,300 g/mol, Mw/Mn = 1.10) were prepared in bulk styrene using benzoyl peroxide in the presence of TEMPO at approximately 130°C under an inert atmosphere. Coupling of the TEMPO-terminated oligomers under optimum conditions resulted in a product with a number average oligomers under optimum conditions resulted in a product with a number average molecular weight exceeding 300,000 g/mol (Mw/Mn = 3.03) after 24 h, suggesting the formation of relatively well-defined star-shaped polymers. Additionally, the intrinsic viscosities of the star-shaped products were lower than calculated values for linear analogs of equivalent molecular weight, which further supported the formation of a star-shaped architecture.
|ジャーナル||Journal of Polymer Science, Part A: Polymer Chemistry|
|出版ステータス||Published - 2001 1 1|
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