The Synthesis And Application Of A New Kind Of Structure Modifier In Solution Styrene And Butadiene Copolymerization

A new kind of structure modifier which was used in solution anionic copolymerization of butadiene (Bd) and styrene (St) initiated by n-BuLi is synthesized in this paper. The method and rute of synthesis of this new modifier are studied in detail. The structural formula of this new compound proved by H- NMR(9OMHz) is as follows: (CE!2 -CH2 -O)~ -R3 wherein n represents an integer within the range of 1 to 3, wherein R?and R2 represent ihe sain&dr different alkyl groups containing from 1 to about 4 carbon atoms, wherein R3 represents an alkyl group containing from 1 to about 6 carbon atoms. The anionic homopolynierization and copolymerization of Bd and St in the solvent of cyclohexane in the presence of a catalyst system which is comprised of n-BuLi and new modifier GABE are investigated separately. The effects of different amount of modifier and polymerizaton temperature on the polymerization rate, microstructure and the random distribution of styrene in copolymer chains are illustrated. The polymerization kinetics and analysis of IR and H-NMR shows that an increase of GABE/n-BuLi(mole ratio) to the homopolymerization of Bd results in an increase in vinyl content of PB and polymerization rate at 50C. With the changing of GABE/n-BuLi from 0 to 5.0, vinyl content increases from 24.4% to 65.2% and k~ from 0.0288min?to 0.O700min? Besides, in the copolymerization of Bd and St (BdISt = 75125;mass ratio), the randomness of styrene in polymer chains will increase too. When GABEIn-BuLi is 2, the distribution of styrene in polymer chains is random. The monomer reactivity ratios are obtained by Kelen-Tudos method at SOt. r~ and r~ are 3.478 and 0.259 respectively for the modifier ratio of 1.0. The consequence is satisfactory.