SYNTHESIS OF CIS-1,4 POLY(BUTADIENE) IN SOLUTION WITH STYRENE AND THEIR USE AS PRECURSOR RUBBER IN HIGH IMPACT POLYSTYRENE BY "IN SITU BULK" POLYMERIZATION PROCESS

In a first step, cis-1,4-poly(butadiene) (cis-1,4-PB) was synthetized through a ternary catalytic system (neodymium versatate/diisobutylaluminum hydride/ethylaluminum sesquicloride) and styrene as solvent. Different molar ratios of Al/Nd and Cl/Nd were evaluated to establish the optimal reaction conditions to produce high cis-1,4-PB with an small polystyrene content. Cis-1,4 microstructure was higher than 94% for all cases, meanwhile the polystyrene content in the rubber was approximately 10%, both percentages were calculated by nuclear magnetic resonance. In a second step, the styrene in the resulting solutions (rubber + styrene) was polymerized by the free radical polymerization technique to produce high impact polystyrene by the "in situ bulk" polymerization, adding an organic peroxide as initiator and pellets of polystyrene in some samples. The obtained results are discussed in terms of morphology and mechanical properties.