Experimental and theoretical study of the use of multifunctional initiators in the high impact polystyrene bulk process

DIANA ESTENOZ; EMILIO BERKENWALD; PABLO ACUÑA; LAURA LAGANA; GRACIELA MORALES; JUAN MAFFI

POLYMER ENGINEERING AND SCIENCE

JOHN WILEY & SONS INC

Lugar: New York; Año: 2018 vol. 58 p. 198 - 212

0032-3888

The performance of three multifunctional peroxide initiatorsin a bulk high impact polystyrene (HIPS) process wasexperimentally and theoretically investigated. For theexperimental work, a series of batch reactions was carriedout, comprising the main stages of an industrial HIPSbulk process using multifunctional initiators with varyingfunctionality and structure: DEKTP (cyclic trifunctional),PDP (cyclic bifunctional) and L331 (linear bifunctional).The theoretical work consisted of the development of acomprehensive, generic yet detailed mathematical modelfor bulk HIPS polymerization using multifunctional initiators.The model predicts the evolution of the main polymerizationvariables (including conversion, molecularweights, grafting efficiency) as well as the detailed molecularstructure of the polymeric species (free polystyrene,residual polybutadiene and graft copolymer), and the meltflow index of the obtained HIPS. The model was adjustedand validated using experimental results, obtaining agood agreement between measured and predicted values.The model was used to theoretically evaluate the effect ofthe operating conditions on the molecular and physicalcharacteristics of the obtained polymer. It was found thatthe use of multifunctional initiators leads to high polymerizationrates and high molecular weights simultaneously,while promoting the grafting of styrene onto butadiene,generating a microstructure with salami-type morphologies.