IN-SITU POLYMER BLENDS VIA CHAIN TRANSFER LIVING POLYMERIZATION (CTLP)

Abstract

In-situ polymer blends of polystyrene (PS)/poly(methyl methacrylate) (PMMA) with controlled and variable different compositions and molecular weights were found to be successfully synthesized by ''chain transfer living polymerization (CTLP)'' methodology by a combination of size-exclusion chromatographic analysis, differential scanning calorimetry (DSC), UV/Vis and H-1 NMR spectroscopy, and optical microscopic analysis. The PMMAs prepared in tetrahydrofuran (THF) in the presence of polystyrene exhibit highly syndiotactic stereoregularity (over 70 mol-%) and a glass transition temperature over 120 degrees C. A dispersed morphology was found even for blends with over 31 vol.-% of the weight fraction of one component due to the discrepancy in the molecular weights of two components in the PS/PMMA blends. A ternary polymer blend system having PS/PMMA/PS -block- PMMA can be generated by control of the concentration of fluorene as the chain transfer agent in the CTLP.