IN-SITU COMPATIBILIZATION OF LOW-DENSITY POLYETHYLENE AND POLYDIMETHYLSILOXANE RUBBER BLENDS USING ETHYLENE METHYL ACRYLATE COPOLYMER AS A CHEMICAL COMPATIBILIZER

The effect of the ethylene-methylacrylate copolymer as a chemical comp atibilizer in the 50:50 blend of low-density polyethylene (LDPE) and p olydimethylsiloxane rubber (PDMS) has been studied in detail. Ethylene -methylacrylate (EMA) reacted with PDMS rubber during melt-mixing at 1 80-degrees-C to form EMA-grafted PDMS rubber (EMA-g-PDMS) in situ, whi ch acted as a compatibilizer in the LDPE-PDMS rubber blend. An optimum proportion of the compatibilizer (EMA) was found to be 6 wt % based o n results of dynamic mechanical analysis, adhesion studies, and phase morphology. Lap shear adhesion between the phases increased significan tly on incorporation of 6 wt % of EMA. Dynamic mechanical analysis sho wed a single glass transition (T(g)) peak at -119-degrees-C. This was further supported by X-ray diffraction studies, which exhibited a rema rkable increase in the degree of crystallinity and phase morphology an d showed a drastic reduction in the size of the dispersed phase at the optimum concentration of EMA. (C) 1993 John Wiley & Sons, Inc.