CHEMICAL MODIFICATION OF BUTYL RUBBER .2. STRUCTURE AND PROPERTIES OFPOLY(ETHYLENE OXIDE)-GRAFTED BUTYL RUBBER

Poly(ethylene oxide)-graft;ed butyl rubbers (IIR-g-PEOs), which were s ynthesized from potassium salt of polyethylene glycol monomethyl ether (PEGM) and chlorinated butyl rubber, were found to behave like thermo plastic elastomers. The poly(ethylene oxide) (PEG) content of these am phiphilic polymers was ca. 10 wt %, and their PEO lengths were 750, 20 00, and 5000, respectively. The grafted segments of PEO in butyl rubbe r (IIR) aggregated to form the PEO domains in IIR matrix. At constant PEO content, the longer the PEO segment length, the larger the size an d the crystallinity of PEO domains became. This PEO domain worked as a cross-linking site and a reinforcing filler. The degree of swelling i n water of IIR-g-PEO film that was prepared from PEGM-5000 was largest , but its emulsification ability was smallest among them. (C) 1995 Joh n Wiley & Sons, Inc.