Anhydride terminated polyisobutylene (PIB) oligomers were synthesized in a one-or two-step process from chlorine terminated oligomers. In the one-step process, chlorine functional oligomers were just heated in the presence of maleic anhydride (MA) for 12 h at 190°C without a catalyst. In the two-step process, the chlorine end functional groups were first converted by selective dehydrochlorination to isopropenylpolyisobutylene end groups with t-BuOK in refluxing tetrahydrofuran during 16 h. In a second step, MA was coupled to the PIB with unsaturated end groups by reacting the oligomer with MA for 12 h at 190°C. These reactions could be followed by i.r. and n.m.r. The PIB-MA obtained had a functionality between 30% and 100%. In order to study the formation of amine functionalities, the PIB-MA was reacted with diamines. The coupling gave an imide bonding.

Segmented block copolymers of polyisobutylene (PIB) and poly(butylene terephthalate) (PBT) were made by condensation polymerization of ~,og-di-anhydride telechelic PIB, with 1,4-butanediol and dimethyl terephthalate. The inherent viscosity of the polymers was between 0.35 and 2.0 dl g-1. The extractability of the polymers with hexane was studied. The thermal behaviour of these polymers was studied by differential scanning calorimetry and dynamic mechanical thermal analysis. PBT-b-PIB had a glass transition temperature of -62°C and a melting temperature of 200-220°C. A shear modulus was found which, at room temperature, increased from 0.4 to 900 MPa with increasing PBT content in the block copolymer. The degradation was followed by measuring the change of inherent viscosity during thermal and hydrolytic treatment. The PBT-b-PIB showed good resistance to thermal and hydrolytic degradation.

Segmented copolymers were obtained through copolymerization of polyamide-4,6 and poly(propylene oxide) (PPOx). An amine-terminated PPOx ('soft') segment of molar mass 430 was reacted with nylon-4,6 salt in an autoclave (30min, 210°C, 7 bar). In this reaction a prepolymer was prepared, which was postcondensed afterwards. In ethanol, a considerable amount of material could be extracted from the solid copolymers of low polyamide content. Extractability was found to be strongly reduced with increasing polyamide content, i.e. increasing length of the polyamide ('hard', crystallizable) segments. Torsional tests showed an extended rubber plateau of fairly constant modulus. Whereas PPOx has a T~ of-60°C, the T~ values of the copolymers were higher as a result of (i) the restricted length of the PPOx segments and (ii) dissolution of uncrystallized polyamide segments in the PPOx phase. The high melting point of polyamide-4,6 was approached by the copolymer of high polyamide content, but the softer copolymers had lower melting points because of insufficient length of the polyamide segments.

A ruthenium tetroxide (RuO4) staining method has been evaluated for segmented polyisobutylene-bpolybutylene terephthalate (PIB-b-PBT). Solution cast films and melt pressed samples have been studied. For comparison PBT has also been studied. PBT and PIB-b-PBT could be stained with RuO4 at room temperature. The observed structures on the PBT and PIB-b-PBT films were spherulitic with lamellae. In some regions in the PIB-b-PBT films large scale phase separation was observed. In the melt pressed PIB-b-PBT samples the spherulitic and lamellar structures were less well developed. The PBT segments appeared to have crystallized out in bundles and the PIB phase was present as microspheres with diameters of 3-6 nm.

Telechelic polyisobutylene with chlorine end-groups was made by cationic polymerization of isobutylene in methylene chloride with difunctional initiators (2,5-dimethoxy-2,5-dimethylhexane and 2,5-diacetyl-2,5dimethylhexane). The structure of these initiators resembles that of polyisobutylene. BC13 and TiCI4 were used as catalysts. The molecular weight of these telechelics was varied between 600 and 3500 g mol-1, with a molecular-weight distribution ranging from 1.3 to 2.1. The materials were characterized by. high-performance liquid chromatography, nuclear magnetic resonance and infra-red spectroscopy.