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RESEARCH PRODUCT

Cooperative self-assembling in statistical copolymers: a new approach to high-temperature thermoplastic elastomers

subject

description

Based on previous work, where it was shown that 4-urazoylbenzoic acid (U4A) groups, which are attached statistically to polybutadiene, form ordered supramolecular arrays in the unpolar polymer matrix, the present work describes the synthesis of a new molecular building block capable of self-assembling in the unpolar polymer matrix. 5-Urazoylisophthalic acid (U35A) groups attached to 1,4-polybutadiene chains cause the formation of a thermoplastic elastomer of improved properties. The clusters of functional groups show an endothermic transition. The melting temperature increases for low levels of modification from 130°C up to 190°C. The mechanical properties (stress–strain and dynamic mechanical) reveal excellent rubbery characteristics and a rubbery plateau which is considerably flatter than those of technical grade thermoplastic elastomers. The IR data indicate that the U35A groups are tetrafunctional with respect to supramolecular self-assembling. Based on detailed knowledge of the structure of the self-assembled domains in U4A groups, a model is developed which describes the observed material properties qualitatively.