Thermoplastic elastomers based on oligo(β-alanine) grafted poly(isobutylene-co-isoprene) were synthesized and studied. The mechanical properties were investigated by the means of uniaxial tensile test and cyclic test. The strain softening process is quite significant for all samples and final extensions are over 900% strain. The modulus and toughness increase dramatically with the repeat units of monodisperse oligo(β-alanine), the increments of toughness can be ascribed to the breaking and reforming of additional H-bond. In cyclic test, hysteresis for all samples are low at small strain (&lt; 200 %), then increase sharply to a plateau, in which longer β-alanine segments will dissipate more energy at large strain (&gt; 200%). Dynamic mechanical analysis (DMA) were carried to study the thermo-mechanical properties of oligo(β-alanine) grafted poly(isobutylene-co-isoprene). A flat rubbery plateau was observed in tri(β-alanine) grafted sample, the dynamic modulus E’ was found keeping around 12 MPa until a sharp melt transition occurred at 160 °C. Furthermore, high temperature mechanical test showed tri(β-alanine) and tetra(β-alanine) grafted sample provide considerable extendibility over 700 % strain at 100 °C, and the tensile stress reached 8 MPa at this temperature. In addition, samples prepared by heat compression and solvent cast are studied and compared.

Synthesis, processing and mechanical properties of monodisperse oligo(β-alanine)-grafted poly(isobutylene-co-isoprene) thermoplastic elastomer

252nd National Meeting (2016)

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