(721h) Thermoplastic Polydimethylsiloxane Realized By Hydrogen-Bond Networks through L-Phenylalanine Terminals

Thermoplastic polydimethylsiloxane (PDMS) containing L-phenylalanine at the end of the molecule was synthesized by the liquid-phase synthesis method with an Fmoc-protected amino acid, followed by the condensation polymerization. In order to investigate the mechanical and the thermoplastic properties of the newly synthesized PDMS with L-phenylalanine, the tensile testing and the dynamic mechanical analysis (DMA) were conducted. From the results of the tensile testing, the stress at break of the PDMS with L-phenylalanine nearly became 7 times higher than that of the PDMS without L-phenylalanine. The DMA results revealed that the PDMS could maintain its storage modulus for 3 cycles, while the melting temperature was also kept at ~120°C. Moreover, the mechanical property was analyzed through 2 remolding cycles, and it was found that the PDMS could almost maintain its mechanical property after the heat remolding. In detail, the strain at break and the stress at break of the sample after the second cycle maintained above 90% of the values observed for the first remolded sample. As for PDMS without L-phenylalanine, the Young’s modulus and the stress at break of the sample after the second cycle maintained above 90% of those of the original (non-remolded) sample. As for PDMS with L-phenylalanine, the stress at break of the sample after the second cycle also maintained over 90% of that of the original (non-remolded) sample.