A melt-drawing technique was applied to crystalline silicone, poly(tetramethyl-p-silphenylenesiloxane) (PTMPS) containing a rigid phenylene ring in the main chain. The resultant melt-drawn membrane had double-melting endotherms located at the usual 130 °C and the higher temperature of 160 °C. The higher melting temperature for PTMPS is expected, but has not been experimentally observed. A series of in situ structural analyses during heating also reveal that it is attributed to the melting of the extended chain crystals within the melt-drawn PTMPS membrane. Due to the highly oriented crystalline structure, the obtained melt-drawn PTMPS membrane is transparent but exhibits an excellent tensile modulus and strength of 2 GPa and 20 MPa, which are a few hundred times greater than those of commercial silicone elastomers.
