Synergistic thermodynamic compatibility of polydimethylsiloxane block in thermoplastic polyurethane for flame retardant materials: Super flexible, highly flame retardant and low smoke release

A method of mixing soft segments was used to solve the thermodynamic incompatibility problem, which provided direction for the synthesis of better-performing silicone-modified thermoplastic polyurethane (TPU). The polytetrahydrofurandiol (PTMG) based TPU blocked by hydroxybutane terminated polydimethylsiloxane (PDMS) was synthesized by the bulk polymerization. Using FTIR fitting, WAXR, DSC and DMA to explore the effect of PDMS on the microstructure of TPU, mechanical tests, TGA, static contact angle and flame retardant tests were used to test the macroscopic properties of TPUs. The results showed that: PDMS had a remodeling effect on the formation of TPU microstructure, which made the fine three-phase structure formed in Si-TPU. PDMS had the effect of increasing elongation at break for TPU, increasing the elongation at break by 173.8%. PDMS reduced the decomposition rate and increased the hydrophobicity with a water contact angle to 111.5°. Moreover, the TPU modified with silicone had good flame retardancy, with the limiting oxygen index (LOI) reaching 27, which reduced the total heat release to less than half of the original and inhibited smoke release.