Effect of poly(ε-caprolactone) glycol soft segment relative molecular mass on properties of polyurethane elastomer based on poly(ε-caprolactone) glycol

Three kinds of poly(ε-caprolactone) glycols with different relative molecular mass were synthesized from s-caprolactone monomer by ring-opening polymerization. A series of casting poly(ε-caprolactone) urethane elastomers (CPUE) were produced with toluene diisocyanate and dimethythiotoluene diamine by two-stage process and characterized by means of electronic universal testing machine, differential scanning calorimeter, dynamic thermal mechanical instruments and visible spectrophotometer. Relative molecular mass of poly(ε-caprolactone) glycol soft segment affects properties of CPUE noticeably. CPUE with lower relative molecular mass of poly(ε-caprolactone) glycols soft segment shows more plastic-like stiffness. Hardness, modulus, tensile and tear strength of CPUE decrease significantly with increase of poly(ε-caprolactone) glycols soft segment relative molecular mass, but resilient properties improve greatly. The crystallization of poly(ε-caprolactone) glycols soft segments results in higher heat build-up and lower light transmittance.