Polyurethane Foams From a Triblock Copolymer Polyol With CO ₂ ‐Derived, High‐ T

ABSTRACT

We report the first polyurethane foams (PUFs) containing polyol segments with a glass transition temperature ( T _g ) above 100°C. The PUF properties are tuned by incorporating polyol with 0–15 wt% CO ₂ ‐derived poly(cyclohexene carbonate) (PCHC) segments ( T _g  = 104°C), and the PUF thermal resistance is markedly improved. The network PUFs are synthesized using a triblock copolymer polyol with PCHC hard segments and a polycaprolactone (PCL) soft segment (PCHC‐ b ‐PCL‐ b ‐PCHC; 16 wt% CO ₂ ‐derived). The room‐temperature polyol is liquid, and its viscosity is adjusted by adding a low‐viscosity PCL homopolymer polyol. Incorporating PCHC segments produces denser PUFs with smaller, more uniform cells. Increasing PCHC content from 0 to 15 wt% decreases PCL crystallinity from 29% to 5%. Compared to a PCHC‐free PUF, at room temperature, a 15 wt% PCHC PUF exhibits ~40% reductions in compression modulus and compression strength (at 25% strain); however, it exhibits a fivefold increase in compression modulus and a 210% rise in compression strength at 70°C, where crystallinity is absent. Thus, certain properties of PCHC‐containing PUFs are much less temperature‐dependent than those of PCHC‐free PUFs: 15 wt% PCHC PUFs retain 54% of their room‐temperature compression modulus at 70°C, but PCHC‐free PUFs retain only 7%.