화학공학소재연구정보센터
Polymer, Vol.175, 320-328, 2019
Alternating crystalline lamellar structures from thermodynamically miscible poly(epsilon-caprolactone) H/D blends
Thermodynamic interaction and non-isothermal crystallization behavior in a series of protiated (H-) and deuterated (D-) poly(epsilon-caprolactone) (PCL) blends have been systematically investigated. The blends were thermodynamically miscible in the melt. The Flory- Huggins interaction parameter (chi) between H- and D-PCL segments was estimated. The hydroxyl groups in the PCL chain-ends were found to contribute significantly to the negative chi values. Combined characterization of small-angle X-ray scattering (SAXS) and small-angle neutron scattering (SANS) revealed that upon slow cooling, unique alternating H-rich and D-rich PCL lamellar structures are formed regardless of the blend ratio, which is attributed to the T-c difference between H- and D-PCLs. While upon rapid cooling, mixed crystals of H- and D-PCLs are predominantly formed. These results provide insightful information on the melt thermodynamics as well as detailed chain arrangements in lamellar crystals for semicrystalline H/D polyester blends.