Flow Temperature of Poly(Lactic Acid) Gel in Solvents with Different Solubility

抄録

Poly(L-lactid acid) (PLLA) forms complex crystals (ε-crystal) with some solvents including N,N-dimethylformamide (DMF), and can be easily gelled in such solvents. The solvent of these gels can be exchanged to some other solvents which do not form ε-crystal with PLLA. The flow temperatures of PLLA gels after exchanging DMF to various solvents were investigated to clarify the relation between the exchangeability and the solubility of solvents to PLLA. After changing the ε-crystals to α-crystals (crystal form of PLLA in films without special treatments) by immersing the gels into 1-propanol, the flow temperatures of PLLA gels could be expected by Hansen solubility parameters. The results suggest that the exchangeability of the solvent of the PLLA gel is determined both by the solubility to PLLA and the ability of the new solvent to induce the change from ε-crystals to α-crystals.