Acetyl tri-Bu citrate (ATBC) and poly(ethyleneglycol)s (PEGs) with different mol. wts. (from 400 to 10000) were used in this study to plasticize poly(L-lactic acid) (PLA). The thermal and mech. properties of the plasticized polymer are reported. Both ATBC and PEG are effective in lowering the glass transition (Tg) of PLA up to a given concn., where the plasticizer reaches its soly. limit in the polymer (50 wt. % in the case of ATBC; 15-30 wt. %, depending on mol. wt., in the case of PEG). The range of applicability of PEGs as PLA plasticizers is given in terms of PEG mol. wt. and concn. The mech. properties of plasticized PLA change with increasing plasticizer concn. In all PLA/plasticizer systems studied, when the blend Tg approaches room temp., a stepwise change in the mech. properties of the system is obsd. The elongation at break drastically increases, whereas tensile strength and modulus decrease. This behavior occurs at a plasticizer concn. that depends on the Tg-depressing efficiency of the plasticizer.
Thermal and mechanical properties of plasticized poly(L-lactic acid)
2003
Abstract
Acetyl tri-Bu citrate (ATBC) and poly(ethyleneglycol)s (PEGs) with different mol. wts. (from 400 to 10000) were used in this study to plasticize poly(L-lactic acid) (PLA). The thermal and mech. properties of the plasticized polymer are reported. Both ATBC and PEG are effective in lowering the glass transition (Tg) of PLA up to a given concn., where the plasticizer reaches its soly. limit in the polymer (50 wt. % in the case of ATBC; 15-30 wt. %, depending on mol. wt., in the case of PEG). The range of applicability of PEGs as PLA plasticizers is given in terms of PEG mol. wt. and concn. The mech. properties of plasticized PLA change with increasing plasticizer concn. In all PLA/plasticizer systems studied, when the blend Tg approaches room temp., a stepwise change in the mech. properties of the system is obsd. The elongation at break drastically increases, whereas tensile strength and modulus decrease. This behavior occurs at a plasticizer concn. that depends on the Tg-depressing efficiency of the plasticizer.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
