Crystallization behaviors of biodegradable poly(l-lactic acid)/graphene oxide nanocomposites from the amorphous state

Crystallization behaviors of biodegradable poly(l-lactic acid) (PLLA)/graphene oxide (GO) nanocomposites at different GO loadings from the amorphous state were investigated in detail in this work. During the nonisothermal cold crystallization, the crystallization peak temperature of PLLA shifts to low temperature range in the nanocomposites with increasing the GO loading relative to neat PLLA despite heating rate; moreover, the overall nonisothermal cold crystallization has been accelerated with increasing heating rate for both neat PLLA and its nanocomposites. In addition, the variations of crystallization enthalpy of PLLA during isothermal and nonisothermal cold crystallization processes were also discussed. Relative to neat PLLA, the overall isothermal cold crystallization rate of PLLA is increased with increasing the GO loading in the nanocomposites despite crystallization temperature. The crystallization rate becomes faster with increasing crystallization temperature, while the crystallization mechanism and crystal structure remain unchanged for both neat PLLA and its nanocomposites.