Crystallization behavior of poly(lactic acid)/elastomer blends

Abstract

Differential Scanning Calorimetry (DSC) was used to evaluate the crystallization behavior of poly(lactic acid) and its blends with elastomer. It has been observed that the cold crystallization temperature of the blends decreased as the weight fraction of elastomer increased as well as the onset temperature of cold crystallization also shifted to lower temperature. In non-isothermal crystallization experiments, the crystallinity of poly(lactic acid) increased with a decrease in the heating and cooling rate. The melt crystallization of poly (lactic acid) appeared in the low cooling rate (1, 5 and 7.5°C/ min). The presence of low elastomer tends also to increase the crystallinity of poly (lactic acid). The DSC thermogram at ramp of 10°C/min showed the maximum crystallinity of poly(lactic acid) is 36.95% with 20 wt% elastomer contents in blends. In isothermal crystallization, the cold crystallization rate increased with increasing crystallization temperature in the blends. The Avrami analysis showed that the cold crystallization was in two stages process and it was clearly seen at low temperature. The Avrami exponent (n) at first stage was varying from 1.59 to 2 which described a one-dimensional crystallization growth with homogeneous nucleation, whereas at second stage was varying from 2.09 to 2.71 which described the transitional mechanism to three dimensional crystallization growth with heterogeneous nucleation mechanism. The equilibrium melting point of poly (lactic acid) was also evaluated at 176°C.

Synthesis of grafted flocculants based on several kinds of starch and its performance in water turbidity removal

“…Copolymerization involves chemical reaction by adding a functional group to enhance chemical properties, i,e: hydrophilicity, hydrophobicity, etc. [4].…”

Effect of wood flour as nucleating agent on the isothermal crystallization of poly(lactic acid)

“…[9,10] Thus, it is necessary to improve the crystallization rate of PLA. So far, numerous researchers have mainly focused on blending PLA with a nucleating agent [11][12][13][14][15] or other flexible polymers, [16][17][18][19][20] which are effective ways to enhance the crystallization rate of PLA.…”

Preparation and characterization of poly(lactic acid)/elastomer blends prepared by melt blending technique

“…The American Society for Testing and Materials (ASTM) samples were prepared as described in our previous article. 9 Characterization Thermal treatment (annealing). Annealing was carried out by placing the molded samples into an oven (Heraeus) at 80 C. The temperature of annealing was fixed at the temperature above where the cold crystallization begins.…”

“…In this article, based on our previous investigation on the crystallization behavior of PLA/ elastomer blends, 9 we investigated the effect of elastomer on PLA properties and the effect of thermal treatment (annealing) on crystallization and mechanical properties of PLA/elastomer blends. The effect of elastomer incorporating on the thermal properties of blends was studied by differential scanning calorimetry (DSC).…”