The Effect of Mold Temperature on the Performance of Injection Molded Poly(lactic acid)‐Based Bioplastic

Abstract

This research investigates the effects of processing parameters, namely molding temperature on the mechanical performance of impact‐modified poly(lactic acid) (PLA). Polymer crystallization dictates many of the final properties of the material. Increasing the mold temperature, crystallization may progress to a further stage, increasing crystallinity. Molding at a lower temperature, and producing a highly amorphous polymer can increase the mechanical properties, namely elongation and impact strength. Molding at 30 versus 90 °C improved the elongation from 22 to 243% and the impact strength from 67 to 133 J · m−1. This improvement is not without its drawbacks. By molding at 30 °C, the polymer becomes very amorphous, and thus is more susceptible to unwanted processes such as physical aging.

Perspective on Polylactic Acid (PLA) based Sustainable Materials for Durable Applications: Focus on Toughness and Heat Resistance

“…In some cases, increased number of spherulite structures with low spherulite size was believed to consume more energy and thus increase the impact strength of PLA samples containing nucleating agents. On the contrary, Vadori et al 94 have showed increasing the mold temperature of PLA decreases the impact toughness and percentage elongation of high impact PLA. Unique approach of using epoxy based PolyJet mold instead of steel mold for conventional injection molding to produce PLA parts with high crystallinity has been proposed to offer promising results ( Table 2).…”

Heat resistance of new biobased polymeric materials, focusing on starch, cellulose, PLA, and PHA

“…A higher mold temperature can increase the crystallization, but it can also effect the mechanical properties. Vadori et al . showed that the elongation at break decreased from 243 to 22% with increasing mold temperatures from 30 to 90°C.…”

Use of the Taguchi Method for Optimization of Poly (Butylene Terephthalate) and Poly (Trimethylene Terephthalate) Blends through Injection Molding

“…It is interesting to note that the melt enthalpy decreases with increasing mold temperature. This is an opposite response to that of many other polymers such as PLA (Vadori et al, 2013) and PTT (Chen et al, 2003) in which ahigher mold temperature produces alarger degree of crystallization.…”