注塑和3D打印聚乳酸/乙烯-醋酸乙烯共聚物共混物形态和韧性

Morphologies and Toughening Modification of PLA/EVA Blends Based on Injection Molding and 3D Printing

将聚乳酸与韧性聚合物共混是改善聚乳酸韧性的有效途径。文中报道了韧性良好的乙烯-醋酸乙烯共聚物(EVA)与聚乳酸共混,获得增韧聚乳酸。发现EVA对聚乳酸的增韧效果与成型加工方法有关:注塑成型的EVA/聚乳酸共混物中,EVA呈球状分布,可以明显提高冲击强度;3D打印成型的EVA/聚乳酸共混物中,EVA呈独特微纤结构,对增韧有利,可以克服3D打印在制品中引入孔隙的负面影响,提高聚乳酸的冲击强度。

Melt-blending with ductile polymers is a versatile and effective method for toughening modification of poly(lactic acid)(PLA). Ethylene-vinyl acetate copolymer (EVA) could be a promising toughening agent for PLA because of its high ductility and low cost. In this work, it is found that different processing methods have diverse influences on toughening. Based on injection molding, EVA shows a spherical distribution and PLA is well toughened by EVA with an increasing impact strength. For 3D printing, it is interesting to identify a microfibrillar phase of EVA in the PLA matrix, which is favorable for toughening of PLA, acting as a compensation of the negative effect of voids on toughening due to the processing of 3D processing.