为了解决在熔融沉积成型(FDM)中产生的聚碳酸酯(PC)制品出现变形、翘曲的缺陷问题,通过双螺杆挤出机熔融共混将少量的乙烯-醋酸乙烯酯共聚物(EVA)添加到聚碳酸酯/聚对苯二甲酸-己二酸丁二酯(PC/PBAT)共混物中。着重研究了EVA对PC/PBAT共混物热性能、流动性、力学性能以及FDM3D打印性能的影响。结果表明:EVA与纯PC或PC/PBAT共混物的相容性较差,形成微米尺度的相分离。EVA对PC/PBAT的流动性没有明显的影响。此外,适当少量EVA的加入会在一定程度上提高PC/PBAT共混物的弹性模量、断裂强度,降低断裂伸长率。然后,将含有EVA的PC/PBAT共混物制备成为适用于FDM的丝材后,测试其打印性能。结果表明:EVA的加入可以有效地降低PC材料在FDM中由于材料内应力释放而导致的翘曲状况。在喷头温度230℃,底板温度100℃时,4%含量的EVA材料可将制件的翘曲率从1.17m-1降至0.18m-1。
To solve the problem of deformation and warpage defects of polycarbonate (PC) in fused deposition modelling (FDM),a small amount of Ethylene-Vinyl Acetate copolymer (EVA) was added to PC/poly (butylene adipate-co-terephthalate)(PBAT) blends by a melt blending process using a twin screw extruder.The effects of EVA on the thermal properties,flowability,mechanical properties,and FDM 3D printing performance of the PC/PBAT blends were studied.The results showed that the compatibility of EVA with pure PC or PC/PBAT was poor,and phase separations on a microscopic scale were observed.EVA had no significant effect on the flowability of PC/PBAT blends.On the other hand,the presence of EVA increased the tensile modulus and fracture strength of the blends,while the elongation at break of the blends decreased.The PC/PBAT/EVA blends were processed into FDM filaments and the 3D printing properties of the filaments were evaluated.It was found that adding EVA to PC/PBAT blends could effectively reduce the warpage issues of PC/PBAT blends caused by the release of internal stress during FDM 3D printing.At a printing nozzle temperature of 230℃and a build platform temperature of 100℃,the addition of 4% EVA significantly reduced the part warpage curvature from 1.17 m-1 to 0.18m-1.
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