Polylactic acid (PLA) and acrylonitrile-butadiene-styrene copolymer (ABS) were selected as the research objects,and the PLA/ABS alloy with different ratios were prepared by melt blending with volume elongational flow extruder.By means of mechanical properties tests,microstructure analysis (scanning electron microscope),thermal analysis (differential scanning calorimetry,thermogravimetry) and thermal mechanical analysis (DMA),the microstructure and properties of PLA/ABS alloy with different ratios at the function of elongational flow were studied.The results show that with the increase of ABS dosage in the alloy,the elongation at break and impact strength of the alloy first increase and then decrease and then increase.SEM shows that the volume elongational flow extruder makes two phases disperse more evenly,and along with the increase of ABS dosage,there appeared "sea-island" structure,continuous phase structure,phase transition and "sea-island" structure in turn.DSC shows that the cold crystallization temperature of PLA/ABS with different ratios are significantly decreased compared with pure PLA;the enthalpy of cold crystallization decreases with the increase of ABS dosage;after the addition of ABS,the crystallinity of PLA increase and the amplitude first increase and then decrease.Thermal stability analysis shows that the addition of ABS increases the heat resistance of the alloy to a certain extent.DMA shows that the compatibility of two phases goes bad first and then goes good with the increase of ABS dosage,and the PLA/ABS (30/70) has the worst compatibility.%选取聚乳酸(PLA)和丙烯腈-丁二烯-苯乙烯(ABS)为研究对象,利用体积拉伸流变挤出机对其进行熔融共混制得了不同配比的PLA/ABS合金.通过力学性能测试分析、微观形貌分析(SEM)、热性能分析(DSC、TG、DTG)、热机械性能分析(DMA)等手段来研究拉伸流场作用对不同配比PLA/ABS合金的微观结构和性能的影响.结果表明,随着合金中ABS的增多,合金的断裂伸长率和冲击强度均出现先增大后减小再增大趋势;SEM表明拉伸流场作用对两相的分散比较均匀,随着ABS的增多依次出现“海-岛”结构、连续相结构、发生相转变并再次出现“海-岛”结构;DSC表明不同配比的PLA/ABS较纯的PLA的冷结晶温度(Tc)显著降低,且随着ABS的增多对应的冷结晶焓逐渐减小,ABS的加入增大了PLA的结晶度且增大幅度先增大后减小;热稳定性分析表明ABS的加入一定程度上增加了合金的耐热性;DMA表明随着ABS含量的增多合金中两相的相容性先由好变差再变好,其中PLA/ABS(30/70)配比的相容性最差.
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