丙烯酸丁酯-N-羟甲基丙烯酰胺无规共聚物增韧PLA的结构与性能

Structure and Properties of PLA Toughened by Poly( butyl acrylate-co-N-methylolacrylamide)

前期研究表明聚丙烯酸丁酯(PBA)能增韧聚乳酸(PLA)并保持PLA的透明性。为了进一步提高PBA与PLA的相容性,在PBA分子中引入极性基团N-羟甲基丙烯酰胺(NHMAAm)。在丙酮溶液中以偶氮二异丁腈自由基引发丙烯酸丁酯和N-羟甲基丙烯酰胺,合成了丙烯酸丁酯和N-羟甲基丙烯酰胺无规共聚物P(BA-co-NHMAAm),然后通过哈克流变仪与PLA熔融共混。凝胶渗透色谱、傅里叶变换红外光谱和热重分析表明,PBA分子链中成功引入了N-羟甲基丙烯酰胺,并且共聚物适应PLA的加工过程。力学性能测试和扫描电子显微镜照片揭示,N-羟甲基丙烯酰胺的引入能增加PBA与PLA的相容性,N-羟甲基丙烯酰胺的含量越高相容性越好。PLA的拉伸强度随P(BA-coNHMAAm)含量的增加而略有降低,但断裂伸长率和冲击强度大幅提高。拉伸强度、冲击强度和断裂伸长率随着P(BA-co-NHMAAm)中NHMAAm比例的增加而增大。

Previousstudies indicated that polylactide （PLA） could be toughened by polybutylacrylate （PBA） efficiently and its transparency maintained. In order to further improve the miscibility between PLA and PBA, polar groups of N-hydroxymethyl acrylamide （NHMAAm） were introduced in the molecule chain of PBA. A random copolymer of butyl acrylate and N-hydroxymethyl acrylamide [ poly （BA-co-NHMAAm） ] was successfully prepared by free radical polymerization in the presence of 2, 2＇-azoisobu-tyronitrile （ AIBN ）, permeatmn then PLA and poly （BA-co-NHMAAm） were melt blended using Haake rheometer. Gel chromatography （ GPC ）, Fourier transform infrared （ FTIR ） and thermogravimetric analysis （TGA） were used to characterize poly （BA-co-NHMAAm）. The results demonstrated that NHMAAm was triumphantly copolymerized with BA and the copolymer matched up with the process of PLA. Mechanical testing and scanning electron micrographs revealed that N-methylol acrylamide improved the miscibility between PLA and PBA. Tensile strength of PLA slightly decreased with increasing poly （BA-co-NHMAAm） content, but the elongation at break and impact strength enhanced dramatically. Tensile and impact strength and longation at break increased with increasing of NHMAAm proportion in P（BA-co-NHMAAm）.