氯仿混合溶剂对聚乳酸薄膜性能的影响
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摘要
在聚乳酸(PLA)良溶剂氯仿中分别添加不良溶剂乙醇、丙酮及非溶剂己烷,配成系列混合溶剂,将PLA溶于系列氯仿混合溶剂中,通过溶剂浇铸法制备PLA膜,研究氯仿混合溶剂对PLA膜性能的影响。结果表明,PLA溶于各种混合溶剂制备出来的PLA膜具有不同的结晶度,PLA溶于氯仿/己烷混合溶剂所铸造的膜结晶度(47.5%)略高于PLA溶于氯仿/丙酮的膜结晶度(44.2%)和氯仿/丙酮所铸造的膜的结晶度(43.5%),明显高于PLA溶于纯氯仿的膜结晶度(24.8%)。力学性能测试表明,PLA溶于氯仿/己烷、氯仿/丙酮、氯仿/乙醇与溶于纯氯仿相比断裂拉伸强度得提高了,断裂伸长率减小了。光学性能表明,PLA溶于氯仿/乙醇混合溶剂所铸造的膜亮度最高,PLA溶于各种混合溶剂的膜泛红和泛黄程度几乎相同,膜的颜色差异小。
In a polylactic acid(PLA) good solvent chloroform, a poor solvent ethanol, acetone and non-solvent hexane were added to prepare a series of mixed solvents, PLA was dissolved in a series of chloroform mixed solvents, and a PLA film was prepared by solvent casting to study chloroform mixing. The effect of solvent on the properties of PLA membranes. The results show that the PLA film prepared by dissolving PLA in various mixed solvents has different crystallinity. The film crystallinity(47.5%) of PLA dissolved in chloroform/hexane mixed solvent is slightly higher than that of PLA dissolved in chloroform/acetone. The crystallinity of the film(44.2%) and the crystallinity of the film cast by chloroform/acetone(43.5%) were significantly higher than those of PLA film dissolved in pure chloroform(24.8%). The mechanical properties test showed that PLA dissolved in chloroform/hexane, chloroform/acetone, and chloroform/ethanol had higher tensile strength at break and less elongation at break than chloroform/ethanol. The optical properties show that the film cast by PLA dissolved in chloroform/ethanol mixed solvent has the highest brightness, and the degree of redness and yellowing of PLA in various mixed solvents is almost the same, and the color difference of the film is small.
In a polylactic acid(PLA) good solvent chloroform, a poor solvent ethanol, acetone and non-solvent hexane were added to prepare a series of mixed solvents, PLA was dissolved in a series of chloroform mixed solvents, and a PLA film was prepared by solvent casting to study chloroform mixing. The effect of solvent on the properties of PLA membranes. The results show that the PLA film prepared by dissolving PLA in various mixed solvents has different crystallinity. The film crystallinity(47.5%) of PLA dissolved in chloroform/hexane mixed solvent is slightly higher than that of PLA dissolved in chloroform/acetone. The crystallinity of the film(44.2%) and the crystallinity of the film cast by chloroform/acetone(43.5%) were significantly higher than those of PLA film dissolved in pure chloroform(24.8%). The mechanical properties test showed that PLA dissolved in chloroform/hexane, chloroform/acetone, and chloroform/ethanol had higher tensile strength at break and less elongation at break than chloroform/ethanol. The optical properties show that the film cast by PLA dissolved in chloroform/ethanol mixed solvent has the highest brightness, and the degree of redness and yellowing of PLA in various mixed solvents is almost the same, and the color difference of the film is small.
引文
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[2]Mano J F,Ribelles J L G,Alves N M,et al.Glass transition dynamics and structural relaxation of PLLA studied by DSC:Influence of crystallinity[J].Polymer,2005,46(19):8258-8265.
[3]Delpouve N,Stoclet G,Saiter A,et al.Water Barrier Properties in Biaxially Drawn Poly(lactic acid)Films[J].Journal of Physical Chemistry B,2012,116(15):4615-4625.
[4]Pillin I,Montrelay N,Grohens Y.Thermo-mechanical characterization of plasticized PLA:Is the miscibility the only significant factor?[J].Polymer,2006,47(13):4676-4682.
[5]Zaman H U,Song J C,Park L S,et al.Poly(lactic acid)blends with desired end-use properties by addition of thermoplastic polyester elastomer and MDI[J].Polymer Bulletin,2011,67(1):187-198.
[6]Pezzin A P T,Van Ekenstein G O R A,Zavaglia C A C,et al.Poly(para‐dioxanone)and poly(L‐lactic acid)blends:thermal,mechanical,and morphological properties[J].Journal of Applied Polymer Science,2010,88(12):2744-2755.
[7]Furuhashi Y,Yoshie N.Stereocomplexation of solvent-cast poly(lactic acid)by addition of non-solvents[J].Polymer International,2012,61(2):301-306.
[8]Sarasua J R,Arraiza A L,Balerdi P,et al.Crystallinity and mechanical properties of optically pure polylactides and their blends[J].Polymer Engineering&Science,2005,45(5):745-753.
[9]Karst D,Yang Y.Using the solubility parameter to explain disperse dye sorption on polylactide[J].Journal of Applied Polymer Science,2005,96(2):416-422.