热塑性纤维素与PVA混溶性的分子动力学模拟

Molecular dynamics simulation of the miscibility of thermoplastic cellulose with PVA

首次提出了将氧化还原改性纤维素(Oxidation-reduction modified cellulose,ORC)与聚乙烯醇(Poly(vinyl alcohol),PVA)共混进行制备复合材料,并采用分子动力学模拟研究了ORC与PVA的混溶性.对分子链间相互作用能和氢键数量分析发现,随着改性程度增加,ORC与PVA会产生更强烈的相互作用,这促进了组分间的混溶.当ORC的改性程度达到40%后,ORC与PVA的溶解度参数差值为2.02(J/cm^(3))^(1/2),达到混溶条件.根据Flory-Huggins理论确定了醇解度为88%和99%的PVA与ORC的混溶性,结果表明PVA(88%)与ORC的混溶性更好.对共混体系中形成氢键原子的径向分布函数分析发现,醋酸乙烯酯重复单元上的羰基更倾向与ORC形成分子链间氢键,而乙烯醇重复单元上的羟基更倾向形成分子链内氢键,这促使PVA(88%)/ORC共混体系中形成更多的分子链间氢键,从而混溶性更好.研究结果可为ORC/PVA复合材料的制备提供理论指导.

For the first time,oxidation-reduction modified cellulose(ORC)was proposed to be blended with poly(vinyl alcohol)(PVA)for the preparation of composites.Molecular dynamics simulation(MD)was used to study the miscibility of ORC with PVA.Analysis of the intermolecular interaction energy and the number of hydrogen bonds revealed that the modification enhances the interaction between ORC and PVA,which promotes miscibility between the components.When the degree of modification of ORC reached 40%,the difference in solubility parameter between ORC and PVA was 2.02(J/cm^(3))^(1/2),reaching the miscibility condition.The miscibility of ORC with 88% and 99% alcoholised PVA was investigated according to the Flory-Huggins theory.The results showed better miscibility of PVA(88%)with ORC.Analysis of the radial distribution function of the atoms forming hydrogen bonds in the blended system revealed that the carbonyl group on vinyl acetate is more inclined to form intermolecular hydrogen bonds with ORC,while the hydroxyl group on vinyl alcohol is more inclined to form intramolecular hydrogen bonds.Therefore,more intermolecular hydrogen bonds were formed in PVA(88%)/ORC blends,resulting in better miscibility.The results can provide theoretical guidance for the preparation of ORC/PVA composites.