油类分子在棉纤维上吸附的分子模拟研究

采用分子动力学方法,以水溶性分子作对比研究了油类分子在棉纤维上的吸附行为。不同压力下的吸附等温线表明,油类大分子在100 kPa内吸附量很快达到最大值,当高于100 kPa时吸附量基本变化不大。由于水溶性小分子六元环和纤维的相互作用较强,吸附量最大;油溶性分子空间位阻较大,吸附量较小。由吸附能分布来看,水溶性L-阿拉伯糖吸附相互作用比较单一;其他各油类大分子吸附相互作用较复杂。由吸附构型得知他们以平铺的方式吸附到纤维表面。L-阿拉伯糖,正构十八烷吸附能绝对值较小,主要为物理吸附。小分子六元环的阿拉伯糖,结合能最高,范德华力和静电力的影响较大;单链疏水烷烃次之,双链疏水分子结合能较小;三链分子其结合能最低,吸附量最小。

Molecular simulation study on adsorption from oil molecules onto cotton fibers

Molecular dynamics was used to simulate the adsorption of oil molecules on cotton fibers.Under different pressure,the adsorption isotherms showed that the adsoption capacity of oil molecules increased quickly in 100 kPa.When more than 100 kPa,the adsoption capacity would not change.There were strong interactions between six-membered ring of water-soluble molecules and fibers,the loadings were largest.Oil molecules had larger steric and the loadings were smaller.From the figures of potential energy distribution,the interactions between water-soluble molecules and fibers were simple while the oil molecules were more complex.It was known that they adsorbed onto the fiber surface by the tiled way.The absolute value of adsorption energy of L-arabinose,octadecane was smaller,they were mainly physical adsorption.Six-membered ring of small molecule L-arabinose had the highest binding energy,the van der Waals and electrostatic gave a greate contrabutions.The binding energy of single hydrophobic hydrocarbon chain was lower,then was double-stranded molecule.The binding energy of three-chain molecule was lowest,it had the minimum adsorption capacity.