摘要
由于壳聚糖和淀粉在机械、力学及热学特性上具有良好的互补作用,研究两者组分之间的共混性质具有重要的意义。为了预测壳聚糖与淀粉的共混相容性,本文在恒温恒压(NPT)系统和COMPASS力场下,利用分子动力学模拟方法,对直链淀粉/壳聚糖(完全脱乙酰化)在不同质量比下的Flory-Huggins参数χ、原子对之间的径向分布函数及聚合物链的扩散系数进行模拟。研究结果显示,在298 K下,相对直链淀粉/壳聚糖质量比为70/30和50/50而言,质量比为30/70时,其共混体系的χ值最小,分子链的分子间作用力最大,两者聚合物链段的扩散系数都为最大,表明此时的共混相容性要优于质量比为70/30和质量比为50/50的共混体系;直链淀粉能够降低壳聚糖体系中链段的弛豫速率和结晶速率,从而抑制其聚合物链的分子流动性。
Miscibility in chitosan/amylose blends is of great significance in research, as chitosan and starch show good complementary effects in terms of mechanical and thermal properties. In order to predict the miscibility of chitosan with starch, the Flory-Huggins parameter χ, radial distribution function of atom pair, and diffusion coefficient of the polymer chain were simulated by molecular dynamics simulation, and under the condensed-phase optimized molecular potential for atomistic simulation studies(COMPASS) force field and NPT ensemble. Results indicated that the value of parameter χ was the smallest, the bonding force of molecular chains and diffusion coefficient between amylose and chitosan chain segment were the largest when the mass ratio of amylose/chitosan was 30/70 at the same temperature when compared to the mass ratios of 70/30 and 50/50. This showed that the miscibility of the binary system(mass ratio of 30/70) was better than that of the other two systems. The addition of amylose into chitosan suppressed the mobility of chitosan chains due to a decrease in crystallization and relaxation rate of chitosan caused by amylose chain segments.
出处
《现代食品科技》
EI
CAS
北大核心
2015年第8期136-142 210,共8页
Modern Food Science and Technology
基金
国家自然科学基金资助项目(81360205)
农业部热带作物产品加工重点实验室开放基金(KLTCPP-201404)资助
