Contribution of covalent bond force to pressure in polymer melts
Contribution of covalent bond force to pressure in polymer melts
复制标题
DOI：
10.1063/1.456937
复制
发表时间：
1989-09
影响因子：
4.4
通讯作者：
J. Gao;J. H. Weiner
中科院分区：
文献类型：
--
作者：
J. Gao;J. H. Weiner
采用分子动力学方法对聚合物熔体的自由连接有效硬球模型进行了模拟，为了计算的方便，采用了连续的共价势和非共价势。维里定理被用来确定从模拟的熔体压力。在很宽的密度和聚合度范围内，与最近引入的Honnell和Hall状态方程有很好的一致性。原子压被定义为每个原子对系统压缩因子的贡献;它被发现沿着聚合物链的内部原子是均匀的，末端原子的值略有不同。这个统一的值几乎与N（链中的键数）无关，并解释了所观察到的压力对N的微小依赖性。特别注意的是支付的贡献的压力所作的力在共价键的系统。对于大于0.3的填充分数，熔体中约30%的压力来自此源。
Molecular dynamics simulations of the freely jointed effective hard sphere model of a polymer melt are performed, with continuous covalent and noncovalent potentials employed for computational convenience. The virial theorem is used to determine the melt pressure from the simulations. Excellent agreement is found over a wide range of density and degree of polymerization with the recently introduced equation of state of Honnell and Hall. The atomic pressure is defined as the contribution made by each atom to the compressibility factor of the system; it is found to be uniform along the interior atoms of the polymer chain, with slightly different values for the end atoms. This uniform value is almost independent of N, the number of bonds in the chain, and explains the small dependence on N of the pressure that is observed. Particular attention is paid to the contribution to the pressure made by the force in the covalent bonds of the system. For packing fractions greater than 0.3, approximately 30% of the pressure in the melt arises from this source.