目的 利用分子动力学模拟并分析不同PVA分子链长度下thymol的释放过程和释放机理。方法 研究基体为聚乙烯醇(PVA)，添加抗菌剂thymol共建PVA/thymol聚合物模型，进行分子动力学模拟，分别从均方位移、扩散系数、自由体积角度研究分子链长度分别为40，80，160下thymol在PVA聚合物中的释放过程。结果 thymol分子在PVA中的自由体积分数会随着分子链长度的增加而减小，thymol分子在PVA中的扩散系数也会相应减小，这是因为分子链越长，分子间的相互作用力越大，束缚了链的运动性。结论 不同分子链长度对于包装材料抗菌剂中的释放具有重要影响。在同等条件下，短链结构中thymol分子在PVA中容易释放，且做缓慢蠕动运动而非跳跃扩散运动。

The work aims to simulate and analyze the release process and release mechanism of thymol from different PVA molecular chain lengths, based on molecular dynamics simulation. With polyving akohol as the research matrix, antibacterial (thymol) was added to jointly establish PVA/thymol polymer model to carry out molecular dynamics simulation. Based on the simulation, the release process of thymol in the PVA polymer under the respective molecular chain lengths (40, 80 and 160) was studied with regard to mean square displacement, diffusion coefficient and free volume. The free volume fraction of thymol molecules in PVA decreased with the increase of the molecular chain length, and the diffusion coefficient of thymol molecules in PVA would also decrease accordingly. The longer the molecular chain, the greater the interaction forces between the molecules, and this limited the movement of the chain. Different molecular chain lengths have an important effect on the release of antimicrobial agents in packaging materials. In the short chain structure, it is easy for the thymol molecules in the PVA to release and to slowly move rather than jump under the same conditions.