SBS增韧石蜡/增塑剂共混相容性的分子动力学模拟

增韧石蜡应用于高聚物粘结炸药(PBX)可提高其力学性能,设计了四种增韧石蜡与增塑剂的配方,建立了增韧石蜡(Wax)与邻苯二甲酸二丁酯(DBP)、癸二酸二辛酯(DOS)、硝化甘油(NG)和乙酰基柠檬酸三丁酯(ATBC)的共混模型,采用分子动力学方法模拟研究了增韧石蜡与增塑剂的相容性以及共混体系中分子间相互作用的本质。结果表明,通过溶度参数、可混合性模拟、结合能以及分子间径向分布函数四个判据可综合评价苯乙烯-丁二烯-苯乙烯嵌段共聚物(SBS)增韧石蜡与增塑剂的相容性。其中溶度参数模拟值与实验值的相对误差在3%以内;可混合性模拟可以快速预判两种物质之间的相容性;ATBC与SBS增韧石蜡的结合能最大,为2.7 k J·g~(-1);SBS增韧石蜡与增塑剂之间相互作用的本质是范德华力和静电力,以范德华力为主。3种增塑剂与SBS增韧石蜡的相容性优劣次序为ATBCDOSDBP,NG与SBS增韧石蜡不相容。

Molecular Dynamics Simulation on Compatibility of SBS Toughened Paraffin Wax/Plasticizer Blends

Toughened paraffin wax applied in polymer bonded explosives(PBXs) is mainly to improve its mechanical properties. In this paper, based on the study of toughened paraffin, four kinds of formulations of toughened paraffin and plasticizers were designed. The blending models of styrene-butadiene-styrene block copolymer(SBS) toughened paraffin Wax with dibutyl phthalate(DBP), dioctyl sebacate(DOS), nitroglycerin(NG) and acetyl tributyl citrate(ATBC) were established. The compatibility of the toughened Wax with plasticizers and the nature of the intermolecular interactions in the blend systems were simulated and studied by molecular dynamics method. Results show that the compatibility of SBS toughened Wax with plasticizers can be comprehensively evaluated by the four criteria of solubility parameter, miscibility simulation, binding energy and intermolecular radial distribution function. In which, the relative error between the simulated value and the experimental one of solubility parameter is within 3% and the miscibility simulation can quickly predict the compatibility between two substances. The binding energy of ATBC and SBS toughened Wax is the largest, which is 2.7 kJ·g^-1. The essence of the interaction between SBS toughened Wax and plasticizers is van der Waals force and electrostatic force, mainly to van der Waals. The compatibility sequence of the three plasticizers with SBS toughened Wax is ATBC> DOS> DBP, NG is incompatible with SBS toughened Wax.