基于分子动力学的生物质透层油稳定性

Molecular dynamics-based stability of biomass prime coat oil

为探究乳化剂掺量对生物质乳化沥青稳定性的影响机理,通过采用Material studio分子动力学模拟及宏微观试验对所制备的1%、3%和5%三种阴离子乳化剂掺量生物质乳化沥青稳定性展开分析。研究结果表明,适量的乳化剂可以降低油水界面间界面张力,扩大两相间的过渡区域,从而阻碍微粒间聚结,降低沉降速度保证乳化稳定性,随着乳化剂增多,会出现团块现象进而导致稳定性下降,由结果可知,3%阴离子乳化剂掺量生物质乳化沥青稳定性最好。

To investigate the effect of different emulsifier contents on the stability performance of biomass emulsified asphalt,three types of emulsified asphalt with 1%,3%and 5%anionic emulsifiers were prepared and analyzed by molecular dynamics simulation and macroscopic experiments.Firstly,the Molecular Simulation Software(Material Studio,MS)was used to construct a model of biomass emulsified asphalt with different emulsifier contents and the microscopic mechanism of the emulsifier was analyzed to improve the stability of the emulsified asphalt by the radial distribution function,interaction energy,interfacial layer thickness and solubility parameters of the emulsified asphalt system with different emulsifier contents.The results were validated by macro and micro tests including storage stability,particle size determination and infrared spectroscopy.The results show that at low emulsifier content,the emulsifier can reduce the interfacial tension between the oil-water interface and expand the transition region between the two phases(interfacial layer thickness),which will prevent interparticle agglomeration and reduce the emulsion particle size,thus reducing the settling rate and ensuring the stability of the emulsion.When the emulsifier content is further increased beyond the critical micelle concentration,the emulsifiers will agglomerate with each other and show larger peaks in the radial distribution function,and the phenomenon of emulsifier agglomeration will appear in the five-day storage stability test,resulting in a corresponding decrease in the proximity of the infrared absorption peak area ratio in the same wavelength band of the upper and lower layers of the biomass emulsified asphalt,and the emulsion stability decreases instead.