摘要
全氟聚醚润滑脂主要是由全氟聚醚(PFPE)基础油和聚四氟乙烯(PTFE)稠化剂组成。PFPE和PTFE之间结合力的强弱是影响全氟聚醚润滑脂胶体安定性的关键因素之一。PFPE和PTFE的特殊分子结构决定了分子之间作用力较弱,进而影响了全氟聚醚润滑脂的胶体安定性。为了提升全氟聚醚润滑脂的胶体安定性,选用大比表面积的疏水型气相二氧化硅(S1、S2、S3、S4)作为添加剂,以自主生产的低黏度、支链型PFPE为基础油,以PTFE粉体为稠化剂,调配一系列不同配比的全氟聚醚润滑脂,并通过XRD、SEM、TEM分析以及氮气等温吸附-脱附、粒径分布、表面自由能、分油测试,研究疏水型气相二氧化硅对全氟聚醚润滑脂胶体安定性的改进效果。研究结果表明:具有介孔结构的疏水型气相二氧化硅具有良好的稠化能力,使得全氟聚醚润滑脂的胶体安定性得到了不同程度的改进;比表面积及孔容最大的添加剂S2对全氟聚醚润滑脂胶体安定性的改进效果最为明显;全氟聚醚润滑脂的分油量随添加剂S2添加量的增大而降低,考虑到目标润滑脂的稠度等级要求,添加剂S2最佳添加量为1.5%(质量分数)。
Perfluoropolyether greases are primarily consisted of perfluoropolyether(PFPE)base oils and polytetrafluoroethylene(PTFE)thickeners.The strength of the binding force between PFPE and PTFE molecules is one of the key factors affecting the colloidal stability of perfluoropolyether greases.The special molecular structure of PFPE as well as PTFE determines the weak binding force between molecules, which effects on the colloidal stability of perfluoropolyether greases. In order to improve the colloidal stability of perfluoropolyether greases, hydrophobic fumed silica(S1,S2,S3,S4)with large specific surface area was selected as additives, self-produced, low-viscosity, and branched PFPE was used as base oil, the PTFE powder was used as thickener, and a series of perfluoropolyether greases with different proportions were prepared.The analysis of XRD,SEM and TEM,the test of nitrogen adsorption-desorption isotherm, pore diagram distribution, surface free energy and oil separation from grease were used to investigate the improvement effect of hydrophobic fumed silica on the colloid stability of perfluoropolyether greases.Results show that hydrophobic fumed silica with mesoporous structure has good thickening ability, which improves the colloidal stability of perfluoropolyether grease.Additive S2 with the most specific surface area and pore volume has the most obvious effect on improving the colloidal stability of perfluoropolyether greases.The oil separation of perfluoropolyether grease decreases with the increase of the addition amount of additive S2.Considering the consistency grade requirements of the target grease, the optimal addition amount of additive S2 is 1.5%(mass fraction).
作者
刘洋
辛虎
李杏涛
赵恒
李倩
曹春兰
LIU Yang;XIN Hu;LI Xingtao;ZHAO Heng;LI Qian;CAO Chunlan(Sinopec Lubricant Company,Beijing 100085,China)
出处
《润滑与密封》
CAS
CSCD
北大核心
2022年第4期164-169,共6页
Lubrication Engineering
关键词
全氟聚醚
润滑脂
胶体安定性
聚四氟乙烯
二氧化硅
perfluoropolyether
greases
colloid stability
polytetrafluoroethylene
silica
