文献类型：期刊文献

英文题名：Reinforcement mechanism of silica surface hydroxyl: The opposite effect

作者：Wang, Bohui[1];Hu, Jinneng[1];Liu, Kunpeng[1];Zhang, Ling[1];Jiang, Haibo[1];Li, Chunzhong[1]

机构：[1]East China Univ Sci & Technol, Shanghai Engn Res Ctr Hierarch Nanomat, Sch Mat Sci & Engn, Key Lab Ultrafine Mat,Minist Educ, Shanghai 200237, Peoples R China

年份：2023

卷号：623

外文期刊名：APPLIED SURFACE SCIENCE

收录：;EI(收录号：20231213782033);WOS:【SCI-EXPANDED(收录号:WOS:000956493700001)】；

基金：Acknowledgments This work was supported by the National Natural Science Foundation of China (21838003, 91834301) , the Shanghai Scientific and Techno-logical Innovation Project (18JC1410600, 19JC1410400) , the Social Development Program of Shanghai (17DZ1200900) , the Innovation Program of Shanghai Municipal Education Commission, and the Fundamental Research Funds for the Central Universities (222201718002) .

语种：英文

外文关键词：Silica; Hydroxyl groups; Reinforcement mechanism; Silicone rubber; Molecular dynamics simulation

摘要：Silica is one of the best reinforcing fillers for silicone rubber due to its similar structure to the main chain of silicone rubber and abundant surface hydroxyl groups. However, for the role of surface hydroxyl groups in reinforcement, there are many conflicting conclusions. This paper combines experiments and molecular dy-namics calculations to illustrate that the reinforcing mechanism of the hydroxyl group is two-sided. Firstly, at 30 phr, the tensile strength increases from 6.34 +/- 0.47 MPa to 8.40 +/- 0.37 MPa as the number of hydroxyl groups decreases; the Payne effect decreases, and the bound rubber content increases from 25.7% to 34.0%, and the filler-rubber interfacial interaction increases; molecular dynamics calculations show that as the number of hy-droxyl groups increases, (I) the interaction forces between the silica particles increase, inhibiting their dispersion in the silicone rubber; (II) physical-adsorption water increases and the strength of the rubber-filler interfacial interaction decreases, reducing the reinforcing effect. Secondly, as the amount of silica added gradually reduces, the difference in tensile strength between Silica (13.1 OH/nm2) /SR composites and A200 (4.5 OH/nm2) /SR composites decreases. At 5 phr, the tensile strength of Silica-5 phr is 0.95 +/- 0.07 MPa, which is higher than that of A200-5 phr, 0.87 +/- 0.19 MPa; the bound rubber content and the filler-rubber interfacial interaction of Silica-5 phr are higher than A200-5 phr; molecular dynamics calculations show that the strength of the filler-rubber interfacial interaction increases gradually with increasing hydroxyl groups for similar dispersion states. This paper would help design more desirable silica structures with a highly branched structure and multiple hydroxyl groups as an ideal reinforcing agent.