Evaluation of a Superior Water-Based Lubrication Behavior of Polyvinyl Alcohol on Styrene-Ethylene-Butylene-Styrene Block Copolymer

Qinghua Fang1),2), Xiaoniu Yang1)* 

1) State Key Laboratory of Polymer Physcis and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Renmin Str. No 5625, Changchun 130022, P.R. China.

2) College of Applied Chemistry and Engineering, University of Science and Technology of China, Jinzhai Road No 96, Baohe District,Hefe 230026, P.R.China

*Corresponding author: xnyang@ciac.ac.cn 

Abstract: Polyvinyl alcohol (PVA) aqueous solution is a type of lubricant that can be used to improve the symptoms of dry eye. This solution, bearing good hydrophilicity and film-forming properties, can play a role similar to artificial tears at the appropriate concentration. In this work, we studied the tribological behaviors between styrene-ethylene-butylene-styrene block copolymer (SEBS) and metal balls lubricated by PVA solutions. It is found that stable friction curves with very low friction coefficient (~0.05) could be achieved from the friction pair composed of SEBS films and stainless steel ball upon lubrication by PVA solutions, instead of deionized water. And the very low friction coefficient in PVA aqueous solution represents at least 95% decline than dry condition. The SEBS films used in the experiments were prepared on soda-lime glass via spin casting method to achieve smooth film surface so as to ensure effective lubrication by PVA solution at a concentration as low as possible, e.g. 0.1%wt. The wear rate of SEBS film in such case is much low compared with conventional cases. It is proposed that the such particular behavior owing to the fast exchange of water molecules are the main factors accounting for the superlow friction and wear. PVA aqueous solution with stability and perfect tribological properties has the potential uses in biological synovial joints and marine environments, especially in the field of micro-friction for the eyes. 

Key Words：polyvinyl alcohol, molecular weight, PVA, viscosity, water lubrication