高分子材料 ポリアミド／ポリエチレンブレンドのトライボロジー特性に及ぼすポリアミドの結晶構造の影響

Abstract

Tribological and morphological properties, and crystalline structure of polyamide 6 (PA6) in polyamide 6/maleic anhydride grafted high density and low density polyethylene (MAH-g-HDPE, LDPE) blends were investigated.Introduction of MAH into HDPE and LDPE greatly decreased the PE particle size in PA6 matrix and converted the crystalline structure of PA6 from α to γ form. Pure LDPE showed highest and HDPE showed lowest coefficient of friction and frictional wear. PA6 showed intermediate values. Although both the coefficient of friction and the frictional wear of HDPE tended to increase with MAH grafting ratio, those of PA6/HDPE blends decreased with MAH grafting ratio and reached to those of HDPE. PA6/LDPE blends showed an opposite tribological behavior, increasing coefficient of friction and wear with MAH content.When α form of PA6 was dominant in PA6/HDPE blends, the coefficient of friction and the frictional wear were almost constant, and these decreased with γ content. Although the coefficient of friction of PA6/LDPE blends had almost constant value irrespective of γ/α ratio, the frictional wear increased with γ/α ratio. These differences are due to the different way of formation of the transferred film onto the counter metal surfaces.