Study On Environmental Impregnation Treatment Of Nylon 66 Cord And Interfacial Adhesion Properties Of Rubber Composites

Fiber cord plays an important role in rubber products such as tires,conveyor belts and hoses.As a skeleton material,fiber cord has high stiffness and strength to resist stress,which can effectively improve the comprehensive performance of fiber/rubber composites.However,due to the strong inertia of fiber surface,it needs to be pretreated.In industry,the interfacial adhesion strength between fiber cord and rubber matrix was improved by impregnating fiber cord in resorcinol-formaldehyde-latex(RFL)impregnation system.However,there are resorcinol and formaldehyde that have great harm to human health and production environment in RFL impregnation system,so it is urgent to develop a new free-RF environmental impregnation system.Based on the above research background,this study aims to explore a new free-RF environmental impregnation system to replace the traditional RFL impregnation system and meet the needs of green environmental protection.(1)In this study,an environmental one-bath impregnation system consisting of acrylic resin A-blocked isocyanate C-epoxy resin G-butadiene pyridine latex was designed.The main reaction of the impregnation system was characterized by FTIR,the optimum formula was obtained by adjusting the molar ratio of epoxy group and isocyanate group.When the molar ratio of epoxy group and isocyanate group was 2.54/1.00,the H pull-out force of the composite was 140.7±11.4 N,which could reach 90%of the RFL impregnation level(149.4±15.3 N),and the fiber strength loss was controlled at about 5%.Through the quantitative characterization of the sulfur content and modulus at the interface of the composites,the migration phenomenon of sulfur-containing compounds in the impregnation layer was found,which was helpful for the cosulfidation between the butadiene pyridine latex and the rubber matrix,thereby improving the adhesion performance of the composites.At the same time,the modulus gradient change of rubber-impregnation layer-fiber was also measured,which proved that the impregnation layer with appropriate modulus could better transfer the load of composite materials under the action of force.(2)In this study,an environmental two-bath impregnation system composed of plant polyphenol P-epoxy resin G-branched amine curing agent Ibutadiene pyridine latex was designed.The reaction mechanism of the impregnation system was verified by FITR,and the optimum formula was obtained by adjusting the molar ratio of plant polyphenol P/branched amine curing agent I.When the molar ratio of plant polyphenol P/branched amine curing agent I was 1.00/0.15,the H pull-out force of the composite reached 168.2±7.7 N,and the cord peeling strength force reached 22.0±0.6 N which reached more than 110%of the level of the traditional RFL impregnation system,and the strength loss of the modified fiber was also controlled at about 5%.This study provides a new strategy for the functionalization of fiber cords surface and the quantitative characterization of the interface mechanical properties of the impregnation layer.