Study On The Interfacial Property And Adhesive Mechanism Of Nylon Fiber/Rubber Composites

Fiber/rubber composites are widely used in tire,hose,conveyor belt and other fields.However,the modulus and polarity of fiber and rubber are very different.It is necessary to modify the surface of fiber to improve the adhesive property of it and rubber.At present,resorcinol-formaldehyde-latex(RFL)system is widely used in industry.But resorcinol and formaldehyde would do great harm to human and the environment.Many researchers are committed to developing new environmentally friendly impregnation systems.Whereas,much work only described the relationship between the fiber surface impregnation system and the adhesive property of fiber/rubber composites,characterizing the interface microstructure qualitatively or semiquantitatively,and did not achieve the quantitative characterization.The purpose of this study is to establish a quantitative characterization method for the interface microstructure and explore the debonding form of fiber/rubber composites,establishing the relationship between the interfacial property and adhesive property of composites.It is hoped to provide guidance for the design of interfacial structure and the study on debonding mechanism of high-performance fiber/rubber composites.Therefore,the following studies are carried out on nylon fiber/rubber composites in this project:(1)Because the modulus and deformation capacity of fiber and rubber are very different,the traditional polishing methods are not suitable for fiber/rubber composites.In this study,based on the optimization of ion beam emission mode,polishing mode,polishing conditions and preparation of sample,the new method was developed to solve the problem,which combined mechanical polishing with the ion beam polishing.And the polished fiber/rubber composites were flat and suitable for quantitative characterization by atomic force microscopy(AFM).The altitude difference of the composites was controlled within 350 nm in the region of 20 μm×20 μm.(2)The interfacial modulus transition gradient of fiber/rubber composites was quantitatively characterized via optimizing the probe parameters and test parameters of the quantitative nanomechanical technology of atomic force microscope(AFM-QNM).And the interfacial thickness of the composites was quantitatively characterized by optimizing probe parameters and test parameters of the tapping mode of atomic force microscope(AFM-Tapping).On this basis,the tested relevant performance parameters were substituted into the KT model and COX model to calculate the interfacial debonding stress,which laid a foundation for exploring the best interfacial structure and debonding mechanism of fiber/rubber composites.(3)Based on AFM characterization,it has been found that the interface of untreated fiber/rubber composites was single-order modulus gradient,the interfacial thickness is only 91 nm,and the interfacial debonding stress is 8.79 MPa.While,the fiber/rubber composites with surface modification had a multi-order modulus gradient.The interfacial thickness of the composites treated by RFL and environmental protection impregnation was 818 nm and740 nm,respectively,and the interfacial debonding stress was 256.93 MPa and 302.53 MPa,respectively.In addition,the adhesive property of the composites with different surface treatment were tested,which were consistent with the law of interfacial debonding stress.Finally,the relationship between the interfacial property and adhesive property of the fiber/rubber composites was established.(4)The nanofiller attapulgite(AT)was used to enhance the adhesive performance of fiber/rubber composites.And effect of fiber embedding depth on H pull-out force was studied.The result showed that reducing the embedding depth of fiber would make the composites fail at the interface of fiber and rubber.In this way,the adhesive property of fiber/rubber composites could be accurately measured.With the increase of the dosage of AT,the modulus of interface increased,but the interfacial bonding property increased first and then decreased.When the dosage of AT was 7.5 wt%,the adhesive property of fiber/rubber composites was the best,which was about 20% higher than that of unenhanced system.However,when the dosage of AT was too large,the dispersion of filler became worse,the coating was not even,and the interfacial modulus is too high,which is not conducive to the bonding performance of composites.