Study On The Interfacial Adhesion Mechanism Of Laminated Flexible Composites Reinforced With Weaving Fabric

In the past few years,flexible composites reinforced with weaving fabric have been broad spaces and application prospects,because of high strength,modulus and dimensional stability.Flexible composites have been not only used in automobile tenting,advertisement light box,inflatable raft and other fields,but also used in science and technology products.Flexible composites in China,especially the laminated and calendar products, have a common problem that is poor peel strength,even worse that reinforced fabric and matrix have been separated.The phenomenon will lead to lower mechanical properties,easy-moisture and reduce shelf life.Meanwhile,it may hamper the development of flexible composites on the international stage.Therefore,how to improve peel strength of flexible composites is worth been thinking.Plain polyester fabric was chose as the reinforcement and flexible composites were made of fabric and PVC film by utilizing heat-melt laminating.According to the existing interfacial bonding theory and three elements which are wettability, reaction and interfacial residual stress,how to improve the interfacial adhesion during the polyester fabric and PVC film and the effects of hygrothermal ageing on the adhesion mechanism were studied in the paper.First of all,the study was focused on weak interface and wettability of polyester fabric,and the different pretreatments on improvement of the interfacial adhesion mechanism of flexible composites were studied.The results have shown that the pretreatment which can clean the oil and increase the surface roughness improve peel strength and tensile strength,but decrease tear strength.As flexible composites reinforced with weaving fabric,basecoat is essential part of the whole process.The orthogonal test method was used to optimize combinations of different processing parameters.The results have shown that the influences of the amount of bonding agent,baking temperature and baking time all affect peel strength of flexible composites to some extent.The influence degree from large to small is as follow:amount of bonding agent＞baking time＞baking temperature,and the best combination is:amount of bonding agent 2.0%,bonding time 40s,bonding temperature 140℃.In order to reduce residual stress of the interface and lower expansion coefficient, the modified calcium carbonate was added in basecoat process.Stearic acid was used to modify the surface under the condition of ultrasonic.To get the optimal modification craft,absorption oil value,activation index,volume of dispersion phase and contact angle were used to evaluate and characterize successively.The results have shown that the best of modifying agent dosage is 2.0%and modified calcium carbonate not only improve interfacial adhesion mechanism but also increase strengthening and toughening mechanisms.Finally,the effects of different medium and hot air aging on interfacial adhesion mechanism of flexible composites were studied.The results have shown that temperature is one of the most important factors that could accelerate aging performance of the adhesive and the characteristic of the medium is also one of the important factors that have affected on durability of the adhesive.In addition,the different temperatures of hot air aging also affect the interfacial bonding.It is expected that the results in this paper will benefit to study the interfacial adhesion property of flexible composites and give some valuable references for the design and manufacturing of flexible composites.