Study On Physical Properties Of Calendered Flexible Composites

As a newly arisen material, flexible composites have been widely used in many fields, like constructions, advertising and transportation. Obviously, it has a promised future in commercial productions.Now we produce flexible composites by coating, calendering or laminating thermoplastic resin onto reinforcing materials. The calendering method is most widely used for its low cost and great efficiency. The reinforcing materials used for calendaring flexible composites are usually warp knitted bi-axial fabrics or woven fabrics. We use polyester fabrics calendered with PVC film to form the flexible composites.Composites will inevitably suffer outside forces while applied to actual use. And its physical properties are most important issues needs to be considered while designing the products. So our study is focused on the tearing, delaminating and tensile performances of the calendered flexible composites.We collected a quantity of various samples, including warp knittedbi-axial fabric reinforced composites and woven fabric reinforced composites, flexible composites with different yarn counts, fabric densities and coating thickness. We tested their tearing, delaminating and tensile performances, to observe the testing process and analyze the acquired data.Firstly, we researched on the tearing performances of warp knitted bi-axial fabric reinforced composites and woven fabric reinforced composites. We analysed the tearing process and compared the differences between these two composites. Moreover, we find the difference between warp and weft tearing properties. We find that the yarn count, fabric density and coating thickness affect the composites' tearing property by affecting the degree of yarn concentrating in tearing process. These factors are linearly related to the composites' tear resistant force. Besides, we studied the differences of various tearing testing standards and analysed how they affect the testing results.Secondly, we studied the delaminating performances started from the interfacial adhesion mechanism. For the warp knitted bi-axial fabric reinforced composites and woven fabric reinforced composites, we found out that for their different fabric structures, they have distinct interfacial adhesion mechanisms and delaminating resistant forces. Then we analyzed the relationships between the tearing and delaminating properties of the flexible composites. And in this paper, we discussed themethod about how to express the delaminating property more correctly. We also try to test some composites' delaminating resistant forces by jointing two specimens together with high frequency electricity.Lastly, we studied the tensile property of the calendered flexible composites and their initial modulus. We compared the tensile properties of different samples and find out the difference between warp and weft tensile property.We studied the physical properties of calendered flexible composites on the basis of current research achievements and tried to resolve the problem we met during our experiment. The research we made on testing method is foundation of further studies. Besides, we find out the factors affecting the composites' physical properties, which has conducting value in practical designing and production.