Study And Optimization On Peeling Strength Of Flexible Composite

During the past few years, weaving fabric reinforced flexible composites hadbeen broad spaces and prospects of applications due to their high strength, modulusand dimensional stability. The composites had larger extensibility, load bearingcapacity and anti-fatigue performance comparing with thermoplastic or thermosettingcomposites. Flexible composites had been not only used in advertisement light box,automobile tenting, agricultures and other fields, but also applied in science andenvironmental products.There existed a general problem among flexible composites that made in China,particularly the calendared and laminated products that the peeling strength was poor,and what is worst was that it would be separated between partial reinforced fabric andPVC membrane. That phenomenon would result in lower mechanical properties anddecrease in useful life. Furthermore, it might hamper the development of flexiblecomposites. As a result, how to improve the peeling strength of flexible compositeswas worth thinking and further researching.Two kinds of plain polyester fabric were used as reinforcement. Fabric and PVCmembrane were bonded by heat-melt laminating. On the basis of the existinginterfacial theory and the analysis of process factors on mechanical properties offlexible composites, how to raise the peeling strength between fabric and PVCmembrane was studied in this paper and the effects of air aging on the adhesionmechanism was also discussed.First of all， the study was focused on the influence of process factors onmechanical properties of flexible composites:(1) the effect of heat treatmentfactors(temperature and time)on the mechanical properties of PVC film and fabricwas discussed, and the results showed that temperature was more significantcomparing with time on the mechanical properties of PVC film and plain polyesterfabric, and at the same condition,2#fabric exhibited better thermal stability than1# fabric, and the results could be the basis for the set of the range of process factors.(2)The quadratic general rotary unitized design of three factors, including thetemperature, stress and time, was used to study the influence of process factors on themechanical properties of flexible composites. The tensile property and peelingstrength were tested, and the mathematical models about breaking strength, breakingelongation and peeling strength were built. The results showed that the temperaturewas the most significant factor among process factors, and remarkable interactionswere exhibited among the three factors. The influence of process factors on the twokinds of composites was different because of different counts and density of the twokinds of fabric. At last, rational process factors of two kinds of materials were got.Aiming to remove the weak interface and increase the wettability of polyesterfabric, the alkaline and low temperature plasma treatments were used. The resultsshowed that (1) because alkaline and LTP treatment could clean the oil on the surfaceof fabric and increase the surface roughness, so both of the treatments could improvepeeling strength,(2) the breaking strength of the materials decreased seriously afteralkaline treatment because of the hydrolysis of the polyester fibers in alkalinesolutions, while the breaking strength of composites was slightly affected by lowtemperature plasma treatment for the treatment just affected the surface of thefibers(about10nm),(3) FTIR revealed that polyester fiber surface was oxidized afterLPT and alkaline treatment and introduced oxygen polar groups, and new absorptionpeaks were found after LPT treatment. At last, rational treatment conditions of twokinds of fabric were got.Finally, the effects of different temperatures of hot air aging on the peelingstrength of flexible composites were studied. The results revealed that the influencesof different temperatures of hot air aging on peeling strength of materials weredifferent, and the effects of temperature was more marked than time. The flexiblecomposites whose reinforced fabrics were treated by LTP exhibited betterthermal-stability than those whose fabrics were treated by alkaline or untreated.