Preparation, Structure And Properties Of The Wsrs Based On Polyvinyl Chloride And Chlorinated Polyethylene

In this research, water-swelling thermoplastic elastomer based on Polyvinyl Chloride (PVC), water-swellable rubbers (WSR) based on chlorinated polyethylene (CM) vulcanizates and water-swelling TPVs based on dynamic vulcanizated PVC/CPNaAA/CM blends were prepared, incorporated with crosslinked sodium polyacrylate (CPNaAA) using as the water-swelling resin. The mechanical, water-swelling, morphological properties and dynamic mechanical properties of the TPVs were investigated systemically, especially the effect of the PVC/CM weight ratio, CPNaAA dosage, dioctyl phthalate (DOP) dosages in the PVC matrix and CM dispersed phase and the reinforcement of CM phase by zinc dimethacrylate (ZDMA) and carbon black (CB) on the properties of the TPVs. Dried colloidal educts of the PVC/CPNaAA/CM TPVs after water-swelling were investigated primarily; moreover, PVC/CPNaAA/sodium acrylate (NaAA)/CM TPVs were prepared by combination in situ formed NaAA (in-situ-NaAA) with CPNaAA. The results were showed as below.(1) The stress-strain curves of the PVC/DOP/CPNaAA blends showed an obvious elastomeric behavior. With the increase of CPNaAA content, the tensile strength, tearing strength, elongation at break and tension set at break of the PVC/DOP/CPNaAA composites were decreased obviously, while the hardness was increased slowly. The remarkable water-swelling behaivors could be achieved when the dosage of CPNaAA was40phr above.(2) The CM/CPNaAA WSR show the representative elastomeric character of being soft and tough. With the increasing of CPNaAA dosage, the water-swelling ratio of the prepared WSR increased remarkably, which reached550%at200h. Compared with that of the first water-swelling behavior, the second water-swelling ratio and the third water-swelling ratio are much higher. The weight loss of the CM/CPNaAA WSR in the first water-swelling was8%.(3) RPA results showed that the storage modulus decreased with increasing strain amplitude, namely, the typical features associated with Payne effect could be found in the strain sweep of the CM/CPNaAA WSR. The interface interaction between CM and CPNaAA significantly influenced the viscoelastic properties, indicating that the Payne effect can characterize the destruction of interface interaction of CM/CPNaAA WSR, which was consistented with the result of the morphology of fracture surface of CM/CPNaAA WSR.(4) The effect of the PVC/CM weight ratio on the properties of the water-swelling PVC/CPNaAA/CM TPVs was investigated. The stress-strain curves of the seris PVC/CPNaAA/CM TPVs showed an obvious elastomeric behavior. TPVs showed strong water-swelling behaviors with the PVC/CM weight ratio below40/60. The water-swelling ratio of the PVC/CPNaAA/CM (30/60/70) TPV reached2,100%at200h in room condition. The water-swelling rate of the TPVs reached to the highest at100h. With increasing the PVC dosage, the mechanical properties of the TPVs decreased. Morphology of the etched surface of water-swelling PVC/CPNaAA/CM TPVs showed that the CPNaAA particles dispersed well in the TPV, embedded in the CM layer. The fracture surfaces of the PVC/CPNaAA/CM TPVs showed that the interface interaction between CM and CPNaAA was poor.(5) The effect of the dosage of CPNaAA on the properties of the water-swelling PVC/CPNaAA/CM TPVs was investigated. TPVs showed strong water-swelling behaviors with the CPNaAA dosage was above40phr, which increased with the content of the CPNaAA; the water-swelling ratio of the sample with60phr CPNaAA reached2,400%at200h; moreover the water-swelling ratio of the TPVs also increased with the increased number of the water-swelling cycles and the TPVs had outstanding water-retention properties. Mechanical properties of the TPVs decreased with increasing the dosage of the CPNaAA. Morphology of free surface of the TPV after the first water-swelling showed that some holes formed, promoting the later water-swelling cycles; morphology of the dried colloidal educts of the TPVs after water-swelling showed that it were not only the CPNaAA migrating from the TPVs, but also some fragment of the TPVs matrix, due to the huge deformation of the TPVs after water-swelling.(6) The effect of the DOP dosage in the PVC matrix and the CM dispersed phase on the properties of the water-swelling PVC/CPNaAA/CM TPVs was investigated. TPVs showed strong water-swelling behaviors with the DOP dosage was above20phr. The water-swelling ratio of the TPVs increased with the DOP content in the PVC matrix and reached above2,000%at200h. The elongation at break of the water-swelling PVC/CPNaAA/CM TPVs increased with the increasing of the DOP content in the PVC matrix, promoting the water-swelling properties of the TPVs. Morphology of the fracture surfaces of the sample with60phr DOP in the PVC matrix showed that the waves of the fracture surfaces weaker compared with the sample with0phr DOP in the PVC matrix.(7) The effect of reinforcement of the CM dispersed phase on the properties of the water-swelling PVC/CPNaAA/CM TPVs was investigated. The mechanical properties of the TPVs were reinforced remarkably with the adding of CB and ZDMA; however the strong network of the reinforced water-swelling PVC/CPNaAA/CM TPVs resulted in the poor water-swelling behavior. When the dosages of the CB and ZDMA in the CM dispersed phase were20phr and10phr, the water-swelling ratio of the samples were200%and300%respectively. Morphology of the fracture surfaces of the sample showed that less CPNaAA particles suspended on the fracture surfaces, compared with that of the non-reinforced TPVs.(8) The effect of the combination in situ formed NaAA and physical blending CPNaAA on the properties of the water-swelling PVC/CPNaAA/CM TPVs was investigated. The results showed that compared with that of WSR prepared by physical blending, the mechanical properties of WSR prepared by in situ formed NaAA were improved obviously; however, the water-swelling ratio of WSR prepared by in situ formed NaAA was low; however, the CPNaAA particles in the WSR prepared by combination in situ formed NaAA with CPNaAA were dispersed well, and the mechanical properties were increased obviously. The excellent mechanical properties of WSR prepared by in situ formed NaAA and the excellent water-swelling properties of WSR prepared by physical blending were complement each other well in the TPE prepared by combination in situ formed NaAA with CPNaAA.(9) The water-swelling PVC/CPNaAA/CM TPVs combinate the thermoplastic properties of the PVC resin phase and high water-swelling properties of the WSR based on CM vulcanizates; the water-swelling PVC/CPNaAA/CM TPVs in this research have strong water-swelling behavior with PVC/CM weight ratio below40/60and CPNaAA content above40phr, however the mechanical properties of the TPVs decreased. Increasing the DOP dosage in the PVC matrix can increase the elongation at break of the water-swelling PVC/CPNaAA/CM TPVs, promoting the water-swelling properties of the TPVs. Adding CB and ZDMA to the CM phase and combination in situ formed NaAA and physical blending CPNaAA both can reinforced the mechanical properties of the TPVs, and the pros and cons of the relationship of the water-swelling properties of the TPVs among them was shown as below:TPVs reinforced by ZDMA<TPVs reinforced by CB<TPVs prepared by combination in-situ-NaAA and physical blending CPNaAA.(10) The dynamic mechanical properties of the water-swelling PVC/CPNaAA/CM TPVs were investigated. Dynamic mechanical results showed that the storage modulus decreased with increasing strain amplitude and increased with increasing content of CPNaAA in the PVC/CPNaAA/CM TPVs. PVC/CPNaAA/CM TPVs showed the typical Payne effect, increasing the PVC dosage and CPNaAA dosage enhanced the Payne effect; however, increasing dioctyl phthalate amount in the PVC matrix weakened the Payne effect.