Research on High Strength Ethylene-Vinyl Acetate Water-Absorbing Swelling Underground Pipeline Sealing Rubber

Water-absorbing, swellable rubber is characterized by its ease of encapsulation and its ability to provide in situ watertight sealing and is widely used in applications such as the sealing of underground pipelines. To enhance the water-absorption properties of water-absorbing, swellable rubber, large quantities of water-absorbing resins or inorganic particles are typically incorporated. However, due to poor compatibility between these two components, the material exhibits low mechanical strength and struggles to meet application requirements. In this study, polyvinyl alcohol (PVA-1788) was employed as the water-absorbing component. As it contains the same vinyl acetate (VA) structural unit as ethylene-vinyl acetate rubber (EVM), this enables co-crosslinking of the composite rubber, thereby improving compatibility between the two components and enhancing the mechanical and water-absorption properties of the composite material. The structural morphology, water absorption, and mechanical properties of the composite were investigated using SEM, AFM, and laser scanning confocal microscopy. The results indicate that when the PVA content reached 22.5 phr, the tensile strength and elongation at break of the composite were 13 MPa and 246% respectively, representing a 10-fold and 0.9-fold increase compared to EVM rubber. This composite holds broad application prospects in fields such as the sealing of underground pipelines.