Study On Preparation And Properties Of High Salt-resistance Water-swellable Rubber

In this dissertation,a nitrile rubber(NBR)was used as the matrix,and a chemically crosslinked interpenetrating network structure was constructed with a macromolecule of a double-bonded hydrophilic polyurethane(PU)active resin,and polyacrylamide(PAM)was used as a water absorbent.Different types of high salt-resistance water-swellable rubber(WSR)materials were prepared.The material overcomes the technical difficulties of traditional WSR materials such as low expansion rate of high-salt mineralized water(20 × 104 mg · L-1),precipitation of water-absorbing agent,poor salt resistance,and short service life.In addition,the material also exhibits better mechanical properties,higher stability,and longer service life.The chemical cross-linked interpenetrating cross-linked network structure built in the material reduces the problem of precipitation of the water-absorbing agent component.The synergistic effect of the added PAM water-absorbing resin and the cross-linked network constructed by the hydrophilic PU resin gives the material a better water-swelling behavior and salt resistance.The paper focuses on the research objectives and mainly carries out the following four parts of the research work:1.Using hydroxyethyl methacrylate(HEMA)to react with hydrophilic PU prepolymer,the macromolecule of hydrophilic double bond capped PU resin was successfully prepared.The results showed that under the action of the initiator(DCP),the macromolecules of the double bond-terminated PU active resin can be grafted onto the main chain of the NBR matrix and a PU/NBR chemically crosslinked interpenetrating network structure was constructed;PU/NBR chemistry Cross-linked WSR materials have a mass expansion ratio of 1.8 times in a 200,000 mineralized water environment,and the rubber sheet has a stable surface.The chemical crosslinked interpenetrating WSR materials of PU/NBR showed good salt resistance and stability,which solved the common precipitation problem of traditional WSR materials.2.The PAM/NBR resin composite WSR material was manufactured.The effectof PAM resin content on the properties of WSR material was studied in this part.With the increase of PAM resin content,the precipitation of hydrophilic agent of composite WSR material becomes more and more obvious.In the 200000 mineralized water environment,the mass expansion ratio of the composite WSR material was 3.5 times,showing better salt tolerance.However,the serious precipitation of PAM absorbent resin makes the composite WSR material exhibit poor expansion stability.3.The synergistic WSR materials of PAM and PU active resins were manufactured,and the effect of PAM resin content on the properties of WSR materials was studied.The results showed that in the 200000 mineralized water environment,the mass expansion of PU/NBR chemically crosslinked and composite WSR materials was nearly 3 times,and the rubber sheet was stable after expansion;The mass expansion of PAM/PU prepolymer synergistic composite WSR material is 4times,and the rubber sheet is stable,only a small amount of precipitation occurs.The results show that the synergistic action of WSR and PU active resin can improve the water swelling rate of WSR and overcome the technical problem of low expansion rate of the material in ultra-high mineralized water environment.4.Fabrication of unsaturated hydrophilic monomer in situ free radical polymerization grafted WSR materials,The effects of the density of PU/NBR chemical crosslinking network and the effect of monomer in situ free radical on the properties of WSR were studied.When the content of DCP is 0.5 phr,the mass expansion of PU/NBR chemically crosslinked composite WSR material is 3.5 times,and the rubber sheet stability does not appear precipitation phenomenon.Monomer in-situ polymerized WSR materials have a relatively low mass expansion ratio and show precipitation and high temperature shrinkage.The results show that the density of chemical crosslinking network can affect the expansion rate of WSR materials,and the expansion properties of WSR materials with monomer in situ radical polymerization need to be further studied.