Study On Preparation And Properties Of High-Strength Polymer Gels

Hydrogels,as a type of soft wet materials,possess excellent deformation and mechanical properties.They can respond to external stimulation and keep shape memory that many rigid materials do not have.So they exhibit tremendous application in the fields of industry,agriculture,biology and material.But the applications of the hydrogels have been limited by their poor mechanical properties, instability and low response rate.Therefore it is significant to prepare high-strength hydrogels and ion gels with high strength.In this work,the properties and mechanism of high-strength interpenetrating polymer network hydrogels,which were synthesized by 2-acrylamide-2-methypropane sulfonic acid(AMPS) and acrylamide(AAm),were studied according to their mechanical and swelling experiments under different monomer concentrations and ionic strength.The results show that the strength of PAMPS/PAAm interpenetrating polymer network hydrogels increases with the increasing of AAm concentration,while the AMPS concentration has a optimal value(1 mol/L) and the highest compressive strength of the interpenetrating polymer network hydrogels is up to 6.46 MPa with 1 mol/L AMPS and 4 mol/L AAm.It is found that the compressive strength of 1p2a PAMPS/PAAm hydrogel increases 67% and the strength of 1p4a PAMPS/PAAm hydrogel increases 29%when increasing the ionic strength of the water in hydrogels to 0.25 mol/kg compared to those of the deionized water.Meanwhile,being combined with ionic liquid's stability,nonvolatile and good conductivity,the preparation of ion gels was studied based on the investigating of compatibility of vinyl monomers and their polymers with the N,N'-dialkylimidazolium-based ionic liquids.High-strength PAAm/[BMIm]Br ion gels were successfully synthesized and their properties were studied.The results show that the strength of PAAm/[BMIm]Br ion gels increases with AAm concentration and crosslinker(MBAA) concentration and the highest compressive strength of PAAm/[BMIm]Br ion gels is up to 30.6 MPa with 5 mol/L AAm and 1 mol%MBAA. PAAm-PHEMA/[BMIm]Br ion gels were synthesized by adding 2-hydroxyethyl methacrylate(HEMA) into PAAm/[BMIm]Br ion gels copolymerized with AAm.The strength of PAAm-PHEMA/[BMIm]Br ion gels decreases with the increasing of HEMA concentration,but the flexibility of the ion gels increases.It is found that the ionic conductivity of PAAm-PHEMA/[BMIm]Br ion gels is about 10^-2 ms cm^-1 at 25℃.And their corresponding TG test show that all the ion gels are stable under 250℃and the content of ionic liquid is up to 70%.