The Preparation And Mechanical Properties Of Poly(AM-AMPS-SSS)/MMT Composite High-strength Hydrogel

Hydrogel is a kind of semi-solid material with water as the dispersion medium.It can swell without melting after absorbing a large amount of water or biological liquids.It is a kind of functional polymer material with spatial three-dimensional network structure.With the features of rapid swelling,high water content,soft texture,outstanding biocompatibility,it has a wide range of application prospects in biomedicine,industrial and agricultural,daily chemical,oilfield and other fields.However,the traditional chemically-crosslinked hydrogels have insufficient mechanical properties,which limits the further application in many fields.In this paper,on the basis of reviewing of hydrogels development and application of high-strength hydrogels,Na-montmorillonite was modified by intercalation,the synthesis and polymerization methods of montmorillonite composite high-strength hydrogels were studied and performance evaluation were conducted.The specific work is as follows:(1)Preparation of intercalated montmorillonite:The cation exchange capacity(CEC)was tested with purified Na-montmorillonite as a basic raw material,with choline chloride(CC)and methacryloyloxyethyl trimethyl ammonium chloride(DMC)as intercalating agents,and Na-montmorillonite was intercalated to prepare the intercalated modified montmorillonite named CC-MMT and DMC-MMT.In order to ensure the good dispersion of the intercalated montmorillonite in the polymer matrix,the influence of the amount of intercalation agent on the sedimentation stability and the colloidal price of the intercalated montmorillonite aqueous solution was investigated,and the optimum addition amount of CC and DMC in the solvent was 0.8CEC and 1.0CEC,respectively.At the same time,the particle size,Zeta potential,and interlayer spacing of the intercalated montmorillonite were measured by instruments.Under the situation of best intercalator addition and intercalated montmorillonite was 3.0 wt%,the results showed that the particle size of CC-MMT was mainly distributed at 901.4 nm,the Zeta potential was 9.19 mV,the interlayer spacing was 1.4039 nm;and the particle size of DMC-MMT was mainly distributed at 914.1 nm,the Zeta potential was 10.04 mV,and the interlayer spacing was 1.4136 nm.(2)Intercalated montmorillonite(CC-MMT and DMC-MMT)as inorganic materials,acrylamide(AM),2-acrylamide-2-methylpropane sulfonic acid(AMPS)and p-styrene sulfonic Sodium(SSS)as reactive monomers.Ammonium persulfate(APS)was used as an initiator,and N,N-methylene bisacrylamide(MBA)was used as a cross-linking agent.Traditional chemical crosslinked hydrogels and Poly(AM-AMPS-SSS)/MMT composite high-strength hydrogels were respectively prepared by queous solution polymerization and in situ free radical polymerization.The prepared hydrogels with excellent properties were tested and characterized including FTIR and DSC-TG.The effects of experimental conditions such as monomer concentration,initiator concentration,concentration of intercalation montmorillonite in water,cross-linker concentration,and polymerization temperature on the mechanical properties of hydrogels were investigated.The results showed that when the monomer concentration was 25.0 wt%,the aqueous phase concentration of DMC-MMT was 3.0 wt%,the initiator concentration was 0.06 wt%,the cross-linker concentration was 0.1 wt%,and the polymerization temperature was 60℃.The tensile strength of the composite high-strength hydrogel was 102.4.9 kPa,and the tensile elongation reached 440.9%.When the monomer concentration was 40.0 wt%,the aqueous phase concentration of the DMC-MMT was 3.0 wt%,the initiator concentration was 0.06 wt%,the cross-linker concentration was 0.2 wt% and the polymerization temperature was 60℃,the compressive strength of the DMC-MMT composite high-strength hydrogel reached 3.60 MPa.(3)Using intercalated montmorillonite DMC-MDMT as inorganic material,AM,AMPS,and SSS as reactive monomers.APS-sodium bisulfite(SBS)as the redox initiation system,and MBA was used as a cross-linking agent.Poly(AM-AMPS-SSS)/MMT composite high-strength hydrogels were prepared by inverse emulsion polymerization.The particle size distribution of emulsion before and after emulsion polymerization was analyzed.It was concluded that the particle size distribution of latexes before polymerization was mainly distributed at 3.8 μm,and the particle size of latexes after polymerization was mainly distributed at 5.8 μm,which was consistent with the mechanism of nucleation of droplets.The influence of synthetic conditions on the mechanical properties of the composite high-strength hydrogels were discussed.The test results showed that when the other conditions were unchanged,the ratio of oil to water was 0.9,the initiator concentration was 0.06 wt%and the polymerization temperature was 30℃,the highest tensile strength of the prepared hydrogel was 212.0 kPa,and the highest compressive strength was 4.97 MPa.And the anti-aging test showed that the high-strength hydrogel had a good short-term plugging.The mechanism of inverse emulsion polymerization for preparing high-strength hydrogels was explained briefly.It was concluded that the reactive hydrogel microspheres were preparaed by inverse emulsion polymerization,and the high-strength composite hydrogels were obtained by the method of demulsification.