Study On Quaternization Modification And Application Of Styrenic Thermoplastic Elastomer(SEBS)

SEBS,as a styrene thermoplastic elastomer,has both rubber and plastic properties due to its special microphase separation structure.However,as a non-polar polymer,SEBS does not contain polar groups in its side chain,which limits it Therefore,researchers pay more and more attention to the polarized modification and modified use of SEBS.In the past,there were few studies on the quaternization of SEBS,mainly focusing on the use of quaternized SEBS to prepare anion exchange membranes in fuel cells.In order to expand the application field of SEBS quaternization,this paper uses SEBS and Short-chain tertiary amine was quaternized,anion exchange membrane was prepared,and its application in the field of electrodialysis was studied;through the quaternization of SEBS and long-chain tertiary amine,the application value of quaternized SEBS in the field of mildew and antibacterial was studied.This topic The research content includes the following aspects:1.Synthesis and characterization of chloromethylated SEBS: using organic electrophilic substitution reaction as the mechanism,SEBS,trioxymethylene and trimethylchlorosilane as raw materials,Lewis acid(tin tetrachloride)as catalyst,chemical reaction,the chloromethyl group is introduced into the styrene thermoplastic elastomer,so as to achieve the purpose of chloromethylation.Various factors affecting the chloromethylation reaction were explored,and it was found that the concentration of SEBS,the temperature and time of the chlorination reaction,the ratio of the chlorination reagent,and the content of the catalyst all had a certain influence on the degree of chlorination of the product.With the increase of temperature,time and catalyst concentration and SEBS concentration,the reaction rate of chloromethylation will be accelerated,when the ratio of trioxymethylene:trimethylchlorosilane(molar ratio)=1:2,1:3 and 1:4 At 60°C,after 11 h of reaction,the reaction degree with the molar ratio of trioxymethylene: trimethylchlorosilane=1:3 reached 32.54%,which was close to the reaction degree of the molar ratio=1:4,while the molar ratio was 1:4.Ratio= 1:2 response rate was only 24%.2.Synthesis of short-chain tertiary amine quaternized SEBS and its application in electrodialysis: CMSEBS with different chloromethylation was synthesized by controlling the reaction time,and then a series of QSEBS-x-TMA were successfully prepared by casting method Anion exchange membrane.As the degree of quaternization increases,more trimethylamine is grafted on the surface of the membrane,which enhances the water absorption capacity of the membrane surface and reduces the tensile strength of the membrane.Both the ion-exchange conductivity and water absorption of QSEBS-x-TMA membranes increased with the increase of ion-exchange capacity.The conductivity of the QSEBS-10-TMA film was 3.45 m S/cm at 85°C,while the conductivity of the QSEBS-25-TMA film reached 17.23 m S/cm.TGA shows that the QSEBS membrane will decompose only when the temperature is 120°C,which is suitable for the daily electrodialysis process.3.Synthesis of long-chain tertiary amine quaternized SEBS and its application in antibacterial and antifungal materials: using SEBS raw materials,by controlling the reaction time to synthesize CMSEBS with different degrees of chloromethylation,and then through quaternization reaction,with different alkyl chain tertiary Amines synthesized QSEBS quaternary ammonium salts.Its viscosity test found that through the quaternization reaction,the side chain of the benzene ring was positively charged with the introduction of long carbon chain amines,which could adsorb the negatively charged solid particles in the solution,so that the viscosity of the solution system increased,and with the increase of the degree of quaternary ammonium and increase.The anti-mildew properties of QSEBS-10-Cy were tested.On the third day of cultivation,the samples without anti-mildew materials covered more than 90% of the area of Penicillium and Aspergillus niger,and the samples coated with QSEBS-10-C18 were in When cultured for three days,no Penicillium grew on the surface of the sample,and the growth area of Aspergillus niger did not exceed 25%.The antibacterial properties of QSEBS-10-Cy were tested,and it was found that QSEBS samples had a certain inhibitory effect on both Bacillus subtilis and Escherichia coli,and with the growth of alkyl chains,the antibacterial properties were improved.The antibacterial effects of C18 samples against Escherichia coli and Bacillus subtilis reached 80% and82.8%,respectively.QSEBS-x-Cy series materials have certain antibacterial and antifungal effects,and have certain application prospects in the fields of environmental protection and biomedicine.