Study On The Modification Of SMA By Aliphatic Alcohol Ether And Its Retan-fatliquor Properties In Leather Processing

In order to improve the performance of styrene-maleic anhydridecopolymer (SMA) applied in leather industry, according to moleculardesign principle, styrene and maleic anhydride were polymerized tocopolymer, then modificated with long chain aliphatic alcohol to get anesterified product, neutralized by sodium hydroxide solution. Thereaction conditions on copolymerization of maleic anhydride withstyrene were studied through orthogonal experiments, then a series ofSMA aliphatic alcohol single esters, including SMA-g-O-3, SMA-g-O-6,SMA-g-O-10, SMA-g-O-15and SMA-g-O-20, were synthesized viaesterification by long chain aliphatic alcohols and the styrene-maleicanhydride which was prepared in optimum reaction conditions. Thestructure of the ultimate product was characterized by IR spectrum, therate of esterification was calculated basing on the change of the acidvalue in the system. A series of SMA aliphatic alcohol single ester saltswas obtained after neutralization. And the properties of surface tension,critical micelle concentration (CMC), wetting ability, foaming ability,emulsifying ability were discussed by surface chemical analysis. Finally,the retanning-fatliquoring property of the salts was researched in thispaper.In the experiment of synthesizing SMA copolymer, conversion rateof the product was regarded as the main target. Then, via experimentsthe best reaction condition to synthesize the SMA copolymer in toluenewas determined: n(St)∶ n(MA)=1∶1, m(toluene)∶ m(St+MA)=4.0∶1(solvent dosage of80%based on the whole reactants’ weight); initiativedosage of6%based on m(St+MA); reaction time of4h; chain transferagent dosage（BPO）of6%based on m(St+MA), reaction temperature of 80℃. Under the condition， the conversion rate reached to99.26%. Thechemical structure of SMA copolymer was characterized by IR and1H-NMR, the thermal stability was examined by DSC.In the experiment of synthesizing SMA odd-alcohlo ether esters,conversion rate of the product was regarded as the main targets. Then,via experiments the best reaction condition to synthesize the SMAodd-alcohlo ether esters in N-N dimethylformamide (DMF) wasdetermined: n(MA unit of SMA copolymer)∶n (-OH of aliphaticalcohol ether)=1∶1, m(DMF)∶ m(SMA+O-n)=3.0∶1, reaction timeof8h, catalyst (p-Toluenesulfonic acid) dosage of1.0%based onm(SMA+O-n), reaction temperature of100℃. The conversion ratereached to93.7%. The chemical structure of SMA odd-alcohlo etheresters was characterized by IR, their molecular weight and distributionwere measured by GPCThrough the esterified modification of SMA copolymer with thealiphatic alcohol ether, there was long chain alkyl on SMA, whichgreatly declined friction between the collagen fibers, and obtainedgood lubrication and compliant effect. At the same time, in molecularside chain of SMA a certain number of ethyoxyls was introduced, andeffectively improved water-solubility and resistance to acids, alkalis,salts etc. So this modification had advantages, not only did it keep thefilling performance of SMA, but also improved the softness of crustleather after retanning. At the same time, SMA tanning agent was soeasy to be emulsified that crust leather was plump, soft, flexible, andtook on excellent tensile strength and tear strength after being retanned.