Synthesis Of High Oil-absorbing Resin By Single-electron Transfer-living Radical Polymerization

With development of industry and improvement of living standard, environmentalproblems resulting from oil pollutions are becoming more and more severe. Highoil-absorbing resin as a novel self-swelling functional material has been researched as apopular topic. Single electron transfer-living radical polymerization (SET-LRP), as a novelCLRP, has unique advantages over other polymerization process, such as low reactiontemperature, wide monomer compatibility, little dosage of catalyst and fast polymerizationrate. In this paper, copolymerization of methacrylate with a small amount of cross-linker,initiated with halogenoalkane and modified macroinitiator was performed for preparation ofhigh oil-absorbing resin by SET-LRP. The influence of experimental parameters onpolymerization was systematically studied.Crosslinking copolymerization of butyl methacrylate with a small amount of cross-linker(DVB or PETA) was carried out using SET-LRP initiated with halohydrocarbons (CCl4orCHBr3) and catalyzed by Cu(0)/HMTA in N,N-dimethylformamide to produce highlyoil-absorbing gels (CCl4-BMA-PETA, CCl4-BMA-DVB, CHBr3-BMA-PETA). Analysis ofmonomer conversion with reaction time showed that the polymerization followed first-orderkinetics for both linear and crosslinking polymerization before gelation. Gelation propertiesrevealed that initiator type influenced gelation time and gel fraction. Effects of crosslinker,initiator, and catalyst on the oil-absorbing properties of the crosslinked gel were investigatedin detail. The oil absorptions of CCl4-BMA-PETA, CCl4-BMA-DVB and CHBr3-BMA-PETA to chloroform could reach51.9g/g,42.1g/g and30.5g/g, respectively. Under conditionof Cu(0)/TEMED, oil absorption of CCl4-BMA-PETA gel was43.5g/g. Reusability capabilityshowed that the gels performed good reusability after5cycles.The cellulose macroinitiator was prepared by esterification of hydroxyl group with2-bromoisobutyryl bromide (BiBB), followed by grafting with butyl methacrylate (BMA) andpentaerythritol triacrylate (PETA) to synthesize high oil-absorbing materials by SET-LRP. Thekinetic plot for SET-LRP grafting of poly-(BMA-co-PETA) onto cotton fibers showed thatpolymerization performed living characters. Under optical conditions, the maximum oilabsorption of poly(BMA-co-PETA) to chloroform and toluene could reach29.0g/g and15.4g/g. Compared with the original unmodified cotton fibers, the surface of cellulose-based poly-(BMA-co-PETA) became coarse, which confirmed the successful polymerization ofBMA onto cotton fibers. Thermogravimetric analysis (TGA) revealed that the oil-absorbingmaterial can be used under normal conditions (<200°C).Keratin extracted from wasted human hair by ammonium thioglycolate reduction methodwas successfully functionalized by2-bromoisobutyryl bromide to produce three differentsubstitution degrees of macroinitiator. The SET-LRP grafting of PMMA on keratin wasdetermined to be first-order kinetics, and substitution degrees did not influencepolymerization kinetics. The keratin-g-poly (MMA-co-PETA) oil-absorbing gel was obtainedwith the maximum oil absorption of chloroform reaching21.4g/g. The order of oil absorptioncapability of keratin-g-poly (BMA-co-PETA) gel was established as chloroform (43.7g/g)>tetrachloromethane (38.8g/g)> tetrahydrofuran (27.9g/g)> toluene (27.5g/g)> n-hexane(2.7g/g). Compared with ordinary gels initiated with halohydrocarbons, the hybridoil–absorbing gel was provided with a robust construction, well oil absorption capacity andgood reusability.