Preparation Of Re-processable Itaconate Rubber And Application Of Crude Carbon Dots In The Field Of Rubber Antioxidants

Rubber is widely used because of its unique high elasticity.However,the rubber industry also has the following unavoidable problems:(1)The vulcanization process of rubber makes it difficult to reprocess the cross-linked rubber products,which causes serious waste of resources;(2)In order to prolong the use of rubber,the method of adding antioxidants is often used in the processing process to inhibit its aging.However,universal antioxidants are environmentally harmful substances and do not conform to the concept of sustainable development.In this context,we propose to solve the problems caused by rubber in a sustainable way.On the one hand,the topological rearrangement of the cross-linked network structure by introducing dynamic covalent bonds into the rubber chains endows the samples with reproducible processability.On the other hand,the simple synthesis process of carbon dots(CDs),low cytotoxicity and excellent antioxidant activity make CDs a promising development in the field of antioxidants.In the first part of this thesis,emulsion polymerization synthesizes epoxidized biobased itaconic acid ester rubber(PDBIBG).Succinic acid(SA)was used as a cross-linking agent and the epoxy group in PDBIBG was used as a cross-linking point,which reacted to generate dynamic covalent bonds that can undergo ester exchange.During reprocessing,a certain percentage of the uncured sample was added.After four repetitions of processing,the mechanical property recovery rate of the samples SA/PDBIBG could all be maintained above 90%,which was a substantial improvement compared with the directly reprocessed samples.In addition,by chemical recovery under acidic conditions,we could obtain linear carboxylated rubber.In the second part of this thesis,diethylenetriamine passivated crude carbon dots(DETA-CCDs)were synthesized by microwave-assisted synthesis.The results of cytotoxicity,TEM,FTIR,Tyndall effect,XPS,UV-vis spectroscopy and PL spectroscopy showed that DETA-CCDs were sphere-like particles with non-uniform particle size distribution and functional groups such as-COOH,-OH and-NH2,and DETA-CCDs had excellent antioxidant activity.After that,DETA-CCDs were mixed with bio-based itaconic acid ester rubber(PDBIB)to prepare.PDBIB/CCDs film samples.the PDBIB/CCDs samples were tested by UV lamp irradiation and PL spectroscopy,and the results showed that the PDBIB/CCDs samples had excellent fluorescence.In the third part of this thesis,composites containing antioxidants(anti-4020/DETA-CCDs)were prepared by using synthetic DETA-CCDs as antioxidants in a simple mechanical compounding method.The effect of DETA-CCDs on the aging resistance of natural rubber(NR)was investigated through comparative experiments.Compared with anti-4020,DETA-CCDs can scavenge the reactive radicals generated during thermal-oxidative aging,effectively delaying the aging of the NR matrix,thus significantly improving the thermal-oxidative aging resistance of NR/CCDs composites.