Synthesis And Application Of Hydroxy-terminated Diene Liquid Rubber

Liquid rubber has the advantages of good fluidity,easy processing and continuous production.The development of functionalized liquid rubber can further expand the application field of liquid rubber.In this paper,a series of hydroxyl-terminated polydiene liquid rubbers were designed and synthesized by anionic polymerization,and then were applied to the preparation of photocurable,polyurethane,bio-based and other elastomers.The main research contents and results are as follows:Firstly,the synthesis and UV curing of double-ended acrylate-based polyisoprene was studied in this paper.A self-made oligomeric isoprene dilithium initiator was used to initiate the polymerization of isoprene,then ethylene oxide and acryloyl chloride were used in sequence to prepare a double-ended acrylate-based polyisoprene.Liquid rubber has a molecular weight of 3000-5000,3,4-PIwas about 55%.The influencing factors of end-capping were explored.The hydroxyl functionality and acrylate functionality could up to 1.93 and 1.89.Using the prepared double-ended acrylate-based polyisoprene as a prepolymer,methyl acrylate as a diluent,the double bond at the end groups could be completely converted under ultraviolet light for 2 minutes.The tensile strength of the photocurable elastomer material could reach 4.60-6.82 MPa,the elongation at break was 97-163%,and the hardness was 86.3-91.3.Secondly,the synthesis of double-ended hydroxyl polystyrene-butadiene liquid rubber and the preparation of styrene-butadiene polyurethane were studied.Lithium naphthalene initiator,butadiene dilithium initiator and protective group initiator 3-(t-butyldimethylsiloxy)-1-propyllithium were used to synthesize double-ended hydroxyl polystyrene-butadiene rubber,and the products under different initiator systems were investigated.structure.Studies showed that the lithium naphthalene initiator precipitated in the solvent,and the initiation effect was poor;The molecular weight distribution of liquid rubber synthesized by butadiene dilithium initiator could be as low as 1.10,1.2-Bd structure content was about 70%,the hydroxyl functionality could reach 1.70;The molecular weight distribution of the product obtained by 3-(t-butyldimethylsiloxy)-1-propyllithium was narrow,After acidification with hydrochloric acid to remove the protective group,the hydroxyl functionality of styrene-butadiene rubber could reach up to 1.95.Using double-ended hydroxyl polystyrene-butadiene rubber as the soft segment and isocyanate TDI cross-linking and chain extension to prepare hydroxystyrene-type polyurethane elastomer.When the ratio of soft and hard segments is 100:30,the Tan? value at 0? could reach 0.727 and the Tan? value at 60? could reach 0.096.Finally,this paper studied the synthesis of polymyrcene-polylactic acid elastomer.Double-terminal hydroxyl polymyrcene liquid rubber was synthesized using 3-(tert-dimethylsiloxy)-1-propyl lithium initiation and ethylene oxide end capping.relative molecular weight was 3000-20000.The structure content of 3,4-My could be increased from 5.9%to 56.5%by increasing m(ETE)/m(PMy),the hydroxyl functionality of the product could reach 1.92.Synthesized double-ended hydroxyl polymyrcene as macroinitiator,DBU as catalyst to initiate the ring-opening polymerization of L-lactide to prepare polymyrcene-polylactic acid block copolymer.The results showed that the relative molecular weight of the block copolymer was between 20,000 and 40,000,and the lactide monomer conversion rate decreased from 90.2%to 53.5%with the increased of the lactide/polymyrcene ratio.