The Design And Synthesis Of Block Copolymer Based On Trans-1,4-polyisoprene

Block copolymers based on polyisoprene have shown a good application in nanofibers, thermoplastic elastomer, pressure-sensitive adhesive, biological friendly materials, coatings and nano porous material. But the current widely used methods that anionic polymerization and living free radical polymerization have poorly control in polyisoprene stereo-microstructure, cannot simply reflect the effect of trans-1,4 microstructure on the properties of block copolymer. In this paper, the block copolymers based on TPI were synthesized by TPI oxidative cleavage accompanied with terminated groups functionalization and modification combined with ATRP polymerization or RAFT polymerization.Firstly, the aldehyde and ketone terminated groups functionalized TPI were successfully synthesized by indirect oxidation claeavage and direct oxidation claeavage two methods by H5IO6, and found that indirect oxidation decomposition by H5IO6 method have better effects than indirect oxidation decomposition. Beside, use CHCl3 dissolve TPI to synthesis CTTPI have lesser residual amount of epoxy group in molecular chain than THF. DSC characterization results showed that the CTTPI still has good crystallization ability. The terminated aldehyde and ketone group of CTTPI were reduced to double temminated-hydroxyl that have better reactivity with NaBH4. The leave group methyl sulfonyl chloride graft to molecular chain double end of TPI through the efficient esterification reaction between double terminated-hydroxyl of HTTPI with sulfonyl chloride group, then the double end azide functionalized of TPI were successfully synthesized by the displacement substitution reaction between NaN3 with methyl sulfonyl chloride.The ATRP macromolecular initiators Br-TPI-Br were successfully synthesized through the efficient esterification reaction between double terminated-hydroxyl of HTTPI and 2-Bromoisobutyryl bromide. Then Br-TPI-Br as initiator, PMDETA as ligands, CuBr as catalyst, though control the time of styrene polymerization, A series of three block copolymer polystyrene-block-trans-1,4-polyisoprene-block-polystyrene(PS-b-TPI-b-PS) were achieved, and characterized by 1H-NMR, FTIR, GPC, DSC.The RAFT macromolecular chain transfer agent CTA-TPI-CTA was successfully synthesized by the esterification reaction between RAFT reagent 2-Methyl-2-[(dodecylsulfanylthiocarbonyl)sulfanyl]propanoic acid and double terminated-hydroxyl of HTTPI with activator DMAP and EDC·HCl. Then AIBN as initiator, though control the time of isopren polymerization, A series of base on TPI three block copolymer polyisoprene-block-trans-1,4-polyisoprene-block-polyisoprene(PI-b-TPI-b-PI) were synthesized, and characterized by 1H-NMR.