Reversible-deactivation Radical Polymerization (RDRP) Of Chloroprene

This thesis mainly studied the RDRP of chloroprene.The specific studies are as follows:The RDRP of chloroprene was carried out utilizing CoⅡ(acac)2 as catalysts.A linear fist-order kinetic plots was observed in all polymerizations,but the induction period decreased with higher ABVN concentrations.When[ABVN]0/[CoⅡ(acac)2]0 =2/1,the molecular weight of polymer increased linearly and molecular weight dispersion index(PDI)decreased to 1.80 versus conversion.It indicated the control effect was improved with monomer conversion.Besides,we used different kinds of solvents in the CMRP of CP,so that we could find out the influence of the solvents on the polymerization.It was found that the solvent effect was much more significant to the molecular weight deviation and distribution.The polymerization in toluene showed a good control compared with other solvents.Whereafter,we used different kinds of electron donors(ED)on the CMRP of chloroprene,so that we could find out the influence of ED on the polymerization.The induction time disappeared by adding ED.Absoluately,appending THF was benefical for improving the effect of control,this can be proved by Mn,GPC is similar to Mn,th,and PDI decreased versus conversion.The[CoⅡ(acac)2]-mediated radical polymerization of CP has been tentatively quenched by adding free radical scavenger of four methyl piperidine nitrogen oxide(TEMPO).The cobalt terminal was removed and polymer structure was analysised by 1H NMR.Three kinds of cobalt complexes were applied to the CMRP of CP,in which Co(salen*)played the best control polymerization of CP.Subsequently,we studied the effect of various factors on the polymerization of CP mediated by Co(salen*).The induction period followed by a linear fist-order kinetic plots was observed in all polymerizations,but the induction period decreased with higher ABVN concentrations.The control of CP polymerization demonstrated by the linearity of molecular weight growth versus conversion,and Mn,GPC was similar to Mn,th.We have used different kinds of solvents in the CMRP of CP,so that we could find out the influence of the solvent on the polymerization.It was found that the solvent effect was much more significant to the molecular weight deviation and distribution.The polymerization in benzene showed a good control compared with other solvents.Then,the influence of ED on the CMRP of CP was further evaluated.Absoluately,appending THF was benefical for improving the effect of control,this can be proved by Mn,GPC was similar to Mn,th,and this progress could keep low polydispersity.We tested cyanopropyl iodide(CP-I)as chain transfer agent,which was easily prepared and reasonably soluble in the radical polymerization of chloroprene initiated by potassium persulfate or redox initiation.The influence of CP-I concentrations on the CP polymerization was examined.The results showed that Mn,GPC was similar to Mn,th and monomer conversion has peaked at over 90%when the concentration of CP-I is low.What’s more,the structure of PCP-I was analysised by ’H NMR.The block copolymerization of CP with butyl acrylate(nBA)was studied and analyzed by GPC,’H NMR and DLS,for proving that PCP-I has the features of living polymerization.The results showed that PCP-b-PnBA and PCP-b-PMMA block copolymers were successfully prepared by continuous seed emulsion method.Furthermore,the block copolymerization efficiency of PCP-b-PnBA was higher than 95%.