Design, Synthesis And Characterization Of Cyclopolymer Based On The Thorpe-Ingold Effect Of Silicon

In this thesis, Thorpe-Ingold effect on the silicon atom for cyclopolymerization of the unconjugate bis(acrylic) monomers was studied. A series of linear cyclic polymers with macro-cyclic8-18were synthesized by atom-transfer radical polymerization (ATRP). The properties of linear cyclic polymers were studied by Thorpe-Ingold effect on the silicon atom, include polymerization condition, reaction dynamic and structure of polymer, etc.1. Synthesis of polymers with ring structure (16and18) by Thorpe-Ingold effect:Linear polymers with14-members ring with predetermined molecular weights and narrow molecular weight distributions had been synthesized by ATRP method. In order to study the Thorpe-Ingold effect for linear cyclic polymers with macro-cyclic(>14), a series of monomers were synthesized by reaction between CH2=CH(CH3)COO(CH2)nOH and Ph2SiCl2and polymers with the bigger size ring structure (16,18) were synthesized based on different n value by ATRP. ATRP polymerization kinetics showed that the polymerization process below a specified conversion rate, and the reaction rate of cyclopolymerization would be reduced with the increasing of ring-size of the polymers. Moreover, Thorpe-Ingold effect cannot effectively induce to cyclopolymerization when the size of the ring is more than20. The intermolecular reaction will be happen and led to crosslink products. Based on the hydrolysis of Si-O bonds, the change of ring structure and molecule weight has been studied to further proved ring structure and ring degree. Stereochemistry of cyclization polymerization showed that these kinds of cyclization polymer have high stereo-selectivity for r (>70%) configuration.2. Synthesis of polymers with ring structure (8) by Thorpe-Ingold effect:Four kinds of monomers were synthesized by the reaction of different substituents of silane and α-hydroxymethylacrylate (MHMA). And the polymers with8-member-ring have been polymerized by traditional free radical polymerization and ATRP polymerization. GPC results showed that molecular weight distributions are range1.05to1.20. Cyclic structures were confirmed by the1H NMR,13C NMR, HSQC spectrums. The thermodynamic properties of polymer and crystallization properties of cyclization polymers have been investigated by TGA, DSC, XRD. The results showed that there are trans-dominated configurations (>90%) and high glass transition temperature owing to strength in cyclo structure and spatial structure.