Studies On Preparation And Polymerization Of Fluoroalkyl Methacrylate

1, 1,3-trihydroperfluoropropyl methacrylate (TFPMA) and 1,1,5-trihydroperfluoropentyl methacrylate (OFPMA) were prepared by esterification of methacrylic acid and the corresponding fluoroalkyl alcohols in the presence of phenothiazine and concentrated sulfuric acid. The effects of the amount of sulfuric acid, reaction duration and the addition of anhydrous sodium sulfate as dehydration agent on the yield of OFPMA were studied. The results shown that the yield of OFPMA was 75%— 80% based on the theoretical calculation under optimized experimental conditions and the addition of anhydrous sodium sulfate as dehydration agent.The second part was study on kinetics of bulk polymerization of TFPMA by Ultraviolet Spectrophotometry. An ultraviolet spetrophotometry was applied to determine the content of TFPMA and thus to detect the kinetics of the initial stage of polymerization in bulk or in solution initiated by 2,2'-azo-bis-iso-butyronitrile (AIBN). The results shown that the maximum absorption (λ max) of TFPMA was observed at 210nm with a molecular extinction coefficient of 8676 L·mol^-1·cm^-1. The kinetics equation was obtained as Rp=Kp[TFPMA]^1.01[AIBN]^0.50. The apparent activation energy of polymerization was determined to be Ea=70. 1kJ·mol^-1.Copolymer latex containing OFPMA was finally prepared by emulsionpolymerization of OFPMA with butyl acrylate(BA) and methyl methacrylate(MMA) using mixture of sodium dodecyl sulfate(SDS) and polyoxyethylene octylphenyl ether(0P emulsifying agent) as emulsifier. The copolymer was characterized by DSC, FT-IR and 'H-NMR techniques. The water absorption feature and the solvent resistance of latex films were investigated and the stabilities of latex were observed. Surface properties of the copolymer film were investigated by contact angle measurement. The results shown that the surface free energy of copolymer film decreased when OFPMA was incojporated into the copolymer structure. The surface free energy of the copolymer was determined to be 25. 12mJ;m"' when the concentration of OFPMA used in copolymerization is 20 wt%. Through annealing treatment, the surface free energy of copolymer film decreased to 23. 52mJ-m"'.