| Polymer optical materials are widely used in display,lighting,medical and packaging fields because of their light weight,high impact resistance and easy processing.However,due to the relatively low refractive index of traditional polymer materials,they can not meet the requirements of high-end optical equipment.At present,many novel polymer optical materials only pursue high refractive index,while ignoring other optical properties such as transmittance and Abbe number,which makes the optical properties of polymers unbalanced and difficult to meet the requirements of practical use.The introduction of sulfur into the polymer system can not only improve the refractive index of the polymer,but also will not reduce the Abbe number too much,so as to obtain polymer with relatively balanced optical properties.The thiol-ene click chemical reaction is characterized by mild reaction conditions,rapid reaction and easy separation of products,so it is chosen to prepare sulfurcontaining optical polymer.In this paper,dithiol monomer with high sulfur content were firstly synthesized and then reacted with dienes monomer to prepare sulfur-containing optical polymers.Using 2,5-dihydroxy-1,4-dithiothane as raw material,2,5-dimercapto-1,4-dithioane with sulfur content up to 69.5% was synthesized through three steps.2,5-diacetoxy 1,4-dithiane(DADT)was first synthesized by esterification of 2,5-dihydroxy 1,4-dithiane with acetic anhydride,and purified by methanol recrystallization.2,5-dithioacetoxy-1,4-dithiothioacetic acid(DTDT)was then synthesized by the substitution reaction of DADT with thioacetic acid,and purified by column chromatography.The effects of reaction temperature,catalyst dosage and raw material concentration on the yield of DTDT were also investigated.Finally,2,5-disulfanyl-1,4-dithiane(DSDT)was synthesized by acidic hydrolysis of DTDT.The structure and purity of the products were characterized by fourier transform infrared spectrometry(FTIR),nuclear magnetic resonance spectrometry(NMR)and gas chromatography-mass spectrometry(GC-MS).Moreover,the thermogravimetric(TGA)property and melting point of DSDT were also determined.The results show that DSDT has been successfully synthesized.The 5% weight-loss temperature of DSDT in nitrogen atmosphere is 161.6?.A mixture of cis-and trans-isomers of DSDT was synthesized.The melting points of cis-isomer and trans-isomer were 49? and 121?,respectively.DSDT can be stored stably at low temperatures for a long time.1,4-phenylbis(methylene)bis(acrylate)(PBMBA)dienes monomer was synthesized by the reaction of 1,4-benzodimethyl alcohol with acryloyl chloride.Sulphur-containing polymer(PTE)was synthesized by thiol-ene click reaction between DSDT and PBMBA with chloroform as solvent and hexamine as catalyst.The effects of reaction temperature,reaction time,feed ratio of DSDT to PBMBA,the ratio of cis-isomer to trans-isomer of DSDT,as well as the monomer concentration on molecular weight of PTE polymer were studied.The structure,molecular weight and its distribution,thermal and optical properties of PTE polymer were characterized by FTIR,NMR,gel permeation chromatography(GPC),TGA,differential scanning calorimetry(DSC),UV-Vis spectrometry and elliptical polarization spectrometry.The results show that under nitrogen atmosphere,the 5% weight loss temperature of PTE is 269.3?,and the glass transition temperature of PTE varies between26.4? and 30.5?.The transmittance of PTE in the visible region is more than 93%,the refractive index is 1.644,and the Abbe number is 39.1,indicating that PTE has good and balanced optical properties... |
PDF Full Text Request