高折射率聚硫醚的结构设计与制备

Structure design and preparation of high refractive index polythioether

为制备综合性能良好的高折射率聚硫醚,以2,5-二羟基-1,4-二噻烷为原料,通过酯化、取代、水解三步反应,设计合成了二元硫醇2,5-二巯基-1,4-二噻烷(DSDT);以双酚S为原料,通过酯化反应,设计合成了双烯4,4′-双(丙烯酰氧基)二苯砜(BADS);继而通过DSDT和BADS的巯基-烯点击反应制备了包含硫醚键、砜基和苯环结构的聚硫醚PDB。采用凝胶渗透色谱仪、傅里叶变换红外光谱仪和核磁共振波谱仪、差示扫描量热仪和热失重分析仪、紫外-可见分光光度计和椭圆偏振光谱仪表征了PDB的分子量及其分布、结构、热性能和光学性能,考察了催化剂、反应温度和溶剂对PDB分子量的影响规律。结果表明:三丙基膦可高效催化DSDT与BADS的巯基-烯点击反应。以三丙基膦为催化剂,在二氯甲烷中15℃反应24 h,可以得到数均分子量为4.08×10^(4)g/mol的PDB。PDB表现出良好的热性能(T_(5%)=273.9℃,T_(g)=93.7℃)、高的光学透明度(T_(450nm)=90%)和较高的折射率(n_(D)=1.6486)和阿贝数(28.5),在光学涂层中具有良好应用前景。

To prepare high refractive index polythioether with balanced thermal and optical properties,monomers 2,5-dimercapto-1,4-dithithiane(DSDT)and 4,4′-bis(allyl oxyl)diphenylsulfone(BADS)were first designed and synthesized,and subsequently polythioether PDB containing thioether bonds,sulfuryl groups and benzene structure was prepared via thiol-ene click reaction between DSDT and BADS.The molecular weight,chemical structure,thermal and optical properties of PDB were characterized by gel permeation chromatography,Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy,differential scanning calorimetry and thermogravimetric analyzer,UV-vis spectrophotometer and elliptical polarization spectrometer,respectively.The effects of catalyst,reaction temperature and solvent on the molecular weight of PDB were studied.The results showed that tripropyl phosphine catalyzed the thiol-ene click reaction between DSDT and BADS with high efficiency,and PDB with a number-average molecular weight of 4.08×10^(4)g/mol and a PDI of 1.59 was obtained after reacting of DSDT with BADS in dichloromethane at 15℃for 24 h.The PDB exhibited good thermal properties with 5%mass loss decomposition temperature of 273.9℃and T_(g)of 93.7℃,high optical transparency with a light transmittance of 90%at 450 nm,as well as high refractive index(n_(586nm)=1.6486)and balanced Abbe number(28.5),thus making it suitable for the application in optical coatings.