The properties of equimolar copolycarbonates of bisphenol A with bisphenol S and 1,4-bis(hydroxymethyl)cyclohexane

Ranges of both alternating and random 1:1 copolycarbonates of Bisphenol-A (2,2-bis(4-hydroxyphenyl)propane) and Bisphenol-S (4,4′-dihydroxydiphenyl sulphone) and of Bisphenol-A and 1,4-dimethanoylcyclohexane have been synthesized in order to test the hypothesis that, other things being equal, a more random structured polymer should exhibit superior thermal ageing characteristics. Studies on these materials' mechanical and thermal properties establish that within each pair they are extremely similar and hence the original hypothesis is disproved.     

4,4′-二羟基二苯砜的研制

研究了由苯酚与浓硫酸在高温下缩合制备4,4′-二羟基二苯砜(双酚S)的工艺。利用高效液相色谱仪对反应过程进行监测,确定了合成双酚S的最佳反应条件和比较经济的提纯方法。利用该方法,原料硫酸的转化率高于76％,未反应苯酚通过蒸馏回收利用,提纯过程中产物损失较少。制得产品的纯度在98.5％以上,熔点为249℃。     

Cure Kinetics and Thermal Property of Bisphenol-S Epoxy Resin and Phthalic Anhydride

Abstract

The cure kinetics of bisphenol-S epoxy resin (BPSER) and curing agent phthalic anhydride, with N,N-dimethyl phenzylamine as an accelerator, were studied by means of differential scanning calorimetry (DSC). Analysis of DSC data indicated that an autocatalytic behavior showed in the first stages of the cure. The autocatalytic behavior was well described by the model proposed by Kamal including two rate constants, k1 and k2, and two reaction orders, m and n. The overall reaction order, m + n, is in the range 2～3. The activation energies for k1 and k2 were 111.69 and 80.47 KJ/mol, respectively. Diffusion control was incorporated to describe the cure in the latter stages. The glass transition temperatures (T_gS) of the BPSER/anhydride samples isothermally cured partially were determined by means of torsional braid analysis (TBA). and the results showed that the reaction rate increased with increasing T_g in terms of the rate constant, but decreased with increasing conversion. The T_g of completely cured BPSER/anhydride system is about 40 K higher than that of BPAER. The thermal degradation kinetics of this system was investigated by thermogravimetric analysis (TGA). It illustrated that the thermal degradation of the BPSER/phthalic anhydride has n-order reaction kinetics.     

Synthesis, characterization, and thermally activated polymerization behavior of bisphenol-S/aniline based benzoxazine

A difunctional benzoxazine monomer, 6,6′-bis(3-phenyl-3,4-dihydro-2H-benzo[e][1,3]oxazinyl) sulfone (BS-a), was synthesized via a solution method from bisphenol-S, aniline and formaldehyde. The chemical structure of the benzoxazine was confirmed by ¹H and ¹³C nuclear magnetic resonance spectroscopy, Fourier transform infrared (FTIR) spectroscopy, elemental analysis, and size exclusion chromatography. The ring-opening polymerization of BS-a monomer was investigated with FTIR under air and nitrogen atmospheres, and with differential scanning calorimetry (DSC) in both dynamic and isothermal conditions. The FTIR results show that the absorption intensities of C-O-C, C-N-C, and oxazine ring decrease gradually with temperature and time rising during the polymerization reaction. The change rates of some absorption intensities of oxazine ring are affected by different atmospheric environments, and a higher degree of conversion is obtained in nitrogen than that in air at the same reaction temperature and in equal time. Kinetic parameters of the dynamic polymerization DSC results were evaluated with Kissinger and Ozawa methods, respectively. The isothermal DSC results show that the polymerization reaction of BS-a monomer follows an autocatalytic mechanism.     

双酚S环氧树脂的研究进展

概述了双酚S环氧树脂的合成方法、固化机理、性能及应用进展。     

4,4′-二羟基二苯砜的研制

研究了由苯酚与浓硫酸在高温下缩合制备4,4′-二羟基二苯砜(双酚S)的工艺。利用高效液相色谱仪对反应过程进行监测,确定了合成双酚S的最佳反应条件和比较经济的提纯方法。利用该方法,原料硫酸的转化率高于76％,未反应苯酚通过蒸馏回收利用,提纯过程中产物损失较少。制得产品的纯度在98.5％以上,熔点为249℃。