复合材料RTM模具的制备

根据树脂传递模塑(RTM)模具对基体树脂的基本要求,选用双酚A环氧乙烯基酯树脂为基体,聚乙酸乙烯酯为低收缩添加剂,玻璃纤维经编织物为增强材料,并加入相应的助剂,制备了复合材料RTM模具。该模具具有成本较低、开发周期短、精度较高等优点,但表面强度和热效率较低。     

Small-angle neutron scattering from branched epoxide resins

Small-angle neutron scattering experiments in the range of q² from 0.01 to 25 nm⁻² have been carried out on branched epoxide resins based on bisphenol-A at the Institute Laue—Langevin (I.L.L) in Grenoble (q=(4π/λ) sin(θ/2)). Measurements were made with six samples in the range of M_W from 1500 to 19 000 and four concentrations between 1.3 and 10% (w/w) in deuterated diglyme. The results are as follows: (i) The mean square radius of gyration follows a relationship S²_z=4.69×10⁻⁴M^1.20_W (nm²). (ii) In all cases fairly large second virial coefficients A₂ are obtained which, however, decrease strongly with molecular weight. Above M_W=2500, the virial coefficient follows the relationship A₂=1.6M^−0.85_W (mol cm³g⁻²). (ii) The reciprocal particle scattering factor as a function of q² exhibits only a slight upturn and otherwise shows the behaviour of a randomly branched polycondensate. The slight upturn is discussed as being caused by the finite volume of the monomeric unit. Possible reasons for the high exponent in the S²_z versus M_W dependence are briefly discussed.     

双酚A溴化过程中的溶剂效应

以脂肪醇-水、氯苯、乙酸、环己烷、硝基苯、氯苯-醇、环己烷-醇为溶剂,采用溴素/双氧水原位溴化-氧化法合成了四溴双酚A.考察了不同溶剂对产品收率、纯度、操作工艺的影响.结果表明,弱极性的环己烷对双酚A的溶解性不佳,不适于作为合成四溴双酚A的溶剂;而环己烷-脂肪醇混合溶剂,由于加大了溶剂的极性使溴化反应成为可能;乙酸、脂肪醇、硝基苯、氯苯、氯苯-脂肪醇为极性溶剂,可加速反应,是合成四溴双酚A的良好溶剂,其中氯苯-脂肪醇混合溶剂,可避免以纯氯苯为溶剂时的碱洗、水洗操作,从而大大简化合成工艺,从工业化的角度看是很好的选择.     

Characterization of Commercial Grades of Poly(Carbonate of Bisphenol A)

This study characterized three different commercial grades of poly(carbonate of bisphenol A) samples (for extrusion, CD, and DVD) by several instrumental analysis methods, such as elemental analysis (EA), inductively coupled plasma mass spectrometry (ICP-MS), Fourier-Transform infrared spectroscopy (FTIR), viscosity measurements, differential scanning calorimetry (DSC), and thermogravimetry analysis (TGA). The results of EA and ICP-MS showed that the chemical composition of the samples has no significant differences and the C/H ratio approaches theoretical value. The most abundant metal element in the samples is Fe. FTIR spectra demonstrated they have the same chain structure. Comparing the intrinsic viscosities and viscosity average molecular weights from the results of viscometry analysis, the values fell in the order: extrusion grade > CD grade > DVD grade. Various thermal properties determined by DSC and TG analysis showed the same sequence as the results of viscometry analysis and a close relationship between molecular weight and thermal properties was found.     

PBPAF／PBPA共混物相容性的研究

研究了双酚ＡＦ基聚合物和双酚Ａ基聚合物的共混相容性。通过用ＤＳＣ，ＴＭＡ测定单一聚合物和共混物的玻璃化温度来判别它们的相容性．结果表明，两种聚合物在部分组成比时有一定的相容性。     

Oestrogenicity of paper and cardboard extracts used as food containers

Bisphenol-A (BPA), dibutyl phthalate (DBP), and di-2-ethylhexyl phthalate (DEHP), which are common chemical residues in food-packaging materials, were investigated in paper and cardboard containers used for take-away food. The oestrogenicity of aqueous extracts was tested in E-Screen bioassay and analysis carried out by high-performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC/MS). Oestrogenicity was demonstrated in 90% of extracts (geometric mean [GM] = 11.97 pM oestradiol equivalents g^-1). DEHP, DBP, and BPA (GM = 341.74, 37.59, and 2.38 ng g^-1 of material) were present in 77.50, 67.50, and 47.50% of samples, respectively. In bivariate analyses, no significant association was found between the levels of these chemicals and oestrogenicity in cardboard/paper extracts. A close-to-significant association was found between oestrogenicity and DBP (β = 1.25; p = 0.06) in paper extracts, which reached statistical significance in multivariate analysis (β = 1.61; p = 0.03). Paper and cardboard used in food packaging may contribute to the inadvertent exposure of consumers to endocrine-disrupting chemicals.     

BMI／ER／DDS三元体系固化反应动力学研究

用差示扫描量热(DSC)研究了BMI／ER／DDS三元固化体系的反应动力学,计算出了表观活化能△E、碰撞因子A和反应级数n,并结合傅里叶变换红外光谱(FTIR)对反应机理进行了探讨,指出了反应过程中生成的叔胺对固化反应的进行有重要促进作用,为进一步研究耐高温复合材料、胶粘剂等奠定了基础。     

Two-component initiator systems for the ring-opening polymerization of oligomeric cyclic bisphenol-A carbonates: The in situ cleavage of disulfides by triarlyphosphines

A two-component initiator system based on the in situ cleavage of phenyl disulfide by a triarylphosphine has been developed for the ring-opening polymerization of cyclic bisphenol-A (BPA) carbonate oligomers. This development has potential use in composite applications such that the prepolymer can suitably wet the composite material before being converted to high-molecular-weight polymer. The initiator precursors (phenyl disulfide and triphenylphosphine) do not independently initiate significant ring-opening polymerization of the oligomeric cyclic BPA carbonate mixture. A mixture of cyclic BPA carbonate oligomers and one of the initiator components (phenyl disulfide), combined and heated at 300°C with a mixture of the cyclics and the other initiator component (triphenylphosphine), does produce a high-molecular-weight polymer (M_w = ∼ 70,000). The polymerization-initiating species is thought to be thiophenyltriphenylphosphonium thiophenoxide. The effects of concentration of the initiator components, reaction temperature, time, and so forth on polymerization were studied; in general, the degree of polymerization ranged from about 65 to 75%. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 2251–2255, 1997     

Influence of Risk Factors for Male Infertility on Sperm Protein Composition

Male infertility is a common health problem that can be influenced by a host of lifestyle risk factors such as environment, nutrition, smoking, stress, and endocrine disruptors. These effects have been largely demonstrated on sperm parameters (e.g., motility, numeration, vitality, DNA integrity). In addition, several studies showed the deregulation of sperm proteins in relation to some of these factors. This review inventories the literature related to the identification of sperm proteins showing abundance variations in response to the four risk factors for male infertility that are the most investigated in this context: obesity, diabetes, tobacco smoking, and exposure to bisphenol-A (BPA). First, we provide an overview of the techniques used to identify deregulated proteins. Then, we summarise the main results obtained in the different studies and provide a compiled list of deregulated proteins in relation to each risk factor. Gene ontology analysis of these deregulated proteins shows that oxidative stress and immune and inflammatory responses are common mechanisms involved in sperm alterations encountered in relation to the risk factors.     

分子蒸馏双酚A环氧树脂的性能研究

采用普通市售128环氧树脂经过分子蒸馏,去除轻馏分和多聚体重组分后,得到双酚A分子环氧树脂,牌号为JF-9955A。通过红外光谱和液相色谱分析,基础性能和Na+含量检测以及对其酸酐固化物性能的测试将JF-9955A与国外陶氏化学的DER 332、BakeliteEPR 162高纯度双酚A环氧树脂进行了对比。结果表明,JF-9955A具有粘度低,纯度高,可水解氯及其他离子杂质含量低等特点,各项性能指标达到国外同类产品水平。