Effects of chain end group composition and concentration on the properties of bisphenol A–tetrabromobisphenol A copolycarbonates

The types and concentrations of end groups present in bisphenol A-tetrabromobisphenol A copolycarbonates (BA-TBBA coPCs) have major effects on the copolymer solution washability and thermal stability. Six types of coPC end groups are possible: two by monophenol capping of each comonomer, two phenolics (BA-OH and TBBA-OH), and two carbamates (one from each comonomer). BA-TBBA coPCs were prepared by typical solution and interfacial methods and their phenolic and carbamate end group concentrations were correlated with their solution washability and thermal discoloration. Both phenolic and carbamate end groups proved deleterious to these two copolymer properties. An improved interfacial process that employs 4-N,N-dimethylaminopyridine as the coupling catalyst provides coPCs having low concentrations of phenolic and carbamate end groups and that, therefore, wash without emulsification and are thermally stable. © 1994 John Wiley & Sons, Inc.     

Parametres cinetiques de systemes epoxy/acide par analyse calorimetrique differentielle (DSC)

We have studied the curing of epoxy resin diglycidylether of bisphenol A (DGEBA), by two different hardeners poly(styrene-co-acrylic acid) (SAAx) at different acid percent and poly(acrylic acid). We follow the kinetics by non-isothermal and isothermal. In non-isothermal mode the heating rates were between 2.5 and 20°C min^-1 in the temperature range of 25-250°C. The reaction was supposed to follow the n ^th order. In isothermal mode, four temperatures for each system were done. In this case the reaction was autocatalysed. The interpretation of the exotherms allowed to determine the kinetic parameters of the studied systems. This revised version was published online in August 2006 with corrections to the Cover Date.     

Depolymerization of Poly（bisphenol A carbonate） in Subcritical and Supercritical Toluene

The depolymerization of poly(bisphenol A carbonate)(PC) in subcritical and supercritical toluene was studied. The experimental parameters, which influence the depolymerization reaction such as temperature (570-633 K), pressure (4.0-7.0 MPa), reaction time (5-60 min), and toluene to PC weight ratio (3.0-11.0), were investigated, and the reaction products were determined by GC, GC/MS and FT-IR spectrometer. It was found that the main product of the depolymerization reaction was bisphenol A(BPA). BPA accounted for over 55.7% of the depolymerization products at reaction temperature 613 K, pressure 5.0-6.0 MPa, reaction time 15 min and toluene/PC weight ratio of around 7.0.     

聚氧乙烯／聚酚氧共混体系的结晶行为及相容性研究

对聚氧化乙烯/聚酚氧(PEO/PH)共混体系的研究表明,随共混体系中非晶组份PH含量的增加,Avrami指数n值由2.0～2.3变为1.5～2.0,体系的结晶由盘状生长转化为纤维状生长;成核方式由方式Ⅰ转化为方式Ⅱ.PEO/PH共混体系的平衡熔点随PH含量的增加而降低,相互作用能量密度B=-1.46cal/mol,说明体系是互容的。     

Effect of prepolymer molecular weight on solid state polymerization of poly(bisphenol a carbonate) with nitrogen as a sweep fluid

The effect of prepolymer molecular weight on the solid‐state polymerization (SSP) of poly(bisphenol A carbonate) was investigated using nitrogen (N₂) as a sweep fluid. Prepolymers with different number–average molecular weights, 3800 and 2400 g/mol, were synthesized using melt transesterification. SSP of the two prepolymers then was carried out at reaction temperatures in the range 120–190 °C, with a prepolymer particle size in the range 20–45 μm and a N₂ flow rate of 1600 mL/min. The glass transition temperature (T_g), number–average molecular weight (M_n), and percent crystallinity were measured at various times during each SSP. The phenyl‐to‐phenolic end‐group ratio of the prepolymers and the solid‐state synthesized polymers was determined using 125.76 MHz ¹³C and 500.13 MHz ¹H nuclear magnetic resonance (NMR) spectroscopy. At each reaction temperature, SSP of the higher‐molecular‐weight prepolymer (M_n = 3800 g/mol) always resulted in higher‐molecular‐weight polymers, compared with the polymers synthesized using the lower molecular weight prepolymer (M_n = 2400 g/mol). Both the crystallinity and the lamellar thickness of the polymers synthesized from the lower‐molecular‐weight prepolymer were significantly higher than for those synthesized from the higher‐molecular‐weight prepolymer. Higher crystallinity and lamellar thickness may lower the reaction rate by reducing chain‐end mobility, effectively reducing the rate constant for the reaction of end groups. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4959–4969, 2008     

Synthesis and characterization of new soluble cardo polyesters derived from 1,1‐bis‐[4‐(4‐chlorocarboxyphenoxy)phenyl]‐4‐tert‐butylcyclohexane with various bisphenols by solution polycondensation

A new cardo diacid chloride, 1,1‐bis‐[4‐(4‐chlorocarboxyphenoxy)phenyl]‐4‐tert‐butylcyclohexane ( 4 ), was synthesized from 1,1‐bis‐[4‐(4‐carboxyphenoxy)phenyl]‐4‐tert‐butylcyclohexane in refluxing thionyl chloride. Subsequently, various new polyesters were prepared from 4 with various bisphenols by solution polycondensation in nitrobenzene using pyridine as a hydrogen chloride quencher at 150 °C. These polyesters were produced with inherent viscosities of 0.32–0.50 dL · g^?1. Most of these polyesters exhibited excellent solubility in a variety of solvents such as N,N‐dimethylformamide, tetrahydrofuran, tetrachloroethane, dimethyl sulfoxide, N,N‐dimethylacetamide, N‐methyl‐2‐pyrrolidinone, m‐cresol, o‐chlorophenol, and chloroform. These polymers showed glass‐transition temperatures (T_g's) between 144 and 197 °C. The polymer containing the adamantane group exhibited the highest T_g value. The 10% weight loss temperatures of the polyesters, measured by thermogravimetric analysis, were found to be in the range of 426–451 °C in nitrogen. These cardo polyesters exhibited higher T_g's and better solubility than bisphenol A‐based polyesters. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2951–2956, 2001     

高效液相色谱法测定饮料类食品中的类雌激素

利用OASIS HLB固相萃取柱富集和净化样品,采用高效液相色谱分离,紫外及荧光检测,建立了不同饮料基质中的壬基酚(NP)、辛基酚(OP)和双酚A(BPA)等类雌激素的测定方法,并用该方法对市售部分产品进行了测定。不同加标水平的BPA,NP和OP的回收率为91.08%~103.19%,其相对标准偏差为0.5%~5.49%。该方法具有操作简单、灵敏度高和重现性好等优点。     

加速溶剂萃取-液相色谱-质谱/质谱法分析动物组织中的壬基酚、辛基酚和双酚A

建立了测定内分泌干扰物质烷基酚、双酚A的液相色谱-电喷雾串联质谱(负离子模式)分析方法,优化了样品前处理方法。以二氯甲烷作提取溶剂,采用加速溶剂萃取法萃取动物组织样品,萃取液用500 mg OASIS氨基固相萃取柱进行浓缩净化。对流动相组分和流动相添加剂对质谱的离子化效率进行了考察,测得3种化合物在高、中、低3个添加水平的回收率为88%~101%,相对标准偏差小于15%;双酚A、壬基酚和辛基酚的方法检出限分别为0.3, 0.05和0.1 μg/kg。对从北京市场上采集的27份动物组织样品进行检测,结果表明壬基酚广泛存在于各种动物源性食品中,检出含量为0.49~55.98 μg/kg,其中鱼肉组织中都检出壬基酚,而且其含量也较高(9.13~55.98 μg/kg)。     

The Use of β-Cyclodextrin Inclusion Complexes for the Analysis of Bisphenol a Residues in Water by Spectrofluorimetry

Abstract

The application of β-cyclodextrin inclusion complexes to determine trace levels of bisphenol A (BPA) in aqueous solution by spectrofluorimetry was investigated. A 1:1 stoichiometry of the host-guest complex between β-CD and BPA, as well as the association constant was determined by using the changes in the fluorescence of BPA that occur when it is included in the hydrophobic cyclodextrin cavity. A simple and sensitive spectrofluorimetric method for the determination of BPA residues is presented; the applicable concentration range was 10.0 to 200.0 μgL^?1. The detection limit obtained was 0.5 μg.L^?1. The accuracy of the proposed method, was checked in the analysis of water samples from different sources previously spiked with different amounts of BPA.     

双酚F型聚酰亚胺的合成及其性能表征

以苯酚和甲醛为原料,合成了双酚F(BPF)和双酚F二酐(BPFDA),用BPFDA分别和间苯二胺(m-PDA)、4,4'-二氨基二苯醚(4,4'-ODA)、1,4-(4-氨基苯氧基)苯(TPEQ)反应,得到了3种双酚F型聚酰亚胺,分别对其结构、溶解性、热性能和力学性能进行了表征.结果表明:聚合物的比浓对数黏度为0.5～...