Fe~(2+)/H_2O_2对脲醛树脂胶ζ电位及其稳定性的影响

采用胶体化学的方法对Fe2+/H2O2影响脲醛树脂(UF)胶ζ电位及其稳定性的因素进行了研究。结果表明,在pH=8.0时,脲醛树脂胶粒的ζ电位平均值约-32.5mV,粒子带负电,并以单分散形式存在。随着Fe2+离子或H2O2加入量的增加,脲醛树脂胶ζ电位的绝对值迅速减小,从而使胶粒间排斥势垒降低,胶粒发生聚集,体系粘度随之增大并最终产生凝胶。其中,Fe2+离子对脲醛树脂胶粒的ζ电位和粘度η变化的影响幅度比H2O2更为明显。pH值对胶体稳定性的影响主要表现在,pH值约为9时,体系具有最大的ζ电位,除此之外,pH值增大或减小ζ电位的绝对值均迅速减小,其中pH9时ζ电位的绝对值下降幅度更为明显。采用胶体的双电层理论对Fe2+/H2O2影响脲醛树脂胶稳定性的机理进行了探讨。     

Influence of Mixing Conditions on Morphologies and Properties of MMT/Epoxy Resin Composite Materials

Montmorillonite(MMT) was directly modified with hexadecyl trimethyl ammonium bromide. The interlayer spacing of the organophilic montmorillonite(organo-MMT) corresponding to the d(001) plane peak was 2.21 nm. The influences of the content of organo-MMT and mixing conditions including mixing temperature and mixing time on the intercalation and exfoliation structures of MMT/epoxy resin composites were investigated by wide X-ray diffraction(WXRD). The X-ray patterns reveal that organo-MMT was intercalated by the epoxy resin during mixing process. Only under certain mixing conditions, could the exfoliation nanocomposites be formed. The mechanical and thermal properties of the composites were measured. The results indicate that the composites have better mechanical properties and higher Tg than those of the pristine epoxy resin.     

弱阴离子超高交联树脂固相萃取-高效液相色谱-紫外法测定人尿中高香草酸的含量

建立了人体尿液中高香草酸含量的固相萃取-高效液相色谱-紫外测定方法.合成了弱阴离子超高交联树脂固相萃取填料,并对其进行吸附性能考察.利用此萃取剂对尿液中的高香草酸进行选择性吸附,洗脱液富集后以甲醇-乙酸(15∶85,V/V)溶液为流动相,C18为固定相,于280 nm测定其中的高香草酸.方法验证结果表明,高香草酸在2.26～145 mg/L浓度范围内呈良好的线性关系;检出限为0.45 mg/L;方法的平均加标回收率大于90％;RSD小于4.2％.采用本方法对8名健康人尿样中的高香草酸含量进行了测定,结果为1.55～6.79 mg/L.表明本方法选择性好、灵敏度高、准确可靠.     

Synthesis and Characterization of Silver Nanoparticle Modified 3-Aminophenol Resin Microspheres with Application for Determination of Carcinoembryonic Antigens by Surface-Enhanced Raman Scattering

Uniform phenolic resin microspheres were prepared by the polycondensation of 3-aminophenol and formaldehyde. On the surface of the 3-aminophenol resin microspheres, silver nanoparticles were synthesized in situ and immobilized by simple heating. The composite was employed as a substrate for surface-enhanced Raman scattering (SERS). The SERS enhancement factor was evaluated using 4-mercaptobenzoic acid and Nile blue A as signal molecules. A highly sensitive SERS immunoassay that combined labeled antibody conjugated silver nanoparticle modified 3-aminophenol resin microspheres and coating antibody conjugated magnetic nanoparticles was fabricated to determine carcinoembryonic antigen. A linear relationship was obtained between the Raman intensity and the concentration of carcinoembryonic antigen. The limit of detection was 1.2 picograms per milliliter at a signal-to-noise ratio of three. This is believed to be the first report of a SERS immunoassay using silver nanoparticle modified 3-aminophenol resin microspheres as substrates.     

环氧树脂共混物相结构的调控方法研究

研究了环氧树脂(E51)/聚砜(PSF)共混物相结构的控制方法.通过抑制相分离、控制预固化的反应程度控制环氧树脂的分子量,固化后可获得不同的共混物相结构.依据红外测定的固化反应程度设定固化程序,可有效控制共混物的相结构.加入促进剂三氟化硼-乙基胺(BTF-EA)可提高固化反应速度,使相分离结构在早期被抑制,以获得小微区的相结构.     

Novolac/乙烯-醋酸乙烯酯共聚物共混体系中的反应诱导Spinodal相分离

Ｎｏｖｏｌａｃ／乙烯 醋酸乙烯酯共聚物共混体系中的反应诱导Ｓｐｉｎｏｄａｌ相分离陈文杰吴坚江明（复旦大学高分子科学系和国家教委聚合物分子工程实验室上海２００４３３）关键词Ｓｐｉｎｏｄａｌ相分离，共混物，光散射，酚醛树脂，固化反应在高分子多相体系中，...     

含刚性链节和脲端基聚醚增韧剂改性环氧树脂的研究———反应活性及力学性能

合成了一系列既含环氧丙烷聚醚（ＰＰＧ）柔性间隔基、又含刚性介晶结构单元的端脲基活性改性剂（ＬＣＥＵＰＰＧ），并对其改性环氧树脂Ｅ ５１／双氰双胺（Ｅ ５１／ｄｉｃｙ）体系的固化反应活性、改性剂含量对增韧体系动态力学性能及冲击性能的影响进行了研究．结果表明：ＬＣＥＵＰＰＧ的加入对固化体系具有明显的增韧作用，冲击强度提高了３～７倍；其对Ｅ ５１／ｄｉｃｙ固化反应具有明显的促进作用，可使固化反应表观活化能（Ｅａ）降低５０～７０ＫＪ／ｍｏｌ、固化温度降低３０～４０℃；体系的玻璃化转变温度（Ｔｇ）略有下降，但模量基本不降低或略有升高；β 转变向低温方向移动．     

氨基树脂透明防火涂料的发展概况

介绍了透明防火涂料的基本组成、类型、特点及其应用 ,概述了透明防火涂料的发展现状。     

Phenolic resins bearing maleimide groups: Synthesis and characterization

Novel phenolic novolac resins, bearing maleimide groups and capable of undergoing curing principally through the addition polymerization of these groups, were synthesized by the polymerization of a mixture of phenol and N‐(4‐hydroxy phenyl)maleimide (HPM) with formaldehyde in the presence of an acid catalyst. The polymerization conditions were optimized to get gel‐free resins. The resins were characterized by chemical, spectral, and thermal analyses. Differential scanning calorimetry and dynamic mechanical analysis revealed an unexpected two‐stage curing for these systems. Although the cure at around 275°C was attributable to the addition polymerization reaction of the maleimide groups, the exotherm at around 150 to 170°C was ascribed to the condensation reaction of the methylol groups formed in minor quantities on the phenyl ring of HPM. Polymerization studies of non‐hydroxy‐functional N‐phenyl maleimides revealed that the phenyl groups of these molecules were activated toward an electrophilic substitution reaction by the protonated methylol intermediates formed by the acid‐catalyzed reaction of phenol and formaldehyde. On a comparative scale, HPM was less reactive than phenol toward formaldehyde. The presence of the phenolic group on N‐phenyl maleimide was not needed for its copolymerization with phenol and formaldehyde. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 641–652, 2000     

对苯二酚改性聚二苯基硼硅氧烷的研究

应用熔融缩聚方法，用对苯二酚对硼硅氧烷聚合物进行改性，得到一种新型耐高温聚合物（ＰＢ）ＰＨ。并对其溶解性、热性能及其结构等作了详尽的论述。