The influence of latex blend composition on crosslinking and mechanical properties

Model reactive latices were synthesized by semicontinuous emulsion copolymerization of n‐butyl methacrylate and acetoacetoxyethyl methacrylate or dimethylaminoethyl methacrylate. The two functional latices were then blended in various ratios to study the influence of blend composition on crosslinking and mechanical properties of the resulting films. Crosslinking was quantified through swelling measurements. It was found that the crosslink density increased with increasing amounts of acetoacetoxy‐functional polymer. In addition, the crosslink density exhibited two maxima, at 30/70 and 70/30 (acetoacetoxy‐functional latex/amino‐functional latex) blend compositions. The mechanical properties of the films were quantified by dynamic mechanical analysis (DMA). It was shown that optimal mechanical properties occurred when the particles packed most efficiently at the 30/70 and 70/30 blend compositions. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 3774–3779, 2007     

Thermal degradation and ageing behavior of microcomposites of natural rubber,carboxylated styrene butadiene rubber latices,and their blends

The effect of microfillers on the thermal stability of natural rubber (NR), carboxylated styrene butadiene rubber (XSBR) latices, and their 70/30 NR/XSBR blend were studied using thermogravimetric method. Microcomposites of XSBR and their blend were found to be thermally more stable than unfilled samples. The activation energy needed for the degradation of polymer chain was calculated from Coats‐Redfern plot. Activation energy needed for the thermal degradation of filled samples was higher than unfilled system. It indicated the improved thermal stability of the filled samples. The ageing resistance of the micro‐filled samples was evaluated from the mechanical properties of aged samples. The thermal ageing was carried out by keeping the samples in hot air oven for 7 days at 70°C. The mechanical properties such as tensile strength, modulus at 300% elongation, and strain at break were computed. As compared to unfilled samples, micron‐sized fillers reinforced systems exhibited higher ageing resistance. Finally, an investigation was made on the influence of ion‐beam irradiation on microcomposites of NR, XSBR latices, and their 70/30 blend systems using ²⁸Si⁸⁺ performed at 100 MeV. The surface changes of the samples after irradiation were analyzed using X‐ray photoelectron spectroscopy. The results of XPS measurements revealed that the host elements were redistributed without any change in binding energies of C_1s, O_1s, and Si_2p. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

絮凝法处理水溶性乳胶漆废水

介绍用絮凝剂法处理水溶性乳胶漆废水。先用石灰将废水的ｐＨ值调节到８，加入絮凝剂硫酸铝、铝离子型有机高分子絮凝剂，静置、过滤，再经粉煤灰、石英砂吸附。经处理后的废水色度、ＳＳ均可达排放标准，ＣＯＤ去除率也较高。     

The Influence of a Phase Transition in Poly(oxyethylene)/Poly(oxypropylene)/Poly(oxyethylene) Block Copolymer Surfactants on the Properties of Material Adsorbed from Dilute Aqueous Solution

In this study the adsorption of poloxamer block copolymer surfactants to polystyrene latex has been studied at a range of temperatures. It has been noted previously that the adsorption first falls, then rises and falls again as the temperature is increased, due to the existence of a phase transition in aqueous solutions of these surfactants at specific temperatures, which may be a critical micelle temperature. The present study shows that the hydrophobicity of the surface changes in a manner related to the amount of poloxamer adsorbed (i.e. is greatly influenced by the temperature of adsorption in relation to the transition temperature). The coating layer thickness, however, is essentially unchanged by the temperature of adsorption (i.e. not related to the amount adsorbed), but is influenced by the temperature at which the sizing was undertaken. This is due to dehydration of the poly (oxyethylene) with increasing temperature. The data presented here provide a possible explanation for the changes in biological distribution of poloxamer coated particles which occur when they are injected into animals.     

天然橡胶胶乳热稳定性测定方法

论述了几种天然橡胶胶乳热稳定性测定方法的特点及其在应用上存在的问题，指出了进一步研究胶乳热稳定性测定方法的必要性     

胶乳水泥浆体系在剑门1井尾管悬挂固井中的应用

剑门1 井是四川石油管理局承钻的一口重点预探井，该井井底压力高达120 MPa，多次发生气侵、井漏。鉴于此种情况，现场决定四开钻至5004 m 中途完钻，下?177.8 mm 尾管固井。为解决深层高压井尾管固井问题，选用了胶乳水泥浆体系，对该体系的失水控制和防漏失性能、防窜性能、水泥石性能，水泥浆流变性，水泥浆的稳定性、水泥浆稠化时间进行了室内试验。工艺方面采用正注反挤、间歇式低压挤水泥的固井工艺，以减少一次注替静液柱压力过大造成的漏失，易于建立挤水泥压力。经优选水泥浆体系和采用适合该井井况的固井工艺，成功地封隔了 4584~4930 m 4 个严重漏失层，取得了较好的作业效果。剑门1 井?177.8 mm 尾管悬挂固井的成功经验可供此类复杂井固井参考。     

Electrochemically instantaneous reduction of conducting polyaniline-coated latex particles dispersed in acidic solution

A cathodic voltammetric wave was observed in an aqueous suspension of mono-dispersed, spherical polyaniline-coated polystyrene particles, whereas no anodic wave was detected. This irreversibility was common to particles with eight different diameters ranging from 0.2 to 7.5 μm. Such irreversibility cannot be found at polyaniline-coated electrodes, and thus is a property of the dispersion of polyaniline latex. The reduction current was controlled by diffusion of dispersed particles. The reduction, being the conversion from the electrical conducting state to the resistive one, should begin at a point of contact between the conducting particle and the electrode in order to be propagated to the whole particle rapidly. In contrast, the oxidation proceeds slowly with the propagation of conducting zone, during which Brownian motion lets the particle detach from the electrode. The number of loaded aniline units per particle, determined by weight analysis, ranged from 6 × 10⁶ (Ø 0.2 μm) to 3 × 10¹¹ (Ø 7.5 μm) and was proportional to 2.9 powers of the particle diameter. The diffusion-controlled current of the cathodic wave was proportional to 2.4 powers of the diameter. The difference in these powers, 0.5, agreed with a theoretical estimation of the diffusion-controlled current, the diffusion coefficient for which was given by the Stokes-Einstein equation.     

浸绒家用手套的配方及工艺选择试验

介绍了浸绒家用胶乳手套的配方及工艺的选择试验，发现增稠剂ＣＭＣ与ＰＨＰ并用能使手套绒层绒毛均匀、平整，工艺性能得到改善。     

苯丙乳液及其乳胶漆的制备

以水作溶剂，以苯乙烯、丙烯酸酯、丙烯酸、聚乙烯醇等共聚合成乳液，在此基础上进一步制备了乳胶漆（内墙涂料），对制得的乳液及内墙涂料进行了测试实验，讨论了影响因素，并给出了乳液和内墙涂料较佳的合成工艺。     

天然橡胶中脂肪酸的分析与研究

天然橡胶和复合橡胶在许可证管理和关税税率方面存在较大的差异,使海关对复合橡胶的进口监管面临着较大风险。本方法紧贴海关监管要求,利用气相色谱和溶解法对天然橡胶中的各种脂肪酸进行分析和测定,通过对比天然橡胶加入工业硬脂酸后制成的复合橡胶中脂肪酸的变化,对添加工业硬脂酸的复合橡胶进行定性分析。