不饱和聚酯树脂室温固化体系研究进展

概述了不饱和聚酯树脂室温固化用氧化还原引发体系中引发剂、促进剂的种类和特点,并介绍了近年来不饱和聚酯树脂室温固化体系及其反应动力学的研究进展,旨在使人们对室温固化体系及其应用有一定的认识和了解。     

芳叔胺促进剂对不饱和聚酯树脂固化的研究

研究了过氧化二苯甲酰（BPO）分别与芳叔胺N，N－二甲基苯胺（DMA）、N，N－二甲基对甲苯胺（DMPT）和N－甲基－N－2－羟乙基对甲苯胺（MHPT）组成的体系引发不饱和聚酯树脂进行固化，在测定的温度范围内（0－40℃），芳叔胺的活性顺序为：MHPT＞DMPT＞DMA。用膨胀计法测定了芳叔胺引发不饱和聚酯树脂在甲苯中的引发速率。同时采用自恰场（SCF)密度泛函法（B3LYP）对三种芳叔胺进行了量化计算和结构分析，发现MHPT促进效果最佳的原因是羟基同氮原子形成分子内氢键，使氮原子上的孤对电子同苯环共轭程度不如DMA和DMPT，从而减少了氮原子电子密度的降低，有利于亲核取代反应。     

酚醛环氧型乙烯基酯树脂固化过程的研究

<正> 酚醛环氧型乙烯基酯树脂(以下简称W2-1树脂),是一类新型的不饱和聚酯树脂。它可用通用不饱和聚醋树脂室温固化的引发体系进行室温固化,固化树脂具有优良的机械强度、耐温性能以及耐腐蚀性能。然而,固化树脂的各种化学、物理性能在很大程度上取决于固化树脂的结构。本文研究了多种不饱和聚酯树脂的氧化-还原引发体系及固化条件对W2-1树脂固化过程及最终固化树脂性能的影响,并与通用不饱和聚酯树脂(307树脂〕和双酚A型聚酯树脂(323树脂)进行了比较。     

不饱和聚酯树脂微乳液的快速固化研究

探讨了过氧化物 (过氧化甲乙酮、过氧化氢、叔丁基过氧化氢、异丙苯过氧化氢 ) /抗坏血酸组成的氧化 -还原引发聚合体系对磺酸盐不饱和聚酯树脂及其油包水型微乳液的固化特性。结果表明 :磺酸盐不饱和聚酯树脂的凝胶时间和固化时间都比相应的微乳液长。 4种过氧化物中 ,过氧化氢的常温引发聚合反应最快 ,能使微乳液 30s内凝胶 ,7min内固化 ,达到了快速固化的目的     

生产不饱和聚酯树脂I号引发剂的新工艺

一、前言不饱和聚酯树脂I号引发剂即过氧化环己酮的邻苯二甲酸二丁酯糊,是国内通用的不饱和聚酯树脂引发剂。其生产工艺一般分为直接法和间接法两种。间接法是在稀硝酸介质中,低温条件下用双氧水氧化环己酮,直接法是以邻苯二甲酸二丁酯(以下简称二     

2005-2006年国外不饱和聚酯树脂工业进展

综述了2005~2006年国外不饱和聚酯树脂的市场动态、工业发展趋势及技术进展。市场动态包括:原油价格及其对UPR的影响;UPR与不同成型方法的FRP的消费概况;面对全球经济发展战略,UPR树脂工业的兼并重组和发展;2005年中国UPR进出口量;2005年日本不饱和聚酯树脂的消费量;不饱和聚酯复合材料及其应用和销售;汽车用复合材料的不饱和聚酯树脂配方。技术进展包括:固化程度监测仪器;不饱和聚酯树脂的新型改性剂—环氧改性酚醛清漆;低轮廓添加剂;双重引发和促进体系。对生物复合材料工业进展进行了重点介绍。     

过氧化甲乙酮/异辛酸钴引发固化UPR的研究

采用过氧化甲乙酮(MEKP)/异辛酸钴氧化还原体系20℃下引发固化不饱和聚酯树脂(UPR),研究MEKP和异辛酸钴用量对UPR凝胶时间和放热峰温度的影响,结果表明,MEKP适用量为树脂质量的2.0%~3.0%,异辛酸钴适用量为树脂质量的0.02%~0.04%。     

N-甲基-N-2-羟乙基对甲苯胺和过氧化物引发体系

研究了N,N 二甲基苯胺(DMA)和N 甲基 N 2 羟乙基对甲苯胺(MHPT)与过氧化物组成的引发体系对不饱和聚酯树脂(UPR)固化的影响。结果表明:在促进剂浓度相同时,MHPT的凝胶时间为DMA的1/4～1/7,固化时间为DMA的缩短50%～25%,放热峰温度和巴氏硬度比DMA的高;固化温度与凝胶时间曲线表明MH PT比DMA的反应活性更高。温度比较低时(5℃),2,4 二氯代过氧化二苯甲酰(DCBPO)和过氧化二苯甲酰(BPO)/DMA体系不能使树脂快速固化,而DCBPO和BPO/MHPT体系能使树脂快速固化。使用DSC对固化的树脂样品进行非等温扫描,结里显示玻璃化转变温度和固化程度比DMA的高。     

不饱和聚酯树脂室温固化引发剂体系

<正>不饱和聚酯树脂的固化是遵循游离基(共)聚合反应原理.游离基(共)聚合反应,除用加热、光照(紫外光)或高能射线(X、γ射线等)辐照引发外,绝大多数都是在引发剂的存在下实现的.引发剂的作用在于受热后分解产生游离基,游离基与不饱和聚酯及不饱和单体(交联剂)作用以引发(共)聚合反应.目前,不饱和聚酯树脂固化用的引发剂主要是有机过氧化物.这些有机过氧化物的分解活化能一般在25—40千卡/摩尔之间,临界温度在60℃以上,对于固化温度要求在     

不饱和聚酯树脂BPO/DMA/MHPT固化体系的研究

采用引发剂过氧化苯甲酰(BPO)和复合促进剂N,N-二甲基苯胺(DMA)/N-甲基-N-2-羟乙基对甲苯胺(MHPT)组成的固化体系,室温条件下对不饱和聚酯树脂(UPR)进行固化,研究了BPO用量为5.0%、促进剂总量为4.0%时改变DMA与MHPT配比对UPR凝胶时间、固化速度及原子灰的凝胶时间、表干时间、附着力的影响,得出了MHPT和DMA的适宜质量比为1.5:2.5,可使UPR在固化过程中有较长的施工期、后期快速固化,且原子灰有适宜的表干时间和良好的附着力。     

Maleic anhydride formation from 1, 3-butadiene oxidation over a vanadia molybdate catalyst

Steady-state and transient studies of the partial oxidation of butadiene to maleic anhydride were performed over a Te-promoted vanadia molybdate catalyst previously used by Fiolitakis et al. (1983) for a study of maleic anhydride production from benzene. Inhibition of the partial oxidation by butadiene was observed. Pathways for CO₂ and maleic anhydride formation are different. False-start behaviour for some products was observed and attributed to conflicting contributions of adsorption and catalyst reduction or oxidation. The reaction mechanism for butadiene differs from that reported from benzene oxidation by Fiolitakis et al. (1983).     

H2O2、金属离子等对Cr（Ⅵ）离子光催化还原及对敌敌畏农药光催化氧化的影响

以Cr(Ⅵ）离子、敌敌畏农药作为污染物的代表，研究了H2O2、金属离子等对Cr(Ⅵ）离子光催化还原及对敌敌畏农药光催化氧化的影响。结果表明，加入少量的H2O2对Cr(Ⅵ）离子的光催化还原起阻碍作用，对敌敌畏农药的光催化氧化起促进作用；加入少量的Cu^2 对Cr(Ⅵ）离子光催化还原及对敌敌畏农药的光催化氧化均起促进作用；加入Zn^2 ,Na^ 对Cr(Ⅵ）离子及敌敌畏农药的光催化降解均无明显的影响；加入甲醇、甲苯对Cr(Ⅵ）离子的光催化还原起促进作用，对敌敌畏农药的光催化氧化起阻碍作用。探讨了H2O2、金属离子等对Cr(Ⅵ）离子光催化还原及对敌敌畏农药光催化氧化影响的机理。     

Total Oxidation of Hydrocarbons on Perovskite Oxides

Perovskite-type oxides containing transition metals are attracting great attention as catalysts for complete oxidation of hydrocarbons as well as electrochemical reduction of oxygen (1). A s far as I know, the use of perovskite-type oxides as catalysts was first reported by Meadowcroft in 1970 (2) for the electrochemical reduction of oxygen. Soon after that, Voorhoeve et al. (3) reported the high catalytic activity of perovskite oxides for heterogeneous oxidation. These studies triggered many studies thereafter which are related to exhaust control catalysts and electrode catalysts.     

Total Oxidation of Hydrocarbons on Perovskite Oxides

Perovskite-type oxides containing transition metals are attracting great attention as catalysts for complete oxidation of hydrocarbons as well as electrochemical reduction of oxygen (1). A s far as I know, the use of perovskite-type oxides as catalysts was first reported by Meadowcroft in 1970 (2) for the electrochemical reduction of oxygen. Soon after that, Voorhoeve et al. (3) reported the high catalytic activity of perovskite oxides for heterogeneous oxidation. These studies triggered many studies thereafter which are related to exhaust control catalysts and electrode catalysts.     

Transport phenomena in packed bed reactor technology for chemical looping combustion

Chemical looping combustion (CLC) is potentially the technology best suited for capturing CO₂ at low cost and efficiently providing a low energy option for the separation of CO₂ from flue gases. The process consists in the cyclic reduction and oxidation of metal oxide particles, which act as oxygen carriers. The particles are exchanged between two reactors, usually a circulating fluidised bed and a bubbling bed reactor, where the oxidation and reduction reactions occur, respectively. Noorman et al. (2007) explored a dynamically operated packed bed for CLC technology. Successive work undertaken by the same group (Noorman et al., 2009) has shown the feasibility of the concept, and expressions for the mass and heat front velocities were determined. In this work, the oxidation of the packed bed reactor is analysed as a problem presenting discontinuities which are sustained by transport processes and are indistinguishable from phase interfaces. Travelling mass and heat fronts arise as a consequence of the reaction kinetics; a specific problem is analysed, where the oxidation is modelled similarly to an adsorption problem and the mass front velocity is calculated for some limiting transport conditions. It is shown that the mass front velocity arises naturally when the Kotchine's procedure (Astarita and Ocone, 2002) is applied to the system. An interesting feature of the analysis presented here is that some general results can be obtained without making any specific assumption about the kinetics. The results obtained are indeed amenable to be extended to other processes where the reacting material is a bed of solid particles. The treatment presented can be implemented when small perturbations occur in the bed, thus giving useful information on predicting whether the unwanted changes in the process conditions are sustained or die out.     

基于铝粉为原料制备的三元碳化物Al4SiC4的研究进展

本文综合介绍Al4SiC4的最新研究进展。三元碳化物Al4SiC4属于六方晶体结构，空间群为P63mc,它具有优异的的高温抗氧化性能；优良的热稳定性和良好的室温及高温力学性能等。     

环己烷催化氧化催化剂的研究进展

综述了国内外环己烷选择性氧化催化剂的研究进展,对目前环己烷氧化所用催化剂体系进行了总结及比较分析,重点介绍了分子筛催化剂体系中TS-1、MCM、SBA-15等分子筛催化体系.     

壳聚糖的改性及其应用进展

介绍了壳聚糖的结构;重点论述了壳聚糖的一些主要的改性方法,包括醚化、氧化、酰化、交联、烷基化、接枝共聚、季铵化及和其他材料复合等方法;并综述了壳聚糖及其衍生物在水处理、医药、食品加工及其他领域的应用现状。     

Differential pulse voltammetry studies of heavy metal fluoride melts

A study of the electrochemistry of trace metals in heavy metal fluoride melts at 550 °C has been conducted at a stationary electrode with a view to establishing electroanalytical methods for these melts. Reproducible differential pulse voltammetry traces were obtained, the trace metal oxidation peaks behaving as predicted by the theory of Osteryoung et al. The peak current for Fe²⁺ reduction in a fluoride melt was found to be linear in pulse amplitude up to 70 mV and linear in (pulse duration)^–1/2. The peak potential was also found to be a linear function of pulse amplitude. Scan rates around 3 mV s^–1 and sampling times around 8 ms were found to produce the optimum analytical response.     

涂装前处理——电泳节能减排实践浅谈

就奇瑞汽车股份有限公司涂装一车间的2奈电泳生产线所做的一些涂装节能减排工作,从生产线的工艺状况、降本措施、措施实施过程中问题的解决以及达到的效果进行介绍。