低温固化双马来酰亚胺树脂基体研究—引发剂的作用

本文以典型的ＸＵ２９２双马体系为研究对象，选用引发剂加速树脂的固化反应，以期得到低温化耐热的双马树脂体，研究结果表明，引发剂能很有效地降低马树脂的固化温度，低温固化阶段比高温固化阶段对树脂耐热性的影响更大，经１２０℃／８ｈ＋１４０℃／２ｈ＋１６０℃／２ｈ固化树脂的热变形温度为２６６℃再经１８０℃／８ｈ的后处理，热变形温度达到３００℃     

改性双氰胺固化环氧树脂研究

用自行研制的改性双氰胺（ＭＤＣ－１）固化环氧树脂Ｅ－５１,经自制咪唑盐及双酚Ａ促进和改性后,环氧树脂的固化反应得到较大加快,可实现较低温度的中温固化。本文考察了组分用量对树脂固化反应特性和性能的影响,并优化了树脂的固化工艺参数,得到的树脂配方为Ｅ－５１／ＭＤＣ－１双酚Ａ／咪唑盐＝１００／８／２０／０．５,固化工艺为８０℃／１ｈ＋１００℃／２ｈ,后处理工艺为１２０℃／２ｈ。树脂浇铸体具有良好的性能,     

低温固化双马来酰亚胶树脂基体研究──引发剂的作用

本文以典型的ＸＵ２９２双马体系作为研究对象，选用引发剂加速树脂的固化反应，以期得到低温固化耐热的双马树脂体系。研究结果表明，引发剂能很有效地降低双马树脂的固化温度，低温固化阶段比高温固化阶段对树脂耐热性的影响更大。经１２０℃／８ｈ＋１４０℃／２ｈ＋１６０℃／２ｈ固化树脂的热变形温度为２６６℃，再经１８０℃／８ｈ的后处理，热变形温度达到３００℃。     

改性双马来酰亚胺树脂的固化工艺研究

本文用ＤＳＣ法研究改性双马来酰亚胺树脂的固化动力学参数和固化工艺,固化度和红外光谱确定了后处理工艺。研究所得的固化工艺条件中１４０℃／ｈ、１９０℃／２ｈ,２４０℃／４ｈ能达到完全固化。     

盐雾老化对风电叶片用环氧树脂性能的影响

采用差示扫描量热(Differential Scanning Calorimetry,简称DSC)、红外光谱(Fourier transform infrared spectroscopy,简称FTIR)、静态力学性能测试等分析方法对复合材料风电叶片用环氧树脂浇铸体老化前后的性能进行分析,通过对比盐雾老化前后树脂浇铸体的玻璃化转变温度(Glass transition temperature,简称Tg)和力学性能,研究了环氧树脂浇铸体的老化机理。结果表明,树脂浇铸体的Tg随着老化时间的增加呈现先上升后下降的趋势,老化20天时Tg由未老化前的55℃升高到62℃,20天后开始下降,到50天时下降为51℃,比未老化的下降了4℃。随着老化时间的增加,树脂浇铸体力学强度和模量均呈下降趋势,50天盐雾老化后树脂浇铸体的弯曲强度和拉伸强度分别下降了13%和12%,而弹性模量和弯曲模量分别下降了16%和9%。     

环氧/咪唑固化体系性能研究

以４,５－环氧基环己烷１,２－二甲二缩水甘油酯为基体,以２－乙基－４－甲基咪唑为固化剂,通过ＤＴＡ分析,体系的固化工艺条件为８０℃／２ｈ＋１１０℃／２ｈ＋１５０℃／２ｈ＋１８０℃／２ｈ,体系活化能为５５．５９ｋＪ／ｍｏｌ,反应级数为０．９２１。结果表明,浇铸体拉伸弹性模量高达５．２６ＧＰａ,可用于高性能复合材料基体。     

华东理工大学华昌聚合物有限公司主要产品一览表

环氧乙烯基酷树月旨几一l耐高温，树脂浇铸体即T125℃，耐溶剂及氧化性介质讯一3耐高温，树脂浇铸体即T145℃，耐蚀、适宜制作耐高温F即制品盯E一l耐蚀性好、耐温树脂浇铸体HDT105℃盯E一2耐酸、耐溶剂、耐温和耐碱腐蚀性能优良、树脂浇铸体即T102℃娜E一3韧性、优异的防渗漏和密封性，耐沮，树脂浇铸体即T102℃舒E一4纸浆厂CI压漂白系统、氛喊行业电解槽专用树脂盯E一5耐蚀抗渗漏，良好的气干性、耐温，树脂浇铸体HDTgO~100℃盯E一6耐温、耐水，适宜制作高档胶衣层价E一7化学阻然、氧指数高达40以_卜娜E一9高柔韧性、断裂延伸率11…     

聚偏氟乙烯乳液后处理工艺的研究

研究了聚偏氟乙烯(PVDF)乳液凝聚、洗涤分离、干燥等后处理工序。结果表明,用凝聚剂破乳、离心分离的PVDF乳液后处理工艺是可行的。凝聚效果明显,凝集粒径达到了28～32μm;离心分离完全,洗涤母液的电导率小于5μS／cm。制得的PVDF制品色泽纯白。合适的后处理工艺条件为：凝聚剂硝酸铝质量分数为1％、凝聚温度大于或等于60℃、凝聚搅拌转速为100r／min、树脂干燥温度115—120℃、树脂干燥时间24h。     

苎麻增强UP树脂复合材料的研究

以邻苯型不饱和聚酯(UP)树脂为基体、以苎麻布为增强材料,在室温条件下模压成型制备苎麻布／UP树脂复合材料,利用同时热分析仪STA研究了该复合材料的耐热性能,并将其力学性能与纯UP树脂浇铸体的相应性能进行了对比研究。结果表明：苎麻／UP树脂复合材料的耐热性能较纯UP树脂浇铸体有所提高;其拉伸强度及拉伸模量、弯曲强度及弯曲模量、冲击强度等各项力学性能指标均明显优于纯UP树脂浇铸体。     

TDE-85/DDM固化体系性能研究

采用胶化时间与ＤＴＡ分析,研究了ＴＤＥ－８５／ＤＤＭ体系的固化工艺,根据ｋｉｓｓｉｎｇｅｒ和Ｏｚａｗａ方程,研究出体系的活化能与反应级数,并对浇铸体的力学性能及断口形貌进行了分析。结果表明,ＴＤＥ－８５／ＤＤＭ体系的固化工艺为８０℃／３ｈ＋１２０℃／４ｈ＋１８０℃／４ｈ,活化能为４２．７４ｋＪ／ｍｏｌ,反应级数为０．９５０６,机械性能较高,是一种刚而韧的基体。     

氢气纯度分析方法准确性的探讨

ONACCURACYOFANALYSISOFOFHYDROGEN1前言我公司目前应用的氢气纯度分析方法有两种,一种是爆炸反应法,另一种是焦性没食子酸吸收法。几年来,人们对两种分析方法的准确性曾有过褒贬不一的评论。这里我们也谈谈自己粗浅的观点。2爆炸法测定氢气纯度一定量的氢气样品与适量的空气之均匀混合物因反应后生成液体水而引起气体体积减少,减少的体积等于参加反应气体体积之和。其中l／3为氧气,2／3为氢气。根据氢气取样量和反应前后混气体体积之差,以及氢气在反应中的体积比例关系,可计算出样品的氢气纯度。计算公式式中：A一混…     

COMPARISON OF METHODS OF ANALYSIS OF GYPSUM1

The different analytical methods proposed for the evaluation of gypsum have been subjected to an experimental test. A combination method, consisting of a fusion with KHCO₃ and determination of CaO by KMnO₄ titration, the SO₃ by Andrews method of titration of BaCrO₄ has been found to give very reliable results with the least consumption of time.     

SEDIMENTATION OF BINARY MIXTURES OF PARTICLES OF UNEQUAL DENSITIES AND OF DIFFERENT SIZES

A model is developed for the sedimentation from a suspension of two particle species of unequal densities and of different sizes. The composition and the thickness of various layers in the sediments are predicted using graphical and analytical methods. The model predictions were in excellent agreement with experimental results, when the particle size ratio was ≥ 108. When size ratio of the particles was 2.60 and 4.31 the agreement occurred in about 50 percent of the cases.     

HEASUREHENT OF INSTANTANEOUS RATES OF LOSS OF VOIATILE COMPOUNDS DURING DRYING OF DROPS

A novel technique serves to monitor instantaneous rates of loss of a volatile solute from a suspended drop during drying. A highly sensitive electron capture detector is used to monitor concentrations of SF6 released into a flowing gas stream from a suspended, drying drop. Simultaneously, the appearance and morphological development of the drop are monitored with a video camera. This provides the wherewithal of relating instantaneous rates of loss of the volatile solute to particular events during the development of particle morphology.

Initial experiments have been carried out with drops of aqueous solutions of glucose, sucrose, maltodextrin and coffee extract. The results clearly display the onset of the volatiles-retentive selective diffusion phenomenon. There is also substantial loss of the volatile component later in the drying process, when the drops undergo repeated ex ansion, bursting and cratering due to the formation of internaf bubbles. These experiments appear to be the first quantitative demonstration of major losses accompanying changes in drop morphology.     

茶多酚提取方法进展

本文综述了国内外现有茶多酚提取方法的现状以及近期的研究进展，并对其优缺点进行了评价。这将有助于中低档茶的综合利用和茶多酚的进一步开发应用。     

ANALYSIS OF RECENT MEASUREMENTS OF THE VISCOSITY OF GLASSES

Viscosity of Simple Soda-Silicate 500° to 1400°C Comparison of the results given by English with those of Washburn, Shelton and Libman, indicates a discrepancy in the absolute values of log₁₀ viscosity amounting to 0.6, those of Washburn et al., being relatively too high. If correction for this is made, the isothermal curves of log₁₀ viscosity as a function of soda content are smooth up to 50% Na₂O, showing no inflection. The observations as a function of temperature T are all represented within accidental error by an equation of the type where all three constants vary regularly with the composition. Change of Viscosity of Glass (6SiO₂, 2Na₂O) due to Molecular Substitution of CaO, MgO and Al₂O₃ for Na₂O The effect is clearly brought out by plotting (from the results of English) the change of log₁₀η due to the substitution as a function of temperature. The curves each show a sharp bend at a temperature between 840° and 1050°C, which is designated the aggregation temperature T_a. If we divide these curves by the corresponding percentage substituted, we get curves for each oxide which are straight and parallel below the aggregation temperatures, the slopes (increase of change of log₁₀η per 100°C) being −0.056 (CaO), −0.055 (MgO), −0.018 (A1₂O₃) per per cent oxide substituted. For substitution of 1/2 molecule the slopes are −0.325 (CaO), −0.23 (MgO) and −0.18 (Al₂O₃) per 100°. At the aggregation temperature the change of log₁₀η per per cent is a minimum, 0.03 to 0.06 for CaO, 0.12 for MgO, 0.07 for Al₂O₃. Evidence of Aggregation in Glasses, from viscosity Measurements The sharp bends in the plots of change of log₁₀η due to substitution of an oxide for Na₂O, suggest the beginning of molecular aggregation at these temperatures. These aggregation temperatures are close to the devitrification temperatures, but the effect on the viscosity curves cannot be due to actual devitrification since it does not change with time. Taking the aggregation temperatures as equal to devitrification temperatures, additional isotherms are roughly sketched into the equilibrium triangle of the system Na₂O-CaO-SiO₂. Change of Viscosity of Glass (4SiO₂, 2Na₂O) due to of Substitution of B₂O₃ for SiO₂ The change of log₁₀η (from the results of English) is plotted as a function of temperature, and also the change of log₁₀η per per cent B₂O₃. The curves are more complex than for the substitution for Na₂O.     

环氧树脂羟基值测定方法的研究

利用乙酸酐、吡啶和浓硫酸混合的乙酰化试剂测定环氧树脂中羟基值含量的方法具有操作简便、滴定终点明显和分析结果误差小等优点。     

骑式摩托车油箱喷涂工艺的改进

面对日益激烈的市场竞争,摩托车油箱外观质量越来越成为影响销售的因素之一。文章介绍了改进工艺后的油箱涂装,该涂装体系提高了油箱外观的丰满度,降低了油箱涂装的生产成本。     

几种针状焦性能对比

针状焦分石油系和煤系两大类,这主要取决于针状焦的原料来源。在同一系列中由于原料不同和工艺条件不同 ,针状焦的各自性能也不相同。针状焦是生产超高功率石墨电极和高功率石墨电极的主要原料 ,针状焦的性能对石墨电极的质量有至关重要的影响。所以对针状焦性能以及其对石墨电极质量影响的研究十分必要的。以下是常用的几种进口针状焦和国产针状焦的性能对比。１原料性能分析对比原料试样包括４种针状焦 ,其中两种为进口针状焦：三菱针状焦和新日化针状焦;另两种为国产针状焦：鞍山针状焦和锦州针状焦。其中除锦州针状焦是石油系针状焦外…     

聚酰亚胺的合成法

本文评述了缩聚型聚酰亚胺的主要合成方法和近年来国际上在合成中所做的探索。