共查询到20条相似文献,搜索用时 765 毫秒
1.
2.
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 … 总被引:1,自引:0,他引:1
合成了一系列既含环氧丙烷聚醚柔性间隔基,又含刚性介晶结构单元的端脲基活性改性剂,并对其改性环氧树脂E-51/双氰双胺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。 相似文献
3.
聚醚增韧环氧树脂的研究 总被引:1,自引:0,他引:1
通过端羟基聚四氢呋喃和顺丁烯二酸酐的反应制备了端羧基聚醚。用浊度测定、动态力学实验和扫描电镜观察等方法研究了聚醚增韧环氧树脂的结构形态。聚醚的分子量、端羧基含量以及固化条件对聚醚相颗粒尺寸有很大的影响。这些因素又进一步影响固化产物的力学性能。端羧基聚四氢呋喃作为环氧树脂的增韧剂有两个优点:(1)橡胶相的玻璃化温度低;(2)环氧树脂的耐热性不因添加增韧剂而降低。 相似文献
4.
工业中大量生产的端羟基聚醚 ,由于羟基的反应活性不够 ,不能直接用于增韧胺类固化的环氧树脂 .Bu2 SnO Bu3PO4 缩合物能催化羟基对环氧基的加成反应 .本文研究在Bu2 SnO Bu3PO4 缩合物Sn P6 70 0的存在下以端羟基聚四氢呋喃 (PTMG)增韧芳香胺 4,4′ 二氨基二苯砜 (DDS)固化的环氧树脂 .PTMG首先与环氧树脂反应生成嵌段共聚物 ,在固化时发生微相分离 .分散相的尺寸在有利于增韧的范围内 .PTMG在分子量与浓度适当时 ,能使树脂的断裂韧性大大提高 ;抗弯强度也有显著提高 ,而Tg 和模量略有降低 . 相似文献
5.
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 总被引:8,自引:0,他引:8
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. 相似文献
6.
聚醚酰亚胺改性TGDDM环氧树脂的相分离研究 总被引:7,自引:0,他引:7
合成了不同化学结构的聚醚酰亚胺(PEI)并用于4,4′-二氨基二苯甲烷四缩水甘油醚(TGDDM)环氧树脂的增韧改性,以DSC,TRLS和SEM等方法研究了体系相分离过程中相容性和熔融粘度对相分离过程和结构的影响,对固化反应诱导相分离中相结构的控制提出初步的看法. 相似文献
7.
含介晶单元的反应性增韧剂改性环氧树脂研究 总被引:3,自引:0,他引:3
合成了既含聚乙二醇醚(PEG)柔性链、又含刚性液晶结构单元的活性增韧促进剂(LCEUPEG),对其促进环氧树脂/双氰双胺体系的固化反应活性、反应机制;增韧剂的用量与动态力学性能、冲击性能之间的关系进行了研究.结果表明:LCEUPEG对E-51/dicy固化体系具有明显的促进作用,能有效的降低固化反应活化能及固化反应温度;改性体系的冲击强度较单纯的E-51/dicy体系提高3~7倍;模量较未增韧体系有所提高. 相似文献
8.
9.
用动态扭摆法测试聚丙烯酸丁酯橡胶增韧环氧树脂的动态力学行为,研究在环氧树脂低固化度和高固化度时,橡胶活性官能团种类(环氧基官能团与羧基官能团)和数量(官能度)对其影响。研究体系中橡胶玻璃化转变温度(Tg)的移动大小,与橡胶和基体树脂健合程度之间的关系。 相似文献
10.
11.
Abstract To study the effect of water affinity of the cured epoxy resin on water sorption and permeation in the cured epoxy resin, a novel hardener (esterfied phenol novolac was synthesized and used for obtaining the cured product without free hydroxyl group. Differential Scanning Calorimetry (DSC) and Fourier Transform Infrared Spectroscopy (FT-IR) were used to study the cure kinetics of o-cresol novolac epoxy resin using esterfied phenol novolac resin as curing agent in the presence of 2-methylimidazole as accelerator. Some kinetic parameters of the curing reaction such as the reaction order, activation energy, and frequency factor were obtained in the temperature range studied. The results show that this curing process is a first-order kinetic mechanism, which was different with that cured with phenol novolac resin. 相似文献
12.
Epoxy resins were cured by an amine telechelic poly(tetramethylene oxide) (PTMO). The telechelic amine was synthesized from hydroxy telechelic PTMO and was characterized. The kinetics of curing of epoxy monomer by the polyether amine was studied in detail by differential scanning calorimetry (DSC) and rheology to optimize the cure conditions. The cured epoxy system exhibited shape memory properties where PTMO served as the switching segment. Molar ratios of the epoxy monomer and the amine were varied to get polymers with different compositions. The developed polymers were analyzed by DSC, X‐ray diffraction, and Dynamic Mechanical Thermal (DMTA) analyses. Shape memory property was evaluated by bending tests. As the concentration of epoxy resin increased, the transition temperature (Ttrans) increased. The tensile strength and % elongation also increased with epoxy resin‐content. The extent of shape recovery increased with PTMO‐content with a minor penalty in recovery time. The polymer with the maximum PTMO‐content exhibited 99% shape recovery with a recovering time of 12 s. 相似文献
13.
电子束作用下双酚A型环氧树脂体系的固化特征 总被引:1,自引:0,他引:1
当前 ,先进树脂基复合材料基本上都是采用加热固化成型的 ,由于其工艺周期长 ,造成复合材料的制造成本较高 ,同时 ,热固化采用的固化剂和有机溶剂往往会对操作人员及环境造成危害 .为顺应复合材料低成本化和无公害化的发展趋势 ,树脂基复合材料的电子束辐射固化技术逐渐发展起来 .复合材料的电子束固化技术是在 2 0世纪 80年代初 ,由法国Aeropaticle的研究人员首先进行的[1] .近年来 ,美国、日本、加拿大及欧洲的许多国家都在积极从事于研究和利用此项技术 ,并且已经取得了可观的成果[2 ] .我国在这方面的研究工作也开始起步 .作… 相似文献
14.
电子束辐射固化环氧树脂的反应过程分析 总被引:2,自引:0,他引:2
对双酚A型环氧树脂的电子束辐射固化反应过程进行了分析.考察了引发剂、稀释剂对树脂体系辐射反应的影响,以环氧丙烷作为模型化合物,研究了环氧丙烷-碘盐体系的电子束辐射反应机理,证实了在电子束辐射下,碘盐分解产生质子酸,引发环氧树脂阳离子开环聚合的反应过程.观测环氧树脂辐射固化区域发现,电子束穿过样品时发生强烈的散射,在辐射方向以及周围一定区域内引发固化反应,固化反应从活性中心开始向体系内部层层扩展,整个固化区域由很多的层状结构组成. 相似文献
15.
环氧树脂与氰酸酯共固化反应的研究 总被引:19,自引:1,他引:18
应用DSC、FT IR对乙酰丙酮过渡金属络合物催化促进的环氧树酯与氰酸酯共固化反应行为、历程以及固化物的结构特征进行了研究探讨 .结果表明 ,促进剂能够明显的降低固化反应温度 ,缩短固化反应时间 .反应历程首先是氰酸酯发生自聚反应形成二聚体或三聚体 (三嗪环 ) ,然后二聚体可进一步共聚形成三嗪环 ,此过程伴随着环氧基的聚醚反应 ,最后是三嗪环与剩余的环氧基反应形成唑烷酮 .在氰酸酯欠量的条件下 ,固化树脂中主要是唑烷酮和聚醚结构 ,三嗪环结构很少 ;在氰酸脂适量或过量条件下 ,固化树脂主要是三嗪环和唑烷酮结构 ,聚醚结构很少 . 相似文献
16.
咪唑固化不同类型环氧树脂的固化特征、固化动力学及其反应活性 总被引:2,自引:0,他引:2
以咪唑为固化剂,对缩水甘油醚型、缩水甘油酯型环氧树脂(简称链型环氧树脂)及脂环环氧树脂的固化特征、固化动力学及反应活性进行了研究.DSC实验结果表明,固化过程均分两阶段进行,链型环氧树脂固化反应表观活化能低于脂环环氧树脂.各树脂第一阶段的表观反应活化能均低于第二阶段活化能.当脂环环氧树脂中混入不同比例的链型环氧树脂后,固化反应速率均较脂环环氧树脂单独固化时快,当链型环氧树脂量大于50%时,更为明显. 相似文献
17.
DSC and FTIR Analyses of The Curing Behavior of Epoxy/dicy/solvent Systems on Hermetic Specimens 总被引:1,自引:0,他引:1
The curing characteristics of adicyandiamide-cured epoxy system under the influence of solvents in a closed environment were
studied by means of isothermal differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR).
The DSC analyses revealed that the presence of solvent results in decreases in the curing exotherm, the initial curing rate,
the glass transition temperature, the reaction rate and the reaction order of the epoxy resin. The greatest decreases were
caused by the solvent with the highest boiling temperature. A change in temperature-dependent curing route due to the heat
absorbed during solvent evaporation is responsible for the difference. The FTIR analyses confirmed that the composition of
the cured resin is affected by the solvent, the curing temperature and the specimen configuration. As compared with those
obtained from open systems, specimens produced in a closed environment have an enhanced curing exotherm, initial curing rate,
glass transition temperature, reaction rate and reaction order because of the retention of volatile catalytic by-products.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
18.
The curing agents of epoxy resin, trimethylsilyl ethers of phenol novolak (TMSPN) and cresol novolak (TMSCN) were prepared
by refluxing phenol novolak and cresol novolak respectively, with the mixture of hexamethyldisilazane and chlorotrimethylsilane
in THF. The curing reaction of epoxy resin with these curing agents and the thermal properties of cured resins were examined.
The Tg values of epoxy resins cured with TMSPN were a little higher than those cured with TMSCN. The maximum of Tg is 118°C
for TMSPN-cured epoxy resin against 112°C for TMSPN-cured epoxy resin. The water absorption of hydrophobic epoxy resins cured
with TMSPN was a little lower than those cured with TMSCN. The clear decrease of water absorption is attributed to the difficulty
of the micro-void formation caused by the more tight primary structures of TMSPN. The water absorption at 25°C containing
trimethylsilyl groups is about one-tenth of that of epoxy resins cured with conventional curing agents and even one-half of
that of the epoxy resins cured with active esters. The low water absorption is attributed to the presence of trimethylsilyl
groups, which are more hydrophobic than ester groups, and to the absence of hydroxyl groups of the cured resins.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
19.
Free volume hole size of Cyanate ester resin/Epoxy resin interpenetrating networks and its correlations with physical properties 总被引:1,自引:0,他引:1
Cyanate ester (CE) resin was blended with epoxy resin (EP) at different mass ratios (CE/EP: 100/0, 90/10, 70/30, 50/50, 30/70, 10/90, and 0/100). The curing process of the blend system was characterized by Fourier transform infrared spectrometry (FTIR) and differential scanning calorimetry (DSC). Examination of the mechanical properties, thermal stability, and morphology of the blend systems showed that addition of epoxy resin resulted in improved toughness but a little sacrifice in thermal stability when compared with neat CE. The free volume size of the blend system determined by positron annihilation lifetime spectroscopy (PALS) decreased with the epoxy resin content, which is consistent with the chemical structure changes for the copolymerization between CE and EP. The crosslinking units of curing products (oxazoline, oxazolidinone, and polyether network) of the blends are all smaller in size than those of triazine ring structure from neat CE. Therefore, the free volume size of the blends decreases with increase of EP content. The correlations between the free volume properties and other physical properties (thermal stability and mechanical properties) have also been discussed. 相似文献
20.
取代脲促进环氧树脂/双氰胺固化体系反应机理 总被引:5,自引:0,他引:5
双氰胺作为环氧树脂的固化剂,由于固化产物具有优良的机械和电性能,广泛应用在汽车、航天及电子等领域中.但由于其固化温度高达180C以上,使应用范围受到很大限制.专利文献曾报道晚衍生物作为环氧树脂/双氰胺固化体系的促进剂,可以使体系的固化温度降低到130~140oC,并且在室温下仍保持一定的潜伏性[‘,’].在以往的研究中,认为取代脉的促进作用在于其与环氧发生反应生成环状化合物2一心竣烷酮和仲胺,仲胺与环氧基进一步反应生成的叔胺可以催化环氧发生阴离子聚合[’~’].实验表明,环氧树脂/双氰胺/取代脉体系的固化温… 相似文献