异氰酸酯/环氧树脂的固化机理

详细研究了异氰酸酯/环氧树脂体系的固化反应和固化机理。采用差示扫描量热法（DSC）和红外光谱法（FTIR）跟踪了异氰酸酯/环氧树脂固化反应过程,定量分析了异氰酸酯、环氧基团和新生成的异氰脲酸酯和口恶唑烷酮的变化。DSC分析结果表明,DSC曲线上出现3个放热峰,说明固化过程中存在至少3种反应;FTIR分析结果表明,在140℃以下固化体系主要发生异氰酸酯的三聚反应生成三嗪环（异氰脲酸酯）;在200℃下,异氰酸酯-NCO基团与环氧基团开环反应生成口恶唑烷酮;在230℃ 下,三嗪环（异氰脲酸酯）进一步与环氧基团开环反应生成口恶唑烷酮。研究了不同温度下环氧基团、异氰酸酯基团、异氰脲酸酯基团、口恶唑烷酮基团随反应时间的变化规律。     

聚氨酯,环氧树脂改性的聚异氰脲酸酯耐温硬质泡沫塑料研究

介绍以聚醚多元醇、聚亚甲基聚苯基异氰酸酯(PAPI)、环氧树脂为主要原料,在催化剂作用下合成聚氨酯、环氧树脂改性聚异氰脲酸酯泡沫塑料。研究了聚醚多元醇和环氧树脂类型以及催化剂品种对合成反应和泡沫性能的影响。由实验结果可知,选用季戊四醇聚醚多元醇、双酚A型环氧树脂以及MC催化剂,采用一步法工艺可制得工艺性好、制品脆性小、热稳定性良好的改性聚异氰脲酸酯泡沫塑料。其脆性(以重量损失计)为25%,在170℃下的热稳定性好。28天时V%为0.2。     

聚异氰脲酸酯的化学和应用

一、前言异氰脲酸酯是具有异氰脲酸酯环(1) 化合物的总称。其合成的最好方法是三聚环化反应。1958年,首先由霍夫曼合成了苯基异氰脲酸酯。其后很多研究人员相继开发了多种三聚催化剂。1960年沙纱(Shashaua)等人研究了单一异氰酸酯的聚合机理,发现在     

HEMA接枝CPP的合成及其性能

以甲苯为溶剂,过氧化二苯甲酰(BPO)为引发剂,采用甲基丙烯酸羟乙酯(HEMA)通过自由基聚合接枝氯化聚丙烯(CPP);考察了引发剂类型对接枝反应的影响;研究了反应时间、反应温度、BIN)用量、HEMA用量对接枝率及接枝CPP黏合性能的影响,并对接枝产物进行了傅里叶变换红外光谱分析。确定了较理想的工艺条件：反应温度为110℃．反应时间为5h,m(CPP)／m(HEMA)／m(BPO)为1．0：1．0：0．1。     

文献文摘

用异氰脲酸酯改性的多异氰酸酯制备聚氨酯橡胶用作密封材料和医疗纤维与空心纤维末端粘合材料的聚氨酯橡胶,其制造方法是:由异氰脲酸酯改性的六甲撑二异氰酸酯(Ⅰ)与胺类多元醇和其他多元醇相反应而制成.其中胺类多元醇与另一种多元醇的比例为10—100∶90—0,活性H与-NCO的当量比为0.8∶1.6.     

聚(异氰脲酸酯—噁唑烷酮)胶粘剂的研究

以4,4’-二苯基甲烷二异氰酸酯(MDI)与双酚A环氧树脂为原料,合成了耐热性好的聚(异氰脲酸酯-(口恶)唑烷酮)胶粘剂.系统地研究了催化剂种类、用量、固化工艺和投料比对胶接性能的影响.     

新型含氮杂环环氧树脂的制备

采用无机路线制备出了产率达55.32%、环氧值达0.257的新型含氮杂环环氧树脂.先制备乙醇钠,再将三羟乙基异氰脲酸酯(THEIC)加到强碱性的乙醇钠中,得到相应的钠盐,然后在催化剂的作用下,以环氧氯丙烷(ECH)与所制备的钠盐反应得到目的产物,并探讨了相关工艺条件对环氧树脂产率和环氧值的影响.在THEIC用量为0.02 mol情况下的最佳合成工艺条件是:用乙醇作溶剂、用量为30 mL,n(THEIC):n(ECH)为1:12,催化荆用量为0.165 g,NaOH用量为2.8 g,反应时间为8～9 h.     

碳氮杂环乙烯基酯树脂的合成与表征

用含异氰脲酸酯基的环氧树脂与甲基丙烯酸反应合成了含有碳氮杂环的乙烯基酯树脂,研究了环氧基／羧基摩尔比、催化剂用量以及温度对反应的影响,确定了最佳反应条件,并利用红外光谱对其结构进行了表征。该树脂采用苯乙烯为交联剂．固化后延伸率达到7．2％,拉伸强度高达74．7MPa,与通用的乙烯基酯树脂相比延伸率得到提高。合成的碳氮杂环乙烯基酯树脂具有较好的力学性能和应用前景。     

苯并恶嗪/氰酸酯共混物固化中三嗪环的稳定性

借助模型化合物2,4,6-三苯氧基-1,3,5-三嗪(Tst)分别与4,4'-二氨基二苯甲烷型苯并恶嗪(Pddm)和环氧树脂(EP)共混,采用傅里叶红外光谱(FTIR)、核磁碳谱(13C-NMR)、光电子能谱(XPS)等手段,研究了EP/Tst和Pddm/Tst体系240℃下的共固化反应。结果表明,EP/Tst体系中,Tst与EP反应,其三嗪环由氰脲酸酯转化为异氰脲酸酯,进一步部分转变成了恶唑烷酮结构;而Pddm/Tst体系中,仅发生Pddm的自聚反应,Tst与Pddm间不发生反应,氰脲酸酯三嗪环没有发生转化。介电性能测试表明,由于三嗪环的稳定性,苯并恶嗪/氰酸酯固化物具有比环氧/氰酸酯固化物更低的介电常数。     

聚醚型聚脲基甲酸酯增强增韧环氧树脂的研究

用原位多相聚合法合成了聚谜型聚脲基甲酸酯环氧树脂互穿网络聚合物 (IPN) ,得到了环氧树脂准分子复合材料 ,测定了产物的力学性能和热性能 ,探讨了聚醚分子量和聚脲基甲酸酯加入量对环氧树脂增强增韧过程的形响。结果表明分子量为 1 0 0 0的聚醚所合成的聚脲基甲酸酯的改性效果较好 ,加入量为1 2 .0 phr可使环氧树脂冲击强度提高 70 % ,拉伸强度提高 45 %。     

低溴环氧/氰酸酯树脂共固化反应及其层压板性能的研究

用差示扫描量热仪(DSC)、傅立叶交换红外光谱(FT-IR)对不同配比的低溴环氧／氰酸酯树脂的共固化反应机理以及固化物的结构特征进行了研究,同时测定和讨论了其层压板的耐热性和介电性能等。研究结果表明,在低溴环氧／氰酸酯树脂的固化体系中,氰酸酯和环氧树脂通过两种途径反应最终生成噁唑烷酮结构：固化反应温度与体系的组成有关,体系中低溴环氧树脂减少固化反应温度降低：加入催化剂能明显促进体系共固化反应,同时也降低了层压板的耐热性和介电性能。在性能方面,低溴环氧树脂中加入氰酸酯使共固化物耐热性增加、Tg升高,但氰酸酯用量增加到一定范围后,低溴环氧树脂／氰酸酯配比对Tg影响不大;低溴环氧树脂／氰酸酯层压板的耐热性和介电性能在一定实验范围内随着氰酸酯用量的增加明显提高。     

Novel flame retardant thermosets from nitrogen‐containing and phosphorus‐containing epoxy resins cured with dicyandiamide

A novel phosphorus‐containing epoxy resin (EPN‐D) was prepared by addition reaction of 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene 10‐oxide (DOPO) and epoxy phenol‐ formaldehyde novolac resin (EPN). The reaction was monitored by epoxide equivalent weight (EEW) titration, and its structure was confirmed by FTIR and NMR spectra. Halogen‐free epoxy resins containing EPN‐D resin and a nitrogen‐containing epoxy resin (XT resin) were cured with dicyandiamide (DICY) to give new halogen‐free epoxy thermosets. Thermal properties of these thermosets were studied by differential scanning calorimeter (DSC), dynamic mechanical analysis (DMA), thermal mechanical analyzer (TMA) and thermal‐gravimetric analysis (TGA). They exhibited very high glass transition temperatures (T_gs, 139–175°C from DSC, 138–155°C from TMA and 159–193°C from DMA), high thermal stability with T_{d,5 wt %} over 300°C when the weight ratio of XT/EPN‐D is ≥1. The flame‐retardancy of these thermosets was evaluated by limiting oxygen index (LOI) and UL‐94 vertical test. The thermosets containing isocyanurate and DOPO moieties showed high LOI (32.7–43.7) and could achieve UL‐94 V‐0/V‐1 grade. Isocyanurate and DOPO moieties had an obvious synergistic effect on the improvement of the flame retardancy. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Synthesis and characterization of a functional polyhedral oligomeric silsesquioxane and its flame retardancy in epoxy resin

A functional polyhedral oligomeric silsesquioxane (NPOSS) with two epoxy ring groups was synthesized via the reaction between trisilanolisobutyl-POSS and triglycidyl isocyanurate, and then a halogen-free epoxy composite containing silicon/nitrogen was prepared. The results of microscale combustion calorimeter indicate that the presence of NPOSS (10% weight ratio) in epoxy resin (EP) can decrease its peak heat release rate by about 30%. The thermal oxidation and degradation behaviors of EP and EP/NPOSS composites were characterized by DSC, TG, FTIR-TG and dynamic FTIR. Scanning electron microscopy and X-ray photoelectron spectroscopy were used to explore the char residues of composites. The thermal degradation and flame retardant mechanism has been evaluated. NPOSS can retard the movement and scission of polymeric chains of EP and form a stable charred layer in the condensed phase to prevent the underlying materials from further combustion.     

丙烯酸改性F-44环氧树脂及其光固化性能研究

研究了丙烯酸改性F - 44环氧树脂的制备条件 ,包括催化剂的用量、反应时间、反应温度对丙烯酸转化率的影响。发现当反应温度为 95℃、催化剂的用量为单体质量的 1 5 %时 ,6h之内反应即可完成 ;用紫外光曝光、FT -IR跟踪碳碳双键含量变化的办法测试并证实了改性树脂具有优良的光敏性 ,紫外光曝光 5s后 ,双键反应程度达到 6 0 % ;残留 5 0 %环氧基的丙烯酸改性F - 44树脂制成的漆膜在紫外光曝光后的附着力达到 1级 ,并在质量分数为 10 %的酸、碱溶液及丙酮、甲苯中 2 5℃浸泡 1h无变化。采用FT -IR对所合成的树脂的结构进行了表征 ,证实改性树脂中含有环氧基、丙烯酸结构     

Effect of Tertiary Amines on Reactivity of Cycloaliphatic Epoxy Resins towards Methacrylic Acid

The kinetics of the esterification of two cycloaliphatic epoxy resins containing glycidyl and epoxy cylohexane group, separately was studied using methacrylic acid in presence of triethyl-amine. The reaction was performed as a function of temperature to determine various kinetics and thermodynamic parameters such as reaction order, reaction rate constant, activation energy, frequency factor, entropy, enthalpy and free energy of the reaction. The reaction order was determined to be 2 and reaction rate constant for the resin containing epoxy cyclohexane group was found higher than that containing glycidyl epoxy group. The reaction was not found to proceed after ∼76% conversion due to the formation of adduct between nitrogen of amine and hydrogen of hydroxyl group of esterified resin. The rate of esterification reaction studied using higher homologue of triethyl-amine (tripropyl- and tributyl-) was found lower than that by triethyl-amine and conversion of acid into ester was ∼80% and ∼83% for tripropyl- and tributyl-amine, respectively due to the steric accessibility of nitrogen atom of higher amine. Based upon these kinetic data a suitable reaction mechanism is proposed for the system.     

Synthesis of isocyanurate-based imidazole carboxylate as thermal latent curing accelerator for thermosetting epoxy resins

A novel thermal latent curing accelerator, 1-(2-cyanoethyl)-2-methylimidazole/tris (2-carboxyethyl) isocyanurate adduct (2MICN-T), was successfully synthesized through an acid–base neutralization of tris(2-carboxyethyl)isocyanurate (TCEIC) and 1-(2-cyanoethyl)-2-methylimidazole (2MICN). It was further added into diglycidylether of bisphenol A based epoxy resin/methylhexahydrophthalic anhydride mixture to form one-component curing systems. With the addition of 2 wt% of 2MICN-T, the one-component system could be steadily stored for more than 1 month at room temperature, while the shelf life of 2MICN curing system was only 2 days. Nonisothermal differential scanning calorimeter also demonstrated the excellent thermal latency of 2MICN-T in low-temperature region and rapid initiation of the curing reaction when raising temperature. Compared to the cured resins with original 2MICN as accelerator, the resulted thermosets exhibited enhanced glassy storage modulus, glass transition temperature, and thermal stability when 2 wt% of 2MICN-T was applied. It was attributed to the chemical incorporation of the isocyanurate moieties with multi carboxyl groups and nitrogen-contained heterocyclic ring, effectively increasing the crosslinking density, chain rigidity, and heat resistance of the cured resin. Thus, it is suggested that 2MICN-T can play both roles as latent curing accelerator and modifier for one-component epoxy compounds, and is particularly recommended for application in electronic packaging fields.     

协同效应对环氧封端聚氨酯柔性树脂室温粘接性能的影响

采用自制环氧封端聚氨酯柔性树脂分别与三缩水甘油异氰尿酸酯(TGIC)和四缩水甘油基-4,4-二氨基二苯醚(TGDDE)混合配比,并用间苯二甲胺(MXDA)和聚醚胺(D-230)作为混合固化剂固化,研究不同官能度环氧的的协同作用对环氧封端聚氨酯柔性树脂室温粘接性能的影响.研究结果显示,三缩水甘油异氰尿酸酯的引入能有效地增...     

季铵盐型水性环氧树脂乳化剂的制备及特性研究

以二乙醇胺、环氧E-44树脂等为原料,合成叔胺结构中间体,与溴乙烷反应制得季铵盐型水性环氧树脂乳化剂,以相反转技术乳化环氧树脂E-44.研究了乳化剂合成过程中反应温度、反应时间和环氧基转化率的关系;探讨了乳化剂用量对水性环氧树脂水分散性,稳定性及固化性能的影响.利用红外光谱对产物的结构进行了表征.结果表明:二乙醇胺与环氧E-44树脂在80 ℃反应3 h,环氧基转化率可达98%以上;乳化剂用量为ω=22%时其乳化效果及所制得乳液的稳定性最好.DSC和TG分析结果表明,水性环氧树脂乳液和工业环氧树脂E-44比较,固化后热性能基本一样,分解温度约在350 ℃,但其玻璃化转变温度有所降低,说明其韧性有一定提高.     

Coatings of PDMS-modified epoxy via urethane linkage: Segmental correlation length,phase morphology,thermomechanical and surface behavior

Modification of an aliphatic epoxy resin with silicone was carried out through urethane route. Hydroxy-terminated polydimethylsiloxane (HTPDMS) was reacted with toluene diisocyanate to form an isocyanate-capped prepolymer. The –NCO group of the prepolymer was further reacted with –OH group of an aliphatic epoxy adipate resin, obtained by reaction of adipic acid with an epoxy resin, to obtain silicone-modified epoxy resin. Silicone-modified epoxy resins containing 15 and 30 wt% of silicone prepolymer have been synthesized by this procedure. TGA analysis of the silicone-modified epoxy resin showed considerable improvement in thermal stability over the unmodified epoxy resin. Modulated differential scanning calorimetry (MDSC) was used to find the segmental correlation length of the silicone-modified polymers. The cured films of silicone-modified resins showed biphasic morphology as evidenced from scanning electron microscopy. Further, the thermomechanical property of the samples was investigated by dynamic mechanical analysis. The surface properties of the silicone-modified matrices were studied by atomic force microscopy and contact angle goniometry. The silicone-modified samples showed considerably lower surface energy, surface roughness and contact angle hysteresis compared to the unmodified resins.