木质素基环氧树脂固化剂的制备

环氧-胺化两步反应法制备生成了含有活性胺基基团的胺化木质素衍生物。采用精制后的木质素与环氧氯丙烷生成反应性较高的环氧木质素,对环氧木质素进行胺化改性,并探讨了反应条件比对最终产物胺化木质素中活性胺基含量的影响。应用红外光谱测试、X射线光电子能谱测试以及热重测试对产物的结构与性质进行了表征,结果表明,当环氧木质素与二胺化合物物料比为1∶8,反应温度80℃,反应时间4 h,得到的胺化木质素产物总胺基含量达到184.8%。最终产物胺化木质素改性物中含有较多反应性较高的伯胺(81.21%)以及仲胺基团(99.82%),产物有较好的热降解稳定性,可以用作环氧树脂的固化剂。     

木质素基环氧树脂固化剂的制备

环氧-胺化两步反应法制备生成了含有活性胺基基团的胺化木质素衍生物。采用精制后的木质素与环氧氯丙烷生成反应性较高的环氧木质素,对环氧木质素进行胺化改性,并探讨了反应条件比对最终产物胺化木质素中活性胺基含量的影响。应用红外光谱测试、X射线光电子能谱测试以及热重测试对产物的结构与性质进行了表征,结果表明,当环氧木质素与二胺化合物物料比为1∶8,反应温度80℃,反应时间4 h,得到的胺化木质素产物总胺基含量达到184.8%。最终产物胺化木质素改性物中含有较多反应性较高的伯胺(81.21%)以及仲胺基团(99.82%),产物有较好的热降解稳定性,可以用作环氧树脂的固化剂。     

肟的清洁还原研究

文章报道在超临界二氧化碳中,以锌粉和水还原肟,生成胺与二氧化碳形成胺基甲酸胺盐,经碱处理可以得到相应的胺。其产物伯胺与体系中的CO2生成氨基甲酸胺盐阻止了其与中间体亚胺的作用从而使伯胺成为主要产物。还探讨了二氧化碳压力、反应温度、反应时间对转化率的影响。结果表明,在优化条件（反应温度100℃,CO2压力8MPa,反应时阿6h）下,锌和水可以顺利地把肟还原成胺。     

新型潮湿表面用固化剂的合成

以间苯二甲胺(MXDA)和环氧氯丙烷(ECH)为原料,在物料物质的量比(MXDA/ECH)为2.1/1,反应温度为60℃,反应时间为2.5 h的工艺条件下合成环氧-胺加成物。然后与N,N-二甲基甲酰胺(DMF)反应,端胺基-多胺加成物与DMF的物质的量的比为1∶2.4,温度为110℃;最后用单环氧化合物封掉多余仲胺生成了一种新型可潮湿固化的固化剂(H-APMD)。对合成条件进行了优化。采用红外光谱法确定了分子结构。采用热重分析研究了涂膜的性能。结果表明,该固化剂是一种优良的潮湿固化固化剂。     

水性环氧-二乙烯三胺固化剂的合成研究--固化剂胺值与表观活化能的关系

通过对合成的环氧-二乙烯三胺的凝胶时间测试,和由此而得来的表观活化能以及它与胺加成物的胺值之间的关系来考察固化剂的反应活性规律。研究了不同摩尔比、反应时间、反应温度、溶剂种类等对反应活性的影响。     

非离子复合型水性环氧固化剂合成及性能研究

以四乙烯五胺(TEPA)作为反应底物,与低相对分子质量的环氧树脂(DER331)和聚乙二醇二缩水甘油醚(PGGE)混合树脂反应,再用单环氧封端剂苯基缩水甘油醚(PGE)和十二至十四烷基缩水甘油醚(AGE)作为复合封端剂进行封端,合成非离子复合型水性环氧固化剂。探究了最佳合成条件,采用红外光谱(FT-IR)对合成的产物进行结构表征,并考察了与水性环氧乳液固化后的涂膜性能。结果表明:最佳合成条件为物料比n(伯胺基)∶n(环氧基)=2.3∶1、初始反应温度65℃、反应时间3 h、复合封端剂的比例n(AGE)∶n(PGE)=3∶7。合成的水性环氧固化剂与水性环氧乳液固化形成的漆膜耐腐蚀性能优越。     

环氧树脂(Ag-80)/砜醚二胺体系固化机理的研究

阶梯升温固化和180℃等温固化的实验结果表明:温度低于200℃时,主要发生环氧基与伯胺基和环氧基与羟基之间的固化反应;温度高于200℃时,主要发生环氧基与仲胺基之间的固化反应,同时还有少量羰基生成.     

用红外光谱法研究环氧树脂固化过程

一、引 言 环氧树脂是玻璃钢手糊工艺最常用的树脂之一,研究其固化过程,对工艺制度的合理选择、产品性能的提高和质量的评定都有一定意义。 手糊成型玻璃钢使用的环氧树脂,通常都以脂肪族伯胺作固化剂。环氧树脂与伯胺的固化反应,一般认为是环氧基团与连接在伯胺氮原子上的氢原子反应,转变成仲胺,再由仲胺转变成叔胺。反应过程中环氧基团逐渐消失,羟基逐渐生成。由于固化反应中化学结构的变化和某些基团的消失或生成情况可以直接反映固     

水性环氧树脂涂料的研究

以酚醛环氧树脂F-51与二乙醇胺为原料进行反应,制得一种分子中含环氧基和亲水基团的改性F-51,以双氰胺为固化剂制备水性环氧树脂涂料,得到最佳工艺:反应温度80℃,n(环氧基)∶n(二乙醇胺)=1∶1,反应时间100 min。     

无溶剂环氧防腐涂料的制备和性能研究

开发了一种以腰果酚改性胺为固化剂的无溶剂环氧防腐涂料,介绍了环氧树脂、固化剂、稀释剂以及填料等原料的选择,探讨了环氧树脂与腰果酚改性胺的固化机理,并考察了硅烷偶联剂对涂层防腐性能的影响。检测结果表明,环氧树脂与腰果酚改性胺的固化主要以环氧基与胺基之间的反应为主;硅烷偶联剂可以提高涂层的附着力,有效地增强涂膜的耐水性。     

Synthesis and thermal properties of combined liquid crystalline epoxy resins

Liquid crystalline epoxy resins were prepared by the curing reaction of epoxy and amine compounds with a mesogenic group in the mesomorphic temperature range. Some epoxy resins exhibited a typical liquid crystalline phase. Curing reaction of a mesogenic epoxy compound with an aliphatic amine compound containing cyano biphenyl group was faster than that of another epoxy resins confirmed by thermally controlled Fourier transform infrared measurements. The glass transition temperature of the liquid crystalline epoxy resin containing cyano biphenyl group increased with increasing curing reaction time. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 1979–1990, 1998     

Molecular Structure of Polymer/Metal Interphases

The molecular structure of interphases in aluminum/epoxy and steel/epoxy adhesive joints was characterized using infrared spectroscopy. In one series of experiments, adhesive joints were prepared by curing beams of epoxy against aluminum or steel substrates. When the joints were cooled to room temperature, the residual stresses were sufficient for crack propagation along the interface. The adhesive and substrate failure surfaces were then analyzed with reflection-absorption infrared spectroscopy (RAIR), attenuated total reflection infrared spectroscopy (ATR) and X-ray photo-electron spectroscopy (XPS). When an epoxy/anhydride adhesive was cured against aluminum substrates primed with an aminosilane coupling agent, amide and imide groups were formed in the interphase. Chemical reaction between the primary amine of the primer and the anhydride of the curing agent precluded chemical bridge formation between the primer and adhesive. Metal cations from the 2024 aluminum substrate reacted with the anhydride to form carboxylate salts on the surface. When an epoxy/tertiary amine adhesive was cured against steel substrates, evidence of oxidation of the primary amine to imine was observed in the interphase.     

Molecular Structure of Polymer/Metal Interphases

The molecular structure of interphases in aluminum/epoxy and steel/epoxy adhesive joints was characterized using infrared spectroscopy. In one series of experiments, adhesive joints were prepared by curing beams of epoxy against aluminum or steel substrates. When the joints were cooled to room temperature, the residual stresses were sufficient for crack propagation along the interface. The adhesive and substrate failure surfaces were then analyzed with reflection-absorption infrared spectroscopy (RAIR), attenuated total reflection infrared spectroscopy (ATR) and X-ray photo-electron spectroscopy (XPS). When an epoxy/anhydride adhesive was cured against aluminum substrates primed with an aminosilane coupling agent, amide and imide groups were formed in the interphase. Chemical reaction between the primary amine of the primer and the anhydride of the curing agent precluded chemical bridge formation between the primer and adhesive. Metal cations from the 2024 aluminum substrate reacted with the anhydride to form carboxylate salts on the surface. When an epoxy/tertiary amine adhesive was cured against steel substrates, evidence of oxidation of the primary amine to imine was observed in the interphase.     

DGEBF/DDS体系固化动力学机理的研究

以4,4′-二氨基二苯砜(DDS)胺类固化剂固化9,9-二[4-(2,3环氧丙氧基)苯基]芴(DGEBF),采用非等温DSC法推导了固化反应参数和固化机理,并用原位红外和移动窗口二维相关红外分析对固化机理和固化模式进行了验证。结果表明:DGEBF/DDS体系固化反应的表观活化能为64.08 kJ/mol,扩散因子为4.05×104s-1,反应级数为1.55;固化工艺为150℃/1.5 h+190℃/2 h+220℃/1.5 h;固化模式为枝状成核的自催化反应;固化机理为伯胺先与环氧基反应生成仲胺,肿胺继续与环氧基反应生成叔胺,2个反应同时进行,以及在高温下的羟基与环氧基的自催化反应,交联的固化网络逐渐形成。     

Cure kinetics of several epoxy–amine systems at ambient and high temperatures

Epoxy-crosslinker curing reactions and the extent of the reactions are critical parameters that influence the performance of each epoxy system. The curing of an epoxy prepolymer with an amine functional group may be accompanied by side reactions such as etherification. Commercial epoxy prepolymers were cured with different commercial amines at ambient as well as at elevated temperatures. Singularly, only epoxy–amine reactions were observed with diglycidyl ether of bisphenol-A (DGEBA)-based epoxides in our research even upon post-curing at 200°C. Etherification side reaction was found to occur at a cure temperature of 200°C in epoxides possessing a tertiary amine moiety. A combined goal of our research was to understand the effect of tougheners on the cure of epoxy–amine blend. To discern the effect of tougheners on the cure, core–shell rubber (CSR) particles were incorporated into the epoxy–amine blend. It was observed that CSR particles did not restrict the system from proceeding to complete reaction of epoxy moieties. Besides, CSR particles were found to accelerate the epoxy-amine reaction at a lower level of epoxy conversion. The lower activation energy of epoxy–amine reaction of CSR incorporated system compared to control supported the catalytic effect of CSR particles on the epoxy-amine reaction of epoxy prepolymer and amine blends.     

Accelerated-curing epoxy structural film adhesive for bonding lightweight honeycomb sandwich structures

Accelerating the curing of epoxy/aromatic amine adhesives and improving their toughness are challenges in heat-resistant epoxy structural adhesives. Herein, we report an epoxy/aromatic amine adhesive accelerated curing system with an oxo-centered trinuclear (chromium III) complex, which is toughened using a thermoplastic block copolymer (TPBC). The reaction characteristics, heat resistance, microstructure, and bonding properties of the accelerated epoxy adhesives were analyzed. The reaction peak temperature of the epoxy with 3% catalyst was 113.1°C, which was 113.6°C lower than that of epoxy without catalyst, and the modified epoxy resin demonstrated a potential for rapid curing at medium temperature. The glass transition temperature of the TPBC-toughened epoxy adhesive was 125°C after curing, indicating excellent thermal stability after medium temperature curing. The introduction of the TPBC increased the single-lap shear strength of the epoxy adhesive without reducing its heat resistance. The shear strength at room temperature and 120°C of the modified epoxy adhesive with 50 phr of TPBC was 25.2 and 10.9 MPa, respectively. Moreover, the epoxy film adhesive exhibited outstanding bonding properties when used in the bonding of lightweight honeycomb sandwich structures.     

无规则羧基丁腈橡胶改性环氧树脂的制备及性能研究

以无规则羧基丁腈橡胶（RCBN）为改性剂,对羧基丁腈橡胶改性环氧树脂的制备工艺及产品性能进行了研究。利用红外光谱及化学分析法等手段,探讨了催化剂用量、反应温度和反应时间对改性环氧树脂性能的影响;通过固化产物力学性能分析,对改性环氧树脂固化性能进行了评价。结果表明：质量配比为环氧树脂：RCBN：催化剂为100：15：0．3的反应体系中于120℃,反应150min,获得了环氧值0．40、黏度（40℃）90—95Pa·s、酸值小于0．4mg／g的改性环氧树脂产品,改性环氧／改性胺411固化产物剪切强度为18．41MPa,断裂伸长率为4．41％;无规则羧基丁腈橡胶对环氧树脂有显著的增韧效果。     

Fluorescence and IR characterization of epoxy cured with aliphatic amines

Cure reactions of the stoichiometric mixtures of diglycidyl ether of bisphenol A (DGEBA) and two very low molecular weight aliphatic polyether diamines (PED) were studied by using fluorescence and mid- and near-IR spectroscopic techniques. As the cure proceeded, the primary amine groups in PED are converted to the secondary and the tertiary amines. Near-IR spectral analysis was used to calculate the concentration of the three amine groups as a function of cure time. The decrease in the fluorescence intensity of DGEBA at about 307 nm was observed due to more effective quenching of the tertiary amine groups in PED, in comparison to the primary and the secondary amine groups. A large decrease in fluorescence intensity at 75 and 95 °C cure was observed. The amount of all the amine species was estimated from NIR spectra to shed light on the cure kinetics of PPO (polypropylene oxide) in comparison with PEO (polyethylene oxide) epoxy, as well as to explain their fluorescence behavior.The fluorescence intensity changes were correlated to the extent of epoxy reaction obtained by mid- and near-IR spectroscopy.     

Real-time monitoring of the cure reaction of a TGDDM/DDS epoxy resin using fiber optic FT-IR

The feasibility of using remote FT-IR spectroscopy to monitor the gelation reaction of an epoxy resin used in advanced composite materials has been studied. The commercial epoxy resins MY720 and MY721, consisting mostly of tetraglycidyl 4,4′-diaminodiphenyl methane (TGDDM) were cured with diaminodiphenylsulfone (DDS) in a microcapillary cell connected to an FT-IR spectrometer by single silica fiber optics. By operating in the near-IR, direct measurement of the consumption of epoxide and primary amine and growth in hydroxyl groups was possible. It was found that the primary amine band at 5067 cm^?1 was the most sensitive for rapid and accurate real-time monitoring of the cure reaction up to gelation. The temperature dependence of amine consumption from 135 to 180°C gave an activation energy of 70 kJ mol^?1 for the cure reaction in agreement with DSC. Several artefacts involved in using fiber optic FT-IR in this way have been identified.     

硫脲改性胺环氧树脂固化剂的合成及性能研究

对硫脲改性胺(3,3′-二乙基4,4′-二氨基二苯基甲烷和二元脂肪胺A)固化剂固化环氧树脂进行了系统研究,分析了合成反应时间、反应温度和单体配料比对固化剂性能的影响,并进一步考察了固化剂与环氧树脂的最佳掺量比以及固化产物的热性能和力学性能。实验结果表明:反应时间为2.5 h,反应温度为130℃,3,3′-二乙基4,4′-二氨基二苯基甲烷与硫脲和二元脂肪胺A的物质的量比为1∶0.5∶0.4时,合成的固化剂以1∶3加入环氧树脂中,体系能在室温环境下1 h左右凝胶,该体系经室温固化再以100℃的温度后固化之后具有较好的耐热性能和冲击韧性。