Cationic electron‐beam curing of a high‐functionality epoxy: effect of post‐curing on glass transition and conversion

This paper reports on the cationic electron‐beam curing of a high‐functionality SU8 epoxy resin, which is extensively used as a UV‐curing negative photoresist for micro‐electronics machine systems (MEMS) applications. Results show that elevated post‐curing treatment significantly increased both the conversion and the glass transition. The degree of conversion and the glass transition temperature were measured by using Fourier‐transform infrared (FTIR) spectroscopy and modulated differential scanning calorimetry (MDSC^®), respectively. The glass transition temperature (T_g), which has been observed to be dependent on the degree of conversion, reaches a maximum of 162 °C at 50 Mrad and post‐curing at 90 °C. The degradation pattern of the cured resin does not show much variation for exposure at 5 Mrad, but does show significant variation for 50 Mrad exposure at various post‐curing temperatures. A degree of conversion of more than 0.8 was achieved at a dosage of 30 Mrad with post curing at 80 °C, for the epoxy resin with an average functionality of 8 a feature simply not achievable when using UV‐curing. Copyright © 2004 Society of Chemical Industry     

采用模型化合物研究环氧树脂电子束固化机理

通过红外光谱、凝胶渗透色谱及核磁共振分析研究了单官能模型化合物苯酚缩水甘油醚在不同辐射剂量、引发剂浓度和羟基化合物掺杂情况下的电子束固化反应特性及机理。结果表明,环氧基团反应完全后,大幅度增加辐射剂量不会导致已经聚合的环氧树脂出现明显的辐射降解,但是引发剂浓度的增加和羟基化合物乙醇使聚合环氧树脂的分子质量下降。     

Effect of electron‐beam irradiation on ethylene–methyl acrylate copolymer

Ethylene–methyl acrylate copolymer (Elvaloy 1330) was irradiated by an electron beam at different levels of radiation both in the presence and absence of a trimethylolpropane trimethacrylate sensitizer at various dosages of incorporation. The mechanical, thermal, and electrical properties of these samples were compared. The mechanical properties were observed to reach an optimum maximum around 6 Mrad of irradiation and 1 phr of sensitizer incorporation. Furthermore, an increase in either the radiation dose or the sensitizer level helped very little to further modify the properties. The thermal properties as determined by the thermogravimetric analysis and differential scanning calorimetry studies were quite supportive of the observation made during the study of the mechanical properties. The thermal stability of the irradiated samples underwent an increase with increasing electron‐beam dosage. In a manner similar to those of the mechanical properties, the increase in thermal stability was found to reach a maximum at a particular level of treatment and sensitizer incorporation, beyond which there was marginal or no effect at all. The α transition temperature underwent a substantial increase with increasing crosslink density, as evidenced by the increase in gel content with increasing proportion of electron‐beam radiation dose. The other glass‐transition temperature, however, appeared to remain unaffected. The electrical properties, as described by the dielectric constant, volume resistivity, and breakdown voltage, appeared to be affected very little by the electron‐beam radiation. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

生物质环氧树脂固化剂的研究进展

综述了近年来生物质环氧树脂固化剂(BEPCA)的研究进展,主要包括以腰果酚、香兰素、松香、木质素和植物油等作为原料制备的生物质胺类固化剂、生物质酸酐类固化剂和多元酚、羧酸及酯类生物质固化剂等;详细介绍了上述BEPCA的结构、制备方法、合成路线以及其固化产物的性能;最后,总结并展望了BEPCA未来的发展趋势.     

不同化学结构环氧树脂电子束固化效果的分析

研究了化学结构对环氧树脂电子束辐射反应速率和辐射固化效果的影响。对于分子量相近的环氧树脂，反应速率大的环氧树脂体系最终达到的反应程度较高。酚醛型环氧树脂辐射反应活性高，固化后的高温模量及玻璃化转变温度高于双酚A型环氧树脂，但固化度沿辐射深度方向下降较快，脂环族环氧树脂的辐射反应活性小，在相同辐射条件下的固化效果差。缩水甘油胺结构的环氧树脂对于碘Wong盐引发的电子束辐射固化反应没有活性。     

Electron‐beam curing of bismaleimide‐reactive diluent resins

Electron‐beam (E‐beam) curing of 4,4′‐bismaleimidodiphenylmethane (BMPM)/BMI‐1,3‐tolyl/o,o′‐diallylbisphenol A (DABPA)–based bismaleimide (BMI) systems and their mixing with various reactive diluents, such as N‐vinylpyrrolidone (NVP) and styrene, were investigated to elucidate how temperature, electron‐beam dosage, and diluent concentration affect the cure extent. The effect of free‐radical initiator on the cure reactions was also studied. It was found that low‐intensity E‐beam exposures cannot cause the polymerization of BMI. High‐intensity E‐beam exposures give high reaction conversion attributed to a high temperature increase, which induced thermal curing. It was shown that the dilution and activation of NVP in BMI cause a more complete BMI cure reaction under E‐beam radiation. BMI/NVP can be initiated easily by low‐intensity E‐beam without thermal curing. FTIR studies indicate that about 70% of the reaction is complete for BMI/NVP with 200 kGy dosage exposure at 10 kGy per pass. The sample temperature only reaches about 75°C. The free‐radical initiator, dicumyl peroxide, can accelerate the reaction rate at the beginning of E‐beam exposure, but does not affect the final reaction conversion. The increase of the concentration of NVP in the BMI/NVP systems increases the reactive conversions almost linearly. © 2004 Wiley Periodicals Inc. J Appl Polym Sci 94: 2407‐2416, 2004     

环氧树脂聚酰胺网络体系性能研究

用红外光谱法表征了4种聚酰胺固化剂与环氧树脂按等当量配比,在一定条件下的固化反应过程。DSC法测定了其固化反应活性。桐马聚酰胺/环氧树脂固化体系较聚酰胺650/环氧树脂固化体系的固化活性大大提高,同时测定了该固化产物的热失重(TG)及玻璃化温度(Tg),对该固化物的热稳定性进行了评价,还测定了不同固化时间的剪切强度以研究其动态力学性能,从浇铸体的冲击强度方面比较其韧性。综合比较分析了聚酰胺固化剂与环氧树脂固化体系的力学性能、耐热性、电绝缘性等。结果表明:桐马聚酰胺Ⅲ型固化剂具有黏度低、粘接强度大、耐热性好、力学性能优等优点。     

环氧粉末涂料的固化动力学和固化工艺的研究

采用非等温示差扫描量热法(DSC)研究了E-12/双氰胺(固化剂)和E-12/双氰胺/2-甲基咪唑(促进剂)体系的固化反应动力学。采用Kissinger法和Crane公式对DSC数据进行处理,获得了固化反应动力学参数,应用热重分析(TGA)研究了固化产物的热稳定性。结果表明:双氰胺、2-甲基咪唑的最佳用量分别为环氧树脂质量的4%和0.4%,最佳固化条件为160℃/15min。E-12/双氰胺体系和E-12/双氰胺/2-甲基咪唑体系的表观活化能分别为105.12kJ/mol和70.62kJ/mol,固化反应级数n=0.92。起始分解温度约为410℃,促进剂2-甲基咪唑的加入对体系热稳定性没有影响。     

Film performance and UV curing of epoxy acrylate resins

Radiation curing technology has encountered increased applications in recent years. The Asian geographical vicinity has and will be an expensive territory for years to succeed. There has been heightened governmental obligation to progress towards diminishing solvent practice to preserve the environment.

In the present study, the novolac as well as bisphenol-A based epoxy acrylates (or vinyl ester resins, VERs) were synthesised and extent of reaction and polymerisation was studied. It was observed that the above prepared oligomer when used with monofunctional/polyfunctional diluents can be cured in seconds time. Evaluation of film performance was also carried out.     

Polymeric reagents: Part 1. Synthesis of polymer-anchored amines useful for curing epoxy resins

A range of polymers carrying amino-functions [NHEt, NHBuⁿ, NEt₂, NPr, N(CH₂CH₂CH₂NH₂)₂, NMeCH₂CH₂CH₂NH₂ or NEtCH₂CH₂CH₂ NH₂] has been synthesised via amination of styrene-vinylbenzyl chloride copolymers, poly(epichlorohydrin) and poly(2-chloroethyl vinyl ether), and via homopolymerisation and copolymerisation (with styrene) of (n-butyl)(vinylbenzyl)-ammonium chloride. Some of the polymers showed promise as curing agents for epoxy resins.     

The synergistic effect of dicyandiamide and resorcinol in the curing of epoxy resins

The synergistic effect of dicyandiamide (Dicy) and phenolic substances was studied, with resorcinol as a model compound. It was found that when Dicy and resorcinol are used jointly, the curing temperature of epoxy resin can be significantly lowered. FTIR and DSC data were used to illustrate the mechanism of the synergism. The addition of the phenolic hydroxyl group to epoxide was facilitated by Dicy, which favors the formation of phenoxy anions. The reaction of Dicy with epoxide was facilitated by resorcinol, which can exert “electrophilic assistance” for the addition of the amino group to epoxide. The presence of resorcinol also favors the addition of the hydroxyl group to the cyano group. The thermal and mechanical properties of the epoxy resins cured with Dicy/resorcinol or Dicy/phloroglucinol were studied. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1869–1874, 2003     

联苯酚醛环氧树脂固化动力学及热性能研究

以4,4'-二氨基二苯砜(DDS)为固化剂,采用非等温示差扫描量热法(DSC)研究了联苯酚醛环氧树脂(BPNE)的固化动力学。通过外推法确定了体系的固化工艺。采用Kissinger、Ozawa法计算出固化体系的表观活化能,根据Crane理论计算得到该体系的固化反应级数。采用DSC,热重分析(TGA)研究了固化物的耐热性。结果表明:BPNE的固化工艺为160℃/2h+200℃/2h+230℃/2h;固化反应的活化能约为61.86kJ/mol,指前因子为5.27×105min-1,反应级数为1.1;玻璃化转变温度(Tg)为167℃,其10%热失重温度为398.1℃,800℃残炭率为29.37%,与双酚A环氧树脂/DDS固化物相比,分别提高了22℃,11.71%。     

Investigation of influence factors in electron beam curing of epoxy resins using a calorimetry technique

Because of the complexity of the electron beam (EB) curing process, current understanding of EB curing of polymer resins and composites is limited. This article describes an investigation of different factors affecting EB curing of epoxy resin such as dose rate, time interval between irradiation doses, moisture, and photoinitiator concentration using a calorimetry technique. Results show that higher dose rate resulted in a higher and faster temperature increment in the uncured resin samples, and thus a higher degree of cure. In the multiple‐step EB irradiation, a shorter time interval between irradiation doses resulted in higher temperature in the resin samples and therefore higher degree of cure. Results indicate that moisture could delay crosslinking reaction in the early stages of the cure reaction, but accelerates it later in the curing process. Given a reasonable percentage of photoinitiator, experiments confirmed that samples with higher photoinitiator concentration reach higher degree of cure under same EB irradiation conditions. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Hybridization of aqueous PU/epoxy resin via a dual self‐curing process

Amino‐terminated and carboxyl‐containing polyurethane (PU) is prepared by an isocyanate‐terminated PU prepolymer process. Carboxyl‐containing epoxy resin is obtained from a half‐esterification of epoxy resin with maleic anhydride. These two aqueous resins are obtained after neutralization with triethylamine and dispersion into water phase, respectively. A latent curing agent (TMPTA‐AZ) is prepared by a Michael addition of aziridine with trimethylolpropane triacrylate (TMPTA). A self‐curing system of PU/epoxy hybrid is obtained from a blending of these two aqueous resins with latent curing agent. PU/epoxy hybrid is derived from two self‐curing reactions on drying. The first curing for hybridization between PU amino groups with oxirane groups of epoxy resin is via a ring‐opening reaction and the secondary curing takes place on carboxyl groups of PU/epoxy hybrid with aziridine of TMPTA‐AZ. The final properties of these dual self‐cured PU/epoxy hybrids are reported. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

含磷羧酸类环氧树脂固化剂的合成及固化性能研究

以邻苯基苯酚和三氯氧磷为原料,无水三氯化铝为催化剂,首先合成9,10-二氢-9-氧杂菲-10-膦酰氯(ODC)。再以乙酸为溶剂,通过ODC与酒石酸(TA)的反应,合成了新型含磷羧酸类环氧树脂固化剂2,3-二9,110-二氢-9-氧杂菲-10-膦氧基)丁二酸(ODC-TA)。通过红外光谱、H核磁共振谱对ODC和ODC-TA的结构进行了表征,并通过DSC和TGA对ODC-TA/CYD-128型环氧树脂固化体系的固化性能及阻燃性能进行了研究。     

Electron‐beam curing of hydrogenated acrylonitrile–butadiene rubber

The electron‐beam‐induced crosslinking of hydrogenated acrylonitrile–butadiene rubber (HNBR) was investigated. HNBR sheets were exposed to electron‐beam irradiation in air at a room temperature of 25 ± 2°C over a dose range of 0–20 Mrad. An attempt was made to correlate the structure of the irradiated rubber with the properties. The ratio of chain scission to crosslinking and the gelation dose were determined by a method proposed elsewhere. The gel content and dynamic storage modulus increased with the radiation dose. Fourier transform infrared studies revealed the formation of double bonds and carbonyl and ether groups. These observations were further supported by a thermogravimetric analysis of the carbonaceous residue of irradiated HNBR. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 648–651, 2005     

潜伏性环氧树脂固化促进剂M-Cd的合成及其应用

采用间苯二胺和溴化镉合成了一种具有潜伏性的环氧树脂固化促进剂M－Cd它是一种络合物，将它应用于二氰二胺／环氧树脂脂固化体系的高温结构粘剂中，能够显著地降低粘剂的固化温度，缩短固化时间，本文还讨论了合成该促进剂主要成分的投料比，应用于二氰二胺／环氧树脂固化体系的高温结构胶粘剂中该促进剂的使用量以及固化条件对粘剂力学性能的影响，同时还考核了应用该促进剂M的高温结构胶粘剂的综合性能。     

E‐beam‐cured layered‐silicate and spherical silica epoxy nanocomposites

This research demonstrates that an epoxy nanocomposite can be made through electron beam (e‐beam) curing. The nanofillers can be two‐dimensional (layered‐silicate) and zero‐dimensional (spherical silica). Both the spherical silica epoxy nanocomposite and the layered‐silicate epoxy nanocomposite can be cured to a high degree of curing. The transmission electron microscopy (TEM) and small‐angle X‐ray scattering of the e‐beam‐cured layered‐silicate epoxy nanocomposites demonstrate the intercalated nanostructure or combination of exfoliated and intercalated nanostructure. The TEM images show that the spherical silica epoxy nanocomposite has the morphology of homogeneous dispersion of aggregates of silica nanoparticles. The aggregate size is ～ 100 nm. The dynamic mechanical analysis shows that the storage modulus of the spherical silica nanocomposite has been improved, and the glass transition temperature can be very high (～ 175°C). © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

环氧树脂室温快速固化剂的合成

以羟基化合物(聚己内酯三元醇、正丁醇)和多聚磷酸为原料合成环氧树脂室温固化剂,研究了原料配比、反应温度和反应时间对固化剂性能的影响,并考察了固化剂用量对环氧树脂胶黏剂性能的影响。结果表明:正丁醇与聚己内酯三元醇、羟基化合物与多聚磷酸的摩尔比分别为1.0∶10.0,2.0∶1.0,在75℃条件下反应4 h,合成了能使环氧树脂室温快速固化的固化剂。该固化剂用量为环氧树脂质量的30%时,环氧树脂在室温条件下5 min即可固化,且胶黏剂具有优异的黏接性能。     

Studies on UV‐stable silicone–epoxy resins

Silicone–epoxy resins were synthesized through hydrosilylation of 1,2‐epoxy‐4‐vinyl‐cyclohexane with 1,3,5,7‐tetramethycyclotetrasiloxane. The silicone–epoxy resins showed high reactivity in the presence of aluminum complex/silanol compound catalysts. Curing of the resins was effected at extremely low concentrations of the aluminum acetylacetonate/Ph₂Si(OH)₂ catalyst to give hard materials with optical clarity. For the silicone–epoxy resins containing Si? H bonds, Al(acac)₃ alone is effective for the curing. The cured silicone–epoxy resins showed excellent UV resistance. An improvement in the lifetime of UV‐LEDs was achieved using the silicone–epoxy compositions as encapsulant. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 3954–3959, 2007