m-Bromophenolic epoxy resins for electronic packaging

Meta-halogenated phenols are generally known to be more chemically and thermally stable than their ortho- or para-halogenated counterparts. A reactive intermediate, produced by the bromination of 2,4,6-trimethylphenol is being used as an alkylating agent to incorporate this stable m-bromophenol moiety into varieties of organic compounds and polymers. In electronic encapsulation applications, epoxy derivatives of novolacs containing m-bromophenol have exhibited superior hydrolytic and thermal stability as compared with the conventional tetrabromo bisphenol-A epoxies which are ortho-brominated phenolics. The m-bromophenol moiety contributes to the extended device reliability while meeting flame retardency requirements as well.     

Meta-bromobiphenol epoxy resins: Applications in electronic packaging and printed circuit board

Novel 2,2′,6,6′-tetrabromo-3,3′,5,5′-tetramethyl-4,4′-biphenol (TBTMBP), and its epoxy derivatives, were synthesized to incorporate the stable meta-brominated phenol moiety into epoxy resin systems. In electronic encapsulation and laminate applications, epoxy systems derived from TBTMBP have exhibited superior hydrolytic and thermal stability as compared with the conventional ortho-brominated epoxy resins. These properties have resulted in an extended device life for semiconductors and a high T_g with excellent blister resistance for the printed circuit board, while meeting flame retardancy requirements as well.     

Amidoamine: Synthesis,disparity in cure with epoxy resins between bulk and solvent systems,and structure–property relationships of its epoxy‐based coatings

Amidoamines are widely used as crosslinkers for epoxy resins in protective coatings on metal substrates; however, their cure chemistry is not well elaborated in the technical literature. During cure, the epoxy–amine and epoxy–amide NH reactions could be accompanied by epoxy–hydroxyl etherification, epoxy–epoxy homopolymerization, and reaction between hydroxyls and amide moiety to form in situ ester and amine. To understand the epoxy–amidoamine cure chemistry and correlate it with coating performance properties, amidoamines of known structure are required. Therefore, amidoamines were synthesized by reacting dimer fatty acids with diethylene triamine. When these amidoamines were cured with epoxy resins, discrepancies were observed between systems cured at ambient and thermal conditions. The presence of solvents were seen to greatly affect the rate of epoxy–amidoamine cure at ambient, and before and after vitrification. Near‐IR and mid‐IR spectroscopy studies indicated that side reactions occurred to some extent during cure. No reaction was noted between the amide NH moiety and the epoxide group below 150°C whereas ester formation was noted above 120°C. Solvent‐based clear epoxy–amidoamine coatings formulated at an epoxy:amine equivalent ratio 1.15 passed basic organic coatings evaluation tests. POLYM. ENG. SCI., 59:E69–E81, 2019. © 2018 Society of Plastics Engineers     

Insights into the Bioactivity of Mensacarcin and Epoxide Formation by MsnO8

Mensacarcin, a potential antitumour drug, is produced by Streptomyces bottropensis. The structure consists of a three‐membered ring system with many oxygen atoms. Of vital importance in this context is an epoxy moiety in the side chain of mensacarcin. Our studies with different mensacarcin derivatives have demonstrated that this epoxy group is primarily responsible for the cytotoxic effect of mensacarcin. In order to obtain further information about this epoxy moiety, inactivation experiments in the gene cluster were carried out to identify the epoxy‐forming enzyme. Therefore the cosmid cos2, which covers almost the complete type II polyketide synthase (PKS) gene cluster, was heterologously expressed in Streptomyces albus. This led to production of didesmethylmensacarcin, due to the fact that methyltransferase genes are missing in the cosmid. Further gene inactivation experiments on this cosmid showed that MsnO8, a luciferase‐like monooxygenase, introduces the epoxy group at the end of the biosynthesis of mensacarcin. In addition, the protein MsnO8 was purified, and its crystal structure was determined to a resolution of 1.80 Å.     

Synthesis of a novel epoxy resin containing pyrene moiety and thermal properties of its cured polymer with phenol novolac

A new epoxy resin containing the pyrene moiety in the backbone (3) was synthesized and confirmed by gel permeation chromatography and field‐desorption mass spectroscopy and infrared spectroscopy. In addition, to evaluate the influence of the pyrene moiety on the structure, epoxy resins having an anthrylene moiety (5) and having a phenylene moiety (7) were synthesized. The cured polymer obtained through the curing reaction between 3 and phenol novolac was used for making a comparison of its thermal properties with those obtained from 5, 7, and bisphenol‐A (4,4′‐isopropylidenediphenyl)‐type epoxy resin (Bis‐EA). The cured polymer obtained from 3 showed a higher glass transition temperature, lower coefficient of linear thermal expansion, lower moisture absorption, and markedly higher anaerobic char yield at 700°C of 37.6 wt %, which might be attributed to the higher aromaticity of 3 containing the pyrene moiety. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 528–535, 2000     

Synthesis of a bifunctional epoxy monomer containing biphenyl moiety and properties of its cured polymer with phenol novolac

A new type of epoxy resin containing a 4,4′‐biphenylene moiety in the backbone (Bis‐EBP) is synthesized and confirmed by elemental analysis, infrared spectroscopy, and ¹H‐nuclear magnetic resonance spectroscopy. In addition, to evaluate the influence of the 4,4′‐biphenylene group in the structure, an epoxy resin having a 1,4‐phenylene group in place of the 4,4′‐biphenylene moiety (Bis‐EP) is synthesized. The cured polymer obtained through the curing reaction between the new biphenyl‐containing epoxy resin and phenol novolac is used for making a comparison of its thermal and physical properties with those obtained from Bis‐EP and bisphenol‐A (4,4′‐isopropylidenediphenyl)‐type epoxy resin (Bis‐EA). The cured polymer obtained from Bis‐EBP shows markedly higher fracture toughness of 1.32 MPa m^1/2, higher glass transition temperature, lower moisture absorption, and higher thermal decomposition temperature. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 690–698, 1999     

Synthesis and curing kinetics of colored epoxy resin containing azo moiety

Colored epoxy resin containing azo moiety was synthesized by reaction between epichlorohydrin and bis-azodiol, which was synthesized by coupling bisphenol-A with aromatic amine. Colored epoxy resin was characterized by epoxy equivalent weight, IR spectra, Viscosity and UV visible spectroscopy. The curing of colored epoxy resin and DGEBA were characterized by differential scanning calorimetry (DSC). The thermal stability of cured products was characterized by thermogr avimetric analysis (TGA). The cured products have good thermal stability. Several glass fiber epoxy composites were fabricated and their mechanical properties, electrical properties and chemical resistance were studied.     

Synthesis,characterization, and properties of a novel epoxy resin containing both binaphthyl and biphenyl moieties

A new epoxy resin containing both binaphthyl and biphenyl moieties in the skeleton (BLBPE) was synthesized and confirmed by electrospray ionization mass spectroscopy, ¹H‐nuclear magnetic resonance spectroscopy, and infrared spectroscopy. To evaluate the combined influence of two moieties, one epoxy resin containing binaphthyl moiety and another containing biphenyl moiety were also synthesized, and a commercial biphenyl‐type epoxy resin (CER3000L) was introduced. Thermal properties of their cured polymers with phenol p‐xylene resins were characterized by differential scanning calorimetry, dynamic mechanical, and thermogravimetric analyses. The cured polymer obtained from BLBPE showed remarkably higher glass transition temperature and lower moisture absorption, as well as comprehensively excellent thermal stability. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Elastomers Formed In-Situ in Epoxy Resins: Chemistry and Toughening

The chemistry of the in-situ formation of elastomer particles in epoxy resins is described. Under normal synthetic conditions, if one polymerizes an acrylic monomer in an epoxy resin, the resulting polymer is soluble in the epoxy resin or it grossly phase separates, depending upon the solubility parameter difference between the acrylic polymer and the epoxy resin. This work shows that with the use of a specifically tailored material (which we believe operates as a “polymeric surfactant”) in the reaction mixture, a free-flowing, stable suspension of acrylic elastomer particles in epoxy resin can be obtained. Thus, the reaction product of isocyanatoethylmethacrylate and EPON^TM 1009 can be used as the polymeric surfactant in a reaction mixture containing hexyl acrylate, azo-bis(isobutyronitrile) and the diglycidyl ether of bisphenol A. The resulting dispersion is stable to settling even after exposure to 150°C. When properly formulated, the resulting modified epoxy resins are improved in their fracture resistance after cure over a similar resin without the elastomeric particles. The effect of the following parameters on the fracture resistance of the cured epoxy resin are discussed: chemistry of the polymeric surfactant, chain extension in the cure of the epoxy resin, type of acrylic monomer and the level of the elastomer. The physical properties of several adhesive formulations based upon these modified epoxy resins are also discussed.     

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.     

Antioxidation Behavior of Milkweed Oil 4-Hydroxy-3-methoxycinnamate Esters in Phospholipid Bilayers

Milkweed (Asclepia syriaca) has seed oil that is rich in polyunsaturated triacylglycerides that contain olefinic groups. The olefinic groups can be chemically oxidized to form either epoxy or polyhydroxy triacylglycerides that can be esterified with trans-4-hydroxy-3-methoxycinnamic acid, commonly known as ferulic acid. Thin layer chromatography experiments demonstrated that these novel lipids incorporated well into phospholipid vesicles, did not form independent micelles, and their incorporation was not limited by the attached ferulic moiety. Leakage experiments showed that both epoxy derived and polyhydroxy ferulated triacylglycerides reduced leakage of vesicles. Lipid peroxidation measurements demonstrated that both epoxy derived and polyhydroxy forms of ferulated milkweed oil are capable of preventing lipid peroxidation with the polyhydroxy form having the greater capability.     

化学改性E-51环氧树脂水性体系工艺研究

利用化学改性法将亲水性基团引入E-51环氧树脂链上,经冰乙酸成盐并加水制备改性树脂水性体系.研究了各反应物用量对体系的影响,确定了最佳的原料配比、反应温度及时间,用红外光谱对改性树脂的结构进行了表征,并用激光粒度分析仪对水性体系的粒度分布进行了测定.结果表明,该改性E-51环氧树脂成盐后可与水以不同的配比形成水溶液或水乳液,且体系具有优良的稳定性,水性体系粒度分布与文献相符.     

酚醛环氧树脂水性化的研究

对酚醛型环氧树脂F-51进行化学改性引入亲水性基团，同时保留尽可能多的环氧基，成盐后制得水性环氧树脂体系。研究了各反应物用量对体系水溶性和水稳定性的影响，确定了最佳的原料配比、反应温度和时间，并利用红外光谱对产物的结构进行了表证?结果表明：该改性F-51环氧树脂可与水以不同的配比形成水溶液或水乳液，且体系具有优良的稳定性。     

化学改性E一51环氧树脂水性体系工艺研究

利用化学改性法将亲水性基团引入E-51环氧树脂链上，经冰乙酸成盐并加水制备改性树脂水性体系。研究了各反应物用量对体系的影响，确定了最佳的原料配比、反应温度及时间，用红外光谱对改性树脂的结构进行了表征，并用激光粒度分析仪对水性体系的粒度分布进行了测定。结果表明，该改性E-51环氧树脂成盐后可与水以不同的配比形成水溶液或水乳液，且体系具有优良的稳定性，水性体系粒度分布与文献相符。     

Synthesis and curing of new epoxycycloaliphatic polyesterimides with dianhydrides and diisocyanates as hardeners

New epoxy resins obtained from a series of bis(4,5-epoxytetrahydrophthalimides) and three different dicarboxylic diacids were prepared and characterized by spectroscopic techniques and thermal analyses. Homopolymerization of epoxy groups was observed as a parallel process to the polycondensation reaction. Using Epiclon B with a tertiary amine and hexamethylene diisocyanate as hardeners, we studied the reaction of epoxy groups and hydroxylic groups attached to the cycloaliphatic moiety in the main chain. No exotherms were clearly detected by DSC, and during the curing process, only increases in the T_g, values were observed. These cycloaliphatic epoxy polyesters have similar thermal characteristics to related aromatic epoxy polyesterimides, but have better processability. © 1996 John Wiley & Sons, Inc.     

环氧树脂改性水性聚氨酯胶粘剂的合成与性能

在用环氧树脂E-51和内交联剂TMP共同改性的水性聚氨酯胶粘剂中,适当添加环氧树脂可得到稳定的乳液,且综合性能较好。文中讨论了以共聚方式加入环氧树脂,结合DSC和力学性能等方面的研究,找出了合适的环氧树脂添加量为4．0%-8．0%。用环氧树脂改性的水性聚氨酯涂膜具有硬度高,耐水性好等特点。     

Functional group selective polymerization of (4-maleimidophenyl)oxirane as a new type of bifunctional monomer

A novel bifunctional monomer, (4-maleimidophenyl)oxirane (MAPO), with very reactive maleimido and epoxy groups, was prepared through the selective oxidation of the two carbon–carbon double bonds of N-(4-vinylphenyl)maleimide. Either of the two different polymerizable groups (vinylene of the maleimide moiety and the mono-substituted epoxide) of MAPO was able to be selectively polymerized by choosing the polymerization method. For radical polymerization, MAPO gave poly{p-[1,2-(epoxyethyl)phenyl]maleimide} (PEPM) with dense pendent epoxy groups in 76% yield without cross-linking. MAPO also gave poly(maleimidostyrene oxide) (PMSO) with dense pendent maleimido groups through cationic polymerization in 60% yield. On the other hand, anionic polymerization with an of MAPO produced only insoluble gel-like materials due to unselective polymerization of the two polymerizable groups (Scheme 1). The vinylene group of the maleimide moiety in PMSO easily reacted with the mercapto group, and the ring-opening reaction of the epoxy groups in PEPM with amino groups took place.     

Curing characteristics of epoxy resin systems that include a biphenyl moiety

The curing characteristics of epoxy resin systems that include a biphenyl moiety were investigated according to the change of curing agents. Their curing kinetics mainly depend on the type of hardener. An autocatalytic kinetic reaction occurs in epoxy resin systems with phenol novolac hardener, regardless of the kinds of epoxy resin and the epoxy resin systems using Xylok and DCPDP (dicyclopentadiene‐type phenol resin) curing agents following an nth‐order kinetic mechanism. The kinetic parameters of all epoxy resin systems were reported in terms of a generalized kinetic equation that considered the diffusion term. The fastest reaction conversion rate among the epoxy resin systems with a phenol novolac curing agent was obtained in the EOCN‐C epoxy resin system, and for systems with Xylok and DCPDP hardeners, the highest reaction rate values were obtained in NC‐3000P and EOCN‐C epoxy resin systems, respectively. The system constants in DiBenedetto's equation of each epoxy resin system with different curing agents were obtained, and their curing characteristics can be interpreted by the curing model using a curing agent as a spacer. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1942–1952, 2002     

环氧树脂改性水性聚氨酯的制备与性能研究

以异氟尔酮二异氰酸酯(IPDI)、聚四氢呋喃醚二醇(PTMG)以及二羟基甲基丙酸(DMPA)为主要原料合成水性聚氨酯(WPU)预聚体,在此基础上加入环氧树脂(EP,E-44)制备了环氧树脂改性水性聚氨酯(PUE)复合乳液。探讨了不同环氧树脂含量对复合乳液性能的影响,并对胶膜的力学性能、吸水率、接触角和热性能等进行了表征。结果表明,适量的环氧树脂改性过后的复合乳液比较稳定;随着环氧树脂含量的增加,乳液粒径和黏度增大,同时胶膜的拉伸强度增大,水的接触角增大,胶膜的热稳定性增加。E-44质量分数为7%~9%时,复合乳液及其胶膜的综合性能较好。     

Perspectives of Epoxy/Graphene Oxide Composite: Significant Features and Technical Applications

In this article, advancement in epoxy/graphene oxide composites is presented. These materials are comprised of graphene oxide (GO) as filler (carbon-based material, thermodynamically stable, two-dimensional, planar and layered structure). Due to improved properties (mechanical response, low density, electrical resistance, and thermal stability), epoxy resins are used in several applications. Graphene oxide proposes unique properties to epoxy composites as high surface area, thermal and electrical conductivity as well as mechanical and barrier properties, relative to neat matrix. The corresponding significance of epoxy/GO-based materials, related challenges, and potential exploitation regarding technical applications (aerospace, gas sensor, electronic devices, etc.) have been overviewed.