Preparation and characterization of printable solder resist inks based on hyperbranched polyester

Two novel solder resist inks containing hyperbranched epoxy resin (HBPE) for thermal curing and hyperbranched epoxy acrylate resin (HBPEA) for UV‐curing were introduced in this work. Different generations of HBPE and HBPEA were synthesized and their chemical structures were determined by FT‐IR. Both curing reactions were monitored under differential scanning calorimetry (DSC) and photo‐DSC. For HBPE, the curing temperature of 7th generation was only 91°C and for HBPEA, the curing duration of 7th generation was under 10 s. The thermal stabilities of cured resins were much more stable than linear resin, as the decomposition temperatures of HBPE and HBPEA were both over 400°C. The ink containing HBPE or HBPEA jetted by piezoelectric printer showed excellent accuracy and consistency of linewidth and the morphologies of cured pattern were observed through a stereo microscope. Other performances of solder masks were tested under China Printed Circuit Association (CPCA) standard (CPCA/JPCA 4306‐2011), which satisfy all requirements of printed circuit board soldering procedure. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41805.     

Synthesis and characterization of emulsion‐type curing agent of water‐borne epoxy resin

Self‐emulsified water‐borne epoxy curing agent of nonionic type was prepared using triethylene tetramine (TETA) and derivative of epoxy resin as a capping agent, which was synthesized by liquid epoxy resin (E51) and polyethylene glycol (PEG), and the curing agent possessed emulsification and curing properties at the same time. The curing agent with good property of emulsifying liquid epoxy resin could be obtained under the condition of the molar ratio of PEG : E51 : TETA as 0.8 : 1 : 3.5 at 80°C for 5 h. The mean particle size of the emulsion liquid was about 220 nm with the prepared curing agent and epoxy resin at the mass ratio of 1 : 3. The structure of the emulsion‐type curing agent was confirmed by FTIR and ¹H NMR spectra, and the mechanism of cured film formation was also analyzed by SEM photographs. The cured film prepared by the emulsion‐type curing agent and epoxy resin under ambient cure conditions showed good properties even at high staving temperature. This study provides useful suggestions for the application of the water‐borne epoxy resins in coating industry. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2652–2659, 2013     

Amine-terminated poly(ethylene glycol) benzoate (ATPEGB)-modified epoxy: mechanical and thermal properties

Amine-terminated poly(ethylene glycol) benzoate (ATPEGB), synthesized from the esterification reaction of poly(ethylene glycol) (PEG) with 4-amino benzoic acid, was used to modify the toughness of bisphenol-A diglycidyl ether epoxy resin (DGEBA) cured with room temperature curing agent, triethylene tetramine. ATPEGB was characterized by FT-IR and H-NMR spectroscopies, viscosity measurements, solubility parameter calculation and molecular weight determination with gel-permeation chromatography (GPC). The modified epoxy network was evaluated for its impact, adhesive, tensile, flexural and thermal properties. Improvement in mechanical properties depends upon the concentration of the ATPEGB modifier. The optimum properties were obtained at 12.5 phr (parts per hundred parts of resin) concentration of the modifier. The ATPEGB modified cured epoxy was thermally stable up to 315°C. The morphology of cured epoxy was also analyzed by scanning electron microscopy (SEM) investigation of fracture surfaces.     

Effect of reactive poly(ethylene glycol) flexible chains on curing kinetics and impact properties of bisphenol‐a glycidyl ether epoxy

Bisphenol‐A glycidyl ether epoxy resin was modified using reactive poly(ethylene glycol) (PEO). Dynamic mechanical analysis showed that introducing PEO chains into the structure of the epoxy resin increased the mobility of the molecular segments of the epoxy network. Impact strength was improved with the addition of PEO at both room (RT) and cryogenic (CT, 77 K) temperature. The curing kinetics of the modified epoxy resin with polyoxypropylene diamines was examined by differential scanning calorimetry (DSC). Curing kinetic parameters were determined from nonisothermal DSC curves. Kinetic analysis suggested that the two‐parameter autocatalytic model suitably describes the kinetics of the curing reaction. Increasing the reactive PEO content decreased the heat flow of curing with little effect on activation energy (E_a), pre‐exponential factor (A), or reaction order (m and n). © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

水性环氧固化剂的制备研究

文章采用环氧树脂E-44和聚乙二醇400为原料合成改性环氧树脂,然后与三乙烯四胺反应制备水性环氧固化剂.研究表明：改性环氧树脂与三乙烯四胺质量比为2∶1,反应温度为60℃,反应时间为2h,制备的水性环氧固化剂性能优良.     

Curing characteristics of epoxy resins filled with cellulose and oxidized cellulose

Gel time and Brookfield viscosity studies of epoxy resins containing varying concentrations of cellulose, periodate oxidized cellulose, chromic acid oxidized cellulose, and ethylene glycol were carried out at 120°C using the tertiary amine hexamethylene tetramine as catalyst. It was found that the hydroxyl groups of cellulose and oxidized cellulose did not only act as accelerators for the tertiary amine catalyzed polymerization of the epoxy resin, but evidence was also found which pointed to the actual participation of the cellulosic fillers in the crosslinking reaction leading to the thermoset epoxy polymer. The gel times of the epoxy curing reaction decreased as the concentrations of the cellulosic fillers increased. The change in viscosity with time (curing characteristics) curves for 40 parts of cellulose or oxidized cellulose per hundred parts of resin (phr) were similar to that of 10 phr ethylene glycol, while the curve for 20 phr cellulose-filled epoxy resin was almost identical to the curve for 10 phr periodatefilled resin. These differences are explained on the basis of the percentage of hydroxyl groups in the various filler molecules that are available for their role as accelerators. The possibility of greater participation of oxidized cellulose in the network formation with the epoxy resin than ordinary cellulose has also been surmised on the basis of its increased viscosity build-up after the gel time is achieved.     

端脂肪氨基聚醚改性环氧树脂的性能研究

用自制的一种既含聚醚柔性链段又含苯脂肪氨基刚性链段的端脂肪氨基聚醚(APPEG)作为固化剂对环氧树脂进行增韧改性。扫描电子显微镜和力学性能测试结果表明,固化剂对环氧树脂具有明显的增强、增韧效果,且改性的环氧树脂胶粘剂具有很好的填充性能,填充比高达50%。与羰基铁粉组成的涂层材料具有优异的力学性能和热稳定性能。     

Flexibility improvement of epoxy resin by chemical modification

Epoxy resin was chemically modified with carboxyl‐terminated poly(ethylene glycol) adipate (CTPEGA) and the modified epoxy networks were made by curing with an ambient‐temperature hardener. The modified epoxy networks containing various concentrations of CTPEGA were characterized for their tensile, flexural and impact properties. It was observed that the mechanical strength gradually decreases and the strain increases with increasing CTPEGA concentration. However, the toughness and impact strength gradually increase with increasing CTPEGA concentration, attain a maximum and then decrease. The optimum CTPEGA concentration was found to be 20 phr. Fracture surface analysis by scanning electron microscopy indicates massive plastic deformation in modified networks. Copyright © 2004 Society of Chemical Industry     

Curing kinetics and viscosity change of a two‐part epoxy resin during mold filling in resin‐transfer molding process

The curing kinetics and the resulting viscosity change of a two‐part epoxy/amine resin during the mold‐filling process of resin‐transfer molding (RTM) of composites was investigated. The curing kinetics of the epoxy/amine resin was analyzed in both the dynamic and the isothermal modes with differential scanning calorimetry (DSC). The dynamic viscosity of the resin at the same temperature as in the mold‐filling process was measured. The curing kinetics of the resin was described by a modified Kamal kinetic model, accounting for the autocatalytic and the diffusion‐control effect. An empirical model correlated the resin viscosity with temperature and the degree of cure was obtained. Predictions of the rate of reaction and the resulting viscosity change by the modified Kamal model and by the empirical model agreed well with the experimental data, respectively, over the temperature range 50–80°C and up to the degree of cure α = 0.4, which are suitable for the mold‐filling stage in the RTM process. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 2139–2148, 2000     

Novel imidazole derivatives with recoverable activity as latent curing agents for epoxy

A series of latent curing agents were developed by replacing the hydrogen atom on secondary amine in imidazole with methoxy polyethylene glycol maleate diesters via Michael addition reaction. Methoxy polyethylene glycol maleate diesters with different molecular weight also restrained the reactivity of tertiary amine in imidazole ring. The curing properties and pot-life of the modified imidazole/epoxy systems were measured by differential scanning calorimeter and rotational rheometer. The modified imidazole/epoxy system could be cured quickly at 175°C. The modified imidazole shows good latency. After stored for more than 1 month, viscosity of modified imidazole/epoxy system remains unchanged. The longer chain polyether had the better thermal latency these curing agents had. Compared with unmodified imidazole, the novel latent curing agents led to better impact strength for cured epoxy. However, the compatibility between epoxy and latent curing agent will get worse if the molecular weight of polyether unite is over 750.     

反应性聚乙二醇与环氧丙烯酸树脂共混改性及其涂膜性能的研究

用马来酸酐和聚乙二醇合成具有反应活性端基的聚乙二醇（PEG-MAH）,并用其对环氧丙烯酸酯（EA）进行物理共混改性,测定了改性环氧丙烯酸酯固化膜的性能.试验结果表明,反应性聚乙二醇参与了环氧丙烯酸树脂的固化反应,提高了环氧丙烯酸树脂的冲击强度和附着力,但耐热性、耐酸碱性和耐水性降低.讨论了不同用量的反应性聚乙二醇（PEG-MAH）对涂膜性能的影响,结果表明加入20％用量的PEG-MAH涂层具有较好的综合性能.     

Synthesis and film properties of epoxy esters modified with amino resins from glycolysis products of postconsumer PET bottles

Glycolysis of waste polyethylene terephthalate (PET) flakes obtained from grinding postconsumer bottles was carried out at 225–250°C and molar ratios of PET/ethylene glycol were taken as 1/1, 1/1.5, 1/5, and 1/10. Reaction product was extracted by hot water for three times and water‐soluble crystallizable fraction and water‐insoluble fraction were obtained. These fractions were characterized by acid and hydroxyl value determinations, differential scanning calorimeter analysis, and ¹H‐NMR analysis. Glycolysis product was used for synthesis of PET‐based epoxy resin. This epoxy resin was used to prepare epoxy ester resins having 40% and 50% oil content. Epoxy ester resin having 40% oil content was modified with urea‐formaldehyde and melamine‐formaldehyde resins for synthesis of epoxy ester–amino resin. Physical and chemical film properties of epoxy ester and modified epoxy ester resins were investigated. All the epoxy ester and modified epoxy ester films were having excellent adhesion, water, and salt water resistance properties. Modification of PET‐based epoxy ester resins with amino resin has significantly improved hardness, impact resistance, and alkaline and acid resistance of resin films. As a result, PET oligomers obtained from glycolysis of postconsumer PET bottles are suitable for manufacturing of amino‐resin‐modified epoxy ester resins that have improved physical and chemical surface coating properties. POLYM. ENG. SCI., 55:2519–2525, 2015. © 2015 Society of Plastics Engineers     

水性环氧固化剂分散体的制备及改性

采用不同分子量的聚乙二醇与液体环氧树脂EPON828合成反应型乳化剂,然后将反应型乳化剂链段引入到以液体环氧树脂EPON828与间苯二甲胺为原料合成的端胺基中间体的分子结构中,再用活性稀释剂进行封端,最后加水分散,制得水性环氧固化剂分散体。采用了γ-氨丙基三乙氧基硅烷(即硅烷偶联剂KH-550)对其进行改性。确定了间苯二甲胺与环氧树脂EPON828的摩尔比为2.2∶1,聚乙二醇6000与环氧树脂EPON828(摩尔比为1∶1)制备的反应型乳化剂用量为9%,硅烷偶联剂KH-550的用量为固化剂分散体的质量的2%时,所制备的水性环氧固化剂分散体稳定性最佳,其粒径为750.8nm,固含量约60%,胺值为118mgKOH/g,黏度为4500mPa·s。室温固化后,涂膜硬度为3H,光泽度(60°)为108%,冲击强度50kg·cm,柔韧性1mm,附着力1级,耐酸碱腐蚀性能好。通过傅立叶变换红外光谱表征了反应产物。     

Study on Curing Kinetics and Thermal Degradation Kinetics of Hyperbranched Poly(Trimellitic Anhydride Ethylene Glycol) Epoxy (HTME)/Diglycidyl Ether of Bisphenol-A Epoxy Hybrid Resin

Hyperbranched poly(trimellitic anhydride ethylene glycol) epoxy (HTME) not only has relatively low viscosity and high molecular weight but also is a functional additive of enhancement and toughness and is used in the thermosetting resin field widely. The curing kinetics and thermal degradation kinetics of HTME/diglycidyl ether of bisphenol-A epoxy hybrid resin were studied in detail using differential scanning calorimetry and thermogravimetric analysis technique, respectively, by the Coats-Redfern model. The effect of molecular weight or generation and content of HTME on activation energy, reaction order, curing time, and curing reaction were discussed and analyzed, and the results indicated that HTME could accelerate curing reaction and reduce activation energy and reaction order of the curing reaction.     

Rheology and curing characteristics of epoxy–clay nanocomposites

Diglycidyl ethers of bisphenol‐A (DGEBA) epoxy resin, filled separately with organoclay (OC) and unmodified clay (UC), were synthesized at room temperature and at high temperature (80 °C) by mechanical shear mixing. The room temperature curing (RTC) and high temperature curing (HTC) were carried out with the addition of triethylene tetramine (TETA) and diaminodiphenylmethane (DDM) curing agents respectively. The OC used was alkyl ammonium modified montmorillonite (MMT) and the UC was Na⁺‐MMT. X‐ray diffraction (XRD) and transmission electron microscopy (TEM) were used to study the structure and morphology of the nanocomposites. The influence of OC and UC particles on rheology and curing characteristics was studied. The rate of increase in viscosity was higher for OC‐filled resin than that of the UC‐filled resin. The curing study showed that the amine ions of the OC aided the polymerization process and favoured the curing at low temperature over the curing of unfilled epoxy resin. The tensile properties were enhanced for epoxy filled with OC particles rather than those filled with UC particles. Copyright © 2005 Society of Chemical Industry     

改性环氧丙烯酸酯胶粘剂预聚体增韧改性研究

采用聚乙二醇改性环氧E-44树脂,改性后E-44与α-甲基丙烯酸进行酯化反应,得到改性环氧丙烯酸酯预聚体。由单因素实验确定反应条件如下：第一步反应温度为90℃,第二步反应温度为95℃,聚乙二醇与环氧树脂的物质的量比为0．20：1,催化剂四丁基溴化铵用量为2．0％,阻聚剂对羟基苯甲醚用量为0．05％。红外光谱分析表明,改性环氧丙烯酸酯预聚体合成成功。由改性预聚体配制的胶粘剂粘度减小,拉伸剪切强度可达5．95MPa,180°剥离强度也有所提高。     

Synthesis and characterization of methacrylated star‐shaped poly(lactic acid) employing core molecules with different hydroxyl groups

A set of novel bio‐based star‐shaped thermoset resins was synthesized via ring‐opening polymerization of lactide and employing different multi‐hydroxyl core molecules, including ethylene glycol, glycerol, and erythritol. The branches were end‐functionalized with methacrylic anhydride. The effect of the core molecule on the melt viscosity, the curing behavior of the thermosets and also, the thermomechanical properties of the cured resins were investigated. Resins were characterized by Fourier‐transform infrared spectroscopy, ¹³C‐NMR, and ¹H‐NMR to confirm the chemical structure. Rheological analysis and differential scanning calorimetry analysis were performed to obtain the melt viscosity and the curing behavior of the studied star‐shaped resins. Thermomechanical properties of the cured resins were also measured by dynamic mechanical analysis. The erythritol‐based resin had superior thermomechanical properties compared to the other resins and also, lower melt viscosity compared to the glycerol‐based resin. These are of desired characteristics for a resin, intended to be used as a matrix for the structural composites. Thermomechanical properties of the cured resins were also compared to a commercial unsaturated polyester resin and the experimental results indicated that erythritol‐based resin with 82% bio‐based content has superior thermomechanical properties, compared to the commercial polyester resin. Results of this study indicated that although core molecule with higher number of hydroxyl groups results in resins with better thermomechanical properties, number of hydroxyl groups is not the only governing factor for average molecular weight and melt viscosity of the uncured S‐LA resins. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45341.     

脂肪族环氧化合物的合成及其共混树脂的研究

以聚丙二醇和环氧氯丙烷为原料合成出了低黏度的脂肪族环氧树脂。使用上述环氧树脂与双酚A型环氧树脂按不同的比例混合后,再加入大分子胺类固化剂,由此构筑出环氧树脂固化体系并对其黏度、凝胶时间和固化物的力学性能进行了表征。结果显示,该环氧树脂固化体系在常温下具有很低的黏度与较长的凝胶时间,其固化物的拉伸与弯曲性能较好,且冲击韧性有了明显的改善。     

Curable resins based on recycled poly(ethylene terephthalate) for coating applications

Poly(ethylene terephthalate) waste was depolymerised in the presence of diethylene- or tetraethylene glycol and manganese acetate as a catalyst. An epoxy resin was then prepared by the reaction of these oligomers with epichlorohydrin in presence of NaOH as a catalyst. The produced oligomers were condensed with maleic anhydride and ethylene glycol to produce unsaturated polyester. The chemical structures of the resulting epoxy and unsaturated polyester resins were confirmed by ¹HNMR. The vinyl ester resins were used as cross-linking agents for unsaturated polyester resin diluted with styrene, using free radical initiator and accelerator. The 2-amino ethyl piprazine was used as hardener for epoxy resins. The curing behaviour of the unsaturated polyester resin, vinyl ester resins and styrene was evaluated at different temperatures ranged from 25 to 55 °C to calculate the curing activation energy of the system. The cured epoxy and unsaturated polyester resins were evaluated in coating application of steel.     

Poly(ester‐amine) hyperbranched polymer as toughening and co‐curing agent for epoxy/clay nanocomposites

The marriage between hardness and flexibility of epoxy resins (improved toughness) is a desired feature, which broads their application in various industrial fields, especially for high impact resistance purposes. Accordingly, this work aims to improve toughness properties of epoxy resin (Epon‐828)/Ancamine (curing agent) system using amino‐terminated hyperbranched poly(ester‐amine) [Poly(PEODA‐NPA)] (HP) as toughening and/or co‐curing agent, in presence of organo‐modified Montmorillonite clay (OMMT) as a reinforcing filler. HP was synthesized via Michael addition reaction of poly(ethylene glycol) diacrylate (PEODA) to N‐methyl‐1,3‐propanediamine (NPA). Chemical structure and molecular weight of HP were elucidated using infrared (FTIR) spectroscopy and gel permeation chromatography (GPC) techniques, respectively. Epoxy/OMMT nanocomposites toughened with HP (at different concentrations) showed remarkable improvement in their toughness without any adverse effect on the other physico‐mechanical properties. The optimum concentration of HP and OMMT was found to be 20 wt % and 1–3 wt% of the epoxy resin, respectively. The extent of exfoliation and dispersion of OMMT platelets within the epoxy cured films was assessed by X‐ray diffraction (XRD) and transmission electron microscopy (TEM) measurements. In addition, thermal gravimetric analyses (TGA‐DTA) of epoxy/OMMT nanocomposites toughened with HP showed a slight increase in their decomposition temperature, particularly at low OMMT loading. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers