合成条件对邻甲酚系线形酚醛树脂的影响

采用双层反应设备,通过碱酸分步催化法合成了一系列纯邻甲酚和以邻甲酚为主成分的邻甲酚系线形酚醛树脂。利用GPC、NMR等研究了催化剂氢氧化钠的用量、醛酚比以及酚的种类和用量对树脂的分子质量(Mw)、分子质量分布(Mw/Mn)及抗碱性等的影响。结果表明,氢氧化钠用量达到酚总质量的0.4%、醛酚比接近于1时可合成分子质量高、分子质量分布窄的树脂。可利用醛酚比控制树脂的分子质量,可通过调整酚的种类和用量控制树脂的双邻位缩聚值(Ro-o)以及酚醛树脂的质量与其所含酚羟基质量之比值。合成的树脂可用于PS版、热敏CTP版以及LCD用抗蚀剂等。     

DOPO与邻甲酚醛环氧树脂反应特性的研究

通过环氧值滴定和红外光谱研究反应型含磷阻燃剂(DOPO)与邻甲酚醛环氧树脂的反应特性,确定其最佳反应条件。实验结果表明:120℃下添加20%催化剂三苯基膦,反应120 min可获得最佳效果。红外谱图进一步确认DOPO与邻甲酚醛环氧树脂反应进行的程度及DOPO含磷环氧树脂的初步结构。采用DTA分析方法研究DOPO与邻甲酚醛环氧树脂的反应动力学,测得DOPO与邻甲酚醛环氧树脂反应的动力学参数lnA0为58.63,表观活化能E为298.51 kJ/mol,反应级数n为0.97。     

红外水分仪测定环氧树脂挥发分的最佳条件

利用红外水分测定仪在各种测试程序下对邻甲酚酚醛环氧树脂的挥发分进行测试记录,并同烘箱法的挥发分测试结果比较,确定了红外水分测定仪法的最佳分析条件:升温程序选择为快速干燥程序;初始温度:90.0℃;终端温度:100.0℃;样品称量范围:(5.0±0.3)g;测试时间:15 min。结果表明:MA100红外水分测定仪目前测试条件下的测试结果与烘箱法一致,比烘箱法省时、高效、准确。每个样品分析节约时间2h;绝对误差≤0.02%;结果平行性更好。     

Toughening of epoxy novolac resin using cardanol based flexibilizers

In this work, two different cardanol based epoxies (Cardolite NC‐514 and Cardanol NC‐547) were employed as flexibilizers to toughen an epoxy novolac resin namely, poly[(phenylglycidyl ether)‐co‐formaldehyde] (PPGEF). 4,4′‐Diamino‐3,3′‐dimethyl dicyclohexyl methane (BMCHA) was used as a curing agent. Differential scanning calorimetry and dynamic mechanical thermal analysis of the composites showed a gradual decrease in glass transition temperatures (T_g) with increase in cardolite content confirming the incorporation of flexible moieties into the brittle resin matrix. Improvement in toughening of PPGEF/Cardolite composites was manifested by increase in the izod impact strength of both the composites. The tensile strength increased marginally for composites with increasing amount of Cardolite NC‐514 but decreased for the composites containing Cardolite NC‐547. This was attributed to the lack of rotational motion in the chain due to close proximity of rigid phenyl rings in NC‐547. SEM of the cryo‐fractured surfaces of composites showed good compatibility between PPGEF and cardanol based flexibilizers. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43318.     

Flexible epoxy novolac coatings: Use of cardanol‐based flexibilizers

Flexible epoxy novolac coatings were developed by reacting an epoxy novolac resin, poly[(phenylglycidyl ether)‐co‐formaldehyde] (PPGEF) with an amine curing agent, 4,4′‐diamino‐3,3′‐dimethyldicyclohexyl methane (BMCHA), cardanol based reactive diluent (Cardolite NC‐513) and two different cardanol‐based flexibilizers (Cardolite NC‐514 and Cardolite NC‐547). The flexibilizer content was varied from 5 to 10% by weight of the resin. These resins were coated onto the stainless steel panels and tested for their gloss, cross‐hatch adhesion, falling weight impact resistance, flexibility, abrasion, scratch hardness, solvent scrub resistance, and chemical resistance. The thermo‐mechanical properties of these coatings were determined by TGA, DSC, DMTA, and tensile strength measurements. The cryofractured specimens were subjected to SEM analysis. The influence of structural differences of two flexibilizers on the coating properties was investigated. These coatings exhibited excellent properties and have great potential in industrial applications. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44920.     

邻甲酚醛环氧树脂合成中的醚化反应研究

苄基三乙基氯化铵作为邻甲酚醛(OCN)环氧树脂合成中醚化反应的相转移催化剂(PTC),用量PTC/OCN(摩尔比)为1∶200,醚化反应最佳时间为1 h。     

High performance waterborne coatings based on dispersions of a solid epoxy resin and an amine-functional curing agent

A novel, waterborne epoxy system comprised of non-ionic stabilized dispersions of a solid epoxy resin and an amine curing agent has been designed for ambient-cure coatings. The performance characteristics of coatings formulated from the new system have been compared to a standard system. The new system produced formulated coatings with robust performance over a wide range of amine-to-epoxy stoichiometries (65 to 130%). At 100% stoichiometry, the new system was found to have lower VOC, faster hardness development, better gloss, and higher impact resistance than the standard system. The new formulations also exhibited superior water and salt spray resistance, and a definitive viscosity rise at the end of potlife. Unlike the standard system, coating morphology of the new waterborne system was found to be similar to a solvent-based coating. For the new system, good coalescing solvents, as judged by gloss and gloss potlife, were found to have low solubility parameters and high boiling points. Presented at the 76th Annual Meeting of the Federation of Societies for Coatings Technology, on October 15, 1998, in New Orleans, LA. P.O. Box 1380, Houston, TX 77251-1380.     

酚醛型环氧树脂改性氰酸酯复合材料性能的研究

通过DSC分析,粘度、介电性能、力学性能及耐油性测试对酚醛型环氧树脂改性氰酸酯树脂复合材料的性能进行了研究。结果表明,改性氰酸酯树体系在70～160℃具有较低的粘度,理想工艺是在125～130℃下30～45min后开始加压;改性氰酸酯树脂表观活化能和反应级数分别为60.81kJ/mol和0.8846。改性氰酸酯复合材料具有良好的力学性能、介电性能和耐油性能。     

环氧树脂涂层表面亲水性对微藻黏附性能的影响

在固体材料表面黏附成膜是微藻细胞的一种生理特性。近些年基于微藻生物膜的生物过程,如生物膜贴壁培养和防附着技术受到了很多关注。微藻在固体材料表面的黏附受藻细胞与材料表面之间的相互作用的影响,建立黏附强度与材料表面性质参数间的关系对于通过材料选择来强化或控制微藻生物膜具有非常重要的意义。本工作的目的是揭示和明确材料亲疏水性对微藻黏附的影响,提出了一种双酚A环氧(EP)树脂表面亲疏水改性的方法。通过将亲水性的二乙醇胺(DEA)或疏水性的聚甲基聚硅氧烷(PMHS)加入到EP树脂中反应,EP树脂表面水接触角在36.80?~98.34?范围内可通过加入不同量的DEA或PMHS实现任意可调,材料的表面水接触角与DEA或PMHS加入量之间有线性关系。重要的是这种改性方法获得的材料,其形貌、结构、表面粗糙度等表面性质几乎没有变化,从而在研究和关联微藻黏附量与材料表面亲疏水性(表面水接触角)之间的关系时可以排除亲疏水性之外的其他表面性质的影响;其次,考察了小球藻和栅藻在不同亲疏水性材料表面的黏附行为,结果表明小球藻和栅藻在亲水性和疏水性材料表面均能黏附成膜,但在亲水性材料表面黏附更多更快;建立了微藻最大黏附容量与材料表面接触角之间关联关系,表明微藻最大黏附容量随材料表面水接触角的增大而线性降低,栅藻的表面黏附容量比小球藻大。     

Spectral and thermal studies on polyaniline–epoxy novolac resin composite materials

Polyaniline–epoxy novolac resin composite materials (PANI–RESIN) were prepared by emulsion polymerization technique and characterized by infrared and electronic absorption spectra, conductivity, particle size, and thermogravimetric and differential scanning calorimetric analysis. The conductivity of PANI–RESIN samples decreased with the addition of the RESIN as 0.1, 0.02, and 0.04 S/cm for 25, 50, and 75% addition of the RESIN, respectively. TGA thermograms of PANI–RESIN samples are more or less similar to those of polyaniline salts (PANI), which were stable up to 225°C. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 3507–3512, 1999     

阻聚剂对酚醛环氧乙烯基酯的贮存及固化影响

通过正交实验法从4种酚醛环氧乙烯基酯树脂(NEVER)阻聚剂:氮杂环、吩噻嗪、对苯二酚、苄基三乙基氯化铵中确定了最佳复配阻聚剂。采用FTIR和DSC研究了含复配阻聚剂NEVER在热贮存下双键的变化及其固化反应动力学,并对固化后产物的不可溶分含量进行了测定。结果表明,最佳复配阻聚剂为氮杂环化合物和吩噻嗪,用量均占树脂质量的0.03%,此时NEVER在80℃下的贮存期可从11 h提高至60 h;树脂经80℃贮存50 h,总的C==C双键保留率达63.7%,说明选定的复配阻聚剂对NEVER具有良好的阻聚作用。固化的表观活化能从79.00 kJ/mol升高至87.44 kJ/mol,复配阻聚剂不影响最终产物的固化完全度。     

The adsorption of an epoxy acrylate resin on aluminium alloy conversion coatings

A thermodynamic study of the adsorption of an epoxy acrylate resin used for UV-cured coatings on two different anticorrosion pretreatments on aluminium alloys relevant to aerospace industry has been undertaken. Aluminium alloy Al2219 specimens, treated with an inorganic chromate based conversion coating (Alodine 1200S) and an organic titanium based conversion coating (Nabutan STI/310), were immersed in solutions of different concentrations of the resin and adsorption isotherms were determined by assessing the uptake of the adsorbate, as a function of solution concentration, by time-of-flight secondary ion mass spectrometry (ToF-SIMS). The results show different behaviour for the two substrates, which can be attributed to the organic component of the titanium based coating. In the case of the inorganic conversion coating a clear plateau is achieved at relatively low concentrations and at a lower level of adsorption than for the hybrid coating. The data for both the coatings conform well to the Langmuir model, the organic coating, as well as showing a higher level of adsorption of the resin, also presents oscillatory behaviour at low concentration, which is shown to be complementary to the behaviour of the reactive diluent included with the epoxy acrylate to aid processing. A discussion of this competitive adsorption of the epoxy resin and the diluent on the different substrates is presented, based on considerations of the chemistry of the systems under investigation.     

酚醛型环氧树脂/双酚A型氰酸酯树脂体系固化动力学的研究

应用差示扫描量热分析(DSC)对不同比例的酚醛型环氧树脂/双酚A型氰酸酯树脂体系固化动力学进行了研究,并通过Kissinger法、Ozawa法和Crane法求得了体系的固化动力学参数。结果表明,当环氧树脂与氰酸酯的摩尔比为2∶1时,由Kissinger法和Ozawa法计算得到的表观活化能在体系中最小,分别为49.05 kJ/mol和54.86 kJ/mol,Crane方程求得的表观反应级数为1~2。     

Effect of an epoxidized novolac resin anhydride structure on the properties of resin

The properties of an epoxidized novolac resin cured with two homologous series of substituted succinic anhydrides (alkenyl and alkyl) have been determined and the effects of anhydride structure on properties have been evaluated. Substituted succinic anhydrides yield cured resins with lower strengths, lower heat distortion temperatures, and lower moduli. Use of substituted succinic anhydrides could broaden the range of application of alicyclic anhydrides to include those requiring a more flexible resin. Effects of specific elements of anhydride structure have been consistently interpreted from properties measurements and from aging and solvent resistance studies.     

水性环氧树脂涂料适用期的研讨

研究探讨了水性环氧树脂涂料适用期方面的相关规律与特点。结果表明固化剂乳化型水性环氧树脂涂料的适用期一般较短;其与溶剂型环氧树脂涂料一样,可以用黏度变化来判断其适用期的长短;而对于水性环氧固化剂乳液与水性环氧树脂乳液所组成的水性环氧树脂涂料体系,其适用期较长,并且应以涂膜的性能,如涂膜光泽度的变化来确定。     

Development of self-healing coatings based on urea-formaldehyde/polyurethane microcapsules containing epoxy resin

In this study, the synthesis of urea-formaldehyde/polyurethane (UF/PU) microcapsules containing epoxy resin for self-healing and anti-corrosion coatings with good stability has been reported. Spherical microcapsules were prepared with a diameter of about 50–720 μm and a shell thickness of 0.6–0.7 μm via in situ polymerization in an oil-in-water emulsion using 2,4-toluene diisocyanate-based pre-polymer along with the urea-formaldehyde. Scanning electron microscopy (SEM) and optical microscopy (OM) were employed to evaluate the shape and morphology of the microcapsules. Fourier transform infrared (FTIR) spectroscopy showed the absence of free isocyanate groups within the microcapsule shell confirming the completion of shell formation reactions. OM illustrated that the microcapsules were stable over a period of 30-days in toluene and xylene. Increasing microcapsule loading improved crack repairing and anti-corrosion performance of the coating layer. Low-carbon steel coupons coated with an epoxy resin containing 10 wt% microcapsules and scribed using a scalpel blade showed no visible sign of corrosion after up to 5 weeks of exposure in a standard salt spray test chamber.     

环氧树脂基复合涂层摩擦磨损性能研究

研究了不同质量分数石墨、碳纤维、纳米ZrO2对环氧树脂(EP)涂层摩擦磨损性能的影响,并用扫描电子显微镜观察了涂层磨损表面形貌并探讨了磨损机理。结果表明:石墨质量分数为20%时复合涂层的磨损率仅为纯EP的7.75%;纳米ZrO2质量分数为4%时复合涂层的磨损率为纯EP的30%;纳米ZrO2与碳纤维以及石墨的协同作用提高了EP的摩擦磨损性能。EP复合涂层的磨损机理以粘着磨损、磨粒磨损以及疲劳磨损为主。     

Effects of novolac resin modification on mechanical properties of carbon fiber/epoxy composites

The epoxy resin matrix of carbon fiber (CF)‐reinforced epoxy composites was modified with novolac resin (NR) to improve the matrix‐dominated mechanical properties of composites. Flexural strength, interlaminar shear strength (ILSS), and impact strength were measured with unfilled, 7 wt% NR, 13 wt% NR, and 18 wt% NR filled to epoxy to identify the effect of adding NR on the mechanical properties of composites. The results showed that both interfacial and impact properties of composites were improved except for flexural property. The largest improvement in ILSS and impact strength were obtained with 13 wt% loading of NR. ILSS and impact strength were improved by 7.3% and 38.6%, respectively, compared with the composite without NR. The fracture and surface morphologies of the composite specimens were characterized by scanning electron microscopy. Intimate bonding of the fibers and the matrix was evident with the content of 7–13 wt% NR range. Decrease of crosslinking density and formation of NR transition layer were deduced with adding NR. POLYM. COMPOS., 2011. © 2010 Society of Plastics Engineers     

Fabrication and evaluation of structural film adhesive using oxazolidinone modified novolac epoxy resin

Epoxy film adhesives are of prime importance for the fabrication of lightweight honeycomb structures for aerospace industries. This work involves the synthesis of oxazolidinone modified epoxy novolac resin (EPN-OXA) via the reaction of EPN and toluene diisocyanate. EPN-OXA was characterized by Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, gel permeation chromatography, and epoxy equivalent weight. EPN-OXA was blended with solid epoxy resin, polyethersulfone (PES) toughened liquid epoxy resin, dicyandiamide, and aluminum powder to fabricate a film adhesive curing at 170–180 °C. Effect of additives and curative on the adhesive property was studied to optimize the composition. Effect of PES on the optimized composition was studied in detail. The best composition exhibited lap shear strength of 370 ± 10 kgf cm⁻² at 25 °C and the strength was retained to 75% at −196 °C and 52% at 120 °C. PES significantly enhanced the interfacial strength at different temperatures (~1.6-fold at −196 and 25 °C and ~1.8-fold at 120 °C). It also improved tensile strength and fracture toughness by 1.4- and 2-fold, respectively. The toughening effect of PES was further confirmed by scanning electron microscopy images. PES marginally reduced the glass-transition temperature and it exhibited no effect on thermal stability. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47520.     

聚氨酯改性环氧树脂的制备及其在涂料中的应用

制备了聚氨酯改性环氧树脂,对其结构进行了表征,测试了以其制备的涂料的性能,结果表明:引入聚氨酯链段可以改善环氧树脂的韧性,对耐热性影响很小,涂料综合性能良好。