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环氧电工塑料的固化反应动力学研究 总被引:1,自引:1,他引:0
以双马来酰亚胺(BMI)/二氨基二苯砜(DDS)为组合固化剂,采用非等温示差扫描量热法(DSC)研究了邻甲酚醛环氧树脂(ECN)/DDS/BMI三元体系的固化反应动力学,用Kissinger法和Crane公式进行DSC数据处理,获得了固化反应动力学参数,并建立了固化动力学模型,同时结合红外光谱分析探讨了该体系的反应机理。结果表明,ECN/DDS/BMI体系固化反应级数n=0.93;表观活化能Ea=58.2 kJ/mol,与ECN/DDS体系相差很小,BMI的加入对体系的固化工艺影响不大,ECN/DDS/BMI体系的固化动力学模型与ECN/DDS体系相似。 相似文献
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为了帮助生产厂家了解现今世界化工生产动向,欧洲化学新闻(ECN)最近报道了1990—1991年度各国化工项目的建设情况。项目以列表形式详细列举了本年度各公司目前计划、正在建设和已经投产的项目进展动态。全部资料均摘自每期出版的ECN,并以信息的形式反馈给各生产厂家和有关设计/承包 相似文献
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采用硅烷偶联剂KH560对提纯后的凹凸棒土(AT)进行改性,得到有机化凹凸棒土,并对其进行FTIR和TG表征,结果表明,KH560对凹凸棒土起到了良好的修饰改性作用。采用熔融复合法制备了AT质量分数为0~5%的邻甲酚醛环氧/凹凸棒土纳米复合材料(ECN/(KH560-AT)x),对其进行了扫描电镜(SEM)分析、动态力学分析(DMA)和热重分析以及力学性能测试。结果表明,KH560-AT的加入使复合材料断裂由脆性断裂向韧性断裂转变。ECN/KH560-AT复合材料的拉伸强度、冲击强度和Tg可比纯ECN分别高出54.12%、78.95%和37.5℃,KH560-AT的加入明显提高了复合材料的力学性能和耐热性。 相似文献
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据"ECN, 1989,52(1367)”报道,加拿大Polysar公司在美国得克萨斯州建了年产1600t氢化丁腈橡胶——Tornac装置,且生产能力可提高1倍。装置所使用的丁腈橡胶原料将由Polysar公司提供。产品用作 相似文献
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据“ECN,1988,48(1267),23”报道,国际橡胶生产者协会预测,世界天然橡胶、合成橡胶总消耗量,将由1986年1270万t上升到1991年1400万t。具体到北美 相似文献
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Theresa W. Lee Christine I. Hastilow 《Journal of the American Oil Chemists' Society》1999,76(12):1405-1413
Two analytical methods have been developed for the qualitative and quantitative analyses of triacylglycerol profile of structured
lipid (SL)-containing medium-chain and long-chain fatty acids. Supercritical fluid chromatography (SFC) was used in the first
method. The SL was dissolved in chloroform/methanol, 95:5 (vol/vol), and analyzed directly using a super-critical fluid chromatograph
equipped with temperature and density programming capabilities. No derivatization was required for sample preparation. An
SB-methyl-100 capillary column (10 m, 100 μ i.d., 0.25 μ film thickness) was used for the separation of the triacylglycerol
species and a flame-ionization detector (FID) was used for the detection. Supercritical fluid carbon dioxide was used as the
mobile phase. In the second method, the SL was hydrogenated to complete saturation prior to analysis using gas chromatography
at high temperatures of up to 375°C. A DB-5HT capillary column (30 m × 0.32 mm i.d., 0.1 μ film thickness) was used for the
separation. FID was used for the detection and helium gas was used as mobile phase. The triacylglycerol species were separated
and identified based on their equivalent carbon number (ECN), the total carbon number of the acyl side chains. A calibration
curve was constructed using a triacylglycerol mixture containing known amounts of monoacyltriacylglycerol standard materials
ranging from ECN 18 (trihexanoin) to ECN 66 (tridocosanoin). The novel triacylglycerol species, ECN 32–43, created by the
interesterification of medium-chain triacylglycerol (MCT) and long-chain triacylglycerol (LCT) were separated and identified
based on their retention times. These triacylglycerols, ECN 32–43, were absent in the physical mixture of MCT and LCT. The
unique triacylglycerol specieis, ECN 32-43, were therefore selected as the fingerprinting region for the qualitative identification
of the SL. Quantitation of the novel triacylglycerol species in the SL was achieved by using the integrated peak area of the
new species. Both methods were employed successfully to distinguish the physical mixture from the corresponding interesterified
SL. Results generated by the two methods were compared and found to be in good agreement. 相似文献
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Zhongguo Liu Gang Zhang Kuifeng Tu Sen Zhao Miaomiao Han Jing Ni Wenjia Ma Hui Na 《Polymer International》2011,60(10):1556-1562
A series of novel composites based on different ratios of epoxidised cresol novolac (ECN) and 4,4′‐diglycidyl(3,3′,5,5′‐tetramethylbiphenyl) epoxy resin (TMBP) have been prepared with the curing agent 4,4′‐methylenediamine (DDM) and 4,4′‐diaminodiphenylsulfone (DDS), respectively. The investigation of cure kinetics was performed by differential scanning calorimetry using an isoconversional method. The high thermal stabilities of the cured samples were also studied by thermogravimetric analysis. In addition, no phase separation was observed for cured ECN/DDM and ECN/DDS blending with different amounts of TMBP by dynamic mechanical analysis and scanning electron microscopy. Moreover, the cured systems also exhibited excellent impact properties and low moisture absorption. All the results indicate that the ECN/TMBP/DDM and ECN/TMBP/DDS systems are promising materials in electronic packaging. Copyright © 2011 Society of Chemical Industry 相似文献
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Guojun Ding Jifang Fu Xing Dong Liya Chen Haisen Jia Yu Wenqi Liyi Shi 《Polymer Composites》2013,34(10):1753-1760
Octaaminophenyl polyhedral oligomeric silsesquioxane (OAPS) was synthesized using three‐step method and used to modify o‐cresol‐novolac epoxy resin (ECN) for printed circuit board. The influence of OAPS on the reactivity and the final properties of the hybrid networks were evaluated. The intercrosslinking reaction between ECN and OAPS was confirmed by Fourier transform infrared spectra. The ECN/OAPS hybrids have better impact strength, higher electrical resistivity and thermal stability, lower water absorption than the unmodified ECN. The volume resistivity and surface resistivity of the hybrids increase by an order of magnitude or more compared to the neat epoxy. The thermal stability of the hybrids improves by the incorporation of OAPS; the initial decomposition temperature and char yield show an increasing tendency up to 4 wt% loading of OAPS. The hybrids exhibit higher storage modulus and glass transition temperature (Tg) than the neat epoxy. The Tg of the hybrids greatly improves up to 153.3°C at 3 wt% content, much higher than 119.4°C of the neat epoxy. POLYM. COMPOS., 34:1753–1760, 2013. © 2013 Society of Plastics Engineers 相似文献
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Bo Xuan Zhou Yi Jun Huang Xing Hong Zhang Zhi Sheng Fu Guo Rong Qi 《Polymer Engineering and Science》2009,49(8):1525-1532
A bismaleimide monomer, 4,4′‐bis(4‐maleimidophenoxy)‐3,3′,5,5′‐tetramethyl biphenyl (BMITB), was synthesized in high yield (94%) via a facile four‐step reaction from 2,2′,6,6′‐tetramethyl‐4,4′‐biphenol. The chemical structure of BMITB was confirmed by FTIR, 1H NMR, 13C NMR and elemental analysis. The monomer used to modify the epoxy cresol‐formaldehyde novolac resin (ECN)/diaminodiphenyl sulfone (DDS) system. Cured ECN/BMITB/DDS blends with higher BMITB content had two distinct glass transition temperatures that were above 250°C according to differential scanning calorimetry, indicating that an interpenetrated polymer network structure may be formed. The initial thermal decomposition temperature and integral procedure decomposition temperature of the cured ECN/BMITB/DDS blends were >390 and 1080°C, respectively, according to thermogravimetric analyses. No phase separation was observed in dynamic mechanical analysis of cured ECN/BMITB/DDS blends with small amounts of BMITB (5 and 10 wt%). POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers 相似文献
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K. P. Unnikrishnan 《Polymer-Plastics Technology and Engineering》2013,52(4):469-474
Epoxy resins are thermosetting polymers widely used for polymer composites, adhesives, high performance coatings, potting and encapsulation, and numerous other applications. These resins have excellent mechanical and electrical properties, low cure shrinkage, and good adhesion to most substrates. This study is an attempt to improve the thermal and aging characteristics of epoxy resin by blending with other multifunctional epoxies such as EPN and ECN. Bis-phenol A epoxy resins containing 2.5 to 20 wt% of epoxy novolac were cured in the presence of a polyamide hardener and tested for thermal and mechanical properties, hardness, water absorption, etc. Blends containing 10 to 15 wt% of epoxy novolac show substantial improvement in properties such as tensile strength, elongation, and energy absorbed to break. The novolac derived from p-cresol was better than that based on phenol in enhancing the properties. TGA, DSC, and DMA were employed for studying the thermal properties of the modified resin. The study reveals that modification using epoxy phenol and p-cresol novolac resins (EPN and ECN, respectively) improves the aging characteristics of the epoxy resin in addition to overall improvement of the mechanical properties. 相似文献
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Vineeta Nigam Dipak K. Setua Gyanesh N. Mathur 《Polymer Engineering and Science》1999,39(8):1425-1432
Toughening of epoxy cresol novolac resin (ECN) by carboxy terminated acrylonitrile-co-butadiene (CTBN) liquid functional rubber have been studied. Wide angle X-ray scattering (WAXS) has been utilized to evaluate average molecular interchain spacing (<R>) from the strong maximum in the diffraction scan using Bragg's equation. The half-width (<HW>) of the maximum was used to qualitatively describe the distribution of <R>. An increase in <R> value signifies formation of a separate packing order as well as increase in the free volume. Fourier transform infrared spectroscopy (FTIR) studies convincingly establish that the interaction between oxirane group of epoxy and carboxyl group of CTBN are responsible for characteristic peak shifts in the blends compared to individual polymers. Physicomechanical properties of the blends e.g., the tensile, flexural and impact strengths showed an optimum concentration of CTBN (10 wt%) into ECN, which can offer maximum toughening. Cross sections of the composite specimens failed during impact testing have been critically studied through scanning electron microscopy (SEM) to gain insight into the mechanism of toughening and phase morphology. 相似文献
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杨明山;何杰;李林楷;肖强 《中国塑料》2010,24(6):36-39
采用3,3′,5,5′-四甲基-4,4′-联苯二酚与环氧氯丙烷在18-冠-6-醚(CE18)为相转移催化剂作用下,利用两步加碱法合成了联苯型环氧树脂(TMBP),在反应温度为80 ℃、反应时间为8 h、NaOH用量为0.2 mol时,产率达83 %。用核磁共振、红外光谱、X射线衍射、热台偏光显微镜和DSC对所制备的产物进行了结构表征。结果表明,合成的产物为TMBP,具有良好的结晶性,熔点为107.8 ℃,在冷却过程中出现液晶态。TMBP熔融黏度极低(0.02 Paos,150 ℃),用TMBP与酚醛环氧树脂(ECN)共混,可降低体系的黏度,从而提高硅微粉的填充量和大规模集成电路封装材料的流动性。 相似文献
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Evaluation of microbially influenced corrosion with electrochemical noise analysis and signal processing 总被引:1,自引:0,他引:1
Corrosion behaviors of stainless steel (SS304), with attached Acidithiobacilus ferrooxidans (ATF) bacteria and exposed to three different types of artificial saliva solutions, namely: (1) Jenkin's solution, (2) Tomasi's solution, and (3) NaCl solution, have been monitored using electrochemical noise (ECN) analysis and signal processing techniques. The ECN data has been analyzed in time and frequency domains, and the time-domain analysis was used to calculate parameters such as skewness, kurtosis and noise resistance, Rn. The corrosion mechanisms were analyzed in terms of the ranges of skewness and kurtosis. The frequency analysis showed that the conventional fast Fourier transforms (FFT) method failed to differentiate among the ECN signals obtained in different solutions with and without the attachment of bacteria. Therefore, the fractional Fourier transform (FrFT) was introduced to process ECN signals and has been demonstrated as a better tool to describe the corrosion behaviors of electrodes in different solutions. 相似文献
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实验发现,随着OCN分子量的增加,产品ECN的分子量也呈线性增长,OCN与ECN树脂的软化点和分子量之间也有较好的线性关系。 相似文献
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Evaluation of Authenticity of Iranian Olive Oil by Fatty Acid and Triacylglycerol Profiles 总被引:4,自引:0,他引:4
Z. Piravi-Vanak M. Ghavami H. Ezzatpanah J. Arab H. Safafar Jahan B. Ghasemi 《Journal of the American Oil Chemists' Society》2009,86(9):827-833
For evaluation of the authenticity of Iranian olive oil, samples from many Iranian olive oil producers especially north of
Iran in the production year 2007 were collected. The fatty acid and triacylglycerol compositions were measured. The most recent
calculation methods including ∆ECN the difference between the actual and theoretical ECN42 (equivalent carbon number), triglyceride
content and R of olive oils according to IOOC methods were applied. On the basis of our results, we were able to classify
the olive oils into the extra virgin, virgin olive and olive oil categories. The important fatty acids are oleic, palmitic
and linoleic acids and their main triacylglycerols are OOO, POO, OOL, PLO, SOS plus POP, and OLL, respectively. On the basis
of the triacylglycerol results, experimental ECN48, ECN46, ECN50, ECN44 and ECN42 were obtained. By using the fatty acids
results and a computer program, the theoretical ECN42 and ECN44 were calculated. Then R values, being the ratio of r ECN42/r ECN44 for authenticity of all olive oils and ∆ECN for determining categories of olive oils, were defined. The results of
olive oil samples were in the accepted limits of Codex and IOOC. Finally we suggest that the R and ∆ECN can be used in identification of adulteration of olive oils and also they are useful from the point of view of authenticity
and classification. 相似文献