共查询到20条相似文献,搜索用时 15 毫秒
1.
2.
S. Varghese P. Yadav S. Jain S. Ghuratia S. K. Nema 《Polymer Engineering and Science》1999,39(8):1558-1566
A matrix resin for carbon fiber reinforced composite was developed that consisted of resol type phenolic and difunctional epoxy resin (PR-EP) condensate or adduct. Carbon fiber reinforced composite with fiber volume fraction of 0.6 was prepared with PR-EP matrix containing 0, 50, 100, 150, and 175 parts of epoxy resin per hundred parts of phenolic resin (php), especially a synthesized resol type. One-shot and prepreg techniques have been adopted and the study of loss of volatiles has indicated the superiority in terms of favorable processability of prepreg technique over the other. FTIR spectroscopic analysis confirmed the PR-EP adduct formation at the prepreg preparation stage. The improvement in properties such as tensile strength and elongation at break was observed in resin matrices with epoxy and phenolic resin; however, the flexural strength and modulus remained more or less unaltered. The prepreg technique of composite preparation has resulted in substantial improvement in mechanical properties and the same was attributed to the formation of PR-EP adduct and low volatiles during cure. Composites of carbon fiber reinforced PR-EP matrix developed here are likely to meet the requirement of aerospace structures in view of the realization of a wide spectrum of properties. 相似文献
3.
4.
本文以N,N,N’,N’-四烯丙基二苯甲烷二胺和二苯甲烷双与来酰亚胺为主要原料合成了一类新型的耐高温双马来酰亚胺共聚树脂,并以此树脂为基体制得了玻璃布预浸料及层压板,考察了共聚树脂及玻璃布预浸料的贮存稳定性和层压板的性能,实验结果表明,共聚树脂及预浸料贮存期长,工艺性良好,层压板制备工艺幅度宽,电性能和高温力学性能优异,可作为耐高温绝缘材料和结构材料使用。 相似文献
5.
以苯酚、甲醛为原料,在催化剂的作用下合成酚醛树脂,然后用硼酸改性得到硼酚醛(FB)树脂.采用FB树脂作为基材树脂制作玻璃布层压板,FB树脂的耐热性比普通酚醛树脂高.FB树脂层压板具有好的耐热、阻燃、机械和电气性能,其阻燃性能达到了UL-94垂直燃烧法V-0级. 相似文献
6.
Changes in the dynamic modulus E′dyn of some phenolic glass cloth systems were studied as a function of cure temperatures and formaldehyde factors. The modulus changes were followed by continuously monitoring in situ the fundamental frequency of vibration of resin-impregnated glass cloth systems bonded to metallic cantilever reeds. The apparent activation energy of crosslinking was a direct function of the formaldehyde content in the resin synthesis, ranging from 9 kcal/mole for a 1.2 formaldehyde factor phenolic, to 20 kcal/mole for a 1.8 factor. Two cure parameters at 50% and 100% apparent mechanical conversion were established. 相似文献
7.
8.
K. C. Cole D. Noël J.-J. Hechler P. Cielo J.-C. Krapez A. Chouliotis K. C. Overbury 《Polymer Composites》1991,12(3):203-212
Samples of Narmco Rigidite 5208/WC3000 carbon-epoxy composite prepreg were exposed to ambient temperature (22°C) and 50 percent relative humidity for different periods up to 66 days. The aging has a significant effect on prepreg physical properties such as tack, volatiles content, and gel time. A set of 4-ply laminates made from aged prepreg was subjected to tensile testing, ultrasonic inspection, and optothermal inspection. No relationship could be discerned between laminate properties and prepreg aging time. However, variations in panel homogeneity were observed, and these correlated with thermal diffusivity and tensile modulus measurements, but not with ultimate tensile strength or elongation. A set of 6-ply laminates was used to measure compressive properties, interlaminar shear strength, and physical properties. These panels also showed variations in porosity, again unrelated to aging, but in addition, the fiber/resin ratio was observed to decrease with aging time. Both factors were found to affect mechanical properties. The implications concerning the importance of monitoring the aging by physicochemical methods are discussed. 相似文献
9.
P.D. Coates S.E. BarnesM.G. Sibley E.C. BrownH.G.M. Edwards I.J. Scowen 《Polymer》2003,44(19):5937-5949
Spectroscopic techniques have the potential to provide powerful, molecular-specific, non-invasive measurements on polymers during melt processing operations. An exploration is reported of the application and assessment of sensitivity of in-process vibrational spectroscopy—on-line mid-infrared (MIR), on-line near-infrared (NIR), in-line NIR and in-line Raman—for monitoring of single screw extrusion of high-density polyethylene and polypropylene blends. These vibrational spectroscopic techniques are compared with novel in-line ultrasound velocity measurements, which were acquired simultaneously, to assess the sensitivity of each method to changes in blend composition and to explore the suitability for their use in real time process monitoring and control. 相似文献
10.
本文对硼酚醛树脂、高残碳酚醛树脂、S-157酚醛树脂的固体含量、粘度、凝胶时间进行了表征和对比,此基础上对比研究了连续玄武岩纤维平纹布增强三种酚醛树脂复合材料的密度、硬度、导热系数,同时对三种复合材料的烧蚀性能和力学性能进行了测试和对比。研究结果表明:硼酚醛树脂复合材料的力学性能最好,S-157酚醛树脂复合材料其次,高残碳酚醛树脂复合材料的力学性能最差;在烧蚀性能方面,硼酚醛树脂复合材料和高残碳酚醛树脂复合材料相当,S-157酚醛树脂复合材料最差。 相似文献
11.
Here, we describe a combination approach using Two Calibration-Free Methods with reflectance near-infrared (TCFM-NIR), which involves detecting end-points for active pharmaceutical ingredients (APIs) blending by simultaneously monitoring specific NIR peak intensity of APIs and calculating moving block standard deviation (MBSD). After determining the specific NIR peak range of nicaldipine hydrochloride, conditions for TCFM-NIR were established by monitoring the differential intensity of the second peak (1136 nm) while MBSD was calculated from the NIR peak intensity between 1100 and 1150 nm. In comparison with the validated reference method of UV-VIS spectroscopy, which is particularly destructive, TCFM-NIR was found to be useful in detecting end-points for blending of nicaldipine hydrochloride. TCFM-NIR monitors two important factors for estimation of blend uniformity: API concentration, using specific NIR peak intensity for APIs, and blend homogeneity, using MBSD. Also, the conditions of TCFM-NIR were confirmed to be adequate by using Partial Least Square (PLS). Further, simultaneously monitoring these two blend uniformity factors is more useful in preventing estimation errors for nondestructive monitoring of blend homogeneity than monitoring only one factor, as with NIR spectroscopy. 相似文献
12.
文章探讨了利用近红外分析技术快速判断聚丙烯粉料中的二甲苯可溶物含量的应用。用近红外漫反射法收集了样品的近红外光谱图。参照化学计量学分析方法测定聚丙烯样品的二甲苯可溶物含量。利用偏最小二乘法线性回归法建立了聚丙烯二甲苯可溶物的近红外光谱预测模型。将近红外法测定结果与化学分析方法测定结果进行了比较,对光谱测量的重复性进行了考察。结果表明,利用近红外光谱法与化学分析法的测定结果无显著差异。 相似文献
13.
应用近红外光谱技术在线监测工业产品质量时,会出现环境条件变化或仪器的部件如探头或光纤更换的情况,使原模型不再具有原来的预测效果,但是完全从头开始采集数据重新建立新模型工作量大,造成原来宝贵的模型和数据的浪费。为了解决这一矛盾,本文以一种中草药口服液中多糖含量、可溶性固形物含量及pH 为研究对象,利用近红外光谱技术对其进行实时在线检测,研究了主从机分辨率不同的光谱之间的模型转移。模型转移过程利用已建模完成并成功上线应用的模型为原模型,在不能获取原主仪器和从仪器一一对应的标准标样的条件下,找到虚拟标样建立转移矩阵。以直接标准化法结合主成分分析降维作为模型转移方法,以质量指标化学参考值与预测值间的相对误差为指标筛选最佳模型。模型转移结果显示,多糖模型预测值与化学参考值间的相对误差可控制在10%以内,可溶性固形物相对误差在5%以内,pH 相对误差在3%以内。在线生产使用表明,转移的模型同原模型一样可有效应用于在线、快速对质量指标做出准确的预测。结果表明,本文提出的采用虚拟标样的模型转移方法对于无法获得主从机一一对应的标准标样的情况下的模型转移,是一个可行的有效方法。 相似文献
14.
15.
The fabrication of composites from polyimide precursors (polyamide acids) that involve condensation reactions requires the removal of volatiles (solvent and reaction by‐products) prior to consolidation in order to achieve a void‐free laminate. Volatile removal is commonly accomplished with a B‐stage processing step. In this study, a PETAA/NMP (p henyle thynyl t erminated a mide a cid in N‐methylpyrrolidinone) solution and prepreg were characterized using therogravimetric analysis (TGA) and microdielectrometry. A master weight loss profile was constructed by superimposing measurements at various heating rates. The TGA results correlated well with the dielectric ionic conductivities. Under the same thermal conditions, volatiles were depleted at slower rates from the wet prepreg than the neat resin solution. Dielectric properties were more sensitive to the residual volatile contents than the TGA measurements in both the neat resin and wet prepreg. Dielectric sensing technology was demonstrated to be a feasible tool for future volatile management in the fabrication of PETI composites. This study demonstrates that the combination of TGA and dielectrometry provides useful information to develop proper processing conditions for composite fabrication from prepregs containing volatiles. © Published 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1906–1916, 2003 相似文献
16.
以自制的磺化酚醛树脂作为交联单体对酶转化淀粉接枝苯丙共聚物进行改性,合成了环保型的苯丙共聚物表面施胶剂。采用FT-IR、DSC、SEM等测试仪器对其性能以及施胶度进行了表征。探讨了引发剂的用量与比例、淀粉与单体比例、乳化剂以及功能单体等合成条件对产品性能的影响。其结果表明当引发剂的量6%,H2O2-FeSO4比例为50:1,m(淀粉)/m(单体)为1:2,阳离子乳化剂添加量2%,磺化酚醛树脂功能单体添加量3%时,优化合成的苯丙共聚物表面施胶剂,其施胶性能达到市场领先水平。 相似文献
17.
制备了连续玄武岩纤维平纹布(CBFTC)增强S-157酚醛树脂复合材料。研究了树脂含量对S-157酚醛树脂/CBFTC复合材料力学性能和烧蚀性能的影响,并借助扫描电子显微镜对复合材料断面的微观形貌进行了分析,同时将S-157酚醛树脂/CBFTC复合材料与S-157酚醛树脂/高强玻璃纤维平纹布(GFTC)复合材料进行了性能对比。结果表明,树脂含量在30%时S-157酚醛树脂/CBFTC复合材料的力学性能和烧蚀性能最佳;S-157酚醛树脂/CBFTC复合材料比S-157酚醛树脂/GFTC复合材料具有更好的力学性能和烧蚀性能。 相似文献
18.
《纤维复合材料》2019,(2)
This study focuses on the insert-injection molding process. The thermoset composite inserts in this study were carbon fiber/epoxy(CF/Epoxy) prepreg sheets. The injected molded part was glass fiber contained phenolic resin(GF/PF). The CF/Epoxy was placed in the mold cavity prior to injecting GF/PF onto the inserted injection molded CF/Epoxy specimens. The role of adhesion between the inserted part and injected resin on the mechanical properties was evaluated by 3 point bending and impact tests. In addition, the effect of prepreg orientation on the mechanical properties of the prepreg inserted-injection molding system was investigated. It was found that the prepreg with unidirectional orientation significantly improved flexural and impact strength of the inserted injection molding composites, providing better support and resistance to bending and impact loading. The main failure modes of the specimens were structural and adhesive failure. 相似文献
19.
《Journal of Adhesion Science and Technology》2013,27(7):549-563
The solution impregnation route is commonly exploited to prepare polymer-based composites. However, the adsorption of polymer components is complicated, which is the result of interactions between reinforcement, solvent and polymer. In this study, the adsorption of phenolic resin onto silica substrate from different solvents was investigated by diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy, UV-visible absorption spectroscopy and thermogravimetric analysis (TGA). Isotherms for phenolic resin adsorption from solvents onto silica substrate have been examined as a function of phenolic resin content in different solvents. The viscosity and surface tension were measured for the solution systems before and after adsorption. Hydrogen bonding interaction was considered to be operative in the resin–solvent–silica system. The adsorption of phenolic resin is dependent on its relative affinity for the solvent on one hand and for the silica surface on the other. UV-visible absorption spectroscopy results suggested that phenolic resin forms hydrogen bonds with the solvent, which competes with the hydrogen-bonding adsorption mechanism for phenolic resin occurring on silica surface. This hydrogen bonding in solution along with the competitive adsorption of solvent onto silica surface suppresses the adsorption of phenolic resin and such suppression is unfavorable in a solution impregnation process. 相似文献
20.
Lena Bengtsson 《European Journal of Lipid Science and Technology》1985,87(7):262-265
In this study some analytical methods, which have been used in oil crop breeding, are compared from the point of view of plant breeding. For oil content determination a gravimetric method, NMR and NIR have been used. Protein content has been determined by the classical Kjeldahl technique, by the Biuret method and by NIR. The results indicate that the NIR spectroscopy is specially useful in screening breeding materials. This method enables the breeder to select for several quality characters simultaneously at a high speed and at a low cost. Since NIR spectroscopy is nondestructive, the same seed lot can be used for analysis and planting. Thus it is possible to select on a large scale for single plants. 相似文献