耐候粉末涂料用环氧树脂

介绍了用于耐候脂环族环氧树脂、丙烯酸(甲基丙烯酸)缩水甘油酯树脂的制备方法、性能及在粉末涂料上的应用。     

液体环氧化聚丁二烯/丙烯酸羟基酯光固化研究

采用DSC法研究了大分子的丙烯酸酯化液体环氧化聚丁二烯(LEPB)与三羟甲基丙烷三丙烯酸酯的混合体系在不同紫外光强、不同浓度各种光致引发剂作用下的紫外光固化行为。通过诱导期与光强倒数的线性关系,光固化反应热与光强关系等实验结果对不同光致引发体系及其反应机制进行了讨论,结果表明:安息香双甲醚具有更好的引发活性,而二苯甲酮-三乙胺所需光强较大,反应时间也延长,但其双键转化率及交联密度较高。     

高性能覆铜板用热固性树脂

介绍了高频高性能覆铜板对基材的性能要求,详细讨论了聚苯醚树脂、氰酸酯树脂及聚酰亚胺树脂的特性,并简要介绍了各种树脂基覆铜板的应用情况。通过分析认为:烯丙基化聚苯醚树脂(A PPE)是高频应用的理想材料,为高频高性能电路基板材料首选的树脂基体。     

甲阶酚醛树脂的合成研究进展

综述了甲阶酚醛树脂合成研究方面取得的进展,分析了酚醛合成时的化学计量比(F/P)在1 0～3 0时对反应的影响(催化剂分别采用了NaOH、KOH、Ba(OH)2、三乙胺和醋酸锌等),并比较了各种催化剂的反应机理,同时还从反应温度等方面介绍了反应条件对合成的影响。     

Use of a simple,inexpensive pressure sensor to measure hydrostatic resin pressure during processing of composite laminates

A simple and cheap method of measuring the resin pressure within a composite laminate during processing is presented. The method consists of using a small diameter, long needle filled with inert fluid and connected to an external pressure sensor, to measure the resin pressure at a point inside a composite laminate. This method can be used to investigate resin flow, laminate compaction, the control of voids, and in several composite material processing methods such as autoclave processing, hot press curing and resin transfer molding. The sensors are suitable for research and development or troubleshooting, but not for production. Sensor assemblies were developed and tested to show that their response is reproducible, linear and stable with temperature and time. Resin pressure profiles for two AS4/3501-6 laminates were generated and compared. The experimental results were also compared to the resin flow simulation of a general processing model for composites, COMPRO. It is shown that the resin profile in the laminate is influenced by the presence of the bleeder cloth and the vacuum bag pressure. A significant pressure drop corresponded to the point of minimum viscosity of the resin. Finally, the resin pressure was stabilized when the resin reached gelation.     

Effect of degree of cure and fiber content on the mechanical and dynamic mechanical properties of carbon fiber reinforced PMR-15 polyimide composites

A unidirectional continuous carbon fiber reinforced polyimide composite is fabricated using the PMR-15 polyimide as a matrix. Mechanical and dynamic mechanical properties of the composite are studied. The effect of variation of the fiber content ranging from 55% to 70% by volume on the properties of the composite is determined. The effects of the laminate thickness and degree of curing of the matrix on the Izod impact strength are examined. The effect of the degree of curing of the matrix on the dynamic mechanical spectrum is studied. Finally, variables such as humidity, environment temperature, vacuum, and pressure during laminate processing, and variation of monomer composition are discussed in terms of change in matrix structure, which is reflected in a variation of Tg between batches.     

Use of the frequency dependence of the impedance to monitor viscosity during cure

The ability to conveniently and continuously measure the processing properties of polymer resins is important both to the resin supplier and to the fabricator. Frequency dependent electromagnetic sensors (FDEMS) provide an in-situ technique for continuous measurement of the resin's rheological changes both in a laboratory press and in manufacturing tools in an autoclave. In this paper the frequency dependence of ?*(w) is used to quantitatively monitor the viscosity for a tetraglycidyl 4,4′-diaminodiphenyl methane (TGDDM) amine epoxy, to quantitatively monitor the viscosity during processing In a styrene-polyester resin, and to monitor the cure process in an autoclave during cure of a high temperature polyimide-graphite prepreg. In addition, the technique is used to measure the viscosity at various ply positions in a thick TGDDM graphite epoxy laminate during processing in an autoclave.     

开环聚合酚醛树脂复合材料的研究──ALPF3-EGF层压板的研制

采用低分子量可溶性酚醛树脂合成了一种新型的苯并噁嗪中间体（ＡＬＰＦ３）树脂溶液,制备了高性能的玻璃布层压板。采用凝胶时间测定、差热分析和热重分析等方法研究了树脂的固化行为和热稳定性,确定了较为合理的玻璃布浸胶、烘焙和压制工艺,测试了玻璃布层压板的一般性能。结果表明,ＡＬＰＦ３树脂溶液及浸胶玻璃布贮存期长、工艺性好;玻璃布层压板性能优良,玻璃化转变温度达２８０℃,常态和１８０℃的弯曲强度为４６３ＭＰａ和３８０ＭＰａ,保留率达８２％。适用于１５５～１８０℃用的耐高温结构材料和电绝缘材料。     

基于广义回归神经网络的PVC树脂颗粒特性预测研究

PVC树脂的颗粒特性对聚合物的成型加工具有重要意义,而目前缺少可靠的在线测量传感器件,通常采用取样离线分析,滞后时间太长,影响先进控制技术的有效应用。另外,聚合过程还呈现出高度的非线性特性。针对这些问题,采用广义回归神经网络对PVC树脂颗粒特性进行预测,验证了该方法的有效性,为保证PVC聚合过程先进控制技术的应用提供了有效方法。     

Electroconductive Adhesives: Comparison of Three Different Polymer Matrices. Epoxy, Polyimide and Silicone

Electrically conductive organic adhesives are used in the microelectronics manufacturing industry for the attachment of silicon dies. These adhesives are composite materials which owe their conductivity to the incorporation of silver flakes. Several polymers have been formulated into electrically-conductive adhesives to meet different applications in the microelectronics industry; these are an epoxy resin, a polyimide and a silicone polymer. The purpose of this paper is to examine properties of these die-bonding adhesives in order to determine the advantages or disadvantages of these materials. This study offers a comparison of hardening chemistry, chemical purity, processing, electrical, thermal, and mechanical properties of three conductive adhesives based on an epoxy, a polyimide and a silicone polymer. We discuss correlation of composite properties with the structure of each matrix. The results indicate that the choice of the matrix is dictated by the application for which the electronic grade conductive adhesive is to be used and the desired properties for best reliability and performance.     

Electroconductive Adhesives: Comparison of Three Different Polymer Matrices. Epoxy,Polyimide and Silicone

Electrically conductive organic adhesives are used in the microelectronics manufacturing industry for the attachment of silicon dies. These adhesives are composite materials which owe their conductivity to the incorporation of silver flakes. Several polymers have been formulated into electrically-conductive adhesives to meet different applications in the microelectronics industry; these are an epoxy resin, a polyimide and a silicone polymer. The purpose of this paper is to examine properties of these die-bonding adhesives in order to determine the advantages or disadvantages of these materials. This study offers a comparison of hardening chemistry, chemical purity, processing, electrical, thermal, and mechanical properties of three conductive adhesives based on an epoxy, a polyimide and a silicone polymer. We discuss correlation of composite properties with the structure of each matrix. The results indicate that the choice of the matrix is dictated by the application for which the electronic grade conductive adhesive is to be used and the desired properties for best reliability and performance.     

Monitoring the changing state of a polymeric coating resin during synthesis, cure and use

Essential to 'intelligent manufacturing' and 'smart materials' is the ability to monitor the state of a polymer coating resin as it is synthesized in a reactor, as it cures during application and as it ages during use in the field. Important aspects of this sensor monitoring capability are: in situ, on-line measurement; that the signal output be related to the relevant processing and use properties; sensitivity with long-term reliability in a manufacturing and field environment. This paper addresses the ability of in situ dielectric sensor measurements to monitor the state and progress of batch reactor resin polymerization both in the laboratory and in an industrial ICI pilot plant, the cure of a coating during application, and the changes in physical properties or durability of the polymer during use in the field.     

The development of C-10 phthalocyanine for composite matrix applications

Thermomechanical analysis was carried out for various phthalocyanine resins. The polymer based on the C-10 diamide resin was then chosen for evaluation as a potential composite matrix material. Prepregs with Thornel 300 graphite reinforcements were successfully prepared using a hot-melt technique. The processability of this material was studied by employing instrumental techniques including differential scanning calorimetry, thermal gravimetric analysis and dynamic dielectric analysis. A cure cycle was developed for the fabrication of angle-ply laminate using the conventional vacuum-bag technique in a hydraulic press. Laminate mechanical properties both in tension and in flexure were determined. The results for the C-10/T-300 samples were shown to be similar to those of an epoxy/graphite and a polyimide/graphite composite system.     

Dual polymer bonding of thermoplastic composite structures

This paper describes a process that facilitates fusion bonding of thermoplastic composite components without the need for complex fixtures and without disrupting the fiber alignment in the component laminates. The dual polymer bonding process, Thermabond, requires that an interlayer polymer be fused to the surface of each laminate prior to bonding. The characteristics of the interlayer polymer allow for joining of the components at a temperature below the softening/melting point of the reinforced polymer in the composite laminates. This leads to significant processing advantages without significant loss in mechanical performance. Discussions of resin compatibility, the effect of process conditions on mechanical performance, and the application of the APC-2/PEI Thermabond system to various structural components are included.     

A model for resin flow during composite processing part 2: Numerical analysis for unidirectional graphite/epoxy laminates

In this paper numerical results are presented for resin flow during processing of unidirectional graphite/epoxy laminates. Resin pressure and velocity profiles, as well as resin loss, specific permeability, and resulting thickness changes, were computed to examine the effects of one and two-dimensional flow, initial laminate thickness, and various cure cycles. Input data to the model are also discussed in detail. Analysis of the input data on the stress-strain behavior of graphite fiber beds showed that the bed consolidation behavior can be divided into three regions. “Free-bleeding” (O psig and negligible bleeder resistance to flow at the boundaries) during two-dimensional resin flow leads to rapid decay in resin pressure. Comparison of the predicted results for the resin mass loss and the average final thickness per ply with experimentally determined values shows good agreement.     

Interaction between the reinforcement and matrix in carbon-fiber-reinforced composite: Effect of forming the thin layer of polyimide resin on carbon fiber by in situ polymerization

For the purpose of enhancing the reinforcement–matrix interaction in carbon-fiber-reinforced polymer composite, mechanical and spectroscopic studies were made on the epoxy resin composite reinforced with the carbon fiber coated with thin Layer of polyimide resin. On the loss modulus and loss tangent vs. temperature curves, a subtransition appears at a temperature above the primary transition. The T-peel strength of a laminated specimen and the fiber efficiency factors for modulus and strength are larger than those of the composite reinforced with nonpolyimide treated fiber. These results show the increased interaction between the epoxy resin and the carbon fiber coated with polyimide resin. The occurrence of specific interaction between an epoxy resin and the polyimide resin are recognized on fourier transform infrared spectra.     

A numerical model of the viscosity of an epoxy prepreg resin system

The development of the viscosity of a thermoset material during processing is complicated because of the dependence of the initial material state and the kinetic rate of conversion from a liquid to a solid material. Uncured thermoset materials typically have a low enough viscosity such that the consumption of energy to generate flow is relatively low. However, as the curing process advances, the flow mechanisms become hindered by the development of a network gel during crosslinking. Once the resin has reached the appropriate degree of cure for gelation, the resin system is incapable of large fluid-like deformations. In this research, the rheological properties of an epoxy resin system used in laminate processing were measured and numerically fit with a modification to the dual Arrhenius model to predict the progression of the viscosity during cure. The numerical results were compared with the experimental measurements, and it was found that the model predicts the experimental observations quite well. It was found that the initial degree of cure of the prepreg is not as significant a factor as the temperature rate dependence on the processing time between the point of flow onset and gelation. However, the minimum viscosity during processing is strongly influenced by the initial degree of cure of the prepreg system.     

Low‐temperature thermal graft copolymerization of 1‐vinyl imidazole on fluorinated polyimide films with simultaneous lamination of copper foils

A simple technique of thermal graft copolymerization of 1‐vinyl imidazole (VIDZ) on pristine and argon plasma pretreated fluorinated polyimide (FPI) films with simultaneous lamination of copper foils was demonstrated. The simultaneous thermal grafting and lamination process was carried out in the temperature range of 80–140°C under atmospheric conditions and in the complete absence of a polymerization initiator. Three different FPI samples of different chemical structures were employed in the present study. An optimum T‐peel strength about 15 N/cm was achieved for the copper/FPI laminate. The adhesion strength, however, decreased with increasing fluorine content in the FPI film. The onset of cohesive failure occurred in the FPI film for assemblies with T‐peel strength greater than 6 N/cm. The T‐peel strengths are reported as a function of the argon plasma pretreatment time of the FPI films and thermal lamination temperature. The adhesion strengths were compared to that of the similarly prepared copper/polyimide (Kapton HN) laminate. Time‐dependent water contact angle (Θ) measurements indicated that the surfaces of FPI films are significantly more hydrophobic and more resistant to water diffusion or hydration than the Kapton HN films. The surface compositions of the pristine FPI films, as well as the delaminated FPI films and copper foils were studied by X‐ray photoelectron spectroscopy. The thickness of the graft VIDZ polymer layer was in the order of 200 nm, as derived from the cross‐sectional view of the scanning electron micrograph. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 1478–1489, 1999     

Impact of processing method and surface functionality on carbon nanofiber dispersion in polyimide matrix and resulting mechanical properties

Composites were produced with functionalized carbon nanofibers (CNF) and polyimide (PI) matrix using either in situ polymerization or blending processes. The impact of the composite processing method, CNF surface chemistry, and fiber loadings on the dispersion of fibers and mechanical properties of composites were investigated. Specifically, functionalization of oxidized CNF with a diamine and polyimide oligomer that mimicked the structure of the base polyimide led to improved dispersion of CNF in the matrix polymer. Samples produced using precipitation blending from hot solvent and in situ polymerization exhibited improved dispersion and reduced agglomeration of CNF relative to samples made using direct blending. While SEM images showed poorly dispersed pristine CNF in PI in the form of agglomerations and thick deposition layer on the bottom of composite film, there was clearly better dispersion for functionalized CNFs. Composites produced with functionalized CNF exhibited improvements in modulus, glass transition temperature and tensile strength relative to the base polyimide. POLYM. COMPOS. 35:1473–1485, 2014. © 2013 Society of Plastics Engineers