粉末NBR和超细碳酸钙填充粉末NBR硫化胶力学性能的研究*

以高分子树脂膜为包覆剂,采用凝聚共沉法制备非填充型粉末ＮＢＲ和超细碳酸钙填充粉末ＮＢＲ。研究了包覆剂及超细碳酸钙的用量对产物粒径及其硫化胶力学性能的影响。结果表明,当包覆剂用量为１０份时,粒径≤０９ｍｍ的产物占９９８％,加入超细碳酸钙后可进一步减小产物的粒径;极性适宜的包覆剂及超细碳酸钙对粉末ＮＢＲ硫化胶有显著的补强作用,故非填充型粉末ＮＢＲ及超细碳酸钙填充粉末ＮＢＲ均有良好的力学性能。扫描电镜分析表明,极性适宜的包覆剂与ＮＢＲ有一定的相容性,并以粒径约０５μｍ的微粒均匀分布于ＮＢＲ基体中;超细碳酸钙则以原生粒子和粒径≤０５μｍ的团粒存在,它在粉末ＮＢＲ中的分散性比块状ＮＢＲ／超细碳酸钙混炼体系有显著改善     

氢氧化铝对导热加成型有机硅灌封胶性能的影响

以粘度为300和1 000 mPa·s的端乙烯基硅油复配,含氢硅油为交联剂,三氧化二铝为导热填料,氢氧化铝[Al(OH)_3]为阻燃剂,制备了无卤阻燃导热加成型有机硅灌封胶,研究Al(OH)_3用量对导热加成型有机硅灌封胶性能的影响。结果表明:随着Al(OH)_3用量的增大,加成型有机硅灌封胶的阻燃性能和导热性能提高,粘度增大,体积电阻率和物理性能下降;当Al(OH)_3用量为60份时,加成型有机硅灌封胶的综合性能最佳。     

固化剂对环氧包封料性能的影响

研究了以甲基四氢苯酐和间苯二胺作固化剂时 ,环氧树脂包封料的固化放热现象 ,测定了不同固化剂体系的包封料力学性能、电性能、密度和吸水性。结果表明 ,间苯二胺的活性大于酸酐固化剂的活性 ,但填料的加入使胺固化的放热降低 ,酸酐固化的升高。胺固化的冲击强度较高 ,加入填料可提高拉伸强度。胺固化的介电常数 ,介电损耗角较高 ,但体积电阻率较低 ,其吸水性较高     

有机硅基体与填料表面处理对电子灌封胶性能的影响

文章研究α,ω-二乙烯基聚二甲基硅氧烷（乙烯基硅油）粘度、硅烷偶联剂类型及用量对电子灌封胶性能的影响。结果表明：随着乙烯基硅油粘度的增加,灌封胶的拉伸性能增加;乙烯基三乙氧基硅烷（A-151）处理的氮化铝所制备的灌封胶的导热率和耐热性能突出,并且填料与基体间界面结合情况良好;优化后,A-151的用量为填料量的1 wt%。     

高耐磨炭黑填充型粉末NR研究(Ⅲ)硫化胶的物理机械性能

研究了高耐磨炭黑(N330)填充型粉末天然橡胶[P(NR/N330)]硫化胶的物理机械性能.结果发现炭黑乳化剂、炭黑、操作油和包覆剂的用量及玻璃化转变温度对P(NR/N330)硫化胶的物理机械性能的影响比较明显.在适宜的粉末化条件下制备的P(NR/N330),其硫化胶的物理机械性能优于天然胶乳与炭黑的简单共沉胶(ENR/N330),而300%定伸应力则低于块状NR/N330机械混炼胶(MNR/N330).P(NR/N330)硫化胶拉伸断面形貌的SEM分析表明,包覆剂在用量为15份时,与NR基体形成互锁结构;DSC分析表明,二者部分相容,因此硫化胶具有较好的物理机械性能.     

大功率LED器件封装材料的研究现状

LED灯具有高效节能、绿色环保等优点,在照明市场的前景备受各国瞩目,对LED封装材料的研究也备受关注.本文介绍环氧树脂及有机硅的LED封装材料的研究现状以及存在的问题.有机硅封装材料被认为是大功率LED器件封装的最佳材料.高性能有机硅封装材料将具有广阔的应用前景及巨大的经济效益.     

高耐磨炭黑填充型粉末SBR研究Ⅱ.硫化胶的物理机械性能

研究了高耐磨炭黑(N330)填充型粉末丁苯橡胶[P(SBR／N330)]硫化胶的物理机械性能。结果发现。炭黑乳化剂的用量、炭黑改性剂和包覆剂的用量及玻璃化转变温度对P(SBR／N330)硫化胶的物理机械性能的影响比较明显。在适宜的粉末化条件下制备的P(SBR／N330)，其硫化胶的物理机械性能与块状SBR／N330通过机械混炼得到的硫化胶的物理机械性能处于相同水平。P(SBR／N330)硫化胶拉伸断面形貌的SEM分析表明，包覆剂在用量为5份时形成的粒子与SBR基体结合紧密，在用量为15份时形成的粒子较易剥离。     

封装用有机硅材料的制备及性能研究

具有高效节能、绿色环保等优点的半导体自光照明LED灯在照明市场的前景备受各国瞩目,对LED封装材料的研究也备受关注。文章采用复合硅树脂和有机硅油混合,在催化剂的条件下发生加成反应,得到无色透明的有机硅封装材料。采用红外光谱仪、紫外可见分光光度计、同步热分析仪等仪器设备对有机硅封装材料进行测试和分析。将制备的有机硅封装材料应用于大功率自光LED上,研究有机硅封装材料的透光率对LED出光效率的影响。     

聚硅氧烷在环氧封装料改性中的应用

综述了用功能性聚硅氧烷对环氧树脂封装料进行改性从而实现环氧封装料低应力化的几种方法；并对改性后封装料的结构、热性能和机械性能作了详细介绍。     

FLAVOR ENCAPSULATION AND RELEASE CHARACTERISTICS OF SPRAY-DRIED POWDER BY THE BLENDED ENCAPSULANT OF CYCLODEXTRIN AND GUM ARABIC

The flavor inclusion powder was prepared by spray drying, using the combined encapsulation method of inclusion by β-cyclodextrin (β-CD) and emulsified by gum arabic (GA). d-Limonene and ethyl n-hexanoate were used as model flavors. The application of high pressure by Microfluidizer to the mixture of flavors and β-CD slurry was an effective means of forming inclusion complex. Flavor retention during spray drying under various compositions of the encapsulants was investigated. The flavor retention using the blended encapsulant was increased by adding GA in the encapsulant. The characteristics of release of encapsulated flavor during storage were evaluated at 50°C and 75% of relative humidity. The release rate of flavor in spray-dried powder depended on kinds of the flavors and composition of the encapsulant. The blending MD and β-CD in the feed liquid decreased the release rate of flavors. The rate of release of flavor was analyzed by Avrami's Equation.     

Effects of the complexed moisture in metal acetylacetonate on the properties of the no‐flow underfill materials

A potential no‐flow (compression filling of encapsulant) underfill encapsulant for simultaneous solder joint reflow and underfill cure has been reported by the authors. The encapsulant is based on a cycloaliphatic epoxy/organic anhydride/Co(II) acetylacetonate system. The key of this no‐flow encapsulant is the use of a latent metal acetylacetonate catalyst that provides the solder reflow prior to the epoxy gellation and fast cure shortly after the solder reflow. However, most of the metal acetylacetonates can easily absorp moisture as their ligand. Therefore, it is of practical importance to understand the effect of the complexed water on the properties of the no‐flow material before and after cure. In this paper, differential scanning calorimetry, thermal gravimetric analysis, thermal mechanical analysis, dynamic mechanical analysis, and Fourier transform infrared spectrometry were used to validate the existence of complexed moisture in the Co(II) acetylacetonate. The effects of the complexed water on the curing profile, glass transition temperature, and storage modulus of the cured no‐flow underfill material were studied. A possible catalytic mechanism of the metal acetylacetonate in the cycloaliphatic epoxy/anhydride system was subsequently discussed and proposed. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 103–111, 1999     

CR244粘接型粉末氯丁橡胶的制备

用凝聚法制备出粉末粘接型氯丁橡胶(PCR244)。研究了包覆剂性质对PCR244粒径分布的影响，并用SEM对所得PCR244的形貌及断面进行了观察分析。研究表明，在CR244粉末化体系中，包覆剂必须具有一定的交联程度才能起粉末化作用。在研究范围内，包覆剂的θg对粒径小于0．9mm产物的成粉率几乎无影响，均达到98．6％以上。SEM分析表明，PCR244宏观粒子表面粗糙，粒子内外均分布着大量空隙，其形成过程可分为三个主要阶段，即在包覆剂作用下，首先由胶乳初级粒子聚结成次级粒子，再由次级粒子凝聚成团粒，最后团粒相互结合成宏观粒子PCR244。     

FLAVOR ENCAPSULATION AND RELEASE CHARACTERISTICS OF SPRAY-DRIED POWDER BY THE BLENDED ENCAPSULANT OF CYCLODEXTRIN AND GUM ARABIC

The flavor inclusion powder was prepared by spray drying, using the combined encapsulation method of inclusion by β-cyclodextrin (β-CD) and emulsified by gum arabic (GA). d-Limonene and ethyl n-hexanoate were used as model flavors. The application of high pressure by Microfluidizer to the mixture of flavors and β-CD slurry was an effective means of forming inclusion complex. Flavor retention during spray drying under various compositions of the encapsulants was investigated. The flavor retention using the blended encapsulant was increased by adding GA in the encapsulant. The characteristics of release of encapsulated flavor during storage were evaluated at 50°C and 75% of relative humidity. The release rate of flavor in spray-dried powder depended on kinds of the flavors and composition of the encapsulant. The blending MD and β-CD in the feed liquid decreased the release rate of flavors. The rate of release of flavor was analyzed by Avrami's Equation.     

高耐磨炉黑填充粉末丁腈橡胶的制备及性能

研究了利用高分子树脂凝聚包覆法制备高耐磨炉黑填充粉末丁腈橡胶的制备过程及其影响硫化胶物理机械性能的因素。结果表明，当分散剂／包覆剂(质量比)为4／6或10／4时，粒径不大于0．90mm的粉末丁腈橡胶粒子的质量分数为100．0％，相应硫化胶的物理机械性能达到块状丁腈橡胶硫化胶的。高耐磨炉黑填充粉末丁腈橡胶硫化胶的物理机械性能极大地依赖于高耐磨炉黑粒子在基体橡胶中的分散程度及其与基体黏结的紧密性。     

丁羟聚氨酯电器灌封胶的研制

以端羟基液体聚丁二烯（简称丁羟）为主要原料制备丁羟聚氨酯电器灌封胶，考察了增塑剂、填料、扩键剂、催化剂以及温度等因素对其性能的影响。     

Synthesis and characterization of a high refractive diglycidyl ether of thiodibenzenethiol epoxy resin

High refractive index of epoxy resins used as encapsulant in light-emitting diode (LED) is essential in improving the light extraction efficiency, reducing heat and prolonging the service life of LED packages. In this study, diglycidyl ether of thiodibenzenethiol (DGETDBT), an epoxy resin with high refractive index, was synthesized via a novel method and its chemical structure was characterized with Fourier-transform infrared (FTIR) spectrometer and ¹H NMR spectrometer. Using m-xylylenediamine (MXDA) as curing agent, the curing behavior of DGETDBT was studied by differential scanning calorimetry (DSC) and was compared with that of diglycidyl ether of bisphenol A (DGEBA), a generally used encapsulant in LED. The thermal behavior and optical performance of these two resins were investigated with thermogravimetric analyses, UV?CVis scanning spectrophotometer, and Abbe refractometer, respectively. The results showed that DGETDBT/MXDA resin demonstrated similar curing and thermal behavior to DGEBA/MXDA resin. But its refractive index reaches 1.698, which is significantly higher than that of DGEBA/MXDA resin (1.604). Comparatively, DGETDBT resin can be expected to be a more effective encapsulant of LED.     

加成型有机硅灌封胶的粘接性能研究

以丙烯酸-2-羟基乙酯(HEA)、γ-缩水甘油醚氧丙基三甲氧基硅烷(KH-560)和正硅酸乙酯(TEOS)为主要原料,制备了两种加成型有机硅灌封胶用粘接增强剂。采用红外光谱(FT-IR)法对其结构进行了表征,并探讨了两种粘接增强剂对灌封胶及其铝基胶接件的剪切强度、黏度、拉伸强度、断裂伸长率和硬度等影响。结果表明:粘接增强剂的引入能明显提高灌封胶的粘接性能,其中含环氧基粘接增强剂的增强效果相对较好;当w(含环氧基粘接增强剂)=0.6%(相对于灌封胶总质量而言)时,灌封胶的剪切强度(1.21 MPa)比无粘接增强剂体系提高了570%左右。     

Starch urea-formaldehyde matrix encapsulation. IV. Influence of solubility and physical state of encapsulant on rate and mechanism of release

The influence of the physical state and solubility of the encapsulant on the rate and mechanism of release and swelling of the cross-linked starch-urea formaldehyde (St-UF) matrix has been studied by encapsulating model organic compounds. The release and swelling data have been analyzed in terms of the generalized equation M_t/M_∞ = ktⁿ applicable for swellable controlled-release systems. This matrix system shows and an inverse relationship of release rate with the cross-link ratio for all the encapsulants studied. The solid encapsulants have n values in the range of 0.22–0.41, indicating a Fickian or anomalous mechanism. Further, the release rate increases with solubility of the encapsulant. The liquid encapsulants have n values in the range of 0.5–1.5, indicating Case II transport mechanism. The release rates for liquid encapsulants are lower by one to three orders of magnitude than those for solid encapsulants and are not influenced by encapsulant solubility. This indicates a polymer chain relaxation-controlled mechanism of release for liquid encapsulants. © 1993 John Wiley & Sons, Inc.     

Effect of Cooling Press on the Optical Transmission Through Photovoltaic Encapsulants

In certain laminators for poly (ethylene-co-vinyl acetate) (EVA) encapsulation process of photovoltaic modules, cooling press (CP) is applied to the module after encapsulation. Here, the effect of CP on the optical transmission through common PV encapsulants is studied. Interestingly, CP is shown to reduce drastically the scattering of the light between 400 and 700 nm traveling through the thermoplastic polyolefin (TPO)-based encapsulant. Post-annealing tests prove this effect to be stable at the temperature up to 85°C. This work has discovered a simple solution to mitigate the milky appearance of the TPO encapsulant and hence greatly enhanced its competitiveness against EVA.     

Heat transfer behavior of high-power light-emitting diode packages

Heat transfer characteristics of a high-power light-emitting diode (HPLED) have been carried out in terms of experiment and simulation. Finite volume method was used to analyze the temperature and thermal stress distributions in the HPLED package as a function of drive current and package structure. Predicted temperatures of silicone encapsulant and epoxy resin showed a good agreement with measured temperatures. The thermal stress increased with the drive current due to a heat burden. The intersection edges between the light emitting diode chip and the silicone encapsulant showed a higher thermal stress. The thermal stress of Cu-thin-film coated package was lower than that of other package structures because of an efficient cooling effect.