促进剂在导电胶中的作用研究

以环氧树脂(EP)为基体树脂、2-乙基-4-甲基咪唑为固化剂、银包铜粉为导电填料、KH-550为硅烷偶联剂和DBGE为促进剂,制备了一种各向同性导电胶。探讨了促进剂用量对导电胶导电性能的影响,并采用红外光谱(FT-IR)、扫描电镜(SEM)及差示扫描量热(DSC)分析法等对导电胶的机理进行了研究。结果表明:随着促进剂用量的增加,导电胶的体积电阻率呈先降后升的趋势;当w(促进剂)=2%时,导电胶的导电性能最好(体积电阻率为1.9×10~(-3)Ω·cm);促进剂的加入能够部分去除导电粒子表面的有机润滑层,从而提高了导电胶的导电性能。     

高强度导电胶膜的制备与性能

以改性环氧树脂为主体,银粉为导电填充物,通过预反应增加聚合度的方法制备出了一种各向同性导电胶膜。研究了不同形貌及添加量的银粉对体积电阻率的影响以及导电胶的热性能,测试分析了不同条件下导电胶的粘接性能、导电性能和耐环境性能。结果表明,微米级片状银粉导电性能最佳,胶膜固化后室温剪切强度为18.7MPa,体积电阻率为3.2×10-4Ω·cm,玻璃化转变温度Tg为118℃,Tg前热膨胀系数为54.6μm/(m·℃)。经温度循环、湿热、盐雾、老化等环境试验后剪切强度均可维持在16MPa以上,体积电阻率无明显变化。     

利用PCB碱性蚀刻废液制备纳米铜导电胶

以碱性蚀刻废液为原料,采用液相还原法制备了纳米铜粉,将制备的纳米铜粉作为导电填充料添加到环氧树脂中制备出纳米铜导电胶。研究了纳米二氧化硅、硅烷偶联剂KH570和纳米铜粉的添加量对导电胶剪切强度以及纳米铜粉添加量对导电胶体积电阻率的影响,探讨了环氧树脂与固化剂聚酰胺适宜的反应时间。实验结果表明,所制备的铜粉为球状,粒径在40～100nm之间;当环氧树脂与固化剂聚酰胺树脂650的质量比为4∶1,纳米二氧化硅、硅烷偶联剂和纳米铜粉的加入量分别占环氧树脂–聚酰胺树脂体系质量的1.5%、4.0%和70%时,在90°C下固化1.0h,可以制备出体积电阻率为3.05×10-3Ω·cm、剪切强度达8.04MPa的导电胶。     

紫外光固化环氧丙烯酸树脂导电胶

以环氧丙烯酸树脂为基体树脂、微米级片状铜粉为导电填料制备紫外光固化导电胶,采用光引发剂与热引发剂复合引发体系实现导电胶的深层固化。对紫外光固化导电胶的影响因素进行研究,制备出的导电胶电阻率可达1.3×10-3Ωcm,剪切强度为1.3MPa。     

石墨烯改性导电胶的制备及导电机理研究

以环氧树脂(EP)为基体、聚苯胺为助剂、铜粉为导电填料和石墨烯为改性剂,采用共混法制备了高导电性、高粘接强度、低成本和固化后不易开裂的导电胶,并对其导电机理进行了分析。研究结果表明:铜粉作为导电填料,可使导电胶的成本大幅降低,当w(铜粉)=60%(相对于EP质量而言)时,导电胶的导电性能相对最佳(体积电阻率为4.14×10~(-3)Ω·cm)。石墨烯可进一步改善导电胶的导电性能,当w(石墨烯)=0.05%(相对于EP质量而言)时,导电胶的体积电阻率(2.78×10~(-3)Ω·cm)相对最低。石墨烯在胶体内形成类似钢筋骨架作用的网络结构,使填料之间连接更紧密,从而有效提高了导电胶的导电性能和力学性能,解决了导电胶固化后易开裂、韧性不足等难题。     

高性能室温固化双组分导电胶的制备及性能研究

以环氧树脂基体与微米片状银粉为原料制备了银导电胶组分A,并与自制固化剂配合制备出无溶剂、室温24 h固化和100℃加热快速固化的双组分导电胶。研究了银粉种类、填料含量及固化剂种类对导电胶室温固化和100℃加热固化后电学和力学性能的影响,并提出固化剂对银粉表面包覆影响双组分导电胶电学性能的导电机理,分析了固化剂对银粉表面包覆状态与导电胶导电性的关系。研究结果表明：对微米片状银粉进行适当处理后,导电胶的较佳填料负载量为81%。自制固化剂(ECA-lab)作为组分B的导电胶,室温固化电阻率低至1.60×10^-3Ω·cm,剪切强度高达11.05 MPa,可与市售进口导电胶媲美。     

银包铜粉环氧导电胶的制备、结构与性能

为了研制性能优良的导电胶,选用双酚A型环氧树脂作为基体、四乙烯五胺作为固化剂、银包铜粉为导电填料、AA-75作为分散剂,制备了银包铜粉导电胶。使用直流低电阻测试仪测定了导电胶的体积电阻率;用红外光谱对添加不同量固化剂的导电胶进行了分析,用差示扫描量热仪对加入固化剂后的固化反应情况进行了测试。在最佳配比和最佳工艺条件下所制备的导电胶的体积电阻率达到8．9×10^-4Ω·cm。     

有机硅导电胶粘剂的性能研究

选用二维片状银粉、纳米一维球状银粉复配用作导电填料,制备了一种单组分加成型有机硅导电胶粘剂。通过电学测试、扫描电镜（SEM）、拉伸剪切测试、流变测试等方法,对其体积电阻率、微观形貌、拉伸剪切强度、固化特性和表观黏度等进行分析。研究结果表明：选用多维导电填料复配制备的导电胶可以良好固化,二维片状银粉占比的增大使得导电胶的弹性模量有小幅上升,均稳定在106～107Pa之间,使导电胶具备基本的力学强度;随着二维片状银粉占比增大,一维球状银粉占比减少,有机硅导电胶的导电性逐渐增强,然而粘接性逐渐变差,通过调整银片与银球的比例可实现二者的平衡,为有机硅导电胶的性能优化提供了一种可行性方法;导电胶的表观黏度随二维片状银粉占比的增大而升高,多维导电填料并用便于调控导电胶的黏度,结合温度调控,可有效调控导电胶的黏度,实现更大范围的工艺应用。     

镀银铜粉导电胶制备及表征

为了制备高抗氧化性能铜粉,采用AgNO_3为银源,化学镀法制备了不同含银量的超细镀银铜粉。将镀银铜粉作为导电填料制备导电胶,系统研究了制备工艺对导电胶性能的影响。结合扫描电镜(SEM)、X射线衍射(XRD)、X射线荧光(XRF)、流变仪测试、四探针电阻率测试、万能电子拉力机、热分析(DSC/TG)等分析手段,研究了镀银铜粉的形貌、晶体结构、导电胶黏度、电性能、强剪切度和固化过程热性能。结果表明:镀银铜粉具有较好的导电性及抗氧化性能。推荐最佳的导电胶制备工艺为:65%镀银铜粉、35%的环氧树脂,在150℃下固化10 min,该导电胶制备出薄膜的电阻率为8.73×10~(-4)?×cm,焊接铜片剪切强度为11 MPa,,具有优异的抗老化性能。     

高导电率导电胶的制备和性能研究

以改性环氧树脂为基体,片状银粉为导电填料制备导电胶,并采用胺类复合固化体系实现导电胶的固化。该导电胶具有体积电阻率低(可达10~(-5)Ω·cm),易配制等特点。主要对存在加温变形问题的电子元器件(如波导管)进行粘接,亦可应用于其他电子元器件的粘接与修复。     

导热环氧灌封胶的研制

以环氧AG-80为主体树脂,端羧基液体丁腈橡胶与1,6-已二醇二缩水甘油醚的反应产物为活性增韧稀释剂,纳米AlN为导热填料,缩胺-105为固化剂制备导热灌封胶。实验结果表明,每100份环氧树脂中活性增韧稀释剂为20份时,灌封胶的力学性能、耐热性能良好;纳米AlN的质量分数为12％,灌封胶的热导率达到0．85W／m·k,可满足使用要求。     

Processing and shape effects on silver paste electrically conductive adhesives (ECAs)

Various amounts of silver flakes and dendrites were used as conductive fillers in an electrically conductive adhesive (ECA) resin with DPM, BCA and xylene as diluent to help uniform distribution of filler particles in the matrix. Due to the fact that the higher the temperature, the higher the shrinkage rate of the polymer resin and, consequently, the larger the connecting area in-between fillers, a better curing condition for processing silver filled ECA was found to be a relatively higher curing temperature. The mechanism of conductivity achievement in conductive adhesives was analyzed by comparing processing conditions, resistivity and microstructures. In addition, the influence of adding nano-sized silver particles on the resistivity of the conductive adhesives was also investigated and the addition of nano-sized silver particles resulted in a lower percolation threshold for ECAs.     

Hyperbranched polysiloxane-modified UV-curable graphene conductive coatings: preparation and characterization

A new UV-curable hyperbranched silicone epoxy acrylate resin was synthesized, and two kinds of carbon-based components, graphite and graphene, were applied as conductive materials. An ultraviolet-curing coating was successfully synthesized with using epoxy acrylate (EA) as oligomer, butyl acrylate (BA), and hyperbranched polysiloxane (HPSi) as monomers, benzoin dimethyl ether (DMPA), and benzophenone (BP) as photo-initiators, triethanolamine (TEA) as photo-activator, and other auxiliaries. In this work, the UV-curing efficiency and cured performance, together with the effect of different conductive fillers and the amount of conductive filler on the integrated performance of the composites, are investigated. The results show that as the HPSi content increases, the curing time is shortened. At the addition amount of 7.5%, it reaches the best conductivity, and at the addition amount of 10%, the corrosion resistance after curing is the best. However, the maximum tensile strength of 10.4% is obtained at 0.75 graphene. The FE-SEM micrographs of the UV-curable conductive coating show that with increasing incorporation of graphene into the substrate, the fractured surface of a rough surface changes to smooth one. Thermal properties of the films investigated using TGA curves indicate that graphene-doped conductive adhesive film (315.1 °C) possesses much higher heat resistance than that of graphite-doped conductive adhesive film.     

复合绝缘导热胶粘剂研究

以增韧的酚醛环氧树脂为基体树脂,氮化铝、氮化硼、氧化铝混杂粒子为导热填料制备了-新型绝缘导热胶粘剂。研究了填料用量对胶粘剂热导率、热阻、介电常数、体积电阻率等性能的影响,发现填料用量为40％时胶粘剂的热导率为O．99 W／mK,热阻为0．70℃／W,介电常数6,体积电阻率4．6×1012Ω·cm,20℃、200℃、250℃下的剪切强度分别为13．0MPa、10．0MPa、5．65MPa。研究结果表明该胶具备良好的电绝缘及力学性能,可以长期在150℃温度下使用,与不加导热填料的相同胶粘剂相比,具有良好的导热能力。     

单组份环氧树脂-银导电胶的制备研究

选用微米级片状银粉作为导电填料,环氧树脂和咪唑类潜伏型固化剂作为基体树脂制备导电胶。通过扫描电镜研究了银粉含量对导电胶固化后的形貌,测试体积电阻率和拉伸性能与银粉填充量变化的关系。依照以上结论,探讨了导电胶的导电机理,并提出导电模型。     

Copper particles/epoxy resin thermosetting conductive adhesive using polyamide resin as curing agent

Thermosetting conductive adhesive (TCA) comprised of epoxy resin E‐51 as matrix, Cu microparticles and nanoparticles modified by silane coupling KH550 as conductive fillers, polyamide resin with low molecular weight as curing agent, and some other additives. It was reported creatively a new liquid curing agent, which solved successfully some difficult problems during preparation of TCA, such as limit of quantity of conductive fillers. Therefore, application of this liquid curing agent decreased greatly the resistivity of TCA under the condition of keeping enough adhesion strength. Antioxidized and mixed Cu particles were developed as conductive fillers in place of expensive Ag. The results showed that optimum conditions of conductive adhesive composed of 16 wt % of epoxy resin E‐51, 8 wt % polyamide resin, 65 wt % of Cu microparticles and nanoparticles, 1.3 wt % of silane coupling agent, and 9 wt % of other additives with curing time for 4 h at 60°C. The adhesion strength reached 16.7 MPa and the bulk resistivity was lower than 3.7 × 10^?4 Ω cm. The variation of bulk resistivity was less than 15% at high temperature (100°C). © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

还原石墨导电胶的研究

采用水合肼(85%)对膨胀石墨进行还原改性,制得导电性能良好的还原石墨。以还原石墨、环氧树脂(EP)、三乙醇胺及活性添加剂(自制)复合制备还原石墨导电胶系列。通过傅里叶红外(FT-IR)分析确定了该还原石墨导电胶系列的适宜固化条件,运用多种检测手段对导电胶的导电性能、力学性能和热学性能等进行分析,利用X-射线能谱仪对还原石墨的表面含氧量进行考察。研究结果表明,该还原石墨导电胶系列的适宜固化条件为120℃×180 min,体积电阻率为0.3439～1.4877Ω·cm,拉伸剪切强度为12.3～19.7 MPa;该导电胶可在不超过300℃的环境下使用,具有巨大的市场潜力和广阔的工业应用前景。     

硅改性BPA-PA酚醛环氧树脂导电胶的合成及性能

以双酚A多聚甲醛酚醛树脂（BPA-PA酚醛树脂）、二甲基二甲氧基硅烷和环氧氯丙烷为原料,通过酯交换反应和亲核取代反应得到硅改性BPA-PA酚醛环氧树脂。采用傅里叶变换红外光谱（FTIR）、X射线光电子能谱（XPS）分析进行结构确证。结合非等温DSC、T-β外推直线和FTIR分析研究了最佳固化工艺条件。探讨了不同硅烷添加量对硅改性BPA-PA酚醛环氧树脂性能的影响。最后以硅改性BPA-PA酚醛环氧树脂为基体树脂,加以导电填料和助剂,制备出中温型导电胶。对导电胶进行拉伸剪切强度、体积电阻率和热重测试分析,结果显示：自制硅改性BPA-PA酚醛环氧树脂导电胶拉伸剪切强度达到20.18MPa、体积电阻率达到7.44×10^-4Ω·cm,残炭量达到68.89%。相对市售E-51环氧树脂所制导电胶,自制硅改性BPA-PA酚醛环氧树脂导电胶拉伸剪切强度提高5.73MPa,体积电阻率降低3.86×10^-4Ω·cm,残炭量提高7.49%。