氮化硅/环氧复合电子基板材料制备及性能

以Si_3N_4粉末作为增强组分与环氧树脂进行复合,采用模压法制备了氮化硅/环氧树脂复合电子基板材料。研究了Si_3N_4含量对复合材料导热性能和介电性能的影响。研究结果表明,随着Si_3N_4含量的增加,复合材料中填料形成导热网络,复合材料的热导率也随之增加,当体积填充量为35%时,导热系数达到1．71 W/m·K。复合材料的介电常数随Si_3N_4含量的增加而增加,但在氮化硅陶瓷颗粒的体积分数达到35%时仍维持在较低的水平(7．08,1 MHz)。     

Thermal conductive composites based on silver‐plating graphite nanosheet and epoxy polymer

Silver plating graphite nanosheet (Ag‐NanoG) prepared by electroless plating method with expanded graphite as starting material is an effective approach to increase thermal conductivity of the filler. Herein, a novel thermal conductive composite was prepared by using Ag‐NanoG as thermal conductive filler and epoxy resin as the polymer matrix. The microstructures of NanoG and Ag‐NanoG were characterized by means of scanning electron microscopy, X‐ray powder diffraction and then the thermal conductivity, impact strength, and thermal stability of the composite were investigated. The results showed that the Ag‐NanoG was successfully obtained and it can be homogeneously dispersed in the epoxy resin. The thermal conductivity of composite increased from 0.328 to 1.847 W/m K with 4 wt% Ag‐NanoG filler content. Moreover, the composite exhibited excellent thermal stability and mechanical property. POLYM. COMPOS., 38:2822–2828, 2017. © 2015 Society of Plastics Engineers     

环氧树脂/氧化锌晶须/氮化硼导热绝缘复合材料的研究

以环氧树(脂EP)为基体,分别以氧化锌晶(须ZnOw)和ZnOw/氮化硼(BN)混合物为导热填料,制备了EP导热绝缘复合材料。研究了填料含量对复合材料导热性能、电绝缘性能及力学性能的影响,并利用扫描电镜对复合材料的断面形貌进行了观察。结果表明:随着导热填料含量的增大,复合材料的导热系数和介电常数增大,体积电阻率下降,而拉伸强度呈先增大后减小的趋势;在填料含量相同的情况下,EP/ZnOw/BN复合材料比EP/ZnOw复合材料具有更好的导热性能;当填料体积分数为15%时,EP/ZnOw/BN复合材料的热导率为1.06W/(mK)而,EP/ZnOw复合材料的热导率仅为0.98W/(mK)。     

低温固化环氧树脂粉末涂料的制备及性能研究

通过双螺杆挤出机用E-12型环氧树脂和YLT-118固化剂及其他助剂在90℃下熔融混合10 min,然后在平板硫化机上冷压3 min,最后经过粉碎机粉碎,过筛制得环氧粉末涂料。采用差示扫描量热法和红外光谱表征粉末涂料,并讨论了填颜料用量、固化条件等对涂料性能的影响。结果表明：该粉末涂料可实现低温固化,固化条件为120℃下恒温固化30 min;固化剂用量为环氧树脂的16.7%时,m（环氧树脂）∶m（填颜料）为150∶135时,得到的涂膜各项物理性能最好。     

废弃环氧模塑料填充聚氯乙烯的研究

用废弃环氧模塑料粉作为填料,采用模压成型的方法制备了聚氯乙烯（PVC）/废弃环氧模塑料复合材料,研究了废弃环氧模塑料粉的组成和性质及其与PVC的界面黏结情况,分别考察了温度和废弃环氧模塑料粉含量对复合材料力学性能和动态力学性能的影响。结果表明,废弃环氧模塑料粉具有一定的活性,能与极性树脂PVC发生作用而产生界面接枝;在模压温度为200 ℃,废弃环氧模塑料粉含量为60 %（质量分数,下同）时,复合材料的拉伸强度为32.13 MPa,弯曲强度和冲击强度分别为60.70 MPa和4.68 kJ/m2,基本可满足相关产品的要求;随着废弃环氧模塑料粉含量的增加,复合材料的储能模量提高,损耗峰向高温方向移动,且损耗峰形先变宽后变窄。     

The dynamic mechanical analysis of epoxy–copper powder composites using azole compounds as coupling agents

The dynamic mechanical properties of cured epoxy resin have been studied in which copper powder treated or untreated with azole compounds was used as fillers. The untreated fillers do not shift the glass transition temperature of the matrix polymer of the composites, whereas the storage modulus rises with increasing content of fillers. The application of azole compounds as coupling agents, which could react with both copper and epoxy resin, extended the polymer–filler interactions. The composite filled with copper powder treated with benzotriazole shows a strong reinforcement effect and high resistance to moisture.     

Dynamic mechanical analysis of particulate‐filled epoxy resin

The dynamic mechanical properties of epoxy composites filled with different amounts of quartz powder were investigated. The storage modulus and loss tangent were measured at frequencies between 7.8 and 323 Hz from room temperature up to 460 K. The influence of the filler content on the temperature and frequency behavior of the dynamic mechanical properties is discussed and explained in terms of models presented in the literature. In particular, the dependence of the composite damping with the quartz content is explained with regard to damping due to particle–particle and polymer–particle interaction. Also, the glass‐transition temperature as a function of filler content was obtained and was related to the results obtained for the apparent activation energies of the α relaxation, which were estimated with the Williams, Landel, and Ferry equation. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 883–892, 2003     

Enhanced Thermal Conductivity of Polymer Matrix Composite via High Solids Loading of Aluminum Nitride in Epoxy Resin

Most semiconductor devices are now packaged in an epoxy polymer composite, which includes silica powder filler for reducing the thermal expansion coefficient. However, increased heat output from near-future semiconductors will require higher thermal conductivity fillers such as aluminum nitride (AlN) powder, instead of silica. Dispersant chemistry is applied, in order to achieve a high volume percentage of AlN powder in epoxy without causing excessive viscosity before the epoxy monomer is crosslinked, thereby increasing the thermal conductivity of the composite. In the preliminary experiment, high solids loading, up to 57 vol%, was achieved with a wide particle size distribution, and the viscosity of that dispersion was 60 000 to 90 000 cps, resulting in easy flow by gravity alone at room temperature. The highest thermal conductivity of the composites measured by the hot-disk method was 3.39 W/mK, which is approximately 15 times higher than pure epoxy. The Agari and Uno model was a good fit to the experimental data. Electronic I – V curves obtained after encapsulation of testing devices indicated that the highly AlN-filled epoxy slip appeared to be feasible for use in the encapsulation of integrated circuit chips.     

Fabrication of an Electrically-Resistive,Varistor-Polymer Composite

This study focuses on the fabrication and electrical characterization of a polymer composite based on nano-sized varistor powder. The polymer composite was fabricated by the melt-blending method. The developed nano-composite was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), field emission scanning electron microscopy (FeSEM), and energy-dispersive X-ray spectroscopy (EDAX). The XRD pattern revealed the crystallinity of the composite. The XRD study also showed the presence of secondary phases due to the substitution of zinc by other cations, such as bismuth and manganese. The TEM picture of the sample revealed the distribution of the spherical, nano-sized, filler particles throughout the matrix, which were in the 10–50 nm range with an average of approximately 11 nm. The presence of a bismuth-rich phase and a ZnO matrix phase in the ZnO-based varistor powder was confirmed by FeSEM images and EDX spectra. From the current-voltage curves, the non-linear coefficient of the varistor polymer composite with 70 wt% of nano filler was 3.57, and its electrical resistivity after the onset point was 861 KΩ. The non-linear coefficient was 1.11 in the sample with 100 wt% polymer content. Thus, it was concluded that the composites established a better electrical non-linearity at higher filler amounts due to the nano-metric structure and closer particle linkages.     

金属基有机硅树脂涂层复合材料的导热性能

以锌粉为导热填充剂对环氧有机硅树脂进行改性,考察了改性环氧有机硅树脂涂层干膜中锌粉含量对涂层导热系数的影响,分析了涂层厚度对碳钢基材导热性能的影响. 结果表明,环氧有机硅树脂涂层的导热系数约为0.19 W/(m?K),其耐温能力在200℃以上,可保证涂层在中低温烟气余热回收换热器表层长期工作而不发生任何热反应;添加锌粉可改善环氧改性有机硅涂层的导热性能,涂层干膜锌粉25wt%时,涂层材料导热系数达0.35 W/(m?K),较未添加锌粉时增大了84%. 复合材料的导热系数随涂层厚度增加而下降,无涂层的碳钢导热系数为47.59 W/(m?K),涂层厚度为200 ?m时,导热系数降至34.33 W/(m?K).     

抗静电环氧树脂胶粘剂的制备与性能研究

以导电碳黑和银粉为导电填料制备了抗静电环氧树脂(EP)胶粘剂,考察了导电填料的种类和用量对胶粘剂导电性能和力学性能的影响。研究结果表明,导电填料的种类对胶粘剂导电性能和力学性能的影响显著不同;以导电碳黑作为导电填料时,当w(导电碳黑)=5.0%时EP胶粘剂开始具备抗静电能力,当w(导电碳黑)≈7.1%时胶粘剂的体积电阻率发生突跃式下降;而以银粉作为导电填料时,当w(银粉)=0～38%时EP胶粘剂不具备抗静电能力。EP胶粘剂的拉伸强度和剪切强度随着导电碳黑用量的增加呈线性下降的趋势,而随着银粉用量的增加则呈线性上升的趋势。     

Preparation of finely macroporous SiOC foams with high mechanical properties and with hierarchical porosity via pyrolysis of a siloxane/epoxide composite

Mechanically strong SiOC foams were prepared via pyrolysis of polysiloxane composites, into which 20–70 wt% of epoxy powder were incorporated as sacrificial filler. The chosen epoxy filler degrades practically quantitatively during the pyrolysis in nitrogen, due to a high content of polyoxypropylene chains. The pyrolysis of the composite precursors yielded SiOC foams with apparent densities between 1.31 and 0.62 g/cm³, which corresponded to macro-porosities of 35–69%. A hierarchical porosity was obtained due to a relatively wide distribution of the sacrificial filler grains׳ size. Compressive strength between 15 and 38 MPa was achieved, depending on the apparent density of the SiOC foams: the best result was obtained for the foam with 56% porosity. In the case of denser foams, their strength was reduced by the presence of pyrolysis cracks, while at 70% porosity, the thinner pore walls led to a reduced strength. The elastic modulus of the most promising foam (56% porosity) was found to be 10 GPa.     

一种特殊纹理效果粉末涂料的研制及稳定性探讨

通过一次挤出工艺,制备了一种特殊纹理效果粉末涂料（新型雪花纹）。探讨了环氧树脂、环氧树脂固化剂、催化剂、颜填料含量及挤出机进料温度和出料温度对雪花纹纹路产生的影响。结果表明：环氧当量小的环氧树脂制备的粉末涂料,其环氧基含量高,反应速度快,反应程度更完全,得到的纹理最清晰;加入 2-甲基咪唑固化剂可以提高涂膜的物理性能。颜填料含量 30%时,雪花纹理效果较好;高速挤出机进料温度控制在 90 ℃,出料温度控制在 120~130 ℃时纹理效果最好。     

PP/POE/滑石粉复合材料的制备及其在汽车内饰件中的应用

通过分析聚丙烯(PP)和乙烯-辛烯共聚物(POE)的流变特性,选用熔体黏度相近的材料作为基体,以滑石粉为填料,制备了PP/POE/滑石粉复合材料.研究了螺杆组合、助剂种类对复合材料性能的影响,并利用扫描电子显微镜观察了POE和滑石粉在复合材料中的分散情况,考察了该复合材料在改善汽车内饰件外观中的应用状况.结果表明,合适...     

More wear‐resistant and ductile UHMWPE composite prepared by the addition of radiation crosslinked UHMWPE powder

Radiation crosslinked ultrahigh molecular weight polyethylene (X‐UHMWPE) powder was prepared by γ‐ray irradiation under nitrogen atmosphere with a dose of 50–200 kGy at a dose rate of 7 kGy/h and further annealing in vacuum at 120 °C for 4 h. The crosslinked powder was characterized by FT‐IR spectroscopy, gel content, and hot‐press molding. Then, X‐UHMWPE was added to pristine UHMWPE to prepare a composite with 0–25 wt % filler. The morphology, wear resistance, and tensile property of the composite were investigated. Using X‐UHMWPE as a filler could sufficiently improve the wear resistance of the composite. Adding 25 wt % X‐UHMWPE (dose: 150 kGy) improved wear resistance by 130% and retained approximately 90% tensile strength and 70% ductility. Wear‐resistant and ductile UHMWPE composite may be potentially used for artificial joint replacement and engineering devices. The proposed route is useful in fabricating UHMWPE material with excellent comprehensive performance or functional polymer composite. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44643.     

Development of Silicon Carbide Reinforced Jute Epoxy Composites: Physical,Mechanical and Thermo-mechanical Characterizations

The aim of the present study was to investigate the physical and thermo-mechanical characterization of silicon carbide filled needle punch nonwoven jute fiber reinforced epoxy composites. The composite materials were prepared by mixing different weight percentages (0–15 wt.%) of silicon carbide in needle punch nonwoven jute fiber reinforced epoxy composites by hand-lay-up techniques. The physical and mechanical tests have been performed to find the void content, water absorption, hardness, tensile strength, impact strength, fracture toughness and thermo-mechanical properties of the silicon carbide filled jute epoxy composites. The results indicated that increase in silicon carbide filler from 0 to 15 wt.% in the jute epoxy composites increased the void content by 1.49 %, water absorption by 1.83 %, hardness by 39.47 %, tensile strength by 52.5 %, flexural strength by 48.5 %, and impact strength by 14.5 % but on the other hand, decreased the thermal conductivity by 11.62 %. The result also indicated that jute epoxy composites reinforced with 15 wt.% silicon carbide particulate filler presented the highest storage modulus and loss modulus as compared with the unfilled jute epoxy composite.     

Effects of nanotube modification on the dielectric behaviors and mechanical properties of multiwall carbon nanotubes/epoxy composites

Multiwall carbon nanotubes (MWNTs) were modified by three methods, namely, oxidizing the tubes and opening both ends, filling the tubes with Ag, and grafting the tubes with hexamethylene diamine. Modified MWNTs/epoxy composites were prepared by melt‐mixing epoxy resin with the tubes. Transmission electron microscope images showed that the modified MWNTs can be dispersed in the epoxy matrix homogeneously. The dielectric behaviors and mechanical properties of the composites were investigated. The dielectric and mechanical properties of the modified MWNTs/epoxy composites were considerably improved compared with those of the epoxy matrix. The tensile strengths of the Ag‐filled, opened, and grafted MWNTs composites at the same filler content of 1.1 wt% were higher by ～30.5%, 35.6%, and 27.4%, respectively, than that of neat epoxy. The Izod notched impact strength of the grafted MWNTs/epoxy composite with filler content of 1.1 wt% was approximately four times higher than that of neat epoxy. A dielectric constant of ～150 of the composite with 1.1 wt% Ag‐filled nanotubes was observed in the low‐frequency range, which was ～40 times higher than that of the epoxy matrix. The proper modification of nanotubes provides a way to improve the properties of the polymer‐based composites. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers     

硅灰石/环氧树脂增强体系性能研究

通过对针状硅灰石粉进行干法表面化学改性,制成不同粒径的增强填料。并填充于环氧树脂中进行十字交叉法试验,探讨了硅灰石／环氧树脂体系的增强机理。力学性能测试结果表明：环氧树脂经硅灰石填充后．可显著提高机械强度和硬度;改性硅灰石与未改性硅灰石相比,改性后填充量增大,增强效果明显。同一粒径的硅灰石,随填充量的增加,环氧树脂的机械强度增大。硅灰石粒径越小。比表面积越大。与环氧树脂的结合力越强,强度越大。     

环氧树脂-有机硅复合改性水性聚氨酯耐温防腐涂料的研究

以异氟尔酮二异氰酸酯(IPDI),聚丙二醇(PPG),二甲基硅油及环氧树脂等为主要原料合成了环氧树脂-有机硅复合改性水性聚氨酯,通过添加无机填料和助剂制备了水性聚氨酯涂料。利用红外光谱和热分析仪对乳液、涂料的结构和性能进行表征。探讨了乳液、镇水粉和铁红的用量对涂膜力学性能、耐水性能和防腐性能的影响。当乳液含量为65%,镇水粉含量为10%,铁粉含量为6%时,其热稳定性能提高了50℃,吸水率降低了3倍,冲击强度增加到80 kg/cm,附着力达到0级,自腐蚀电位提高至450 mV。结果表明,无机填料的加入,可极大改善水性聚氨酯涂层的综合性能。     

Thermal conductivity enhancement of liquid crystalline epoxy/MgO composites by formation of highly ordered network structure

To develop a high thermal conductive composite, an MgO filler was incorporated into a liquid crystalline (LC) epoxy containing a mesogenic moiety. The thermal conductivity of the obtained composite was 1.41 W/(m∙K) at 33 vol% content, which was remarkably higher than the value predicted using Bruggeman's model. To investigate the reason for this significant enhancement of the thermal conductivity in the LC epoxy composites, the LC phase structure of the composite was analyzed by a polarized optical microscope, an X-ray diffractometry (XRD) and a polarized IR mapping measurement. An XRD analysis indicated the local formation of a highly ordered smectic phase structure, even in the high-loading composite. This result indicated the promotion of the self-assembly of the mesogenic network polymer chains by the MgO filler loading. We considered that this highly ordered structural formation can lead to an increase in the matrix resin's thermal conductivity, which can result in the effective enhancement of the thermal conductivity in the LC epoxy/MgO composite.