中文摘要：

利用端羟基超支化聚胺-酯（HBP3-OH）与马来酸酐的酯化反应，合成了含双键的超支化聚胺-酯（HBP3-MA），并用红外光谱和核磁共振光谱对HBP3-MA进行了表征．将HBP3-MA作为改性剂，液体硅橡胶为基体，镀银铜粉为导电填料，制备了改性硅橡胶导电复合材料．HBP3-MA参与到液体硅橡胶的固化，采用示差扫描量热仪（DSC）对复合体系的固化条件进行了研究．采用原位还原法在复合体系中生成纳米银，利用透射电子显微镜（TEM）、扫描电子显微镜（SEM）对银纳米粒子的形貌和复合体系的结构进行了表征，探讨了纳米粒子增强复合物体系导电性的机理，即银纳米粒子具有低温烧结的特性，固化时可在镀银铜粉表面烧结，降低了镀银铜粉之间的接触电阻．最后，对导电复合材料的导电性能和粘结性能进行了研究．研究发现，当醋酸银用量为4．4份时，导电复合材料的体积电阻率和剪切强度均达到最佳值，分别为3．6×10^-3Ω·cm和0．32MPa．

英文摘要：

This paper presents an approach to prepare polysiloxane-based conductive composites filled with low-cost silver coated copper （Ag-coated Cu） microscale flakes by using the hyperbranched poly（amine-ester） （HBP3-MA） as modifier which is obtained by the reaction between the hyperbranched poly （amine-ester） （ HBP3-OH） with terminal hydroxyl and maleic anhydride. The structure of the HBP3-MA was characterized by Fourier transform infrared （FTIR） and nuclear magnetic resonance （NMR）. Curing condition of the compound system was studied by differential scanning calorimetry （DSC） since HBP3-MA was involved in the curing reaction of polysiloxane. The structural morphology （the size and dispersion） of in situ reduced AgNPs and the composite system was studied by transmission electron microscopy （TEM） and scanning electron microscopy （SEM）. Also, conductivity mechanism of the composites reinforced by metal nanoparticles was discussed. At the curing temperature, silver acetate decomposed and silver nanoparticles （AgNPs） were in situ generated in the polymer matrix. The low temperature sintering of AgNPs anchored on the surface of Ag-coated Cu flakes enhanced the interracial bond of Ag-coated Cu flakes and decreased the overall contact resistance. Last, the conductivity and shear strength of the composites were studied. When the content of silver acetate was 4.4 phr, the optimum volume resistivity and the shear strength were achieved,which were 3.6×10^-3Ω·cm and 0.32 MPa, respectively.