The Matrix Resin Applied To High-Frequency PCB

The fast development of modern industry has been requiring the information-related electrical equipments to deliver information at even greater speed. Therefore, the reliable high performance composite materials of light-weight with low dielectric constant (ε) and dissipation factor (δ) as well as excellent mechanical properties are strongly desired for the high-speed printed-circuit boards. Cyanate esters (CEs) attract worldwide attentions and are considered as the candidate matrix with great potential to produce CCLs, desirable properties such as low dielectric constant, easy to process and high service temperature. However, the cured CEs are generally brittle and low conversion of-OCN groups. These are the major factors that restrict further prosperity of cyanate esters into the advanced industrial applications. Thereby we are desirous to toughening them within the limits of compromising their good electrical properties.In this paper, two kinds of materials applied to modify cyanate ester are epoxidized polysiloxane and organic-inorganic hybrid SiO₂ obtained via sol-gel method.A novel modified cyanate ester (CE) resin by epoxidized polysiloxane (E-Si) has been developed. E-Si was prepared by the reactions between octamethylcyclotetra-siloxane (D₄), hexamethyldisiloxane (MM), (3-aminopropyl)-methyldiethoxysilane (AMDES) and diglycidyl ether of bisphenol-A resin (DGEBA). Differential scanning calorimetric analysis revealed that the reaction exothermic peak of resin system became broaden and sharply shifted to a lower temperature with the increasing of E-Si content in the formulations due to the existence of the hydroxyl. The glass transition temperature (T_g) and thermal degradation temperature of the cured modified resin systems decreased with the epoxidized polysiloxane incorporation. Water resistance of the modified CE was improved drastically owing to the hydrophobic methyl of the siloxane chains.A new nano-silicon particle has been used to modify the cyanate ester. This kind of silicon was prepared with tetra-ethyl orthosilicate (TEOS) and γ-Aminopropyl triethoxy silane (KH550) via sol-gel method. The advantage is that organic chain can insert inorganic network in the molecular scale via sol-gel method. The nano-partiele has lower surface energy and better hydrophobicity than the traditional nano-silicon particle due to the existence of abundant organic chain. The ratio of organic groups in the SiO₂ prepared by sol-gel reaches 20%～30% and this type of SiO₂ has low water absorption.