Study on Preparation and Properties of Polysiloxane Modified Epoxy Encapsulating Material
|School||Harbin University of Science and Technology|
|Keywords||electronic packaging epoxy resin mechanical properties thermalstability electrical insulation|
Epoxy has been widely used in the field of the encapsulation of circuits and IC.However, because EP is a typical thermosetting resin, cured products exist poortoughness, fatigue durability and shock resistance defects and poor, which limitthe using of epoxy resin.To solve this problem, in this paper, EP as a matrix, dichlorodiphenyl silane toas a modifier, we chose the method of chemical modification. A series ofsilicone-modified resin are prepared by varying the content ofdichlorodiphenylsilane. In the paper, methyl nadic anhydride (MNA) as a curingagent, and2,4,6-tris(dimethyl amino methyl)phenol, dibenzoyl peroxide, acetylacetone aluminum as a curing accelerator, a nitrile rubber (CTBN) as atoughening agent. Investigation of dichlorodiphenylsilane content, curing andtoughening agent effect on cured products’ heat properties, mechanical andelectrical properties. The modified materials used for electronic packagingapplication.In this paper, we did a qualitative analysis for epoxy resin before and aftermodified by measuring the infrared spectrum and the epoxy value, it showed thatdichlorodiphenylsilane has been completely grafted into the epoxy chain. Curedsystem is analyzed by scanning electron microscopy, and epoxy resin happenedductile fracture after modified. We found out the thermal stability of cured systemis best when epoxy resin10g and dichlorodiphenylsilane2.8g through TG-DTGanalysis and dynamic mechanical test methods (DMA). And when cured systemhas5%weight loss, Tdecis186℃and Char residue at500℃is19.03%, andincreased by33℃and7.34%higher than pure epoxy. DMA analysis showed thatthe glass transition temperature of the modified system is169℃, the glass transition temperature increased19℃than the pure epoxy resin. Through theanalysis of shear properties of the material, showed shear strength of the systemis26.38MPa, when the amount of the modified resin is10g and CTBN dosage is1.5g. We tested the electrical properties, and it showed the dielectric strength is23.0kv/mm, the dielectric constant is4.01, the loss tangent values is0.0043,when the amount of the modified resin is10g and the amount of curing agent is7.6g. When the modified epoxy and pure epoxy with the mass ration of6:10, theelectrical properties of composite to the top, and the dielectric strength is27.0kv/mm, the dielectric constant is3.52, the loss tangent values is0.0036.