Study On Structure And Properties Of Magnesium Aluminum Borosilicate Glass Fibre With Low Dielectric Constant

Low dielectric glass fiber,a main reinforced material of high-performance copper-clad laminate?CCL?which satisfies high speed transmission of signal,mostly belongs to the aluminum borosilicate glass system on the current market,and are mostly developed by developed countries.International fiber glass giants consistently implement policies of products monopoly and technology embargo against China.This paper jumped out of conventional calcium aluminum borosilicate system to explore suitable composition for low dielectric glass in the magnesium aluminum borosilicate system,and studied the relationship between structure and properties.It is of great significance for developing independent intellectual property rights of low dielectric fiberglass.SiO₂-B₂O₃-Al₂O₃-MgO glass was prepared by conventional melt quenching method.The structure of the magnesium aluminum borosilicate glass was studied by NMR,FTIR,DSC and XRD.The density,dielectric properties and chemical stability were also studied.The main conclusions are as follow:?1?The structure of magnesium aluminum borosilicate glass,with a small quantity of [AlO₅] and [AlO₆],were mainly built by [BO₃] trigonal,[AlO₄] tetrahedral,[SiO₄] tetrahedral and [BO₄] tetrahedral.B element mainly existed as [BO₃] trigonal and Al element mainly existed as [AlO₄] tetrahedral with a small amount of [AlO₅] and [AlO₆].The result showed that with the increasing of SiO₂/B₂O₃ mole ratio,the amount of [SiO₄] tetrahedral increased,the amount of [BO₃] trigonal decreased,the glass devitrification temperature range decreased,the density gradually increased,but the rate of increase gradually decreased,weight loss ratio of acid and alkali resistance decreased,dielectric constant increased,and dielectric loss reduced first and then increased.With the increasing of B₂O₃/MgO mole ratio,the density of [BO₃] trigonal increased,the density decreased,weight loss ratio of acid and alkali resistance decreased,dielectric constant decreased,and dielectric loss increased.?2?In addition,the paper as well studied the influence of magnesium aluminum borosilicate glass structure and performance by using BaO to partly replace MgO.The results showed that the structure of magnesium aluminum borosilicate glass were mainly built by [BO₃] trigonal,[AlO₄] tetrahedral,[SiO₄] tetrahedral and [BO₄] tetrahedral.When the BaO was increasingly replaced,the amount of the [BO₄] tetrahedral increased first and then reduced,the amount of the [AlO₄] tetrahedral gradually increased,and network structure became more complete.Devitrification temperature range gradually decreased.while up to 5mol% of BaO was replaced,the samples had no obvious phenomenon of devitrification.When BaO increased,Transition temperature Tg increased gradually.?T increases when more amount of BaO was replaced,crystallization of the glass tended to become smaller.Density showed a trend of gradual increase,but the rate of increase obviously declined;weight loss ratio in acid gradually decreased and weight loss ratio in alkali gradually increased.