采用5%(wt,质量分数,下同)含氟苯并口恶嗪(BAF-a)与氰酸酯树脂(CE)进行共聚,得到黄色不透明粘稠状的改性树脂BAF-a/CE。实验结果表明,浇铸体BAF-a/CE的加工窗口比CE树脂更宽,BAF-a的加入减小了CE树脂的固化收缩,并提高了其弯曲强度;BAF-a/CE的介电常数为2.9,Td5为391℃,玻璃化转变温度(Tg)为257℃。通过向BAF-a/CE树脂基体中添加10%的氮化硼(BN)颗粒制备了BN填充的复合材料BN/BAF-a/CE,相对于纯CE树脂[导热系数为0.197W/(m·K)],复合材料的导热系数提高80%,为0.354W/(m·K),Tg升高至265℃,并且BN的加入并未降低CE树脂的弯曲强度。扫描电镜测试结果显示,BN/BAF-a/CE复合材料为致密的均相结构,断面呈现韧性断裂。本研究在保证复合材料介电性能的基础上,减小了其固化收缩率,提高了力学性能和导热性能,研制了改性氰酸酯树脂体系。
5%wt fluorinated benzoxazines (BAF-a) were used to copolymerize with cyanante ester (CE),obtaining a yellow opaque viscous resin (BAF-a/CE).The results shown that the processing window of BAF-a/CE was wider than that of CE resin.Meanwhile,the addition of BAF-a reduced the cure shrinkage of CE resin,and increased the flexural strength of CE resin.The dielectric constant of BAF-a/CE was 2.9,the Td5 was 391℃,and the glass transition temperature (Tg) was 257℃.BN-filled composite (BN/BAF-a/CE) was prepared by adding 10wt% of boron nitride (BN) particles to the BAF-a/CE matrix.Compared with the pure CE with the λ of 0.197W/(m·K),the thermal conductivity of BN/BAF-a/CE composites was increased by 80% to 0.354W/(m·K),and Tg was increased to 265℃.Moreover,the addition of BN did not reduce the flexural strength of CE resin.It can be seen from SEM that the composites was dense homogeneous structure and exhibited ductile fracture.Therefore,on the basis of ensuring the dielectric properties of the composites,the curing shrinkage was reduced,the mechanical properties and thermal conductivity were improved,and the modified cyanate resin system was prepared.
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