BN纤维先驱体的合成

SYNTHESIS OF PRECURSOR FOR BN FIBERS

以三聚氰胺和硼酸为原料,用湿化学法合成纤维状先驱体,由氮化制备了BN纤维。确定了合成先驱体的工艺参数。反应物的摩尔比为1∶1、浓度为0.5321mol/L时,反应较为完全。用综合热分析(TGDSC)、红外吸收光谱(IR)、X射线衍射(XRD)、扫描电镜(SEM)对合成的先驱体进行热分析、结构、物相、形貌及成分分析。结果表明:先驱体中含有B,C,N,O,H元素,存在C3H3,—OH,B—O,CN,N—H,C—H,B—N等结构单元;先驱体结晶良好,其形貌为纤维状结构,截面尺寸为2～20μm,长径比为20～100;1700℃保温3h氮化制备的BN纤维截面尺寸为2～10μm,长径比为40～50。

The process for synthesizing the precursor of boron nitride (BN) fibers was studied. The precursor was prepared by a wet chemical approach using melamine (C3N6H6) and boric acid (H3BO3) as starting materials. A better precursor was synthesized by using the molar ratio of 1:1 for the melamine and boric acid and the solution concentration of 0.5321 mol/L for the reactants. The synthesized product was analyzed by means of TG-DSC, IR, XRD, SEM, etc. The results show that the precursor consists of elements of B, C, N, O, H, which mainly form the structural units of C3N3, B-O, C=N, N-H, C-H, B-N, -OH. The synthesized precursor is long-pillared fibers with the cross section dimension of 2-20 μm and the length/diameter ratio of 20-100. BN fibers prepared by nitridation at 1700°C for 3 h have diameter of 2-10 μm and length/diameter ratio of 30-40.