SiO_2-A1_2O_3-MgO玻璃纤维结构与性能-MgO/(Li_2O+B_2O_3)的影响

The Structure and Properties of SiO_2-A1_2O_3-MgO Glass Fibers-Influence of MgO/( Li_2O + B_2O_3)

以不同含量的氧化锂、氧化硼、氧化镁成分的SiO_2-A1_2O_3-MgO高强(HS)玻璃为研究对象,测试了HS玻璃纤维密度、纤维新生态强度和模量,以及浸胶纱的拉伸强度和模量。采用高温粘度旋转仪、梯度炉以及红外光谱(IR)、核磁共振(NMR)等方法,研究了玻璃中不同比例的MgO/(Li_2O+B2O3)对高强玻璃结构和性能的影响。玻璃成分中SiO_2和Al_2O_3含量相近,增大Li_2O和B2O3含量替代MgO含量可以使玻璃的低温粘度和液相温度均降低,而增加MgO含量则提高了离子堆积密度和玻璃纤维的模量。红外光谱及核磁共振分析表明,HS高强玻璃的结构主要由硅氧四面体[SiO_4]和铝氧四面体[AlO_4]构成。在玻璃结构中,增加Li_2O和B2O3含量可提供的游离氧可使更多的Al^(3+)形成[AlO_4]而进入玻璃网络。相应地,增加MgO含量,提高MgO/(Li_2O+B_2O_3)比例,增加了网络断键和无序度,但增大了断网间的集合程度,有利于玻璃模量的提升。研究表明提高玻璃中SiO_2含量或在玻璃中加入Li_2O,有利于SiO_2-A12O3-MgO系统玻璃纤维强度的提升。

Based on the compositions of HS high strength glass fibers with different Li2O, B2O3 and MgO contents, the density of HS glass fibers, the strength and modulus of virgin fibers and resin-impregnated strands were tested. The influence of adjusted ratio of MgO/（ Li2O ＋ B2O3 ）on the structure and properties of HS glass fibers were investigated by means of rotating crucible viscometer, gradient furnace, IR and MNR. In case of similar contents of SiO2 and Al2O3 in HS glass, increasing the contents of B2O3 and Li2O substitute for MgO could decrease the glass viscosity at lower temperature and liquid temperature of glass,while increasing MgO content would promote the enhancement of ionic packing factor and glass fiber modulus. IR and NMR analyses showed that the HS glass structure was mainly composed of tetrahedron [ SiO4 ] and tetrahedral [ AlO4 ]. Decreasing MgO/（ Li2O ＋ B2O3 ） ratio could increase free oxygen content and make more Al^3＋ form [ AlO4 ] and enter the glass network. In contrast, increasing the MgO/（ Li2O ＋ B2O3 ） ratio could increase broken-bonds and make network disorder, but increase the degree of aggregation between networks. Increasing the content of SiO2 or Li2O in glass was beneficial to enhance the strength of SiO2-Al2O3-MgO glass fibers.