竹浆纤维/水化硅酸镁复合材料制备及性能研究

Preparation and Properties of Hydrated Magnesium Silicate Composites Reinforced with Bamboo Fibers

采用抄取法制备竹浆纤维素纤维/水化硅酸镁复合材料,研究纤维掺量对复合材料物理和力学性能的影响。通过干湿循环加速老化试验评估纤维素纤维在水化硅酸镁基体中的长期稳定性,并对复合材料孔隙溶液pH值进行了测定。结果表明,随着纤维掺量的增加,复合材料密度逐渐降低,吸水率和气孔率逐渐升高,抗弯强度和断裂韧性明显改善。纤维掺量为4%~16%时,28 d抗弯强度较未添加时提高5.4~10.9倍,断裂韧性提高31~228倍。基体孔隙溶液pH值在9.63~9.85范围,老化试验后,复合材料力学性能几乎不受影响,纤维在硅酸镁基体中长期稳定性好,无劣化和降解迹象。

In this paper,bamboo cellulosic fibers reinforced hydrated magnesium silicate-based composites were prepared by a slurry vacuum de-watering technique,and the effect of fiber content on the physical and mechanical properties of the composite was studied.In addition,the longterm stability of cellulosic fiber in the hydrated magnesium silicate matrix was evaluated by the accelerated aging test of wetting and drying cycles,and the pH value of the pore solution of the composite materials was determined.The results showed that with the increase of cellulosic fiber content,the porosity and water absorption of the composites increased gradually,while the bulk density decreased.Moreover,the addition of bamboo cellulosic fibers obviously improved the flexural strength and fracture toughness of the composites.With fiber contents ranging from 4%to 16%by weight,the measurements of the flexural strength and the fracture toughness of 28 d increased by 5.4-10.9 and 31-228 times,respectively.The pH value of the matrix pore solution is between 9.63-9.85.Additionally,the increasing aging test almost has no effect on the mechanical properties of the composite materials,and the bamboo cellulosic fibers can maintain good stability in the magnesium silicate hydrate for a long time.