双氧水对镁系无机泡沫材料性能和孔结构的影响

Effect of Hydrogen Peroxide on Properties and Pore Structure of Magnesium Inorganic Foam Materials

以镁系胶凝材料为基体,双氧水为发泡剂,采用化学发泡工艺制备了内部含有大量密闭气孔的镁系无机泡沫材料。研究了双氧水添加量对泡沫材料发泡倍率、体积密度、压缩强度、弯曲强度、孔结构参数以及导热系数的影响。研究结果表明:双氧水添加量增加,导致胶凝体中的气泡核增加以及气泡生长的内动力增大,气孔孔径变大,体积密度和力学强度减小;随着双氧水添加量增加,材料的导热系数不断减小,在双氧水添加量大于16‰时增大。镁系无机泡沫材料的压缩强度和弯曲强度与体积密度的回归方程分别为y=-6.06+24.19x,y=-0.64+3.82x,均为密切线性相关关系。且在双氧水添加量为8‰时泡沫材料取得最大力学强度,此时气孔孔径最小,孔结构参数较优,导热系数为0.071 W/(m·K),体积密度仅为0.54g/cm3。

Magnesium inorganic foam materials with a large number of closed pores were prepared by chemical foaming process using magnesium cementitious materials as matrix and hydrogen peroxide as foaming agent.The effects of addictive amount of hydrogen peroxide on the foaming ratio,bulk density,compressive strength,bending strength,pore structure parameters and thermal conductivity of foam materials were studied.The results demonstrated that the addition of hydrogen peroxide increased,the bubble nuclei in the slurry increased,and the internal force of the bubble growth increased,which made the pore diameter become larger and the bulk density and mechanical strength reduced.Furthermore,the thermal conductivity decreased,and then increased when the addictive amount of hydrogen peroxide was lager than 16‰.Regression equations of the compressive strength,flexural strength with bulk density of the magnesium inorganic foam materials are y=-6.06+24.19 x,y=-0.64+3.82 x,respectively,which are closely linear correlations.When the addictive amount of hydrogen peroxide was 8‰,the maximum mechanical strength was obtained.At this time,the pore diameter was the smallest,the pore structure parameter was better,the thermal conductivity was 0.071 W/(m·K)and the bulk density was only 0.54 g/cm 3.