摘要
研究了高残炭率硼酚醛 (mass>70 % )炭化时的线性收缩率及PAN基炭布增强酚醛层压板复合材料的自由热应变。结果表明 ,硼酚醛在 430℃以前是膨胀行为 ,在 2 80℃达到最大膨胀量 1.8% ,在 80 0℃线性收缩率达 11.3%。炭布增强酚醛层压板两个方向在 5 70～ 5 80℃之间是零膨胀零应变 ,较纯酚醛推迟 140℃左右。在面内 (X—Y向 ) ,在 2 2 0～ 5 0 0℃是一个膨胀平台 ,最大自由热应变是 0 .15 % ;10 0 0℃最大自由热应变是 -0 .2 0 6 %。而在厚度方向 (Z向 ) 4 5 0℃达到 4.6 1%的最大正自由热应变 ,是X—Y向的 31倍 ;10 0 0℃最大自由热应变是 - 2 .34 % ,是X—Y向的 13倍。二维炭 /酚醛复合材料在炭化时的各向异性收缩 ,将导致在材料中产生高的热应力 。
The linear contraction ratio of high char yield boron contained phenolics(mass>70%) and PAN based carbon fabrics reinforced phenolics laminates during carbonization are studied and discussed. Before 430 ℃ boron phenolics shows expansive behavior and reaches the maximum linear expansion ratio of 1.8% at 280 ℃; the linear contraction ratio is up to 11.3% at 800 ℃. The carbon fabrics reinforced phenolics composites shows zero free thermal strain at 570 ℃ or so in both X-Y and Z directions, which is about 140 ℃ lower than non reinforced phenolic resin is. In X-Y direction a expansive flat is occurred between 220 ℃ and 580 ℃, the maximum free thermal strain is 0.15%; at 1 000 ℃ it emerges the negative maximum free thermal strain of -0.206%. While through the thickness(Z direction), at 450 ℃ it reaches the positive maximum free thermal strain of 4.61%, 31 times bigger than that in X-Y direction; at 1 000 ℃ the negative maximum free thermal strain is -2.34%, 13 times bigger than that in X-Y direction. The anisotropic shrinkage of 2 directional carbon fabric reinforced phenolics composites during carbonization would result in high thermal stress in composites, which possibly leads to delamination.
出处
《炭素技术》
CAS
CSCD
2001年第5期14-16,共3页
Carbon Techniques
