导电炭黑及与沥青基碳纤维并用对NBR导电、导热性能的影响

研究了导电炭黑(VXC72)用量及与沥青基短切碳纤维(CF)并用对丁腈橡胶(NBR)的力学性能及导电、导热性能的影响；并用扫描电镜(SEM)观察填料的分散状态,同时考察了双辊开炼机对CF长径比的剪切破破坏程度。结果表明,随VXC72用量的增加,NBR/VXC72硫化胶的拉伸强度、撕裂强度和导热系数基本呈线性增加；体积电阻率呈阶梯形下降,逾渗阈值为25 phr。随VXC72/CF并用比的增大,NBR硫化胶的拉伸强度和撕裂强度明显降低,体积电阻率略有减小,而导热系数有一定程度的增加。填充20 phr CF时,NBR的导热系数较填充VXC72时提高了约30%。混炼使CF的长径比L/D剧烈降低,由原来的600降低到10-20,这也许是CF对NBR体积电阻率降低幅度不大的主要原因。

Effect of conductive carbon black and blending with pitch-base CF on electrical and thermal conductivity of NBR

The mechanical properties, electrical and thermal conductivity of NBR has been investigated against the loading of conductive carbon black (VXC72) and the blending ratio of VXC72 with pitch-based carbon fiber (CF). SEM was employed to observe the filler disperse state in NBR matrix and the influence of double roller mill on L/D of CF by strong shear force. Result shows that with increasing VXC72 loading, tensile strength, tear strength and thermal conductivity of NBR increases almost linearly, volume resistivity of NBR decreases in the form of ladder type, and the percolation threshold is about 25phr. With the ratio of VXC72/CF raising, tensile strength and tear strength of NBR drops evidently, volume resistivity drops marginally, but thermal conductivity increases some extent. thermal conductivity of NBR filled 20 phr CF is higher than that of VXC72 by 30%. Blending sharply reduces the L/D of CF which decreasing from the original 600 to 10-20, that maybe the mainly reason why CF is only little effective in reducing the volume resistivity of NBR.