超临界条件制备有机小分子接枝纳米炭黑及其对橡胶的补强作用

Preparation of Nano-Carbon Black Particles by Grafted with Small Organic Molecule in Supercritical CO_2 and Its Reinforcing Effect to Rubber

在超临界CO2流体中,用有机小分子(AO-80)对炭黑(CB)进行表面接枝,制备了有机小分子接枝的纳米炭黑粒子。红外分析表明:改性炭黑具有AO-80的分子结构特征,表明AO-80成功地接枝到炭黑表面,用TGA测得的接枝率为0.8%。粒径分析和透射电镜观察结果显示,与原始炭黑相比,改性炭黑的粒径明显减小,粒径分布变窄。将接枝炭黑(SCB)添加到苯乙烯-丁二烯-苯乙烯三嵌段共聚物(SBS)中,发现SCB对SBS具有明显的补强效果。SCB加入量为0.2%时,SBS/SCB的拉断伸长率由1039%(纯SBS)提高到1297%,提高了25%,而拉伸强度则由11.9 MPa(纯SBS)提高到14.6 MPa,提高了19%。

The modified nano-earbon black was prepared by grafting reaction with small organic molecule in supercritical carbon dioxide （scCO2）. The IR spectrum of the grafted carbon black exhibited some characteristics of AO-80 molecule, and that was indicated that AO-80 was successfully grafted on the surface of carbon black. The grafting degree of the AO-80 on the carbon black, determined by thermogravimetric analysis （TGA）, was about 0.8%. The particle sizes of the unmodified and the modified carbon blacks were analyzed by dynamic light scattering （DLS） and observed by TEM, it was shown that the modified carbon black （SCB） possessed a smaller average size and a narrower distribution compared with unmodified carbon black. The composites of styrene--butadiene-styrene triblock copolymer （SBS） with SCB or CB were prepared by solvent casting, and it was found that the mechanical properties of the composite were greatly improved with addition of 0.2% SCB, the elongation at break of the SCB/SBS increased 25% and the tensile strength increased 19% compared with that of pure SBS.