硼及其团聚颗粒在HTPB中流变性能研究

Effect of boron powder and agglomerated boron particles on the rheological property of HTPB

采用MiniLab微型双螺杆流变仪,对高固含量的硼粉/端羟基聚丁二烯（B/HTPB）、团聚硼/端羟基聚丁二烯（TB/HTPB）混合体系高剪切速率范围时的粘-切依赖性、粘-温依赖性及粘流活化能进行分析研究。结果表明,剪切速率分别为70～142、142～320、320～533 s^-1时,B/HTPB体系为胀流体,随剪切速率增大而胀流性减弱,流动指数分别为2.03、1.31、1.10;温度由25℃升至40℃时,B/HTPB体系粘度急剧升高,在剪切速率为142～320 s^-1时为Herschel-Bulkley流体,剪切速率为70～142 s^-1和320～533 s^-1时流动方程则符合Ostwald-de Wale幂律方程。对于TB/HTPB体系,70～320 s^-1时,其为胀流体,而剪切速率达到320～533 s^-1时,体系则呈牛顿流体;与B/HTPB相反,体系粘度随温度升高而减小;体系恒切速率活化能随剪切速率增大而减小,恒切应力活化能恒定不变,约为0.286 kJ/mol;相同测试条件下,TB/HTPB体系粘度较B/HTPB体系大大降低;与B/HTPB体系相同,在剪切速率为142～320 s^-1时,TB/HTPB体系也为Herschel-Bulkley流体,在剪切速率为70～142 s^-1和320～533 s^-1时,流动方程符合Ostwald-de Wale幂律方程。

The rheological properties of HTPB filled with boron powder / agglomerated boron particles were carefully investigated with MiniLab micro-rheology compounder. The dependences of temperature and shear rate on viscosity of B（TB） /HTPB slurries were obtained and the viscous flow activation energy was analyzed. The results show that B /HTPB slurry presents shear-thickening property in shear-rate range of 70 ～ 142,142 ～ 320 and 320 ～ 533 s^- 1,and the flow exponent of the slurry decreases from2. 03 to 1. 10 with the increasing of shear rate. The viscosity of B /HTPB rises sharply as temperature increases from 25 ℃ to 40℃. The rheological models of B /HTPB slurry accords with the Herschel-Bulkley Equation when the shear rate is 142 ～ 320 s^- 1,while the relation of shear rate with stress conforms with the Ostwald-de Wale Equation in the shear-rate range of 70 ～ 142 s^-1 and 320 ～ 533 s^-1. For the sample of TB /HTPB,the slurry belongs to dilatant fluid under the shear-rate range of 70 ～ 320 s^-1 and behaves as a Newtonian fluid when the shear-rate ranges from 320 s^-1 to 533 s^-1. Contrary to B /HTPB,the viscosity of TB /HTPB decreases as the temperature increases. The activation energy（Eγ·η） of TB/HTPB decreases and the activation energy（Eση） of that is kept stably at about 0. 286 kJ /mol as the shear rises. Under the same conditions,the rheological property of B /HTPB slurry could be significantly improved by agglomerated boron. The rheological models of TB /HTPB slurry are similar to that of B /HTPB,the relation of shear rate with stress conforms with Herschel-Bulkley Equation when the shear rate is 142 ～ 320 s^-1,while accords with Ostwald-de Wale Equation in the shear-rate range of 70 ～ 142 s^-1 and 320 ～ 533 s^-1.