摘要
在液体燃料中添加高能固体硼粉是提高燃料能量密度的一种有效途径,但未经修饰的硼粉会急剧加大液体燃料体系的表观黏度,因而提高硼粉添加量的同时防止表观黏度的急剧增大,是当前固液复合燃料亟需解决的问题。为此,研究采用4种有机硅烷(丙基三甲氧基硅烷、辛基三甲氧基硅烷、十二烷基三甲氧基硅烷和十六烷基三甲氧基硅烷)对硼粉进行表面修饰,并通过扫描电镜(SEM)、接触角测定、X射线衍射(XRD)、动态激光散射(DLS)粒径分析、热重(TG)等对其进行了表征,研究了有机硅烷修饰硼/JP‑10复合燃料的流变性能,考察了温度对有机硅烷修饰硼/JP‑10复合燃料流变性能的影响。结果表明:有机硅烷修饰可去除硼粉表面的硼酸,硼粉表面特性从亲水性转变为疏水性;修饰硼中有机硅烷的含量低于1.5%,对硼粉热值影响不大;有机硅烷修饰硼添加到JP‑10燃料中,当硼含量高达50%时,在25℃、剪切速率为100 s-1的条件下,表观黏度低于0.3 Pa·s,具有良好的流动性。在其它条件相同的情况下,复合燃料表观黏度大小与有机硅烷侧链烷基长短有关:丙基>辛基≈十二烷基≈十六烷基。有机硅烷修饰硼/JP‑10复合燃料具有剪切变稀的特性,表观黏度与剪切速率之间的定量关系符合幂律型方程。温度对有机硅烷修饰硼/JP‑10复合燃料的表观黏度有显著影响,两者的定量关系符合阿伦尼乌斯方程,且剪切活化能随有机硅烷侧链烷基长度的增加而增大。
Addition of high energy boron into the liquid fuel is an effective method to improve the energy density of the blended fuel.However,the added content of boron is limited,due to the dramatic increase in the viscosity of the blended fuel.So it is im‑portant to increase the boron content as much as possible without obvious viscosity increase.Four organosilanes including prop‑yltrimethoxysilane(C3‑silane),octyltrimethoxysilane(C8‑silane),dodecyltrimethoxysilane(C12‑silane)and hexadecyltrime‑thoxysilanes(C16‑silane)were used to modify boron particles.First,the modified boron particles were characterized by scan‑ning electron microscopy,contact angle measurement,X‑ray diffraction,particle size analysis(using dynamic laser scattering)and thermogravimetric analysis.Then the rheological properties of organosilane modified boron/JP‑10 blend fuels were investigat‑ed.Finally,the effect of temperature on the apparent viscosities at different shear rates was studied.The results show that boric acid on the boron surface was removed upon surface modification with organosilanes and the surface characteristics of boron powder were transformed from hydrophilicity to hydrophobicity.The content of organosilane was less than 1.5%in the organosi‑lane modified boron particles,which would have marginal effect on the total heat value.Organosilane modified boron/JP‑10 blend fuels with solids content of 50%showed good fluidity and their apparent viscosities were lower than 0.3 Pa·s at 25℃and 100 s-1 of shear rate.Keeping other conditions the same,the apparent viscosity of blend fuels depends on the length of side chain alkyl group of organosilane:C3‑silane>C8‑silane≈C12‑silane≈C16‑silane.Organosilane modified boron/JP‑10 blend fuels showed shear‑thinning characteristics and the relationship between the apparent viscosity and the shear rate could be well fitted by power‑law equation.The apparent viscosity of blend fuels depends strongly on the temperature and their relationship could be well expressed by Arrhenius equation.The shear activation energy of blend fuels increases with increasing the length of side chain alkyl group of organosilane coated on the boron.
作者
杜歆旖
厉刚
Du Xin-yi;LI Gang(Department of Chemistry,Zhejiang University,Hangzhou 310027,China;Center of Chemistry for Frontier Technologies,Zhejiang University,Hangzhou 310027,China)
出处
《含能材料》
EI
CAS
CSCD
北大核心
2022年第12期1205-1212,共8页
Chinese Journal of Energetic Materials
基金
航天科技创新基金资助(CASC201603)。
关键词
硼粉
有机硅烷
表观黏度
疏水性
流变性能
boron
organosilane
apparent viscosity
hydrophobicity
rheological properties
