张曦
,
郑亚萍
,
兰岚
,
杨海成
新型炭材料
采用3-硅羟基-1-丙基磺酸(SIT8378.3)和聚氧乙烯十八烷基胺(Ethomeen18/25)在酸化多壁纳米碳管表面上生成长链壳层，相当于“溶剂”，使碳纳米管在没有溶剂时，损耗模量G″高于储能模量G′，具有流体特性。结果表明，长链分子接枝于碳纳米管表面使碳纳米管的直径增大，碳纳米管质量分数为16.03%。碳纳米管在去离子水中稳定分散，渗流阈值为5 mg/g。
关键词:
碳纳米管
,
无溶剂纳米流体
,
固-液转变
,
流变性能
石佩洛
,
梁洪涛
,
白雪莲
,
臧千
,
阙伟婧
宇航材料工艺
doi:10.3969/j.issn.1007-2330.2016.06.016
针对复合材料预浸料工艺性缺少可量化表征方法的现状,研究了4种C/E预浸料的黏性及其环氧树脂体系的物理特性.发现预浸料黏性可以通过环氧树脂体系动态复数黏度η*和Tg两个物理量表征,环氧树脂的η*=35 kPa·s附近,T=0℃附近预浸料黏性较为合适.
关键词:
预浸料
,
黏性
,
流变
,
玻璃化转变
Guimei WANG
,
Xigao JIAN
,
Gongxiong LIAO
,
Lihao WU
材料科学技术（英文）
Poly (phthalazinone ether sulfone ketone) (PPESK) was melt blended with bisphenol-A polysulfone oligomer (O-PSF) to produce a thermoplastic polymer blends. The miscibility, thermal stability, rheological and mechanical properties of the blends were investigated by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and capillary rheometry. The blends showed single Tg over the composition range and possess homogeneous microstructure. The addition of O-PSF slightly affected the thermal properties of the blends. PSF oligomer, as a processing aid, could markedly improve the processability of the PPESK. In addition, the mechanical properties of the blends were increased, to some degree, by adding O-PSF.
关键词:
PPESK
,
null
,
null
,
null
,
null
,
null
Wen LIU
材料科学技术（英文）
The energy dissipation caused by the viscous force has great effects on the flow property of semi-solid metal during rheological processes such as slurry preparing, delivering and cavity filling. Experimental results in this paper indicate that the viscous friction between semi-solid metal and pipe wall, the collisions among the solid particles, and the liquid flow around particles are the three main types of energy dissipation. On the basis of the hydromechanics, the energy dissipation calculation model is built. It is demonstrated that the micro-structural parameters such as effective solid fraction, particle size and shape, and flow parameters such as the mean velocity, the fluctuant velocity of particles and the relative velocity between the fluid and solid phase, affect the energy dissipation of semi-solid metal.PartⅡ：This study investigates the rheological behavior of semi-solid metal. An analytical model of apparent viscosity was built up based on analysis of energy dissipation during rheological processes such as slurry preparing, delivering and model filling. The rheological behavior of SSM slurries was described by an analytical model in terms of micro structural parameters, which consist of effective solid fraction, particle size and shape, and flow parameters such as mean velocity, fluctuation velocity and relative velocity between liquid and solid phase. The model was verified in the experiment of A356 alloys with a coaxial double-bucket rheometer. And the maximum relative error between the theoretical value and measured value is less than 10%. The results of experiment and theoretical calculation also indicate that the micro structural parameters and flow parameters are two major factors that affect the apparent viscosity of semi-solid alloys, and fluctuation velocity and relative velocity between liquid and solid phase are the key factors to distinguish between steady and transient rheological behaviors.
关键词:
Semi-solid metal
,
能量耗散
,
流变
,
表观粘度
,
模型
Xiaoli WANG
,
Lucun GUO
材料科学技术（英文）
The relationship between processing route and suspension stability in ZrO2-H2O-PANH4 system was investigated through rheology study. The work showed that two suspensions with identical PANH4 concentration and final solution condition but prepared by different routes differed greatly in stability. This behavior is attributed to their different distribution state of PANH4 on ZrO2 surface that is determined by the adsorption affinity depending on pH condition in solution. High affinity at pH 5.0 induces a nonuniform distribution of soluble PAA－ (polyacrylicacid) on particle surface, which can flocculate the suspension strongly, while low affinity at pH 9.0 induces an uniform distribution of polymer so that the higher stabilization can be achieved. A simple mathematical model was used to account for the observed results.
关键词:
Zirconia
,
制备途径
,
稳定性
,
流变性
