Shear thinning behavior of linear polymer melts under shear flow via nonequilibrium molecular dynamics
文献类型：期刊论文
| 作者 | Xu, Xiaolei ; Chen, Jizhong ; An, Lijia |
| 刊名 | journal of chemical physics
 |
| 出版日期 | 2014 |
| 卷号 | 140期号:17页码:5057-5115 |
| 关键词 | INDIVIDUAL RING POLYMERS STEADY SHEAR ENTANGLED POLYMERS POLYETHYLENE MELT RHEOLOGY SIMULATION LIQUIDS PATH VISCOSITY CROSSOVER |
| 通讯作者 | xu,xl |
| 英文摘要 | the properties of both untangled and entangled linear polymer melts under shear flow are studied by nonequilibrium molecular dynamics simulations. the results reveal that the dependence of shear viscosity eta on shear rate (gamma) over dot, expressed by eta similar to (gamma) over dot(-n), exhibits three distinct regimes. the first is the well-known newtonian regime, namely, eta independent of shear rate at small shear rates (gamma) over dot < tau(-1)(0) (where tau(0) is the longest polymer relaxation time at equilibrium). in the non-newtonian regime ((gamma) over dot > tau(-1)(0)), the shear dependence of viscosity exhibits a crossover at a critical shear rate (gamma) over dot(c) dividing this regime into two different regimes, shear thinning regime i (st-i) and ii (st-ii), respectively. in the st-i regime (tau(-1)(0) < (gamma) over dot < (gamma) over dot(c)), the exponent eta increases with increasing chain length n, while in the st-ii regime ((gamma) over dot > (gamma) over dot(c)) a universal power law eta similar to (gamma) over dot(-0.37) is found for considered chain lengths. furthermore, the longer the polymer chain is, the smaller the shear viscosity for a given shear rate in the st-ii regime. the simulation also shows that a characteristic chain length, below which (gamma) over dot(c) will be equal to tau(-1)(0), lies in the interval 30 < n < 50. for all considered chain lengths in the st-ii regime, we also find that the first and second normal stress differences n-1 and n-2 follow power laws of n-1 similar to (gamma) over dot(2/3) and n-2 similar to (gamma) over dot(0.82), respectively; the orientation resistance parameter m(g) follows the relation m(g) similar to (gamma) over dot(0.75) and the tumbling frequency f(tb) similar to follows f(tb) similar to (gamma) over dot(0.75). these results imply that the effects of entanglement on the shear dependences of these properties may be negligible in the st-ii regime. these findings may shed some light on the nature of shear thinning in flexible linear polymer melts. (c) 2014 aip publishing llc. |
| 收录类别 | SCI |
| 语种 | 英语 |
| 公开日期 | 2015-10-27 |
| 源URL | [http://ir.ciac.jl.cn/handle/322003/57386]  |
| 专题 | 长春应用化学研究所_长春应用化学研究所知识产出_期刊论文 |
| 推荐引用方式 GB/T 7714 | Xu, Xiaolei,Chen, Jizhong,An, Lijia. Shear thinning behavior of linear polymer melts under shear flow via nonequilibrium molecular dynamics[J]. journal of chemical physics,2014,140(17):5057-5115. |
| APA | Xu, Xiaolei,Chen, Jizhong,&An, Lijia.(2014).Shear thinning behavior of linear polymer melts under shear flow via nonequilibrium molecular dynamics.journal of chemical physics,140(17),5057-5115. |
| MLA | Xu, Xiaolei,et al."Shear thinning behavior of linear polymer melts under shear flow via nonequilibrium molecular dynamics".journal of chemical physics 140.17(2014):5057-5115. |
入库方式： OAI收割
来源：长春应用化学研究所
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