聚合物分子量对润滑颗粒-颗粒相互作用的依赖性,Industrial & Engineering Chemistry Research

当前位置： X-MOL 学术 › Ind. Eng. Chem. Res. › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

聚合物分子量对润滑颗粒-颗粒相互作用的依赖性
Industrial & Engineering Chemistry Research ( IF 3.8 ) Pub Date : 2018-01-30 00:00:00 , DOI: 10.1021/acs.iecr.7b04609
Kai Yu ₁ , Chris Hodges ₁ , Simon Biggs ₂ , Olivier J. Cayre ₁ , David Harbottle ₁

Affiliation

使用水溶性聚合物的超薄表面涂层来改善界面摩擦是相对较新的技术，但是在使用明显较低的聚合物浓度的同时，可以提供形成有益涂层的途径。在当前的研究中，二氧化硅表面是通过水溶液中聚乙烯吡咯烷酮（PVP）的物理吸附而改性的。在此检查了四个分子量从8到1300 kDa不等的聚合物样品。光反射率测量表明，每个PVP样品的饱和表面过量量约为1 mg / m ^2。。发现在8 kDa PVP膜（〜10 wt％）中的被捕集的水量比由较高分子量PVP（40、360和1300 kDa）形成的膜中的被捕集的水（40–55 wt％）要少得多。）。此外，8 kDa PVP膜的QCM耗散值比高分子量PVP的QCM耗散值小四倍以上，这表明8 kDa PVP符合平坦膜（主要是取向），而高分子量PVP缓慢地重组，导致更多的有损薄膜（增加了Sauerbrey薄膜的厚度）。胶体探针AFM横向力测量表明，8 kDa PVP薄膜的横向阻力与水中未涂覆的二氧化硅表面所观察到的相似，而更高分子量的PVP薄膜则显示出明显减小的横向力。这种润滑效果，通过测量浓缩颗粒悬浮液的流变性，进一步探索了由吸附的较高分子量PVP样品引起的碳纳米管的形成。当悬浮液浓度高于60 vol％（即接近球体的密堆积极限）时，与未涂覆的颗粒相比，PVP涂覆的颗粒的悬浮屈服应力数据显示屈服应力降低了2倍。

"点击查看英文标题和摘要"

Polymer Molecular Weight Dependence on Lubricating Particle–Particle Interactions

Using ultrathin surface coatings of water-soluble polymers to modify interfacial friction is relatively new, but may offer routes to form beneficial coatings while using significantly lower polymer concentrations. In the current study, silica surfaces were modified by the physisorption of poly(vinylpyrrolidone) (PVP) from water solution. Four polymer samples with different molecular weights, ranging from 8 to 1300 kDa, were examined here. Optical reflectivity measurements showed that the saturated surface excess for each PVP sample was ∼1 mg/m². The amount of trapped water within the 8 kDa PVP film (∼10 wt %) was found to be much less than the trapped water (40–55 wt %) in films formed from higher molecular weight PVPs (40, 360, and 1300 kDa). In addition, QCM dissipation values for the 8 kDa PVP film was more than four times smaller than those measured for the higher molecular weight PVPs, suggesting that the 8 kDa PVP conforms to a flat film (predominantly train orientation), whereas the high molecular weight PVPs slowly reorganize resulting in more lossy films (increased Sauerbrey film thickness). Colloid-probe AFM lateral force measurements showed that 8 kDa PVP films exhibited similar lateral resistance to that seen for uncoated silica surfaces in water, whereas higher molecular weight PVP films showed significantly reduced lateral forces. This lubrication effect, induced by the adsorbed higher molecular weight PVP samples was explored further by measuring the rheology of concentrated particle suspensions. Suspension yield stress data for PVP-coated particles showed a reduction by a factor of 2 in the yield stress when compared to the uncoated particles for suspension concentrations above 60 vol %, i.e., approaching the close-packed limit of spheres.

更新日期：2018-01-30

点击分享查看原文

点击收藏

公开下载

阅读更多本刊新发论文本刊介绍/投稿指南