The authors dissolved various molecular weights of polyethylene oxide (PEO) in water, either by shaking the containers or by stirring them, in both cases over a period of 4 days. Surprise, surprise, the shaken samples had a higher viscosity than the stirred ones due to the mechanical breakdown in molecular weight of the more aggressive process. This only happened with higher molecular weight materials with 35,000 g/mole being the cut off.
As I said, I was pretty disappointed with the article. This is one of those cases where the results were pretty much expected even if they had never been published. Much like those data on the nonlinear rheology of polystyrene that I posted here a couple of weeks ago. It might not be a completely worthless effort to publish them somewhere but a 12-page article is overkill.
But it is pretty apparent that the referees never looked at the article. Consider this blooper on page 1 of the article:
"The specific chemical structure of PEO, HO − [(CH2)n − O]x −H with n = 2, confers to this polymer very unusual interactions with water. Indeed, while poly(methylene oxide) with n = 1 and poly(butylenes oxide) with n = 3 are both hydrophobic and insoluble in water..."Psst! For n = 3, these would be poly(PROPYL-ene oxides). Oh brother...Thankfully, the quality of the other articles that I am reading is higher.
[*] You are taking advantage of this access, right? It also includes Colloid and Polymer Science,Polymer Bulletin, and Polymer Science Series A
2 comments:
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