Ethylene Polymerization over Supported Vanadium-Magnesium Catalysts with Different Vanadium Content: The Effect of Hydrogen on Molecular Weight Characteristics of the Produced Bimodal Polyethylene
, Mikhail Matsko 1, Vladimir Zakharov 1 and Wei Wu 4
Mauro Bassetti
Round 1
Reviewer 1 Report
The article describes the effect of hydrogen pressure on molecular weight distribution of bimodal polyethylene in presence of supported vanadium magnesium catalysts, at different vanadium contents.
The article describes in detail the backgrounds, the methodology and the results, and it is presented in a clear rational manner. It is publishable in the journal with attention to these minor questions.
In the introduction, for instance after first paragraph, it would be instructive to read few comments on the different uses or technological applications of narrow and broad molecular weight distribution of PE.
Lines 242 and 244: should that be… equation (1)?
Lines 332 and 334: should that be…equation (2)?
In material and methods, polymerization section, lines 314-318. A typical polymerization reaction should be described in more detail, including specific amounts (mg, moles etc) of catalyst and cocatalysts or any other reagent, atmosphere, sequence of additions, etc.
In the experimental section, more details should be given on the kinetic analysis, specifically on the equations used to obtain values of rate constants in Table 1 from the experimental data.
In the references, the inclusion of more recent reviews and articles may highlight the current general interest in the subject.
Author Response
Please see the attachment
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The authors present the effect of vanadium content in VMCs on the activity of these catalysts, and the effect of hydrogen on polymerization rate and molecular weight characteristics of the polyethylene produced over two VMC samples with different content of vanadium. The article is interesting but requires some modifications. In my opinion, the scope of the research is not appropriate for the article, but more for the communication and I suggest adapting the article to this type of manuscript. Furthermore, I kindly suggest broadening the introduction part with the known research which is not within the group of authors.
In the results part, I suggest writing about the preparation of the catalyst before discussing the effect of hydrogen on the activity of VMCs with different content of vanadium.
Moreover, is there a possibility to investigate the effect of hydrogen content on the shape of kinetic curves of ethylene polymerization over the “low-loading” VMC (VC1), but within the range 0 and 0.5 bar of hydrogen? I believe those results would be beneficial for further discussion, comparison, and explanation.
With all the comments, I suggest major revision.
Author Response
Please see the attachment
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
The authors took into account all the comments and suggestions and I accept the article to be published.
