The Effect of Molecular Weight on the (Re)-Processability and Material Properties of Bio-Based, Thermoreversibly Cross-Linked Polyesters

Round 1

Reviewer 1 Report

Beljaars et al. investigate the molecular weight effect of thermoreversibly crosslinked PE-fur (furan-functionalised) polyester, which reacted with bismaleimide via Diels-Alder reaction. This is interesting topic, but I found there are some problems. Those problems were list as follows: 

1. I suggest that authors pay particular attention to the quality of manuscript. For example:"...them are strong indications for the presence of__short-chain polyesters.." (line 202); "The stiffness of the polymers generaly decreases for with the crosslink densitiy (line 324)" should be "The stiffness of the polymers generaly decreases with decreasing the crosslink densitiy"; "The coupling (DA) and decoupling (RDA) temperatures for the furan maleimide pair... (line 73)" should be "The coupling (DA) and decoupling (rDA) temperatures for the furan maleimide pair... ". (RDA or rDA) 

2. I suggest that the authors provide diagrammatic scheme of the crosslinked PE-fur/Bism chemical structure for better understanding.
 
3. I suggest that the authors provide chemical structure scheme of the DA adducts (PE-fur/Bism) with endo/exo conformations chemical structure for better understanding.

4. The authors should provide the reaction conduction or figure caption for the Bath1, Bath2, Bath3, Bath4, and Bath5 in Figure 2.

5. The authors should provide more clearly DSC curves in Figure 3, especially which curve is heating trace, which curve is cooling trace, and the sequence of DSC cycles.  

6. Why did the transition of DA adducts from the endo to the exo conformation look like a step in the heat capacity curve at the glass transition? There are no endothermic peaks or exothermic peaks in Figure 3. It requires authors' more detail interpretation.

7. I suggest that the authors should provide the Table of the DA and rDA shifted temperature via DSC and DMTA. 

8. The authors' state (line 351): "Analysis of the reprocessed material still indicated no impurities."
 The authors should provide the NMR or FTIR evidences.

In conclusion, major modifications and detailed discussions will be required.

Author Response

please see attachment

Author Response File: Author Response.pdf

Reviewer 2 Report

Very interesting project relating to the preparation and characterization of a partially bio-based short-chain polyester through interfacial polycondensation of furan-functionalized diphenolic acid with terephthalic chloride, for incorporation in a polymeric system in order to introduce thermoreversible crosslinking.

Overall, the paper is well written and contains important information about the subject addressed. The analysis is clearly presented and all the sections (including the Discussion and Conclusion sections) are rather interesting and seem to be quite thorough.

In my opinion only a few corrections should be done:

The Abstract should be clearer in terms of the general objectives of the work (polycondenzation?).

Improve the quality of Figure 3.

Correct the formatting of the References list (Ref. 18 seems incomplete).

Author Response

please see attachment

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

After carefully reading line by line of the revised paper, there are still some problems. Those problems are list as follows: 

1. The authors should provide the high resolution version of DSC curves in Figure 3.

2. The authors should provide the range of the DA and rDA shifted temperature via DSC and DMTA.

In conclusion, minor modifications and detailed discussions will be required. 

Author Response

We would like to thank the reviewer for his/her suggestions.

1) We increased the resolution of the DSC figures and provided the editor with alternative version as to make these pictures as clear as possible.

2) a Table with DSC and DTA temperatures has been added to the SI and a short discussion on this added to the main text.