The Effects of Some Phosphorus-Containing Fire Retardants on the Properties of Glass Fibre-Reinforced Composite Laminates Made from Blends of Unsaturated Polyester and Phenolic Resins

Round 1

Reviewer 1 Report

The paper is written in a clear manner. The topics are as relevant as possible. The authors have described the research issue well. In order to publish the paper, I recommend addressing a few minor comments:

1. In the introduction, please demonstrate the novelty of this paper in relation to other similar thematic research papers.
2. Given the topic on research on GFRP composites, I recommend strengthening the introduction section with work: 10.1016/j.compstruct.2018.09.005.
3. There is no standardized notation font between equations 1 and 2. Please ensure that all equations are written in the same font.
4. Conclusions should clearly show the qualitative and quantitative assessment of the research - please complete the conclusions.

Author Response

See attached file

Author Response File: Author Response.docx

Reviewer 2 Report

The manuscript described the effects of phosphorus fire retardants (FRs) in matrices from 9 co-cured blends of an unsaturated polyester (UP) with inherently fire-retardant phenolic resin (PH) on the mechanical and flammability properties of resultant glass fiber-reinforced composites. The manuscript introduction provides an adequate foundation for the work done. The experiment, results, and discussion were well presented. The paper can be published in the MDPI journal of composites Science after the authors address these few concerns. 

1. Figure 3. Why did the author decide to use digital microscopic images of GFRC samples after cone experiments? SEM micrographs would have given  clearer images to buttress the claims made in the manuscript
2. Evidence of the fire retardants acting as plasticizers in the systems has not been sufficiently evidenced. 
3. The authors stated that the fire-retardant action of the FR additives involves both gas-phase and condensed-phase actions in UP/PH-Ep and UP/PH-Al as indicated by increased yields of both smoke and char on combustion. This statement ought to be supported by evidence of char yield and other tests if possible. For Instance TG-IR. 
4. Alternatively, kindly provide an illustrative diagram of the flame retardant mechanism for each FR used thus RDP and DOPO GFRC UP composites.
5. Kindly check the few instances of plagiarised text and edit appropriately.

 

Author Response

See attached file

Author Response File: Author Response.docx