Kinetics of PTSA-Catalysed Polycondensation of Citric Acid with 1,3-Propanediol

Round 1

Reviewer 1 Report

The manuscript “Kinetics of PTSA-catalysed Polycondensation of Citric Acid with 1,3-Propanediol” provides extensive study on spectral analysis as well as the kinetic model of elementary reactions of described polycondensation. Also, the gel point was determined as a function of temperature and reaction time.

The Authors noted in the manuscript the lack of information in the literature of poly(1,3-propanediol citrate), in regarding to its biomedical application. Thus, the novelty of this manuscript should be a synthesis and spectral analysis of the new material poly(1,3-propanediol citrate). Nevertheless, the concept of preparation of citric acid esters is already known and described in literature, with the variation of selected diols used in polycondensation reactions, including propanediol, as it was presented in following references:

1.    Tran, R. T., Yang, J., & Ameer, G. A. (2015). Citrate-Based Biomaterials and Their Applications in Regenerative Engineering. Annual Review of Materials Research, 45(1), 277–310. doi:10.1146/annurev-matsci-070214-020815 

2.     Lei, L., Ding, T., Shi, R., Liu, Q., Zhang, L., Chen, D., & Tian, W. (2007). Synthesis, characterization and in vitro degradation of a novel degradable poly((1,2-propanediol-sebacate)-citrate) bioelastomer. Polymer Degradation and Stability, 92(3), 389–396. doi:10.1016/j.polymdegradstab.2006.12.004 

3. Li, J., Zheng, W., Pan, P., Sun, X., & Zhang, Y. (2014). Synthesis and Characterization of Poly(1,2-propanediol-co-1,8-octanediol-co-citrate) Biodegradable Elastomers for Tissue Engineering. Bio-Medical Materials and Engineering, 24(1), 619–624. doi:10.3233/bme-130849. 

As this synthesized ester of citric acid is aimed for biomedical application, the manuscript should include some further investigations on adequate physicochemical properties, such as mechanical properties, degradation, swelling and other, as well as some biological tests (antimicrobial activity, biocompatibility etc.).

Author Response

[poniedziałek 10:33] Bandzerewicz Aleksandra (DOKT)

The introduction further indicates the differences between the described polyester and previous literature reports on similar polymers. In the "conclusions" section, the potential use of poly(1,3-propanediol citrate) as a potential biomaterial and the benefits of the described model is further indicated. Please note that the research presented is extensive and concerns preliminary analyses of the described polymer. The described kinetic, and gelation model will allow easier processing of the obtained polymer to produce cellular scaffolds. Physicochemical and mechanical properties, biocompatibility, etc. will be the subject of further studies.

Reviewer 2 Report

Based on the reviewed of all the content in this paper, this paper is recommended to accepted with minor revision.

The novelty of this research was explaining clearly and well, hence the originality of this study is high.

The research is important for the bio-compatible materials field research due to giving the new information related to find the new formula for the environmentally friendly biomedical material. However, the title of this paper mentioned clearly citric acid as a part of main composition in the development of new material in this study, hence the previous study related to the citric application should be more referred in this paper such as citric acid as a binder in the composite board. In the conclusion is better mentioned for the future suggestion application for this new material.

Author Response

The introduction was expanded with information on citric acid in medical and biomaterials engineering applications, including using the acid as a crosslinking agent. The 'conclusions' section has been expanded to include possible further uses of poly(1,3-propanediol citrate) resulting from its chemical structure. Additional benefits of the developed kinetic and gelation model are indicated.

Round 2

Reviewer 1 Report

Authors corrected the manuscript as it was suggested and answered to the questions. Hense, the manuscript can be published in the present form.