Weathering of Wood Modified with Acetic Anhydride—Physical, Chemical, and Aesthetical Evaluation
Round 1
Reviewer 1 Report
Comments and Suggestions for Authors1 The abstract of the paper should encompass the research objective, methodology, results, conclusions, and future directions of the study. The introduction delves too extensively into the research background, lacks adequate detail on the research objective, and provides a brief overview of the research methods.
2 The introduction would benefit from a more comprehensive literature review section to elucidate the connections and disparities between the current study and prior research.
3 It is advisable to specify the parameters of the acetylation treatment, including the ratio of acetic anhydride to wood, treatment duration, temperature, pressure, etc.
4 Considering wood’s inherent variability in color distribution, clarification is needed regarding the suitability of randomly selecting five spots for Lab* measurement. This aspect should be elaborated on in section 2.3.2.
5 Adding a header to the first column of Table 3 is recommended.
6 Section 3 could be subdivided into multiple subsections to enhance the clarity and organization of information presentation.
7 In Figure 7, the contact angle of radiata pine #3 at the 3-month exposure mark significantly diverges from the other data. A detailed explanation elucidating the underlying cause is warranted.
8 The article omits mention of the statistical analysis method employed. Conducting a significance analysis on the experimental data is advised.
9 In the conclusion section, while a thorough analysis and discussion have been provided, further expansion on how these findings impact practical applications is recommended. Additionally, articulating clear directions or suggestions for future research based on the accomplishments and limitations of prior research would enhance the conclusion.
10 Exploring the potential transformation of research outcomes into practical applications, such as in material selection for construction, development of maintenance strategies, or evaluation of environmental impacts, would also add value to the study.
Author Response
Dear Reviewer, please find our responses in the attached file
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsThe study presents the alteration in appearance of acetylated wood due to natural weathering. While the research provides valuable insights, several critical issues need to be addressed for a more comprehensive understanding.
Firstly, the lightening observed after three months of exposure for all three acetylated wood species (alder, beech, and radiata pine) is noted, but the subsequent stability in color is only briefly mentioned. The mechanisms behind this initial lightening and subsequent stability are not explored in depth. Understanding these processes is crucial for predicting long-term performance and aesthetic changes.
The study attributes photo bleaching primarily to visible light, yet this explanation lacks specificity. The roles of other environmental factors, such as UV radiation and moisture, are not sufficiently discussed. Furthermore, the progression to a grey tonality is described, but the chemical and physical changes leading to this transformation are not detailed.
Mould growth, beginning in the 9th month and expanding progressively, is attributed to favorable outdoor conditions. However, the specific conditions (e.g., humidity, temperature variations) are not quantified, making it difficult to generalize these findings to different climatic regions. Additionally, while the presence of mould is noted, the study does not assess its impact on the structural integrity of the wood.
The wood acetylation process, which reduces hydroxyl groups and minimizes moisture interaction, is stated to prevent shrinkage and swelling. However, the study provides only qualitative descriptions of surface disintegration (small cracks or raised fibers). Quantitative data on the extent of these changes and their implications for wood durability are missing.
Surface roughness parameters (Sa, Ra, Ssk, Skt) are analyzed, with Sa increasing for hardwoods but remaining constant for radiata pine. The study correlates roughness with erosion and dirt/spore accumulation, yet it does not delve into how these factors interact. The implication that planing contributes to surface irregularities is mentioned, but the influence of different finishing techniques on weathering is not considered.
While mould spores were observed at both high magnification and macro scales, the study fails to quantify mould coverage or its rate of spread. The statement that acetylated beech was most affected by mould, despite improved mould resistance, raises questions about the effectiveness of acetylation under prolonged exposure.
Author Response
Dear Reviewer, please find our responses in the attached file
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsReview of the article: “Weathering of Wood Modified with Acetic Anhydride - Physical, Chemical, and Aesthetical Evaluation”
The topic of this research and output might be useful for the Forests readers. The article is very interesting and presents a rarely discussed but valuable topic regarding the weathering of wood modified with acetic anhydride. The conducted work is worth to publish, however needs some corrections.
Abstract
Lines 22 – 23: …alder, beech, and radiata pine…
§ Please enter full species names and Latin names.
§ The abstract is very general. The identified relationships should be presented by providing numerical data. This is a more interesting form of presenting results than in a descriptive way. This will increase the citation of the article.
Introduction
In the Introduction section, please indicate whether other researchers have undertaken similar research. And if so, to what extent, using what methods, what results they obtained etc.
Line 84: …three wood species representing hardwood and softwood…
§ This statement is too general and, in my opinion, misleading. It should be written down: … two wood species representing hardwood and one representing softwood…
Materials and Methods
Line 95: The edges of the samples were sealed to avoid water uptake from the unexposed side.
§ How?
§ Using what materials?
Line 112: … CIE Lab…
§ Please use one notation system, because line 114 shows CIE Lab*.
§ Please supplement the methodology with a statistical analysis of the research results.
Results and Discussion
§ This section lacks a statistical discussion of the research results. This allows you to draw the right conclusions.
Figure 10
§ The figure is difficult to read. Please improve the quality of the figure.
Conclusions
§ This section is too long. Please present the most important conclusions in this part of the article.
Author Response
Dear Reviewer, please find our responses in the attached file
Author Response File: Author Response.pdf
