Fire Suppression and Thermal Behavior of Biobased Rigid Polyurethane Foam Filled with Biomass Incineration Waste Ash
Round 1
Reviewer 1 Report
Dear authors,
The topic which was choosed in your paper is very meaningful. From my point of view, there are
some results should be explained or added in your manuscript. Here my suggestions:
(1) SEM images of four types of foams should be offered by author, from the SEM, author should
mark the size of typical foam cells. From those SEM images, author may find the relationship of
density with the size of foam cells. in this way, it can also explain the WA contents influence the
density of foams.
(2) It is recommended to test the limiting oxygen index (LOI) of the foam samples.
(3) If author has enough time, the char residue of foams should be tested to obtain the different
contents of the flame retardant elements by EDAX.
Author Response
Authors would like to thank reviewer for his/her efforsts. The comments were very valuable for the improvement of the article. Please find bellow the answers to your remarks:
(1) SEM images of four types of foams should be offered by author, from the SEM, author should mark the size of typical foam cells. From those SEM images, author may find the relationship of density with the size of foam cells. in this way, it can also explain the WA contents influence the density of foams.
Answer: the research of the structure using SEM imaging and calculation of cell size was already done by authors in previous publication in Composites Part A journal. Authors do not want to repeat the results which were already published. However, the dependence of cell size and density of these foams was not observed. 10-50 wt.% WA particles reduce average cells to almost the same size while the extent of apparent density increase with the addition of WA particles is very high.
(2) It is recommended to test the limiting oxygen index (LOI) of the foam samples.
Answer: LOI test was conducted and the results are presented in Figure 4.
(3) If author has enough time, the char residue of foams should be tested to obtain the different contents of the flame retardant elements by EDAX.
Answer: EDS test was conducted and the results are presented in Figure 6.
Reviewer 2 Report
Dear Authors, i find this article quite interesting, below are my remarks and questions.
Line 34 – Grammar
Together with growing use of biomass-based fuels for energy generation will lead to large amounts of biomass incineration ash which causes serious environmental problems.
Growing use of biomass-based fuels for energy generation will lead to large amounts of biomass incineration ash which causes serious environmental problems.
Line 43 – Grammar
It was shown that WA should be used as a pozzolan in up to 20 wt.% [6–7] and as an additive mainly 43 in 10 wt.% [8] to obtain concrete material with an optimal characteristics as well as reduce CO2
emissions and price [9]. -> It was shown that WA could be used as a pozzolan up to 20 wt.% [6–7] and as an additive mainly up to 10 wt.% [8] to obtain concrete material with an optimal characteristics as well as to reduce price and CO2 emissions [9].
Line 49 – Question
Why water absorption should belong to valuable performance characteristics?
LINE 54 Grammar
and lower price ->and low price
Line 55 Grammar
compounds it emit toxic smoke -> compounds emit toxic smoke.
Line 63 - Style
[21– 22]. [23] observed that the addition of up to 40 wt.% of basalt waste reduces compressive strength of 64 PU composites and worsens their dimensional stability while [24] tested feldspar
Some researchers [21– 22, 23] observed that the addition of up to 40 wt.% of basalt waste reduces compressive strength of 64 PU composites and worsens their dimensional stability while others [24] tested feldspar
Line 66 - Question
However, a study [10] showed that WA particles as waste-based and filler-type additive can be used in higher amounts, i.e. up to 50 wt.%, because they act as a plasticizer in polyol premix.
Is this correct? How solid, inorganic particles can act as a plasticizer?
Line 86 – Question
Have you characterized the shape and size distribution of the WA particles?
Line 93
Isocianate index -> Isocyanate index
|
WA amount, wt.% |
0 |
10; 30 and 50 |
|
WA amount, wt.% |
0 |
10 or 30 or 50 |
Line 96 – Logical
Further, 10 wt.%, 30 wt.% and 50 wt.% of WA were added -> Further, 10 wt.% or 30 wt.% or 50 wt.% of WA were added
Line 113 – Grammar – changing present to past tense
For the evaluation of WA particles impact on PU and WAPU foams under high temperatures, thermogravimetric (TGA) and difference thermogravimetric (DTG) are conducted under the air 114 atmosphere using STA 449 F1 Jupiter Analyzer (Netzsch Group, Germany) at temperature interval from 25°C to 600°C. Temperature raising speed is 10°C/min. -) For the evaluation of WA particles impact on PU and WAPU foams under high temperatures, 113 thermogravimetric (TGA) and difference thermogravimetric (DTG) analyses were conducted under the air atmosphere using STA 449 F1 Jupiter Analyzer (Netzsch Group, Germany) at temperature interval from 25°C to 600°C. Temperature raising speed was 10°C/min.
Line 117 – 125: Grammar - Please change present to past tense and use upper index for square meter
Line 143 - Style
It can be noticed from the thermal conductivity data, WA particles do not significantly increase the parameter of WAPU-50 foam and it is only by 7% higher than that of the PU foam.->
It can be noticed that WA particles do not significantly increase the thermal conductivity of WAPU-50 foam and it is only by 7% higher than that of the PU foam.
Line 144 -
Even through -> Even though
Line 146 – improve this chaotic sentence!
As [38] stated, it can be due enhanced effect of thermal conductivity from the solid parts, in this case WA particles and thicker cell walls, as the cell size decreases under the same blowing agent contents.
Line 167 Grammar
process consisting of a multiple physical and chemical reactions -> process consisting of multiple physical and chemical reactions
Line 177
Additionally, 28.2 wt.% of char yield at 600°C is obtained. -> Additionally, 28.2 wt.% of char at 600°C is obtained. (or : Char yield at 600°C was 28.2 wt.%)
Line 185 - Question
It means that WA particles are capable to shift onset degradation temperature towards higher temperature, reduce weight loss and increase thermal stability of WAPU foams. This behaviour can be attributed to the barrier effect provided by WA particles which reduces both the heat and oxygen fluxes toward the PU foam surface.
Comment: Exactly speaking T5 wt.% is not the onset degradation temperature. The WA particles probably do not influence the thermal degradation of urethane linkages in the hard segments. WA particles are thermally stable and the shift of T5 wt.%, T10 wt.% results mainly lower amount of the polymer in the foam. With the size of samples used for TGA the barrier effect for heat flux is of lower significance, there is no oxidation at the beginning of thermal degradation of hard and soft segments, the oxidation occurs later at higher temperatures, therefore oxygen diffusion is of no importance for the onset of thermal degradation of PU foams (how big were the samples? Were the foams crushed to fit into the weighting cell?)
Have you run the TGA with pure WA for comparison?
Author Response
Authors would like to thank reviewer for his/her efforts. The comments were very valuable for the improvement of the article. Please find bellow the answers to your remarks:
1) Line 34 – Grammar
Together with growing use of biomass-based fuels for energy generation will lead to large amounts of biomass incineration ash which causes serious environmental problems.
Growing use of biomass-based fuels for energy generation will lead to large amounts of biomass incineration ash which causes serious environmental problems.
Answer: corrected.
2) Line 43 – Grammar
It was shown that WA should be used as a pozzolan in up to 20 wt.% [6–7] and as an additive mainly 43 in 10 wt.% [8] to obtain concrete material with an optimal characteristics as well as reduce CO2
emissions and price [9]. -> It was shown that WA could be used as a pozzolan up to 20 wt.% [6–7] and as an additive mainly up to 10 wt.% [8] to obtain concrete material with an optimal characteristics as well as to reduce price and CO2 emissions [9].
Answer: corrected.
3) Line 49 – Question
Why water absorption should belong to valuable performance characteristics?
Answer: water absorption is the mandatory property to test for manufacturers in order to get conformity assessment from notified body (sprayed polyurethane foams acc. EN 14315-1 and factory made polyurethane foams acc. EN 13165, Annex ZA).
4) LINE 54 Grammar
and lower price ->and low price
Answer: corrected.
5) Line 55 Grammar
compounds it emit toxic smoke -> compounds emit toxic smoke.
Answer: corrected.
6) Line 63 - Style
[21– 22]. [23] observed that the addition of up to 40 wt.% of basalt waste reduces compressive strength of 64 PU composites and worsens their dimensional stability while [24] tested feldspar
Some researchers [21– 22, 23] observed that the addition of up to 40 wt.% of basalt waste reduces compressive strength of 64 PU composites and worsens their dimensional stability while others [24] tested feldspar
Answer: corrected.
7) Line 66 - Question
However, a study [10] showed that WA particles as waste-based and filler-type additive can be used in higher amounts, i.e. up to 50 wt.%, because they act as a plasticizer in polyol premix.
Is this correct? How solid, inorganic particles can act as a plasticizer?
Answer: authors would like to apologize, it is a honest mistake. The sentence was corrected.
8) Line 86 – Question
Have you characterized the shape and size distribution of the WA particles?
Answer: the shape and size distribution was characterized in authors previous work published in Composites Part A journal.
9) Line 93
Isocianate index -> Isocyanate index
Answer: corrected.
10)
|
WA amount, wt.% |
0 |
10; 30 and 50 |
|
WA amount, wt.% |
0 |
10 or 30 or 50 |
Answer: corrected.
11) Line 96 – Logical
Further, 10 wt.%, 30 wt.% and 50 wt.% of WA were added -> Further, 10 wt.% or 30 wt.% or 50 wt.% of WA were added
Answer: corrected.
12) Line 113 – Grammar – changing present to past tense
For the evaluation of WA particles impact on PU and WAPU foams under high temperatures, thermogravimetric (TGA) and difference thermogravimetric (DTG) are conducted under the air 114 atmosphere using STA 449 F1 Jupiter Analyzer (Netzsch Group, Germany) at temperature interval from 25°C to 600°C. Temperature raising speed is 10°C/min. -) For the evaluation of WA particles impact on PU and WAPU foams under high temperatures, 113 thermogravimetric (TGA) and difference thermogravimetric (DTG) analyses were conducted under the air atmosphere using STA 449 F1 Jupiter Analyzer (Netzsch Group, Germany) at temperature interval from 25°C to 600°C. Temperature raising speed was 10°C/min.
Answer: corrected.
13) Line 117 – 125: Grammar - Please change present to past tense and use upper index for square meter
Answer: corrected.
14) Line 143 - Style
It can be noticed from the thermal conductivity data, WA particles do not significantly increase the parameter of WAPU-50 foam and it is only by 7% higher than that of the PU foam.->
It can be noticed that WA particles do not significantly increase the thermal conductivity of WAPU-50 foam and it is only by 7% higher than that of the PU foam.
Answer: corrected.
15) Line 144 -
Even through -> Even though
Answer: corrected.
16) Line 146 – improve this chaotic sentence!
As [38] stated, it can be due enhanced effect of thermal conductivity from the solid parts, in this case WA particles and thicker cell walls, as the cell size decreases under the same blowing agent contents.
Answer: improved.
17) Line 167 Grammar
process consisting of a multiple physical and chemical reactions -> process consisting of multiple physical and chemical reactions
Answer: corrected.
18) Line 177
Additionally, 28.2 wt.% of char yield at 600°C is obtained. -> Additionally, 28.2 wt.% of char at 600°C is obtained. (or : Char yield at 600°C was 28.2 wt.%)
Answer: corrected.
19) Line 185 - Question
It means that WA particles are capable to shift onset degradation temperature towards higher temperature, reduce weight loss and increase thermal stability of WAPU foams. This behaviour can be attributed to the barrier effect provided by WA particles which reduces both the heat and oxygen fluxes toward the PU foam surface.
Comment: Exactly speaking T5 wt.% is not the onset degradation temperature. The WA particles probably do not influence the thermal degradation of urethane linkages in the hard segments. WA particles are thermally stable and the shift of T5 wt.%, T10 wt.% results mainly lower amount of the polymer in the foam. With the size of samples used for TGA the barrier effect for heat flux is of lower significance, there is no oxidation at the beginning of thermal degradation of hard and soft segments, the oxidation occurs later at higher temperatures, therefore oxygen diffusion is of no importance for the onset of thermal degradation of PU foams (how big were the samples? Were the foams crushed to fit into the weighting cell?)
Have you run the TGA with pure WA for comparison?
Answer: the TGA of pure WA particles was conducted and Figure 2 was supplemented with the obtained results. And yes, the foam was crushed into the weighting cell before the conducting TGA test. Additionally, the amount of polymer in the foam does not reduce with the addition of WA particles. The discussion was a little bit improved.
