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. 2022 Jun 16;7(25):21775-21787.
doi: 10.1021/acsomega.2c01870. eCollection 2022 Jun 28.

Investigation and Optimization of Vacuum Plasma Treatment of PA66 Fabric for Reduced Fire Retardant Consumption

Carlo Boaretti  1 , Gabriele Rossignolo  1 , Martina Roso  1 , Michele Modesti  1 , Baljinder Kandola  2 , Arianna Vendrame  1 , Alessandra Lorenzetti  1
Affiliations

Investigation and Optimization of Vacuum Plasma Treatment of PA66 Fabric for Reduced Fire Retardant Consumption

Carlo Boaretti et al. ACS Omega. .

Abstract

Flame retardant (FR) textiles were obtained by surface treatments of polyamide 66 fabrics with microwave (MW) plasma technology in order to reduce the amount of FR involved in the fabric finishing process. More specifically, MW vacuum plasma was employed for polymer surface activation by using a helium/oxygen (He/O2) gas mixture, evaluating the effect of different treatment parameters on the affinity toward thiourea impregnation. Surface fabric modification was investigated both in terms of uniformity and increased thiourea absorption by infrared spectroscopy, wicking properties, and gravimetric characterization to define an operative window for plasma treatment conditions. According to the results obtained, the dry add-on content of thiourea improved up to 38%, thanks to the increase of the fabric surface activation. The effectiveness of plasma treatment resulted in an absolute increase up to 2% in limiting oxygen index (LOI) performance with respect to untreated fabric. As a consequence, a drastic reduction of 50% in thiourea concentration was required to achieve a similar fire retardant performance for plasma-treated fabric. On the basis of these preliminary results, a design of experiment (DoE) methodology was applied to the selected parameters to build a suitable response surface, experimentally validated, and to identify optimized treatment conditions. At the end, a final LOI index up to 43% has been reached.

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Conflict of interest statement

The authors declare no competing financial interest.

Figures

Figure 1
Figure 1
FTIR spectrum of untreated and plasma-treated PA66 fabric.
Figure 2
Figure 2
NPH values versus power for the three different IR peaks investigated (NPH maximum standard deviation: ± 0.1).
Figure 3
Figure 3
Capillary rise height [cm] vs plasma power [W] for vacuum plasma treated fabrics with a 5:1 He/O2 gas mixture for 5 min.
Figure 4
Figure 4
NPH versus treatment time at the center and at the edge of the samples for the −NH and −CONH– groups (NPH maximum standard deviation: ± 0.1).
Figure 5
Figure 5
FTIR spectra comparison between the plasma-treated and untreated samples, after soaking in thiourea (TU) solution: whole range (a); detailed view of the 3177 (b) and 730 cm–1 peaks (c).
Figure 6
Figure 6
TGA thermograms employed for the calculation of the amount of adsorbed thiourea: (a) comparison of the degradation profile of thiourea and plasma-treated (PA66 P) and pristine PA66 (PA66 NP); (b) comparison of PA66 after treatment with 10% thiourea solution with (PA66 P + T) and without (PA66 NP + T) plasma treatment.
Figure 7
Figure 7
Graphical representation of the quadratic model developed: (a) contour plot of power against time parametric in ΔLOI (%) and (b) response surface.
Figure 8
Figure 8
SEM micrographs of thiourea impregnated PA66: without plasma treatment (a,c); with plasma treatment (b,d).
See this image and copyright information in PMC

References

    1. Choudhury A. K. R.Principles of Textile Finishing; The Textile Institute Book Series; Elsevier Science, 2017.
    1. Aldalbahi A.; El-Naggar M.; El-Newehy M.; Rahaman M.; Hatshan M.; Khattab T. Effects of Technical Textiles and Synthetic Nanofibers on Environmental Pollution. Polymers 2021, 13, 155.10.3390/polym13010155. - DOI - PMC - PubMed
    1. Madhav S.; Ahamad A.; Singh P.; Mishra P. K. A Review of Textile Industry: Wet Processing, Environmental Impacts, and Effluent Treatment Methods. Environ. Qual. Manage. 2018, 27, 31–41. 10.1002/tqem.21538. - DOI
    1. Blackburn R.Sustainable Apparel: Production, Processing and Recycling; Woodhead Publishing Series in Textiles; Elsevier Science, 2015.
    1. Yasuda H.Plasma Polymerization; Academic Press, 1985.