5th International Color and Coatings Congress (ICCC 2013) December 18-19, 2013 Isfahan–Iran

Investigation of near infrared reflectance on printed fabric by using the multi-walled carbon nanotube particles (MWCNT’s)

M. Khajeh Mehrizi*, F. Bokaei , N. Jamshidi

Department of Textile Engineering, Yazd University, Yazd, 89195-741, I. R. Iranmkhajeh@yazd.ac.ir

AbstractIn order to match the reflectance profile of dark and light brown in the Visible-near IR (Vis-NIR) regions, some selected colored pigments were applied to print cotton/nylon fabrics. Multi-walled carbon nanotube particles (MWCNT’s) were also added to the printing pastes. The effect of MWCNT’s on Vis/NIR reflectance, wettability, perspiration, light fastnesses and colorimetric values of each printed sample were evaluated. The results indicated that the presence of MWCNT’s in concentration range of 0.04-0.12 g/kg in printing formulations was found to cause decline in Near Infrared (NIR) reflectance whilst a surprising increase in Visible reflectance of samples was observed.

IntroductionFibers and coatings with distinctive optical, magnetic, and electrical properties are being extensively studied for various commercial applications. Novel materials are being developed with exclusive tunable coloration properties across the visible band as well as spanning the infrared and ultraviolet region of the electromagnetic spectrum [1].The near IR (NIR) region of the spectrum covers the wavelength range from 700 nm to 2000 nm, although some current researches focus on the 700 nm – 1200 nm. All bodies and objects have a convinced reflection factor or reduction percentage in this region. The reflection factors of most natural objects (tree branches and leaves, soil and rocks, bodies of water, etc.) differ within the limits of 10-80% [2].Printing, coating and dyeing methods have been used in order to tune infrared radiation reflectance of textiles in the near IR region.There exists a selected vat dyes for cellulosic fibers and blends thereof, which present both visual and NIR reflectances [3]. An another technique for matching ususal colors including in desert area on cotton/polyester and cotton/nylon is adding carbon black and titanium dioxide pigments in the printing pastes [4-6].In this research, in order to add MWCNT’s to the printing paste formulations, reflectance of printed patterns in Vis-NIR regions was studied. Required dark and light brown colors in desert area were tunned on cotton/polyamide 6 (Co/PA) fabrics using various colored pigments. Then required colored and fastness properties of printed samples were evaluated. ExperimentalIn this study, samples of fabric were printed using a mixture of some special pigments and MWCNT’s (Outer diameter: 10-20 nm, Inner diameter 5-10 nm and purity ˃ 95%) to produce light and dark brown shades which are present in concealment patterns of textiles employed in deserts. Conventional screen-printing method was followed in all printing experiments. MWCNT’s (0.04 -0.12 g/kg) were added to the Stock printing paste containing a MT binder and thickener. Print formulations containing of special pigments were tuned in a way to mimic visible and NIR reflectance behavior of required shades in the desert area. Selected pigments applied in print formulations for covering up purposes in Vis/NIR regions are listed in Table 1.Printing pastes were all hand printed on fabrics using a flat screen. Subsequently, printed fabrics were dried in an air dryer at 100oc for 3 minutes, and then cured in a laboratory stenter at 140oC for 5 minutes. Spectral reflectance of printed samples was measured on a Jasco ARN-570 reflectance spectrophotometer in Vis/NIR (400-1500 nm) wavelength.

Table1. Colored pigments used in printing formulations

5th International Color and Coatings Congress (ICCC 2013) December 18-19, 2013 Isfahan–Iran

Commercial name Manufacturing factoryEsta Print Yellow R Ebrism Chemie, IranEsta Print Red GC Ebrism Chemie, IranPigmaprint Brown R Guray kimya, TurkeyBercolin Black CB Bersa, Turkey

Results and discussionThe reflectance profiles of Co/PA fabrics printed with pigmented pastes containing different quantities of MWCNT’s is presented in figures 1.

Figure 1. Vis-NIR reflectance profile of dark brown printed fabrics with different concentrations of MWCNT’s

The result in Figure 1 indicated that by adding MWCNT’s to dark brown paste in the concentration of 0.04-0.12 g/kg MWCNT’s, the reflectance of samples increases in Visible band but NIR curve of sample decreases about 5%. Increasing the quantity of MWCNT’s in brown printed areas could enhance NIR absorption. The results showd that the wettability time of printed samples containing quantities of MWCNT’s follows a rising trend. According to obtained results, the wettability time of printed samples was enhanced from 37.3 to higher than 100 sec for dark brown printed fabric whilst for light brown printed fabric; it changed from 27.2 to 83.7 sec.

ConclusionsUsing high load of MWCNT’s pigment can cause high color difference to the reference in comparison to the sample with no MWCNT’s especially in deep shades like dark brown.

References[1] E. Wilusz, Military Textiles, Cambridge: CRC Press, 2008, 392.[2] NP. Puzikova, EV. Uvarova, IM. Filyaev, LA. Yarovaya, Principles of an approach for coloring military camouflage. Fiber chem., 2008, 40(2), 53-56.[3] H. Zhang, JCH. Zhang. Near-infrared green camouflage of cotton fabric susing vat dyes, J Text Inst. 2008, 99, 83–88.[4] M. Khajeh Mehrizi, SM. Mortazavi, Sh. Mallakpour, SM. Bidoki , M. Vik, M. Vikova, Effect of carbon black nanoparticles on reflective behavior of printed cotton/nylon fabrics in Visible/Near infrared regions, Fiber Polym, 2012, 13(4), 501-506.[5] M. Khajeh Mehrizi, SM. Mortazavi, Sh. Mallakpour, SM. Bidoki, The effect of nano and micro-TiO 2

particles on reflective behavior of printed cotton/nylon fabrics in Vis-NIR regions, Color Res Appl, 2012, 37(3), 199-205.[6] M. Abbasipour, M. Khajeh Mehrizi, Investigation of changes of reflective behavior of cotton/polyester fabric by TiO2 and carbon black nanoparticles, Scientia Iranica F, 2012, 19(3), 954-957.