Coloration of textiles with nanoparticle pigments

Nanosized pigment dyeing was performed for both synthetic and natural fibers with the aim of exploring the feasibility of coloration of textiles using pigment nanoparticles based on a diffusion mechanism and developing a binder-independent pigment dyeing method for textile industry with less environmental concern. Carbon black (CB) nanoparticles, the model pigment nanoparticles selected in this study, were proven to be able to penetrate and diffuse in polyester (PET) fibers when the size is as small as 8nm. The corresponding diffusion coefficient (D) was estimated with Einstein-Smoluchowski equation by transmission electron microscopy (TEM) cross-sectional images. The dyebath with 8nm CB nanoparticles was optimized and it was found that 3--5 wt% of CB with a 1:1 to 2:1 BDHAC:CB weight ratio resulted in the best add-on %wt of CB on fabrics. Both PET and acrylic fabrics dyed with the optimized formulation showed enhanced surface conductivity, indicating there is a potential use for CB nanoparticle-dyed PET and acrylics as anti-static clothing.; Further studies were focused on characterization of CB nanoparticles that are smaller than 8nm but were not able to be prepared at a laboratory level currently. A series of solvent dyes and pigments with various sizes that can be calculated with HyperChemRTM was chosen as model diffusants and their D's were obtained based on Hill's solution to Fick's Laws of Diffusion through K/S measurement. With the measured D's of these diffusants and that estimated for CB nanoparticles, an exponential correlation between D and the size was established and further confirmed by molecular mechanics simulations, which can serve to predict the diffusion behavior of CB nanoparticles smaller than 8nm.; Surface modification of CB nanoparticles using nitric acid oxidation was performed and self-dispersible carbon black (SDCB) nanoparticles were successfully prepared. SDCB nanoparticles were applied to coloration of cellulose through exhaustion dyeing and TEM cross-sectional images showed that SDCB nanoparticles were mostly located on the surface of cellulose, presumably by hydrogen bonding, and formed a uniform layer of 100nm thick surrounding the fibers' surfaces when dyebath concentration is 50%owf. SDCB-dyed cotton fabrics were characterized by iodometric titration with regard to the available carboxylic groups and showed a moderate antibacterial efficacy before and after H2O2 bleach. However, no correlation was found between the amount of carboxylic groups available on the dyed fabrics and the percentage reduction of E. coli, which made us believe that it is not the available -COOH, or -COOOH groups after H2O 2 bleach, but the SDCB nanoparticle layer itself that is responsible for the inhibition of growth of bacteria.