The sample was allowed to stand overnight fi ltered

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400 rpm) to obtain an opalescent solution. The sample was allowed to stand overnight, fi ltered through sintered glass fi lter of porosity grade G3, and preserved 18 N. Gokarneshan et al.
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in refrigerator. The prepared nanochitosan was termed as CHT1 N (Chattopadhyay and Inamdar 2013 ). The synthesized nanochitosan was applied to cotton fabric within 24 h since the stability of nanochitosan gets adversely affected with time as discussed earlier. The various grades of chitosan and nanochitosan have been speci fi ed. A particle size analyser has been used to determine the particle size and size distribution of the chitosan. A two-dip two-nip technique has been used to apply nanochitosan dispersion (1 gpL) onto fabric, using a padding mangle with wet pickup of 70 %. After drying, the fabric was cured in oven at 150 °C for 4 min. The sample was then washed in the following sequence: rinse alkali wash (soda ash 1 gpL, MLR 1:50) hot wash (twice) (85 °C/20 min) cold wash dry. The following studies have been done SEM Evaluation of Indices Fabric Stiffness, Tenacity and Absorbency Crease Recovery Angle and Antimicrobial Activity. 7.4 Synthesis and Characterization of Nanochitosan Chitosan possesses quite a long linear structure and has rigid conformation. The CHTI (Parent chitosan sample 1) has a characteristic size of hydrodynamic sphere of 4014 nm. The higher viscosity of the solution is due to the higher particle size in the solution. Any molecular size chitosan can reduce the particle size to nanolevel by bottom-up approach (Patel and Jivani 2009 ). Due to its polycationic nature, chitosan is subjected to ionic gelation with poly anions like pentasodium tripolyphosphate (TPP), ethylene diamine tetra acetic acid (EDTA), resulting in formation of nanoparticles. Such particles are stabilized by electrostatic hindrance due to coulombic repulsion between particles of same ionic charges (Zhang et al. 2010 ; Trapani et al. 2009 ; Chattopadhyay and Inamdar 2010 ). Owing to faster ionic reactions between chitosan and TPP, non-toxic nature of these components and ease of operation, we adopted the gel ionization technique for the synthesis of nanochitosan particles. The particle size distribution of CHT5 N, having particle size of 110.74 nm, is given in Fig. 15 . Scaling down the particle size of large polymeric materials to nanolevel is a big challenge. It is clear from them present study that the molecular weight (Table 1 ) has a great role in controlling the particle size and by reducing the molecular weight we achieved about 110-nm particle size. The study evidently shows that the particle size can be decreased below 100 nm by conducting a trial with parent chitosan of low molecular weight (lesser than 10,000). This investigation would provide a platform for future work of such a type and would serve basic information to the future researchers.
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  • Fall '19
  • N. Gokarneshan

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