bstractThe main purpose of this research work is to improve anti-static properties of Cashmere fabric by introducing application comprising anti-static agent by foaming which was made with cationic waterborne polyurethane and graphene-CNC. Three forms of waterborne polyurethanes such as two form of Cationic waterborne polyurethane (CWPU) and a form of Anionic waterborne polyurethane (AWPU) were synthesized. Cationic waterborne polyurethane (CWPU) with Methyl diethanolamine (MDEA) volume ratio 20 % was synthesized by reaction of polytetramethylene glycol (PTMG), 3667(PEG), Isophorone diisocyanate (IPDI), Methyl diethanolamine (MDEA) і-Aminopropyl Triethoxysilane (KH550) and as a catalyst dibutyltin dilaurate (DBTDL), whilst second of CWPU was prepared with difference of two reagents used such as polyether triol (ZC330) and 1,4-butanediol (BDO1,4).
carbon black (N220), 2,2 -bis(hydroxymethyl) propionic acid (DMPA), polyether triol ZC330, isophorone diisocyanate (IPDI), Triethylamine (TEA), Ethylenediamine (EA) and as a catalyst dibutyltin dilaurate DBTDL were used by synthesizing Anionic waterborne polyurethane (AWPU). In order to use Graphene-crystal nanocellulose for applying as an antistatic agent with three forms of WPUs such as CWPUs and AWPU by coating on the surface of Cashmere fabric, the properties of the fabric and obtaining the method of graphene-CNC were studied.
Moreover, the chemical structure of WPUs was characterized by Fourier transform infrared spectrometer (FTIR) and scanning electron microscopy (SEM). The results show that when a solution that was prepared by mixing WPUs and graphene-CNC was coated by foaming, the anti-static property of Cashmere can be obviously improved.Keywords: Cashmere fabric, anionic and cationic Waterborne polyurethane, graphene, cellulose nanocrystal, anti-static property1.Introduction The utilization of traditional solvent that is based on Polyurethane (PU) has regularly been being deterred, because of firm environmental and governmental influences. Textiles and other spheres such as adhesives, coatings, construction materials, inks as well as biological materials could be fields in which Waterborne polyurethane (WPU) might be utilized as a kind of multifunctional environmentally friendly substance due to its excellent properties. In terms of the outlook of material technology, the electrical properties, acoustic, optical properties as well as static and dynamic mechanical features are considered as essential properties and the performances of PU plastic are chemical, biological and corrosion resistance, adhesive properties. In spite of being a substantial number of excellent advantages of WPU, there might be found several drawbacks published for WPUs developing in their existing state. As an example, it can be shown that if compared to a traditional solvent which is based on polyurethanes, a feebler drying rate is observed on WPUs because of the high secretive heat and evaporation of water. Furthermore, the linear hydrophilic groups that WPUs contain in their chain instigate to require too much drying time and higher energy utilization for WPUs in order to reach expected mechanical power. In the case of meeting the time efficiency and economic profit requirements, this could not be useful. Hence anionic and cationic waterborne polyurethanes are focused on by functionalizing for anti-pilling and anti-static properties of Cashmere fabric. For that reason that Cashmere is a soft wool fabric woven from the hair of the Cashmere, or Kashmir goat. Cashmere fibers are extremely soft and silky to the touch and weigh practically nothing. When even compared to Merino, Cashmere can be found softer and fine-drawn, and it is more delicate than other types of animal wool. In addition, Cashmere is especially useful in terms of using it for accessories and curtains. In many cases of specifications of wool fabrics, Cashmere can be admitted as the king of the fiber and treasure, owing to its pros and cons. When comes to advantages of Cashmere, it can be counted that increasing the deep sleep which illustrates in experiments that cashmere material could enhance about more than 25 percentage of the individuals deep sleep time as well it can maintain heart rate slowly and steady. Additionally, moisture absorption and it keeps dry, warm in cold weather due to the fact that cashmere special molecule structure can absorb the water vapor more than 35 % into the hollow structure which cannot feel wettability and can remove quickly. Also, it presents no less than 40 % natural elastic, after pressing, it has been observed that it could recover approximately 95% of initial ply. Moreover, as advantages of cashmere, fluffy, softness, natural fire resistant, dust preventive are considered and cashmere has 17 kinds of abundant amino acid which provide the cashmere the feature of closing to the skin. Although here several pros have been mentioned, there some cons of cashmere which are caused problems to fabricate products form it, because of the fact that cashmere is wool, it is a hydrophilic fiber, and wool fabrics frequently are highly charged caused by the firm friction between the wool scales. So as to solve this issue of cashmere fabric, anti-static finishing is required. The importance of optimal performance is uniform fabric penetration while applying ant-static finishes to fabrics. In the finish formulation, the utilization of wetting agents is recommended, Cationic anti-static agents fit for exhaust processes. The low add-on values (mostly about one or a few percents on the weight of fiber) enables spray and foam applications. Padding leads to lesser effects than foam does application with an identical add-on. The higher concentrations of anti-static agents on the fiber surface by the foam application can be the actual factor for this. Some of the potential side effects of the use of anti-static finishes include wearing comfort (no clinging and pleasant skin contact caused by hydrophilicity). To improve the electrostatic ability of WPUs, graphene has been widely used over the last decade due to possessing excellent thermal, mechanical and electrical properties and high surface area. Graphene, a primary constructing block of graphite, possessing a one-atom-thick sheet of hexagonally comprised sp2-hybridized carbon atoms. There have lamellar structure and stacked jointly by van der Waals forces in the graphitic layers. Extraordinary electronic properties were anticipated to have in these individual layers. Graphene has extraordinary electrical and thermal conductivities, ultra-high theoretic specific surface area (2630 m2/g) and high mechanical strength. These excellent properties make graphene a promising candidate for energy storage devices, composites, and electronics. High specific surface area and electrical conductivity with mechanical strength make this material a promising choice for energy storage devices. For those aspects, some researchers have investigated experiments regarding graphene based on cellulose nanocrystal (CNC) which has hydroxyl group (OH) presenting hydrophilicity as to improve electrical conductivity. Anti-static agents can be prepared by making of three forms of WPUs such as an anionic waterborne polyurethane and two cationic waterborne polyurethanes and graphene-based on cellulose nanocrystal (CNC) so as to apply that solution to coat on the surface of Cashmere fabric through foaming finishing.The cost was high for the moisture evaporation of chemical reagents in the conventional fabric, finishing, however, the foam dyeing and finishing technology can save more energy in the drying process. Foam finishing is a kind of dying and finishing technology with great energy saving effect because foam as a medium carrier of dyes was applied to substitute for part of the water. The processing effect can reduce 65%- 75% compared with the conventional water consumption In addition, multifunctional textiles can be produced through the foam finishing technology to meet the higher demand for market consumption. It is a good prospect for the application that the foam finishing technology is applied to Cashmere fabric finishing, including anti-pilling and anti-static. In this current study, in order to enhance anti-static properties of Cashmere fabric by casting film solution, which was prepared by mixing three types of WPUs and graphene-CNC with some concentration of ratio for each sample, on the surface of it. The results obtained showed that the anti-static properties of fabric were improved when compared with examples.2.Experimental 2.1. Materials Cashmere was purchased from Beta Textiles Co., Limited (BTEXCO). Isophorone diisocyanate (IPDI) and Methyl diethanolamine (MDEA), dibutyltin dilaurate (DBTDL),і-Aminopropyl Triethoxysilane (KH550) chemical pure were obtained from Shanghai Jingchun Reagent Co., Ltd., and Aladdin Reagent (Shanghai) Co.,Ltd; polyether triol (ZC330) industrial products Guangzhou Jinwang Chemical Co.,Ltd; N220, DMPA, Ethyleneamine (EA), Triethylamine (TEA) analytical purity China Pharmaceutical Group Chemical Reagent Co.,Ltd. Graphene -CNC was derived by reaction of Graphite and cellulose nanocrystal with holding cold water temperature and centrifugal force in order to remove particles’ residues. Anionic and cationic waterborne polyurethanes were synthesized by reacting reagents in accordance with their recipe. In synthesizing PTMG and PEG were dried and degassed under 110o C and other materials were used as received.2.2. Preparation of cationic waterborne polyurethanes with MDEA volume ratio 20% and 13% The first form of cationic waterborne polyurethane was synthesized via the chosen recipe that is given tab 1. The first step in the synthesis of the cationic WPUs was to introduce PTMG 2000 and 3667 which were vacuumed to remove water in them under 110oC and 0.01Mpa for 120 minutes with Isophorone diisocyanate (IDPI) which has functional group isocyanate which can react with chemicals when it is effected as a second step is done under 85oC for 150 minutes. The first prepolymer I was synthesized based on IDPI and PTMG. Then MDEA was reacted to build the second prepolymer in order for the final product to make it ready. A 250 mL round-bottomed, four-necked flask equipped with a nitrogen inlet, a condenser with a drying tube, a mechanical stirrer and a thermometer was used for the reaction. After being kept two chemicals at the required time, a drop of DBTDL was added as a catalyst and simultaneously by repeating six times of adding, MDEA was dropped at 400C during the 30 minutes, then with the same repetition and the duration of time, NEP was added at 40-500C. In the next step, KH550 was added and mixed for 10 minutes and as a catalyst DBTDL was introduced. Then, acetic acid as a neutralizing agent was not added into the reaction until the mixture was slowly cooled to 40oC. The neutralization reaction proceeded at the same temperature for 30 min. When the synthesis of CWPU with MDEA volume ratio 13% was done, 1,4 – butanediol (BDO 1,4) was used as a different reagent. Chemical structure of CWPUs is shown in Fig 1.Fig 1. Chemical structure of cationic waterborne polyurethane (MDEA volume ratio 13% and 20%)2.3. Preparation of cationic waterborne polyurethanes At the duration of synthesizing anionic waterborne polyurethane (AWPU), the first was commenced by dehydrating three reagents such as carbon black (N220),2,2-bis(hydroxymethyl) propionic acid (DMPA), polyether triol ZC330 under the temperature of 110oC for 120 minutes with 0.01Mpa. Then in order to accomplish the second step named polymer reaction, firstly Acetone was added to reduce the viscosity and IPDI was added through the temperature of 60oC. The importance of this step is that the holding at 15 minutes with temperature which must be less than 80o. at the following stage, dibutyltin dilaurate (DBTDL) was added and kept at 90oC for 4hours. After keeping raw material at 90oC for 4h, 5ml Acetone was added every 20 minutes to decrease the reaction of the process to low viscosity. In the neutralization, the reaction system was cooled to 50oC so as to be added triethylamine neutralize in the duration of 30 minutes. The final reaction process is chain extension reaction which was carried out by adding ethylenediamine and water to mix through stirring at high speed for 30 minutes, and methanol was added to seal the end with stirring at high speed for 10 minutes.Fig 2. Chemical structure of anionic waterborne polyurethane 2.4. Preparation of Graphene-based on Cellulose nanocrystal Graphene solution was prepared by using graphite oxide, cellulose nanocrystal and water to make at three types of ratio 0.5:1, 1:1, 2:1. The volume of solution was 100 ml including graphite oxide, CNC and water and it was kept at cold water temperature for 90 minutes by mixing with stirring instrument and then the solution was held on centrifugal force instrument in order for removing residue of particles at speed of 4000 for 2 minutes.2.5. Application of anti-static agent for foaming on the surface of Cashmere2.6.Characterization of WPUs, Graphene and anti-static property of Cashmere