Ecofriendly Protective Medical Textiles from Cotton Fabric Modified with Chitosan Derivatives

on different enormously. The basement of is textile fibres which either (cotton, etc.) or synthetic (nylon, polyester, etc.) but among them, cotton is the most used textile its day by due to some excellent properties like usability, fineness, high tensile strength, good dyeability, biodegradability, biocompatibility, renewability, etc. Due to higher cellulose content, cotton fibre can retain more moisture than that of other natural fibres. This property of cotton is either good or bad depending on its end uses such as when cotton used as absorbent then it is good but when cotton used in manufacturing casual wears it’s not a good property [1]. ABSTRACT The objectives of this research were to develop important properties of cotton fabric, such as antibacterial activity, moisture absorption, swelling capacity, water vapour permeability, and soil degradation by using chitosan and its water-soluble derivatives e.g., N-(2-hydroxy) propyl-3- trimethylammonium chitosan chloride (HTACC), and N-methylolacrylamide-N-(2- hydroxy) propyl-3- trimethylammonium chitosan chloride (NMA-HTACC). HTACC was synthesized from chitosan through the dispersion of chitosan with glycidyltrimethylammonium chloride (GTMAC) in aqueous medium and NMAHTACC was synthesized from the dissolution of HTACC in aqueous N-methylolacrylamide (NMA) solution in presence of NH4Cl and 4-methoxyphenol, respectively. The chitosan, HTACC and NMA-HTACC were applied on cotton fabrics by an exhaustion method and showed antibacterial activity against Escherichia coli and Staphylococcus aureus. Among all of the modifiers, NMA-HTACC showed antibacterial activity against S. aureus and E. coli at a minimum concentration of 3.3 ppm and 5.8 ppm. The NMA-HTCC has better attachment capacity on the cotton fabric due to having hydrophilic groups and the positive charge on its structure of nitrogen atom. For this NMA-HTACC treated cotton fabric has better washing durability in water than other modifiers treated and untreated cotton fabrics and maintained over 93% of bacterial reduction against E. coli and over 94% of bacterial reduction against S. aureus even after 30 home launderings. It may also be applied to textiles to play a role in addressing hygiene and comfortable in clinical and sensitive environments by minimizing the chances for bacterial colonization of textiles and the potential for transfer from fabric surfaces.

Clothing textiles made of cotton fabric create a warm and often moist environment on the skin, which leads to the growth of bacteria which leads to the growth of microorganism (bacteria, fungi) and create unfavourable effects like unpleasant odours, staining, fabric deterioration. Not only that it also affects consumer health such as skin irritation and allergies, skin infections, etc. [2,3]. The health care market is evolving and driving the need for new technologies to protect the human body from the adverse environment. Hundred years ago, all serious sickness was handled in the hospital or the operating room in highly controlled environments for patients and workers. Today, patient care takes place in hospitals, surgery centres, nursing homes, clinics, labs, doctor's offices and sometimes even in patient's homes. As a result, protective medical textiles have become a very essential issue for daily life activities. Hygiene has become essential to human being way of life. This positive attitude of users towards hygiene textiles is facilitating a booming world market for a wide range of protective or specially designed textiles which is reviving the field of rigorous research and development.
Value addition in clothing has changed the global textile scenario.
Research has quite convincingly shown that apparel consumers all over the world are demanding functionality in the products that they use. This Functional or Protective clothing is referred to the garments and other fabric to protect the wearer from harsh environmental effects that may result in bacterial contamination, injuries and even death [4]. Considering the consumer's hygiene of the pathogenic microorganism, numerous anti-microbial textile products are developed using various agents like metal and their oxides, quaternary compounds, triclosan, organometallics, etc. But these are synthetic active agents with desired microbial inhibition activity. These are toxic and can create unfavourable effects on consumer health such as skin irritation, allergy and finally skin cancer. These synthetic agents also have a hazardous effect on the environment. So, for these reasons, the anti-microbial materials based on natural products are more demanded to avoid all the problems created by the synthetic anti-microbial materials [5].
Prawn and shrimp are the most important aqua-based products of Bangladesh due to their domestic and foreign demand.
Bangladesh earns more than 500 million US dollar each year by exporting shrimp [6] and achieved 6th position of prawn and shrimp production in the world [7]. These are exported in frozen form, before that, they are processed according to the buyer's requirements which generates huge amounts of waste (shell, head, tail, etc.) and make unfavourable environmental and hazardous problems [8][9][10][11]. Unfortunately, the prawn processing industries of Bangladesh are indeed disposing of their prawn processing waste by employing additional manpower [12]. Approximately 40-50% weight of prawn or shrimp is generally lost due to processing which is estimated about 30-kilo metric tons on dry basis per year of prawn waste is disposing of in Bangladesh [12]. But this waste contains about 8-10% a valuable component known as chitin which is extensively used in various industries like pharmaceuticals, cosmetics, foods, textiles and so on [8]. Chitin can be extracted from prawn shell wastes which turn into chitosan through deacetylation.
Every year, near about a hundred tons of chitosan, is imported by the Bangladesh government for industrial purposes which market price approximately 600 million takas [13]. So, the value addition of prawn processing industrial waste is so much necessary which will reduce the present import dependency of chitosan. The utilization of waste materials to chitin and then to chitosan will fulfil the domestic demand and further will make huge foreign currency by exporting. Generally, chitosan is a copolymer of glucosamine and N-acetyl-glucosamine units linked by 1,4-glucosidic bonds and it is obtained through the alkaline hydrolysis of chitin obtained from the prawn shell waste. The unique structural feature of chitosan consists in the presence of primary amines at the C-2 position of the D-glucosamine residues and two hydroxyl functionalities.
Consequently, chitosan has a polycationic nature [14]. Due to having polycationic nature, chitosan and its derivatives (e, g. HTACC and NMA-HTACC) may show antibacterial activity on cotton fabric. But the important properties such as textile strength, stiffness, shelf life, dye-ability, durability and anti-microbial efficiency etc are the issues of concern. In this research gap, intensive research should be carried out to develop antimicrobial textiles using bio-agents instead of synthetic agents [15]. The novelty of this research work is to develop bioactive textiles with specially designed chitosan derivatives i.e., HTACC and NMA-HTACC, and at the same time, an approach to highlight the economic, social and environmental impacts of prawn or shrimp processing waste's value addition.

Materials
Prawn shell was collected from sea fish processing area of Bagerhat, Khulna, Bangladesh. Cotton fabrics were collected from the local market, Rajshahi, Bangladesh. Escherichia coli and Staphylococcus aureus bacteria were collected from Rajshahi

Preparation of Quaternary Chitosan Derivatives
Extraction of Chitosan: Successive chemical treatment is required for the extraction of chitin from prawn shell waste.
Before the chemical treatments, the collected raw sample (prawn shell) was thoroughly washed with hot water and dried then the sample was reduced to the desired size using an electric grinder.
Finally, the deacetylation reaction was carried out for the conversion of chitin to Chitosan [17,18].

Preparation of HTACC:
The HTACC was synthesized by the following steps [19].

HTACC and NMA-HTACC Liquor: Different % (w/v) of HTACC
or NMA-HTACC was dissolved in water by stirring for 2-3 h and sonicated for 2h. To the solution, 50 µL of Triton-X was added to improve the wettability Farouk et al. [23]

Cotton Fabric Treatment
In this work, cotton fabric was treated by pad dry cure method where the fabric was dipped in the liquor of various modifier concentration and sonicated for 1 h at 70 C. The fabric was dried at 100•C for 10 min and cured at 170•C for 5 min and again dried at room temperature [24].

Characterization of Modified Fabrics
Moisture Absorption Study: The moisture absorption study of the modified cotton fabrics, as well as washed fabric, was performed at a constant humidity level. For this purpose, both the treated and untreated fabric samples were kept in a humidity chamber. Then the moisture saturated fabric samples were analyzed by a Moisture Analyzer [25]. Moisture content is determined using the following formula: Where W w is the weight of moisture saturated sample and W d is the weight of the dry sample.

Swelling Behavior Study; Swelling behaviour of the modified
and raw cotton fabric were determined by dripping into the water.
About 1 cm 2 fabric sample of known initial weight (W i ) was dipped in 100 ml distilled water at 30°C for one day. The samples were filtered, and the excess solvent was removed with the help of filter paper, then the final weight (W f ) was determined on an electronic balance. The percent swelling was calculated from the increase in initial weight in the following manner [26].
Percent Swelling (Ps) = 100 Where Wi is the initial weight of the fabric and Wf is the final weight of the fabric.

Water Vapor Permeability Test: This test was carried out
according to ASTM E96 (procedure B) testing standard where weight loss of water through the fabric sample due to evaporation at room temperature for 24 h was measured. In this case, the fabric sample was covered over the top of water containing a cup using a cover ring. The experiment is performed in triplicate for reproducibility. The distance between water surface underside of the specimen and specimen was maintained by 10 mm. The water loss due to evaporation via fabric specimen was measured in terms of weight loss after a certain time of interval. The water vapour permeability of modified and unmodified fabric samples was determined using the following equation-DOI: 10.26717/BJSTR.2020.32.005319 Where, M is the loss in mass of water (g); T, the time interval (h); and A, the internal area of the cup (m 2 ). A was calculated using the following relationship: Where d is the internal diameter of the cup (mm) [27].  fabric sample after the desire contact period (18h) [30].    Swelling Test: The swelling capacity is an important test for protective medical textiles which affects the overall properties like antimicrobial activity, wound healing capacity and biomedical uses.

Characterization Modified Cotton Fabric
The experimental results are shown in Figure 3. From the figure we see that untreated fabric shows the lower swelling capacity than that of treated cotton fabrics. Because treated fabrics contain more cross-linked channel structure which can retain much water for being swollen. Then the swelling capacity of NMA-HTACC modified cotton fabric is higher than others (raw, chitosan modified and HTACC modified fabric) for having not only the presence of hydrophilic groups in the film networks but also N-atom containing positive charge and higher attachment capacity as well as higher add-on percentage to the fabric [26].

Water Vapor Permeability Test (WVPT): Bolton studied a variety of dressings and determined that a WVTR (Water Vapor
Transmission Rate) of about 840 g/m 2 /day is required to maintain a moist wound surface [32]. Water Vapor permeability occurs mainly for having different vapour pressure on both sides of the cotton fabrics. The WVP test results are shown in Figure 4. In Figure 4,  shows higher degradation value due to having direct contact with soil particles and NMA-HTACC treated cotton fabric shows lower degradation value due to having a covering of NMA-HTACC that helps to not come in direct contact between soil and cotton fabric [28]. Biodegradability of the cotton fabric is determined with soil burial test.

Fourier Transform Infrared (FTIR) Spectroscopy Analysis:
The FTIR spectra of untreated, chitosan, HTACC and NMA-HTACC treated cotton fabrics were near about same except the additional characteristic peaks of modifiers were appeared due to modification as shown in Figure 6.    aureus. Chitosan modified cotton was showed comparatively lower antibacterial activity due to its lower solubility and lower positive charge content. Whereas quaternary chitosan derivatives modified cotton fabric were showed better antibacterial activity due to their capability to cause cellular leakage and hence bacteria died [34]. On the other hand, these quaternary derivatives were highly soluble in water which also responsible for higher antibacterial activity       (colony-forming units) CFU/mL and 5.26x10 7 (colony-forming units) CFU/mL respectively were used in nutrient broth [30].

Determination of the Bacterial Reduction (%) Modified
Cotton Fabrics against Both E. coli and S. aureus   it is also obtained that HTACC and NMA-HTACC treated cotton fabrics show bacterial reduction above 85% up to 30 laundry wash.
A strong hydrogen bond was formed between quaternary chitosan derivatives (HTACC and NMA-HTACC) and cellulose of cotton fabric.
At the same time, Van-der Waals Force existed between them which is also responsible for strong fixation [35].

Conclusion
In this study cotton fabric is treated with chitosan as a natural modifier to improve the properties of antibacterial activity, moisture absorption, swelling capacity, water vapour permeability, and soil degradation. Chitosan possesses strong antibacterial activity. However, to some extent, applications of chitosan are limited due to its high viscosity and low solubility. To overcome the drawbacks of chitosan, two water-soluble chitosan derivatives