CHEMICAL SCIENCES
BIODEGRADABLE PACKAGING MATERIALS WITH ANTIBACTERIAL PROPERTIES BASED ON POLYLACTIDE AND TITANIUM DIOXIDE NANOPARTICLES
Nusipbekova A.
Master's degree of Chemistry, Chemical Technology and Ecology, Almaty Technological University
Taussarova B.
Doctor of Chemical Sciences, Professor, Chemical Technology and Ecology,
Almaty Technological University
Abstract
Research has been conducted on the development of paper packaging materials with antibacterial properties using titanium dioxide nanoparticles. The synthesis of titanium dioxide nanoparticles was obtained by hydrolysis of titanium tetrachloride in an alkaline medium, adjusting the pH value with an aqueous solution of ammonia at a temperature of 30°C. The influence of the reaction conditions on the synthesis of titanium dioxide nanoparticles and the pH of the medium is studied, and optimal synthesis conditions are found.The parameters of processing paper packaging materials with aqueous solutions of titanium dioxide nanoparticles that impart antimicrobial properties are determined.
Keywords: biodegradable; antimicrobial properties; polylactide acid; titanium dioxide.
INTRODUCTION
Packaging materials play an important role in ensuring the safety and security of food products mainly due to the increased requirements in terms of product safety, shelf life extension, cost efficiency, environmental concerns and convenience for consumers. Traditional polymers made of hydrocarbons (polypropylene, polystyrene, polyethylene, etc.), which are used for the manufacture of various types of packaging, remain unchanged after disposal for many centuries.
They do not decompose and are not absorbed by nature, while releasing harmful compounds into the environment: soil and water, also remaining intact and indestructible, can cause a lot of mechanical damage to animals, pollute water bodies and land. Packaging made of traditional polymers, when the temperature of the external environment increases, begins to release harmful compounds directly into food products and water, then entering the body. Polymers made from hydrocarbons are good breeding grounds for pathogenic bacteria, which has been proven by scientists from around the world.
Industry and consumers are increasingly focusing on developing biodegradable packaging materials that could better preserve the quality of food and increase its shelf life. During processing, packaging, storage, delivery and marketing, foodproducts are exposed to daylight and artificial light, which significantly reduces their shelf life and degrades their quality.
One of the innovative ways to influence food safety is the introduction of additives in the packaging material that have antimicrobial and antioxidant activity. This allows you to provide additional protection against microbiological risk by reducing the growth of surface microflora. The main requirements for antimicrobial additives are their sanitary and hygienic safety in contact with food, polyfunctionality and stability at all stages of processing of the polymer composition. The performance characteristics of packaging materials
after the introduction of additives should be maintained. The development of nanotechnology makes it possible to obtain materials that have unique properties and are ideally suited for the role of packaging materials that can significantly increase the shelf life of food products.
The aim of this study is to develop an antimicrobial composition based on titanium dioxide nanoparti-cles, which gives packaging materials antimicrobial properties by fixing titanium dioxide nanoparticles on the surface.
Experimental part.
Titanium chloride, titanium tetrachloride - a binary compound of titanium and chlorine with the formula TiCl4. Under normal conditions, a colorless mobile transparent toxic liquid, steaming in the air, is hy-drolyzed by water and water vapor with the release of hydrogen chloride and the formation of titanium oxides and oxychlorides. Molecular weight - 189.71 g/mol.
Hydrochloric acid -is a solution of hydrogen chloride (HCl) in water, a strong monobasic acid, a colorless, transparent, caustic liquid that steams in the air. Molecular weight- 36.46 g /mol.
Ammonia (hydrogen nitride) is a chemical compound of nitrogen and hydrogen with the formula NH3, under normal conditions a colorless gas with a sharp characteristic odor, has a high polarity and good solubility in water. Molecular weight-17.3 g/mol.
Microscopic studies were performed using JSM-6510LA electron scanning microscopy.
The study of the bactericidal properties of modified packaging materials was carried out according to the following method. The samples were placed in Petri dishes containing Endo-medium with pre-seeded bacteria, and thermostated at 19°C. The clearance zone was determined 24 hours after bacterial inoculation by measuring the clearance diameter around the treated material. Escherichia coli bacterial strains were used as test cultures.
RESULTS AND DISCUSSION adjusting the pH value with an aqueous solution of am-
TiO2 nanoparticles were prepared by hydrolysis of monia at a temperature of 30°C. To determine the opti-titanium tetrachloride (TiCZ4) in an alkaline medium, mal concentrations of the initial components, a series of
experiments was conducted (Table 1).
Table 1.
Concentrations of the initial components.
Samples Initial reagent (TiCU) PH Temperature (0C) HCl (1 h)/ H2O NH4OH
1 2.74 ml pH=2-7 T=30°C 9 ml/ 50 ml 18 ml
2 5.48 ml pH=2-7 T=30°C 9 ml/ 50 ml 18 ml
3 8.22 ml pH=2-7 T=30°C 9 ml/ 50 ml 18 ml
4 10.96 ml pH=2-7 T=30°C 9 ml/ 50 ml 18 ml
In order to determine the size of titanium dioxide study of the presented samples showed (Fig. 1) that at nanoparticles and study their aggregate stability, elec- a pH of 2-7, titanium dioxide nanoparticles with a size tron-scanning microscopy studies were performed. The of 148nm-2.01 microns are formed.
Pic 1. Photos of nanoparticles Ti02 at pH 2-7 (a), (b), (c), (d).
An aqueous solution of TiO2 nanoparticles was all materials for food packaging, such a base is environ-sprayed onto the packaging material-a polylactide. This mentally safe, hygienic, and quickly degradable in a choice was based on the fact that, in comparison with natural way, which is especially important when processing waste.
Table 2.
Antimicrobial properties of packaging materials modified with titanium dioxide nanoparticles
№ Antimicrobial properties Clearance zone, mm
Control sample Solid growth
I Solid growth
II Strong growth
III 2-3
IV 2-5
The antimicrobial effect was evaluated by the degree of inhibition of bacterial growth at different incubation times compared to control samples. The results of the studies showed that a high growth of microorganisms was observed in the control samples. In the samples treated with solutions of titanium dioxide na-noparticles, a growth delay zone of E. coli microorganisms is observed in the range of 2-5 mm (Table 2). With an increase in the concentration of titanium dioxide na-noparticles, the antibacterial properties of polylactide packaging materials increase.
CONCLUSION
Titanium dioxide nanoparticles with a size of 148nm-2.01 microns were synthesized, and the size of the nanoparticles increases with increasing temperature and pH of the medium.
The results of the conducted studies have shown the effectiveness of the proposed antimicrobial composition based on titanium dioxide nanoparticles. The developed antimicrobial composition based on titanium dioxide nanoparticles for polylactide packaging materials prevents food spoilage by suppressing the development of microorganisms, which allows to increase the shelf life of food products.
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LINEN MATERIALS WITH ANTIBACTERIAL PROPERTIES MODIFIED WITH TITANIUM
DIOXIDE NANOPARTICLES
Sadykova M.
Master's degree student, Technology ofproduction of textile materials, Almaty Technological University
Tausarova B.
Doctor of Chemical Sciences, Professor, Chemical Technology and Ecology,
Almaty Technological University
Abstract
The work is devoted to giving antibacterial properties to textile materials to improve their hygienic characteristics by modifying them with titanium dioxide nanoparticles. A method for obtaining titanium dioxide nanoparticles by hydrolysis of titanium tetrachloride in an aqueous medium has been developed.
Keywords: nanoparticles, titanium dioxide, linen material, antibacterial properties
INTRODUCTION
The great attention shown in the world to nano-technology is largely determined by the possibility of directed modification of the physical and chemical properties of substances with a decrease in the particle size.
The study of new dimensional effects characteristic of nanomaterials and their quantitative determination require the development of scalable and reproducible methods for obtaining substances in nanostructured form.
A consequence of the development of nanotech-nology is the creation of a variety of materials contain-
ing nanoscale particles. Currently, the industrial volume of production of various nanoproducts has already reached hundreds of thousands of tons.
Due to its high chemical inertness, lack of toxicity and low cost, titanium dioxide is increasingly being used, while it has a number of significant disadvantages: low quantum efficiency of the process due to weak electron-hole pair separation, limited absorption spectrum in the ultraviolet region, which makes it impossible to use the energy of sunlight. Scientists in all the leading countries of the world are engaged in solving these problems. [1-6].