Khashayar Mohajer shojaei* , Ali Farrahi,Hossein Farrahi ,Ahmad Farrahi
Farrokh Sepehr Kashan Company , Kashan , Iran
Nowadays, polyester filament yarn with permanent anti bacterial characteristic is known as an innovative yarn in textile industries such as machine made carpet and garment.
Different methods such as chemical modification, entrapment and encapsulation were applied to stabilize nano silver particle on polyester filament yarn for using in machine made carpet.
In this article, we modified nano silver particle by chemical reaction in order to produce polyester filament yarn with permanent anti bacterial characteristic by spraying method.
Antibacterial tests were carried out on nano silver coated machine made carpet according to the ATCC 27853, 25923 and 25922 in 72 hrs before and after washing process. Results showed that nano silver coated polyester machine made carpet has a permanent anti bacterial characteristic.
Microbial organisms, bacteria and micro organisms are as main reasons for sickness, infections and bad smelling, etc.
Increasing death rate in many undeveloped countries such as many African countries led to legislation of global and social policies in order to overcome this challenge. Such problems and needs have led to resurgence in use of silver and copper based antiseptics that may be linked to broad spectrum activity and far lower propensity to induce microbial resistance than antibiotics .
The antibacterial characteristic of silver and silver salts has been noticed since antiquity . Ag is currently used to control bacterial growth in a variety of applications including dental work ,catheters and burn wounds[3,4].
In fact, it is well known that Ag ions, Ag based compounds, copper and brass compounds showing strong biotical effect on many bacteria species such as E.coli, P.aeruginosa and s.aureus .
Different factors have influence on efficiency of silver and copper based compounds such as particle size and particle size distribution. In these cases, reduction of the particle size of silver and copper nano particle is as a reliable solution to improve their efficiency and biocompatibility.
In this field, nano technology has a direct effect on elimination of particle size limitations and changing the world outlook regarding science [10, 11].
A lot of information is available about practical use of nano particles for food safety and hygiene, disinfection of water in swimming pools and hospitals, wound healing, air disinfection and surface sanitation [6, 7, 8].
It is believed that the germicidal property of metals especially heavy metals is due to oligodynamic effect in which metal and metal compounds, when introduced in to the interior of bacterial cells , have ability to change and finally kill them in a specific way. Copper and silver are the most studied metals for oligodynamic action .
Data from silver suggest that its ions denature proteins in the bacterial cells by binding to reactive groups resulting in their inactivation .
In this study, we investigated about the stabilization of nano silver on polyester filament yarn in order to produce machine made carpet with permanent antibacterial characteristic.
Materials and methods
Nano silver colloid was obtained from US Research Nano material Company. Polyester filament yarns as a pile, warp and weft in machine made carpet were provided by Farrokh Sepehr Kashan Textie Company. Gluteraldehyde (cross linking agent) and α-amino propyl tri etoxy silane were provided by Sigma –Aldrich Company in laboratory scale. Amphoteric surfactant based on amino betaine was provided by Carp Company.
Nano silver colloids including cross linking agent and amphoteric surfactant in different concentrations were applied to the polyester filament yarn and back of machine made carpet by spraying method.
Nano silver coated polyester filament yarn and polyester machine made carpet were dried and cured in the stenter at 130 0c for 6 minutes.
To predict the stability of antibacterial characteristic, characteristic of nano silver back coated polyester machine made carpets were analyzed according to the ATCC 27853, 25923 and 25922 in 72 hrs before and after washing process in Pasteur Institute of Iran.
Antibacterial characteristic of nano silver coated machine made carpet were measured based on the growth of different bacteria such as E.coli ,P.aeruginosa and s.aureus in according to the reference sample .
Stability of nano silver colloids and their particle size distribution were analyzed by DLS (dynamic light scattering) method in 25 0C (Malvern seri nano (zeta sizer) model DLS).
FTIR analysis of obtained solution from washing of nano silver coated polyester filament carried out by Fourier transform spectroscopy in 300 to 4000 cm-1.
Distribution of nano silver on the back of polyester filament machine made carpet was analyzed by FESEM method in 1.89 KX (Philips model FESEM).
Mac Farlan solution of different bacteria such as P.aeruginosa (ATCC: 27853), S.aureus (ATCC: 25923) and E.coli (ATCC: 25922) at concentration of 1.5* 10 8 CFU/ml were prepared in first stage.
At following stage, nano silver coated machine made carpet and reference machine made carpet put in contact with the Mac Farlen solution of different bacteria for 24 hrs.
After cultivation and incubation process for 72 hrs in 37 0c, the growth of bacteria were analyzed.
Results and discussion
Particle size distribution of nano silver colloid
Particle size distribution of nano silver colloid was measured by DLS method. Results showed that the average size of nano silver colloid and Pdi constant were about 49.08 nm and 0.408 respectively. In fig. 1, size distribution of nano silver was shown.
Fig. 1: size distribution of nano silver colloid
Stability of nano silver colloid
Stability of nano silver colloid was measured by DLS method according to the zeta potential amount. Results showed that the nano silver colloid has a suitable stability under normal condition. In figure 2, zeta potential distribution of nano silver was shown. According to the fig. 2, the zeta potential for nano silver colloid is about -17.2 Mv. On the other hand, nano silver particle colloid has a suitable stability against sedimentation.
Distribution of nano silver on the back of polyester machine made carpet
Distribution of nano silver on the back of machine made carpet was shown by FESEM micrograph in 1.89 KX.
According to the fig.3, it can be concluded that antibacterial characteristic of polyester filament machine made carpet is due to the nano silver material has been applied on polyester filament yarn and the back of machine made carpet.
Fig. 3: SEM micrographs of samples
a) Polyester filament yarn b) Nano silver coated polyester filament yarn
Anti bacterial test
Nano silver back coated machine made carpet before and after washing were tested according to the ATCC 27853, 25923 and 25922 in 72 hrs. In table 1 and 2, concentration of bacteria before and after washing processes were represented.
Table 1: Anti bacterial characteristic of samples before washing
Table 2: Anti bacterial characteristic of samples after washing
Results showed that nano silver coated polyester filament machine made carpet before and after washing has suitable antibacterial characteristic against E.coli ,P.aeruginosa and s.aureus (99.9 %anti bacterial characteristic).
FTIR analysis of nano silver coated polyester filament machine made carpet
In order to demonstrate permanentness of antibacterial characteristic in polyester filament machine made carpet, FTIR analysis carried out on nano silver colloid and obtained solution from washing of nano silver coated polyester filament machine made carpet . In fig. 3, FTIR analysis of nano silver colloid and obtained solution from washing of nano silver coated polyester filament machine made carpet have been shown.
According to the Fig. 4a, the sharp peaks in 1634 and 1384 cm-1 indicate the formation of asymmetric and symmetric stretching mode of metal carbonyl groups. It is due to the stabilization of silver nano particles by the –COO- group of amino betaine (as amphoteric surfactant). The peaks in 3432 and 2922 cm-1 are related to C-H stretching bond of propyl and the amine group of α-amino propyl tri etoxy silane.
According to the Fig. 4b, the sharp peaks in 3444 and 2934 cm-1 are related to the O-H and C-H groups of soap solution which are used for washing of nano silver coated polyester filament machine made carpet.
Moreover, lack of any peak in 1634 and 1384 cm-1 indicates that washing process hadn’t effect on the removing of silver nano particle from antibacterial polyester filament machine made carpet.
Results showed that nano silver coated polyester filament machine made carpet has a permanent anti bacterial characteristic. It is due to the modification process carried out on nano silver before applying on polyester filament yarn and the back of machine made carpet.
Having permanent antibacterial characteristic in machine made carpet, make it more suitable for using in crowded places by outlawing from making bad odor in machine made carpet due to the direct contact of people with machine made carpet surface.
This work was done in Farrokh Sepehr Kashan Company. Mr. Ali Farrahi and Mr.Ahmad Farrahi are grateful for the financial support.
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