الفهرس 
Chapter I IntroductionOnly 14 pages are availabe for public view
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Abstract
The present work was under taken to impart different protected finishes for cotton and cotton/polyester fabrics for using in the fields of antimicrobial, fire retardancy and UV protection. These finishes were carried out via treatments with nanocomposites based on blends loaded with different additives under the effect of gamma irradiation. An important objective is that these finishes do not affect the original properties but enhances these properties. The present work falls in three parts and the important results obtained may be classified as follows:
Part 1
Antibacterial functionalization of cotton and cotton/polyester fabrics applying hybrid coating of copper/chitosan nanocomposites loaded polymer blends via gamma irradiation
Textile fabrics especially those based on natural fibers such as cotton and wool, can act as a media for the growth of microorganisms. Natural textile materials can be exposed to contamination with microbes (bacteria, fungi, algae) during production, usage or storage. The microbial attack of textiles leads to quality losses due to changes of color and appearance or to reduction in strength. The contact with the human body also, such materials offer an ideal environment for microbial growth because of their large surface area and ability to retain oxygen, moisture and warmth. Therefore, the antimicrobial finishing of natural fabrics has attracted much attention in recent years.
In this part, copper/chitosan nanocomposites (Cu/CS) were prepared in an aqueous solution in the presence of CS as stabilizer and CuSO4•5H2O precursor. Cotton and cotton/polyester fabrics were gamma-radiation grafted by padding to pickup of 100%, in nanocomposites based on Cu/CS NPs loaded in polymer blends of poly(vinyl alcohol) (PVA) and plasticized starch (PLST). The coated fabrics were characterized in terms of tensile mechanical, crease recovery and water absorption properties. The important results may be summarized as follows:
(1) The Cu/CS NPs formation was proved through transmission electron microscopy (TEM), Dynamic light scattering (DLS), Fourier Transform infrared (FT-IR) spectroscopy and XRD diffraction.
(2) The results showed that cotton fabrics displayed higher water absorption (%) than cotton/polyester fabrics for all PVA/PLST compositions and water absorption was found to decrease with increasing the ratio of PVA in the PVA/PLST blends.
(3) Cotton/polyester fabrics displays crease recovery angle (CRA) value of 147.6 upon treated with PVA/PLST (80/20%) and gamma irradiated to 30 kGy compared to CRA value of 125.0 for cotton fabrics treated under the same conditions.
(4) For cotton fabrics, the tensile strength was largely depends on the irradiation dose, in which the tensile strength of the treated fabric with the different formulations is higher than the untreated fabric.
(5) The antimicrobial activity of the fabrics against gram-positive bacteria (Staphylococcus aurous) and gram-negative bacteria (Escherichia coli) was investigated. In case of gram-positive bacteria cotton fabric showed the highest impact, for both 50/50 and 20/80 PVA/PLST of 14 and 14.5 mm inhibition zone, whilst, cotton/polyester fabric recorded 6 and 5 mm inhibition zone against gram-negative bacteria for 50/50 and 20/80 PVA/PLST, respectively. However, the highest activity was achieved in the case polymer blends rich in plasticized starch.
Part 2
Flame retardancy of cotton and cotton/polyester fabrics treated by gamma-radiation grafting of PVA/PLST blends containing aluminum and phosphorus compounds
The main objective of this part is to impart flame retardancy properties to cotton and cotton/polyester fabrics by coating with poly(vinyl alcohol)/plasticized starch blends loaded with aluminum and phosphorus metals under the effect of gamma irradiation. The treated fabrics were characterized in terms of water absorption, crease recovery, thermal stability, surface morphology and tensile mechanical. The important results may be summarized as follows:
(1) The results showed that the coated cotton fabrics loaded with aluminum metal displayed higher water absorption (%) than grafted cotton/polyester fabrics loaded with aluminum. However, the grafted fabrics loaded with phosphorous, in general, showed relatively higher water absorption than those loaded with aluminum metal. The results indicated that the coating of cotton or cotton/PET fabrics and loaded with aluminum and phosphorous metals enhanced water absorption (%).
(2) The grafting of fabrics and loaded with Al or Ph metals caused significant increase in the CRA, regardless of the kind of fabric or content of metals. However, the CRA was found to increase with increasing the content of metals. The grafted fabrics loaded with Ph showed higher CRA than those fabrics loaded with Al, regardless of the kind of fabric or content of metals. The CRA was found to increase with increasing irradiation dose.
(3) Cotton/PET blend fabric showed higher tensile strength than cotton fabric, regardless of grafting or the metal content. The tensile strength of cotton and cotton/PET was largely depends on the irradiation dose, in which the tensile strength of untreated fabrics was found to decrease with increasing irradiation dose. The grafted cotton and cotton/PET fabrics displayed higher tensile strength than the ungrafted-unirradiated fabrics, regardless of Al and Ph contents. However, the tensile strength of either grafted cotton or cotton/PET fabrics was found to increase with increasing Al or Ph contents associated with increasing irradiation dose. Meanwhile, the grafted fabrics loaded with Ph displayed higher tensile strength than the grafted fabrics loaded with Al. similar trends were observed in the of elongation at break.
(4) The SEM micrographs of grafted fabrics showed that the surface was changed to become rough, in which the fibers forming the fabric structure was covered with the grafting layer with tiny metal clumps. This roughness is found to increase with increasing particularly the content of Al element. The SEM micrographs of the grafted cotton fabrics and loaded with Ph metal showed a thicker layer of grafting, in which the tiny metal particles was entirely deposited in the grafting structure.
(5) The TGA study showed that the temperatures, at which different weight loss (%) occurred of the untreated cotton/PET fabric is thermally stable than untreated cotton fabrics. The grafted cotton fabrics loaded with Al and Ph metals displayed higher temperatures than untreated cotton fabrics indicating higher thermal stability. The untreated cotton fabrics undergo thermal decomposition through single rate of thermal decomposition reaction; the untreated cotton/polyester undergoes thermal decomposition through two stages. In this regard, the untreated cotton/PET fabrics displayed higher thermal stability with first Tmax at 250.3oC and second Tmax of 390.3oC compared to a single stage at 235.1oC. The grafted cotton or cotton/PET fabric undergoes thermal decomposition through two stages of thermal decomposition reaction rate, irrespective of the type of loaded metal. However, the two Tmax were still higher than that of the untreated fabrics.
(6) The flammability test in terms of time to catch fire (TF), time after glowing (TG) and weight left (WL) showed that the grafted fabric displayed improved flammability than untreated fabrics. Grafted cotton fabric showed higher stability against fire, versus the blend fabric for both Al ad Ph treatments. The Ph-treated fabric manifested high char formation on the surface of the fabric that suppressed the ignition of samples over that of Al-treated ones. Both Al ad Ph metal proved to satisfy the highest flame retardancy with minimum weight lose percent.
Part 3
UV protection of cotton and cotton/polyester blend fabrics coated with PVA/PLST/ZnO NPs nanocomposites under the effect of gamma irradiation
The main objective of this part is to impart UV protection properties to cotton, and cotton/polyester fabrics and enhancing the original chemical and physical properties. In this procedure, the fabrics were treated by coating with nanocomposites based on poly(vinyl alcohol)/plasticized starch (PVA/PLST) blends loaded with Zn NPs. The coated fabrics were then exposed to gamma radiation to induce crosslinked hybrid structure. The important results may be summarized as follows:
(1) The formation of Zn NPs was confirmed by UV/vis absorption and XRD patterns measurements.
(2) Water absorption was suddenly increased after " ~ " one hour and then tends to increase gradually up to 5 hours and then reached to the equilibrium state up to 48 hours, irrespective of the of fabric kind or the irradiation dose. However, the untreated cotton fabrics displayed higher water absorption (%) than the untreated cotton/polyester fabrics due to the presence of synthetic component.
(3) The unirradiated cotton fabric displayed CRA of 78.0o, while unirradiated cotton/polyester blend displayed CRA of 95.0o due to presence of the synthetic polyester component. The coated cotton/PET blend fabrics with [(PVA/PLST)/Zn NPs displayed higher CRA than the treated cotton fabrics with the same nanocomposite, regardless of irradiation dose. The CRA of either cotton or cotton/PET fabrics were found to increase with increasing irradiation dose up to 20 kGy and then tend to decrease at relatively higher doses.
(4) Cotton/PET blend fabric showed higher tensile strength than cotton fabric, due to the presence of synthetic component. The tensile strength of cotton and cotton/PET was largely depends on the irradiation dose, in which the tensile strength of untreated fabrics was found to decrease with increasing irradiation dose. The treated cotton and cotton/PET fabrics displayed higher tensile strength than the untreated fabrics, regardless of irradiation dose.
(5) The SEM micrographs of coated fabrics showed homogeneous distribution on the fabric surface, regardless of the fabric kind. However, the amount of coating on the fiber surface of cotton fabrics was relatively thicker than those coating deposited on the surface of cotton/polyester fabrics.
(6) The treated fabrics with PLST/PVA (50/50%)/Zn NPs showed relatively higher thermal stability than the untreated fabrics within the temperature range of " ~ "200-400oC. The rate of thermal decomposition reaction curves displayed similar trends; however, the temperatures of the maximum rate of reaction (Tmax) differ from material to another. Meanwhile, either the untreated or treated cotton/PET fabrics displayed two Tmax temperatures due to the presence of two fiber components. The temperatures at which the different weight loss (%) occurred or the temperatures of the maximum rate of reaction (Tmax) indicate that the untreated and the treated cotton/PET fabric is thermally stable than untreated or treated cotton fabrics. The higher thermal stability of treated fabrics than the untreated ones is due to the occurrence of crosslinking results from the treatment with gamma irradiation.
(7) The results indicated that the treated fabrics showed highly reducing UV-A, UV-B and ultraviolet protection factor (UPF), particularly with increasing irradiation dose, regardless of fabric kind. It was found that cotton and cotton/PET fabrics coated with PVA/PLST/Zn NPs nanocomposites irradiated to a dose of 30 kGy displayed UPF excellent rating values of 44.31 and 58.23, respectively.