Samir Kamel

Thermal behaviour and infrared spectroscopy of cellulose carbamates

Cotton linters, swelled cotton linters and carbamated cotton linters of different nitrogen content were followed by IR spectroscopy and thermal analyses. Crystallinity indexes of the swollen and carbamated cotton linters are lower than untreated cotton linters. The decomposition temperature is lower in the case of swelled and carbamated cotton linters than untreated ones. Also the rate constant of thermal treated samples decrease by carbamation and swelling.

Infra-red spectroscopic study of lignins

Infra-red spectra from 200–4000cm−1 of lignin precipitated from black liquor produced from different pulping processes of bagasse, e.g. soda, kraft, sulfite, peroxyacid and butanol, have been characterized. Peroxyacid lignins are more degraded than other lignins. However, peroxyacid lignin has a higher intensity band at 1720cm−1 than other types of lignins. At the same time, the aromatic ring of lignin produced from peroxyacid pulping of bagasse undergoes severe degradation. Syringyl type of lignin is predominant in all isolated lignins. Peroxyacid and butanol lignins have lower quantities of syringyl lignin shown by the lower ratio of relative absorbance of band intensity at 1500cm−1 to the band at 1600cm−1 than other lignins. Kraft lignin has a broad weak band at about 630cm−1 that is probably due to a CS bond. A sharp band at 655cm−1, which is due to SO3H, is characteristic of lignosulfonate, which is precipitated from black liquor produced from sulfite pulping process of bagasse. Generally, degradation of different lignins during pulping of bagasse with different processes has the following sequence: peroxyformic > peroxyacetic > butanol-water > butanol-alkali > kraft > sulfite > soda.

Mechanical and antibacterial properties of novel high performance chitosan/nanocomposite films

Zinc oxide (ZnO) nanoparticle was successfully synthesized using hydrothermal method as well as, silver (Ag) nanoparticle was direct prepared during chitosan nanocomposites preparation. Chitosan films were investigated by recognized the effect of kinds of acids (formic or acetic acid). Correspondingly, using of concentrated NaOH was checking for facilitating de-casting of the films. Utilization of formic acid arisen higher quality films than those films produced using acetic acid as solvent. Optimization was based on the mechanical properties for both types of acids solvent. Furthermore, the elasticity of the prepared films was enhanced by blending hydroxyl ethylcellulose (HEC) with chitosan. Loading the films by silver and zinc oxide nanoparticles (Ag-NPs and ZnO) was achieved during the preparation of films under the optimum conditions. Characterizations of the prepared ZnO nanoparticles and the prepared nanocomposites films were investigated by FT-IR, XRD, SEM, TEM and EDAX. Chitosan nanocomposite films displayed good Antimicrobial activity against Staphylococcus aureus, Escherichia coli, Salmonella typhamrium, Bacillus cereus, and Listeria monocyte. Therefore, these films can be used for packaging applications.

Morphological and antibacterial properties of modified paper by PS nanocomposites for packaging applications.

With the increasing sustainability trend with packaging materials, paper and polymer nanocomposites represent a novel class of packaging materials. This study evaluates the potential achievement of alternative sustainable materials as antibacterial packaging application. Paper sheet from rice straw coated with 5 or 10% polystyrene (PS) nanocomposites using titanium dioxide nanoparticles (TiO2-NPs) doped or undoped with sliver nanoparticles (Ag-NPs) were prepared. The morphology of the uncoated and coated paper sheets was studied by SEM. The treated paper sheets were analyzed for their elemental composition using EDAX. The Barrier, air permeability, cob test, as well as mechanical properties and tensile strength were also evaluated. The inhibitory effect of modified paper sheets against Pseudomonas, Staphylococcus aureus, Candida, and Staphylococcus were investigated.

Lignocellulosic polymer composite IV

Palm leaves as a woody lignocellulose, together with polystyrene, were used to produce composites. Chemithermal mechanical pulps (CTMP) were obtained from palm leaves under alkaline or acidic conditions. Appropriate bending strength was obtained from palm leaves and their CTMP pulps prepared under neutral or acidic conditions. The bulky fibers resulted from the alkaline pulps lead to composites of low bending strength. Thus, the cooking conditions of the palm leaves to obtain CTMP pulp play an important role on the properties of the composites. The nonbulky fibers lead to the formation of trapped pockets air as the number of the hydrogen bond are few. The presence of these air pockets allows the polystyrene solution to enter forming bonding between the interfaces. It is also found that the lower the density of the composites, the lower the internal bond strengths. The chemical constituents of the CTMP pulps, as well as the yields of the pulps, may influence the properties of the composites. Increasing the percentage of polystyrene in the composites, the mechanical properties increased. The water uptake and the swellability decreased until 20% polystyrene concentration and then levelled off. The thickness and density behaved the same. However, the type of substrate of the composite and the weight fraction are the important factors in determining the properties of the composites.

Biological studies and electrical conductivity of paper sheet based on PANI/PS/Ag-NPs nanocomposite

Polyaniline (PANI) with/without polystyrene (PS), was successfully manufactured in the occurrence of dispersed pulp fibers via the oxidative polymerization reaction of aniline monomer to produce conductive paper sheets containing PANI, PANI/PS composites. Additionally, sliver nitrate (Ag-NO3) was added by varied loadings to the oxidative polymerization of aniline monomer to provide sliver nanoparticles (Ag-NPs) emptied into the prepared paper sheets. The prepared paper sheets were examined using scanning electron microscopy (SEM), X-ray diffraction (XRD) and infrared spectroscopy (IR), the mechanical properties of the prepared paper sheets were evaluated. Moreover, the electrical conductivity and biological studies such as cellulases assay, Microorganism & culture condition and detection of the released of Ag-NPs were evaluated. Furthermore, the prepared paper sheets were displayed good antibacterial properties contrary to gram positive and gram negative bacteria. Consequently, the prepared paper sheet may be used as novel materials for packaging applications.

Structural and electrical properties of paper–polyaniline composite

Conducting polymers have generated a great deal of interest because of their physical and chemical properties as well as their potential application in industry particularly in packaging applications. However one of short comings of most conducting polymer is that they are often formed as intractable films that are difficult to process. To overcome this problem we have incorporated conducting polymer, namely polyaniline into sheets of paper in order to create new composite material which combine the universal properties of paper product with the chemical and electrically conducting properties of the conducting polymer. Paper conducting polymer composite have been prepared by polymerizing aniline directly onto the paper sheet using ammonium peroxydisulfate (APS) as an oxidant at different temperatures. The prepared composite was characterized by FT-IR and SEM. The thermo-oxidative degradation was studied by thermo gravimetric analysis (TGA); electrical conductivities measurements of the composites were significantly increased over those of the precursor paper.

Rapid synthesis of antimicrobial paper under microwave irradiation.

The silver-nanoparticle (AgNP) containing paper was successfully prepared. The AgNP is deposited by the in situ reduction of silver nitrate on the acrylamide grafted bagasse paper sheets in the presence of citrate molecules as stabilizing agent. In the present paper, grafting of acrylamide onto bagasse paper sheets using potassium persulfate was carried out under the influence of microwave radiations (MWR). The modified paper sheets were characterized by Fourier transform infrared spectroscopy (FTIR), UV-spectroscopy, and scanning electron microscopy (SEM). Antimicrobial activities of the prepared paper sheets were also investigated against G+ve bacterium Staphylococcus aureus, G-ve bacterium Pseudomomas aeruginosa, and yeast Candida albicans, which are model microorganisms for testing bactericidal properties. The AgNP containing paper sheets exhibited antibacterial activity.

Optimization of Carboxymethylation of Starch in Organic Solvents

A comparative study of the influence of ethanol, benzene, acetone, isopropanol, and mixtures of ethanol-acetone, ethanol-benzene, and ethanol-isopropanol as slurry media on the degree of substitution and viscosity of carboxymethyl starch during carboxymethylation is presented. It is shown that the degree of substitution increases with increasing acetone, isopropanol, or benzene content in the mixed solvent. After the same carboxymethylation steps the degree of substitution with ethanol/benzene mixture is higher than that with ethanol/isopropanol mixture.

Carboxymethyl cellulose based hybrid material for sustained release of protein drugs.

Hybrid materials contain polysaccharide based network and biomimetic calcium phosphate are potentially appropriate for bone repair and drug release. Novel hydrogel composed of carboxymethyl cellulose backbone grafted with crosslinked poly(dimethylaminoethyl methacrylate) CMC-g-PDMAEMA was subjected to biomimetic calcium phosphate mineralization through simulated body fluid. Infrared spectroscopy (IR), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA) confirmed calcium phosphate mineralization while X-ray diffraction and transmission electron microscopy (TEM) results suggested that the deposited phase contains mineralized component of bone, hydroxyapatite. CMC-g-PDMAEMA hydrogels before and after calcium phosphate mineralization were investigated as a drug carrier and the results showed significant efficiency of the mineralized hydrogel to deliver bovine serum albumin (BSA). These results indicated that CMC-g-PDMAEMA/calcium phosphate could serve as a new class of multifunctional hybrid materials for various biomedical applications.