Starch and cellulose are naturally abundant biodegradable polymers. Starch has disadvantages such as weak barrier properties against water and poor thermal properties. Polyvinyl Alcohol (PVA) is anticipated to be a good candidate for incorporation into these natural polymers. Also PVA shows high resistance to solvents and good barrier properties to oxygen. Because of their weak barrier properties of Starch or carboxymethyl cellulose and PVA polymeric blend other approach is needed. Making nanocomposites by adding nanoclay to improve barrier properties of these films is a new way. In this research, nanocomposites of carboxymethyl cellulose/polyvinyl Alcohol/clay and starch/polyvinyl Alcohol/clay at three different weight percentage of PVA (15, 30, and 45) and two nanoclay level (5 and 10) were prepared and their films were made after drying. Optical and thermal properties of the nanocomposites were investigated using UV-Vis spectrophotometry, thermogravimetry analysis (TGA/DTG). The energy gap of the samples was calculated using the graph (α hν )2 against hν and tauc equation. The results showed that addition of PVA and nanoclay increased the thermal resistance of nanocomposite. The energy gap of the nanocomposites films is obtained less than the 5 eV, indicating that these nanocomposites has the potential to use in electronic components such as diodes.

Hypothesis: Discovering new chemical modifications for polymers is an interesting way to change the properties and final applications of the polymers. Poly(vinyl Alcohol) (PVA) and ethylene-vinyl Alcohol copolymer (EVA) are useful in practical investigations of functional polymers because they can be modified through their hydroxyl groups. In this study, PVA and EVA were modified to incorporate different reactive functional groups using esterification reaction. Then, substitution reaction was used to incorporate benzimidazole groups into the modified EVA. Azolated EVA can be utilized in other applications such as fuel cell as a proton exchange membrane. Methods: Functional modification of PVA was carried out by acryloyl chloride and maleic anhydride in 1-methyl-2-pyrolydone (NMP, room temperature) and dimethyl sulfoxide (DMSO, 100° C), respectively. Similarly, EVA was modified with chloroacetyl chloride and α-bromoisobutyryl bromide via esterification reaction in NMP at room temperature. Next, benzimidazole group was incorporated into the α-bromoisobutyrylated EVA through substitution nucleation reaction with sodium-2-mercaptobenzimidazole in THF at 80° C. Findings: Chemical structures of polymers were investigated by FTIR and 1H NMR. Functionalization of PVA with acryloyl chloride and maleic anhydride was calculated to be 9. 31 and 46. 28 mol% and that of EVA with chloroacetyl chloride and α-bromoisobutyryl bromide was obtained to be 71. 50 and 63. 46 mol%. The high yield obtained in all of the different proposed routes makes them feasible for activation of EVA copolymers. Moreover, to predict the solubility behavior of functionalized polymers, the Hansen solubility parameters of original and modified polymers were calculated via Hoftyzer-Van Krevelen's (HVK) and Hoy's group contribution methods. Calculations showed that, among studied solvents, dimethylacetamide is the best solvent for acryloylated PVA, carboxyvinylated PVA and EVA copolymer, while acetone is the best one for copolymers modified with chloroacetyl chloride and α-bromoisobutyryl bromide and azolated copolymer, which was in good agreement with the experimental results.

Dehydrogenation and biooxidation of organic compounds such as aliphatic and aromatic petrochemicals can potentially give rise to production of precious substances. Much more expensive chemical feed stocks are produced from low cost substrates using microbial dehydrogenases and biotechnological methods. A screening program resulted to isolation of 14 strains of Bacillus spp. with bioconversion capability from forest soils of north of Iran. Presence of Alcohol dehydrogenase was indicated spectrophotometrically and assayed by determining the amount of NADH yielded through the reactions. Most of the isolates showed an enzymatic activity ranging between 0.2 to 0.7 U/mg-1 proteins.One of the isolates (Bacillus megaterium strain L2) showed the highest dehydrogenase activity (0.8U/mg-1protein). The strain showed the ability to consume a wide range of substrates as the sole carbon source including xylol benzyl Alcohol, cyclohexane, and aliphatic Alcohols such as methanol, ethanol, propanol, and buthanol. Crude extract of the bacterial cells showed dehydrogenase activity in the presence of all of these substrates. Higher dehydrogenase activities were obtained in the presence of linear Alcohols, in comparison with aromatic ones. When benzyl Alcohol was used as substrate, the reactions were not limited to a simple dehydrogenation bioconversion, and further enzymatic reactions occurred and several metabolites were produced at different concentrations. 4-hydroxy- 4-methyl-2-penthenon was produced as one of abundant end products with final relative concentration of 45.6 percent. Thus, it is expected that a range of enzymatic reactions or bioconversion processes such as biooxidation can be catalyzed by further extraction and purification of enzymes.