Advanced Materials Research Vols. 123-125

Abstract: Castor oil based polyurethane (PU) interpenetrating polymer network (IPN) has been prepared by using castor oil, toluene diisocyanate and styrene monomer. The coconut shell powder (CSP) particulate filler with different weight ratios viz., 0, 5, 10, 20 and 30 wt % were incorporated into polyurethane/polystyrene (PU/PS, 90/10) IPN. The effects of CSP particulate filler loading on the physico - mechanical and thermal properties of PU/PS IPN biocomposites have been studied. From the tensile behavior, it was noticed that a significant improvement in tensile strength and tensile modulus with increase in CSP filler content. It was found that the degradation of all composites takes place in two steps. Degradation kinetic parameters were obtained for the composites using Broido (BR), Coats–Redfern (CR) and Horowitz-Metzger methods (HM). The damping property reduced after the incorporation of CSP filler. Morphology of the cryo-fractured composites was studied using scanning electron microscopic technique (SEM).

Abstract: Multiform morphologies of hydroxyapatite nanostructures were synthesized by different methods. Some novel methods were adopted for preparing different morphologies. The morphological analysis confirms that the preparation method greatly influences the morphological characterization. The morphological analysis further confirmed by the TEM analysis. The nanostructure clearly depicts the growth stages of the HAp. The interplanar distances measured in segments (fringes) of the HRTEM micrograph were ~0.35 nm, corresponding to the interplanar spacing of the [002] plane of the hexagonal hydroxyapatite. X-ray Diffraction (XRD) measurements indicate the formation of crystalline hexagonal hydroxyapatite. The morphological dependent properties were analyzed in detail.

Abstract: Composite powders in the calcium carbonate (CC) – hydroxyapatite (HA) system with carbonate content up to 50 wt. % were synthesized by the precipitation from aqueous solution and characterized in detail. Specific area of the powders decreases with an increase in carbonate content due to appearance of large elongated CC crystals of about 0,5 micrometer size. The use of highly active to sintering nanodisperse powders resulted in lowering of sintering temperature below 7200C, preventing thermal decomposition. Ceramics of about 20 wt.% carbonate content revealed the highest strength of about 77 MPa, having the grain size of about 100 nm. According to in vitro testing, the materials are non toxic for human fibroblast cells.

Abstract: Gelatin films were prepared from granular gelatin by casting. Gelatin films were modified by photocuring with a trifunftional monomer Trimethylolpropane trimethacrylate (TMPTMA). Optimum condition for photocuring were established. Water aging of untreated and modified gelatin films was studied. Thermal aging of untreated and TMPTMA treated films were determined at different temperatures (50°C, 70°C and 100°C) for 60 min. pH aging of gelatin films were investigated in different pH solutions (3.2, 4.1, 4.8, 6.9, 9.2, 12.2) for 1min. Water aging, thermal aging and pH aging showed that the TMPTMA grafted gelatin films experienced less deterioration of mechanical properties than pure gelatin films.

Abstract: Gelatin-PVA blend films of different compositions (0%, 5%, 10%, 15% of PVA) were prepared by casting. The tensile strength (TS) and elongation at break (Eb) of the films were studied. The TS and Eb of pure gelatin films were found to be 32 MPa and 3.3% respectively. The films were irradiated under different gamma radiation dose (50 Krad, 100 Krad, 150 Krad, 250 Krad, 500 Krad). 5% PVA containing gelatin films irradiated under 100 Krad gamma radiation showed highest TS of 42 MPa and highest Eb of 4.2%. Thermal property of the films was studied by Thermomechanical analysis (TMA) and Thermogravimetric Analysis (TGA). The grafting of PVA onto gelatin is studied by IR. In order to study surface morphology SEM study was undertaken.

Abstract: Polymer films of rice starch/Polyvinyl alcohol (PVA) were prepared by casting method. Different blends were made varying the concentration of rice starch and PVA. Tensile strength (TS) and elongation at break (Eb) of the prepared films were studied. Films made up of rice starch and PVA with a ratio of 2:8 showed highest TS. 10% sugar was added with highest TS giving four composition of Starch/PVA blend in order to increase TS and Eb. Films made up of rice starch and PVA and sugar with a ratio of 1:8:1 showed highest TS and Eb and the recorded value was 14.96MPa and 637% respectively. The physico-mechanical properties of the prepared sugar incorporated films were improved by grafting with acrylic monomer with the aid of UV radiation. A formulation was prepared with monomer, methylmethacrylat in methanol, and a photo initiator. The highest TS of the grafted films were recorded and the value was 16.38 MPa. The water uptake and weight loss in both soil and water of the grafted films are lower than the non-grafted films. The prepared films were further characterized with stereo micrograph and XRD. Finally, the produced film can be used as biodegradable packaging materials for shopping and garbage bags that are very popular and environment friendly.

Abstract: In this research, a highly volatile membrane forming solution of gelatin with quick membrane forming property (30 sec) was prepared to investigate the suitability of solution spray system in the treatment of wound at dermal surface. A nontoxic Aromatic Ketone (AK) and a highly volatile solvent (VS) were introduced in gelatin solution to ensure high volatility. The solution was subjected to antibiotic dosing using Ciprofloxacin to ensure its anti-infectiveness. The pH of the raw gelatin solution and the highly volatile gelatin solution were 4.95 and 6.17 respectively. Viscosity of gelatin/AK/VS solution was 62.12mPa.s. Wound healing characteristic of the highly volatile solution (gelatin/AK/VS) was evaluated using a rat (Rattus norvegicus) model. Full-thickness wounds were created on the ventral side of the Rattus norvegicus and were dressed with the volatile solution and “eco-plaster” (control). Wound healing and bioadhesion were monitored in 3-days interval. The results revealed that prepared volatile solution was more effective in preventing blood loss as well as healing wounds than the conventional wound dresser.

Abstract: Tencel® is famous for its green manufacturing process and biodegradable ability. In this study, Tencel® was used as dressing matrix materials owing to its good water absorption and smooth fiber surface. Tencel® nonwoven fabric is prepared by needle punching. Then pectin/Chitosan composite solution was coated onto the Tencel® nonwoven fabric to fabricate pectin/Chitosan/Tencel® composite dressing. The best parameters were prepared by compounding the 3 wt% pectin and 1 wt% Chitosan in volume ratio of 60/40 for good moisture retention, proper swelling rate and slower degradable speed. Coating the pectin/Chitosan solution onto the Tencel® fabric brought low the pectin/Chitosan/Tencel® composite dressing’s permeability by 40%. Nevertheless, tensile strength and tearing strength of that pectin/Chitosan/Tencel® composite fabric were improved by 11% and 2%, respectively.

Abstract: The objective of this work is make tissue adhesives agent from Thai rice starch, then test the final products for scientific and medical properties following the laws of Thai health ministry, to demonstrate that this product can be used safely, as same as the standard product. The principal raw material is pharmaceutical grade, Thai rice starch powder. The additives are hydroxyapatite (HA) nanopowder, carboxymethylcellulose, lactic acid, gelatin, polyvinylalcohol and glycerol. All materials will be mixed in distilled water under high temperature, and dried into starch tissue adhesives plate hydrogel. The final product will be kept in medical package and sent for sterilization by gamma radiation. These products will be characterized by scanning electron microscopy (SEM), x-ray diffraction (XRD), stability in water, and adhesive bond strength test in wet environment.

Abstract: Adsorption of cationic dye, methylene blue (MB) onto Xanthoceras Sorbifolia Bunge hull activated carbon (XSBHAC) developed by zinc chloride solution activation has been investigated. Exp eriments were carried out as function of contact time, pH (2-10) and temperature (293, 303, 313 and 323K). Adsorption isotherms were modeled with the Langmuir and Freundlich isotherms. The data fitte d well with the Langmuir isotherm. The Langmuir monolayer saturation capacities of MB adsorbed onto activated carbon were 501.32, 534.54, 588.30 and 593.28mg/g at 293, 303,313, and 323 K, respect ively. The kinetic models were also studied. The rates of adsorption were found to conform to the pseu do-second-order kinetics with good correlation. Using the equilibrium concentration contents obtained at different temperatures, various thermodynamic parameters, such as△G, △H and△S, have been calc ulated.The thermodynamics parameters of system indicated spontaneous and endothermic process.