Film Formation of Inclusion Complexes between Acetyl-Beta-Cyclodextrin and Chitosan
Wirach Taweepreda, Pikul Wanichapichart
Advanced materials research · 2012
In this research, the films which were prepared from inclusion complexes (ICs) of acetyl-beta-cyclodextrin (Acetyl-β-CD) with chitosan were characterized and the membrane properties were investigated. Acetyl-β-CD either improved the solubility of chitosan or increased the salt rejection of the membrane. The crystalline ICs, were formed and found on the membrane surface. There were isolated and characterized by scanning electron microscopy (SEM), X-ray diffraction and atomic force microscopy (AFM). The stability and conformation of the inclusion complexes in solvent and limited number of acetyl-β-CD threaded on chitosan molecules were studied and compared the results on a molecular level of the pseudopolyrotaxane.
Removal of organic impurities in waste glycerol from biodiesel production process through the acidification and coagulation processes
Qiao-guang Xie, Wirach Taweepreda, Charongpun Musikavong, Chaisri Suksaroj
Water Science & Technology · 2012
Treatment of waste glycerol, a by-product of the biodiesel production process, can reduce water pollution and bring significant economic benefits for biodiesel facilities. In the present study, hydrochloric acid (HCl) was used as acidification to convert soaps into salts and free fatty acids which were recovered after treatment. The pH value, dosages of polyaluminum chloride (PACl) and dosage of polyacrylamide (PAM) were considered to be the factors that can influence coagulation efficiency. The pH value of waste glycerol was adjusted to a pH range of 3-9. The PACl and PAM added were in the range of 1-6 g/L and 0.005-0.07 g/L. The results showed best coagulation efficiency occurs at pH 4 when dosage of PACl and PAM were 2 and 0.01 g/L. The removal of chemical oxygen demand (COD), biochemical oxygen demand (BOD(5)), total suspended solids (TSS) and soaps were 80, 68, 97 and 100%, respectively. The compositions of organic matters in the treated waste glycerol were glycerol (288 g/L), methanol (3.8 g/L), and other impurities (0.3 g/L).
Oxidative Degradation Monitoring of Natural Rubber Using S K-Edge X-Ray Absorption near-Edge Spectroscopy (XANES)
Wirach Taweepreda, Wanwisa Limphirat, Prayoon Songsiriritthigul
Advanced materials research · 2012
In this work, we present the results of sulfur crosslinking and degradation in natural rubber (NR) studied by X-ray absorption near-edge structure spectroscopy (XANES). Sulfur K-edge XANES spectra has been collected and analyzed to provide the geometry and electronic environment of sulfur crosslinks during vulcanization and degradation processes by ozone aging. We found that reversion took place before the onset of oxidative process at the sulfur bridge. Parallel to the oxidative process, the production of cyclic sulfanes took places. This physico-chemical properties which were calculated from S K-edge XANES spectra were correlated with the mechanical of NR films by varying accelerator type. The accelerator zinc diethyldithiocarbamate (ZDEC) gave highest film strength when compared with other accelerators: N-cyclohexylbenzothiazole sulfenamide (CBS), 2,2' dibenzothiazyl disulfide (MBTS), and tetramethylthiuram disulfide (TMTD).
Preparation of Deproteinized Natural Rubber Latex and Properties of Films Formed by Itself and Several Adhesive Polymer Blends
Wiwat Pichayakorn, Jirapornchai Suksaeree, Prapaporn Boonme, Wirach Taweepreda, Garnpimol C. Ritthidej
Industrial & Engineering Chemistry Research · 2012
This work aimed first to prepare deproteinized natural rubber latex (DNRL) and investigate the properties of films after it was blended with various adhesive polymers: hydroxypropylmethyl cellulose (HPMC), methyl cellulose (MC), sodium carboxymethyl cellulose (SCMC), poly(vinyl alcohol) (PVA), poloxamer 407, and sodium alginate. The second aim was to identify the films that would be the best for medical and pharmaceutical applications. Dibutyl phthalate (DBP), diethyl phthalate, dibutyl sebacate, triethyl citrate, and glycerin (GLY) were used as plasticizers to improve the elasticity and adhesiveness of the novel materials. DNRL was prepared by proteolytic alcalase enzyme treatment, followed by centrifugation. The DNRL was virtually free of protein, produced no significant reaction in the rabbit skin irritation test, and formed a good elastic film, but it had low skin adhesive properties. Blending DNRL with several polymers produced better films with different elastic and adhesive properties. Moisture uptake and swelling tests indicated that its films provided increasing hydrophilicity when blended with several polymers. SEM showed homogeneous films, and water hydraulic permeability tests indicated some porosity in matrix films. Blending DNRL with HPMC or PVA and DBP or GLY produced films with the best potential for novel materials. FT-IR, DSC, and XRD studies indicated the compatibility of the blended ingredients. In conclusion, DNRL blends could be used suitably for medical and pharmaceutical applications.
Deproteinized natural rubber film forming polymeric solutions for nicotine transdermal delivery
Wiwat Pichayakorn, Jirapornchai Suksaeree, Prapaporn Boonme, Thanaporn Amnuaikit, Wirach Taweepreda, Garnpimol C. Ritthidej
Pharmaceutical Development and Technology · 2012
Film forming polymeric solutions were prepared from DNRL blended with MC, PVA, or SAG, together with dibutylphthalate or glycerine used as plasticizers. These formulations were easily prepared by simple mixing. In a preliminary step, in situ films were prepared by solvent evaporation in a Petri-dish. Their mechanical and physicochemical properties were determined. The in vitro release and skin permeation of nicotine dissolved in these blended polymers were investigated by a modified Franz diffusion cell. The formulations had a white milky appearance, and were homogeneous and smooth in texture. Their pH was suitable for usage in skin contact. The mechanical property of in situ films depended on the ingredients but all compatible films were in an amorphous phase. The DNRL/PVA was shown to be the most suitable mixture to form completed films. The in vitro release and skin permeation studies demonstrated a biphasic release that provided an initial rapid release followed by a constant release rate that fitted the Higuchi's model. Nicotine loaded DNRL/PVA series were selected for the stability test for 3 months. These formulations needed to be kept at 4°C in tight fitting containers. In conclusion, film forming polymeric solutions could be developed for transdermal nicotine delivery systems.
Polyethylene Thin Film Coating Preventing the Degradation of Natural Rubber
Wirach Taweepreda, Kritsada Phatcharasit
Engineering Journal · 2012
In this research, natural rubber (NR) was directly mixed with polyethylene (PE) and was compressed at 150 o C. The PE was then separated and migrated to form a thin film on the rubber surface during the vulcanization process. The tensile properties of composite film were rising with increasing the PE contents from 15 to 150 phr as well as the ozone aging properties. The surface topography of the composite film was examined by using scanning electron microscopy (SEM) and was found that the PE form lamellar crystallites on the rubber interface after ozone treatment. The effect of PE on NR crosslinking was also investigated using S K-edge XANES Spectroscopy.
Shrinkage and Compressive Strength Behaviors of Clay Brick Blended with Concentrated Latex IndustryBs Waste Residue
Warintorn Banchapattanasakda, Wirach Taweepreda, Thunwadee Tachapattaworakul Suksaroj, Chaisri Suksaroj
Engineering and Applied Science Research · 2012
This research aims to study the utilization of the waste residue from concentrated latex industry asa raw material for clay brick making process, in order to dispose the waste residue from concentrated latexindustry. The experiments were done in laboratory scale and the variation ratios of fat clay and waste residue,100 : 0, 80 : 20, 70 : 30, 60 : 40 and 50 : 50 (w/w) were investigated. The blended materials were bakedat 200oC and then burned at 1,050oC for 24 hours. The burned clay bricks obtained were tested for civilengineering purpose. The results found that the texture of the surface of the waste residue amended claybricks was porous and their weights were lighter than native clay brick weight by 30%. Their linear shrinkagetest showed the percentage of linear shrinkage increased accordingly the increasing of waste residue portionin clay brick. Beside, the waste residue amended clay brick had the compressive strength in range of20-30 kg/cm3 that met the ASTM C-67 clay brick standard.
Self-assembled nanometric spacer on surface of natural rubber composited with TiO2
Wirach Taweepreda, Kritsada Phatcharasit
World Journal of Engineering · 2012
The dispersion of titanium dioxide (TiO2) was mixed with natural rubber latex (NRL) and other additives before casting on glass slide. The dispersion of TiO2 (75% by wt.) were prepared using high pressure homogenizer by varying the concentration of stabilizer, poly (ethylene glycol) (PEG). The results were found that PEG can disperse TiO2 in water phase and the mechanical properties of NRL film composited with TiO2 dispersion is enhancement with increasing the PEG concentration. The effects of the stabilizer and NRL compounding on composited films properties were discussed using surface morphology. The morphology of TiO2 dispersion and composited NRL films were investigated using scanning electron microscopy (SEM) and atomic force microscopy (AFM).