Composites based on jute fabrics and polypropylene was fabricated by heat-press molding technique. The mechanical properties of the composites such as tensile strength, tensile modulus, bending strength, bending modul...Composites based on jute fabrics and polypropylene was fabricated by heat-press molding technique. The mechanical properties of the composites such as tensile strength, tensile modulus, bending strength, bending modulus and impact strength were measured in dependence of fiber contents. In order to improve fiber-matrix interaction, jute fabrics were treated with aqueous solutions of K2Cr2O7 (0.005-0.05% w/v). Composite prepared with 0.02% K2Cr2O7 treated jute fabrics showed the highest values of the mechanical properties. Thermogravimetric (TG/DTG) data of PP, jute fabrics and composites showed that thermal degradation temperatures of composites shifted to higher temperature regions compared to PP or jute fabrics. Treatment of jute fabrics improved the thermal stability of the composite considerably. Scanning electron microscopic images of tensile fractured sides of untreated and treated composites illustrated that better fiber-matrix interfacial interaction occurred in treated composite. The relative tendency of water absorption of both untreated and treated composites was also explored.展开更多
In the pharmaceutical world the majority of the active pharmaceutical ingredients (API) have been obtained from the natural products. Piperine is such naturally occurring alkaloid which can be considered as major bioa...In the pharmaceutical world the majority of the active pharmaceutical ingredients (API) have been obtained from the natural products. Piperine is such naturally occurring alkaloid which can be considered as major bioactive phytochemical having broad spectrum of pharmacological activities. It is obtained from the most valuable ethnomedicinal spices peppercorns i.e. black pepper and white pepper, which are the fruits of the Asian vine Piper nigrum L. Because of the widespread traditional uses of this medicinal compound, present article reveals a simple and effective isolation method of bulk piperine. The novelty of this investigation is to provide an idea for utilizing such natural method of large scale commercial piperine production as API drug in spite of chemical synthesis. Piperine was isolated in a pure crystal form and characterized by its melting point, X-Ray diffraction (XRD) studies and spectral data, including two-dimensional nuclear magnetic resonance (2D-NMR) spectroscopy. Chromatographic techniques like Thin Layer Chromatography (TLC) and High Performance Liquid Chromatography (HPLC) were applied to determine the purity of the yielded piperine. It was found that piperine yield from black pepper was within 2.5% - 3.0% and from white pepper within 4.0% - 4.5% and the purity of the yielded piperine was found to be up to 98.5% for black pepper and 98.2% for white pepper. Considering this yield value and purity it is indicated that, such effective isolation method can be successfully utilized for industrial large-scale production commercially. According to the result, it can be claimed that, as a natural product the isolated piperine can also be utilized as API drug like other expensive chemically synthesized piperine in different drug formulation.展开更多
文摘Composites based on jute fabrics and polypropylene was fabricated by heat-press molding technique. The mechanical properties of the composites such as tensile strength, tensile modulus, bending strength, bending modulus and impact strength were measured in dependence of fiber contents. In order to improve fiber-matrix interaction, jute fabrics were treated with aqueous solutions of K2Cr2O7 (0.005-0.05% w/v). Composite prepared with 0.02% K2Cr2O7 treated jute fabrics showed the highest values of the mechanical properties. Thermogravimetric (TG/DTG) data of PP, jute fabrics and composites showed that thermal degradation temperatures of composites shifted to higher temperature regions compared to PP or jute fabrics. Treatment of jute fabrics improved the thermal stability of the composite considerably. Scanning electron microscopic images of tensile fractured sides of untreated and treated composites illustrated that better fiber-matrix interfacial interaction occurred in treated composite. The relative tendency of water absorption of both untreated and treated composites was also explored.
文摘In the pharmaceutical world the majority of the active pharmaceutical ingredients (API) have been obtained from the natural products. Piperine is such naturally occurring alkaloid which can be considered as major bioactive phytochemical having broad spectrum of pharmacological activities. It is obtained from the most valuable ethnomedicinal spices peppercorns i.e. black pepper and white pepper, which are the fruits of the Asian vine Piper nigrum L. Because of the widespread traditional uses of this medicinal compound, present article reveals a simple and effective isolation method of bulk piperine. The novelty of this investigation is to provide an idea for utilizing such natural method of large scale commercial piperine production as API drug in spite of chemical synthesis. Piperine was isolated in a pure crystal form and characterized by its melting point, X-Ray diffraction (XRD) studies and spectral data, including two-dimensional nuclear magnetic resonance (2D-NMR) spectroscopy. Chromatographic techniques like Thin Layer Chromatography (TLC) and High Performance Liquid Chromatography (HPLC) were applied to determine the purity of the yielded piperine. It was found that piperine yield from black pepper was within 2.5% - 3.0% and from white pepper within 4.0% - 4.5% and the purity of the yielded piperine was found to be up to 98.5% for black pepper and 98.2% for white pepper. Considering this yield value and purity it is indicated that, such effective isolation method can be successfully utilized for industrial large-scale production commercially. According to the result, it can be claimed that, as a natural product the isolated piperine can also be utilized as API drug like other expensive chemically synthesized piperine in different drug formulation.
