S. Asha

Preparation and characterization of silk fibroin/hydroxypropyl methyl cellulose (HPMC) blend films

The present research work deals with the characterization of blend films obtained by mixing silk fibroin (SF) and hydroxypropyl methylcellulose (HPMC) solutions. Structural, chemical, surface morphology, mechanical and thermal property changes of silk fibroin by the addition of HPMC were investigated by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), universal testing machine (UTM), thermogravimetric (TGA) and differential scanning calorimetry (DSC). The results indicate that with the introduction of HPMC, the interactions between SF and HPMC in the blend films induced the conformation transition of SF from random coil form or silk I to β-sheet structure or silk II form. The SF/HPMC blend films are flexible, and showed enhanced mechanical properties also the thermal stability of the films was improved significantly.

Microstructural, thermal and antibacterial properties of electron beam irradiated Bombyx mori silk fibroin films

The Bombyx mori silk fibroin (SF) films were prepared by solution casting method and the effects of electron beam on structural, thermal and antibacterial responses of the prepared films were studied. The electron irradiation for different doses was carried out using 8 MeV Microtron facility at Mangalore University. The changes in microstructural parameters and thermal stability of the films were investigated using Wide Angle X-ray Scattering (WAXS) and thermogravimetric analysis (TGA) respectively. Both microstructuralline parameters (crystallite size and lattice strain (g in %)) and thermal stability of the irradiated films have increased with radiation dosage. Agar diffusion method demonstrated the antibacterial activity of SF film which was increased after irradiation on both Gram-positive and Gram-negative species.

Quantification of Degradation and Surface Morphology of NB7 Silk Fibers Irradiated by 8 MeV Electron Beam Using XRD and SEM Techniques

NB7 silk fiber (Bombyx mori) was irradiated with the maximum dose range of 100 kGy using 8 MeV electron beam at room temperature. Irradiation effect in these fibers is quantified in terms of the changes in microstructural parameters employing X-ray diffraction line profile analysis technique. For this purpose we have used three asymmetric distribution functions for column lengths in a crystal. The decreasing trend of crystallite size values (〈N〉 as well as Ds) and crystallinity with increasing dosage of radiation clearly indicates the degradation of fiber. Of the several factors responsible for such a behavior, we presume that the chain scission of polymer network is a significant one over others and it is well pronounced here, leading to low molecular weight of the samples. This degradation is attributed to many changes in tensile properties of the polymer. Comparison of SEM photographs also confirms the X-ray results.

Structural, surface wettability and antibacterial properties of HPMC-ZnO nanocomposite

The developed hydroxypropyl methylcellulose (HPMC)/Zinc oxide (ZnO) nanocomposite films were examined for structural property and surface wettability using X-ray diffraction and contact angle measurement. Antibacterial activity of these films was evaluated as a function of ZnO concentration. The microstructuralline parameters ( and (g in %)) decreased with increasing concentration of ZnO nanoparticles and there was increase in hydrophilicity. Addition of ZnO nanoparticles in films resulted in antimicrobial activity against tested microorganisms.

Effect of gamma irradiation on HPMC/ZnO nanocomposite films

The present work looks into the structural and mechanical properties modification in ZnO nanoparticle incorporated Hydroxypropyl methylcellulose (HPMC) polymer films, induced by gamma irradiation. The irradiation process was performed in gamma chamber at room temperature by use of Cobalt-60 source (Average energy of 1.25MeV) at different doses: 0, 50, 100, 150 and 200 kGy respectively. The changes in structural parameters and mechanical properties in pure and gamma irradiated HPMC/ZnO nanocomposite films have been studied using X-ray scattering (XRD) data and universal testing machine (UTM). It is found that gamma irradiation decreases the structural parameters and improves the mechanical properties of nanocomposite films.

Preparation and characterization of silk fibroin/HPMC blend film

In this work, the structural and mechanical stability of silk fibroin/Hydroxypropylmethyl cellulose (SF-HPMC) blend films were characterized by X-ray diffraction (XRD) and Universal Testing Machine (UTM). The results indicate that with the introduction of HPMC, the interactions between SF and HPMC results in improved crystallite size and increase in mechanical properties. The blend film obtained is more flexible compared to pure SF film.

Influence of Electron Irradiation on Tassr Non-mulberry Silk Fibers

Influence of Electron Irradiation on Tassr Non-mulberry Silk Fibers In this work the effect of electron irradiation on the structural, chemical and thermal properties of tassar non-mulberry silk fibers was investigated. Tassar silk fiber (Antheraea mylitta) samples were irradiated in air at room temperature using 8 MeV electron beam in the range 0 to 100 kGy. Various properties of the irradiated fibers were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). The wide angle X-ray scattering (WAXS) study shows the crystallite size (L) increases with increasing radiation dosage. It was found that the thermal stability of the fibers improved after electron irradiation.

The preparation and characterization of silk fibroin blended with low molecular weight hydroxypropyl methylcellulose (HPMC)

In this work, the structure and optical properties of Silk Fibroin (SF), lower molecular weight Hydroxypropyl Methylcellulose (HPMC(L)) and its blend film of SF-HPMC(L) were studied by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Scanning electron Microscope (SEM) and UV-Visible spectroscopy (UV-Vis). The results indicates that the homogeneous miscible blend of SF-HPMC(L) has lower crystallite size and lower optical band gap compared to virgin SF and HPMC(L). FTIR study confirms the presence of both SF and HPMC(L) molecules in the prepared blend films.In this work, the structure and optical properties of Silk Fibroin (SF), lower molecular weight Hydroxypropyl Methylcellulose (HPMC(L)) and its blend film of SF-HPMC(L) were studied by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Scanning electron Microscope (SEM) and UV-Visible spectroscopy (UV-Vis). The results indicates that the homogeneous miscible blend of SF-HPMC(L) has lower crystallite size and lower optical band gap compared to virgin SF and HPMC(L). FTIR study confirms the presence of both SF and HPMC(L) molecules in the prepared blend films.

The gamma irradiation effects on structural and optical properties of silk fibroin/HPMC blend films

In this paper the structural, chemical and optical properties of gamma irradiated silk fibroin/Hydroxypropyl methyl cellulose (SF-HPMC) blend films were studied using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and UV-visible spectroscopy. The results indicate that the gamma radiation did not affect significantly the primary structure of polypeptide arrangement in the blend films. But the optical properties of the blends changed with gamma irradiation dosage.

Influence of electron irradiation on the structural and thermal properties of silk fibroin films

Radiation-induced changes in Bombyx mori silk fibroin (SF) films under electron irradiation were investigated and correlated with dose. SF films were irradiated in air at room temperature using 8 MeV electron beam in the range 0-150 kGy. Various properties of the irradiated SF films were studied using X-ray diffraction (XRD), Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA). Electron irradiation was found to induce changes in the physical and thermal properties, depending on the radiation dose.