In the current study, chitosan films were prepared by dispersing different commercially-modified nanoclays, such as C-Na, C-10A, C-15A, C-30B, and C-93A. The exfoliation and morphology were studied using XRD and SEM. The C-15A, C-30B and C-93A nanoclays/Cts BNCs (Bionanocomposites) showed very good uniform exfoliation compared to that of other clays. The thermal analyses were evaluated using DSC and TGA. These results also confirmed that because of exfoliation, the thermal properties were improved in the case of C-15A, C-30B and C-93A nanoclays/Cts BNCs. The swelling capacity of a chitosan/clay films were studied. Increasing the chitosan content in the film increased the swelling capacity significantly; the decreasing order of swelling capacity of Cts/Clay films is in accordance with the decrease in clay content. Greater swelling capacity is shown by films Cts, C-Na and C-10A is because of the presence of greater hydrophilic agencies in the film makeup, which assist in improving the swelling characteristics of the films. The antibacterial activities of Cts/clay were also investigated against Gram-negative and Gram-positive bacteria (E. coli and S. aureus) according to the zone of inhibition in the disc diffusion method.
Porous SiC ceramics were successfully fabricated by silica bonding of SiC compacts and porogen burnout technique. Silica coating on SiC particle was carried out using TEOS hydrolysis and crystallizes during the sintering process at 1200°C, which forms a well-developed neck growth between the SiC particles. Different volume fractions of sodium chloride porogen were used to obtain varied porosity content in porous SiC ceramics from 36 to 62.47 % leading to wide-ranging compressive strength from 8.11 to 0.69 MPa. Interconnected bimodal pores were created throughout the sample due to the burnt out of salt and stacking of SiC particles. The pore size distribution of porous SiC measured using mercury intrusion porosimetry shows that average pore size due to the salt particle is around 74-110 lm and stacking of SiC particle result 4-10 lm. Direct squeeze infiltration method is successfully adopted for infiltration of 6061 aluminium molten alloy into SiC preforms with the controlled process parameters of initial preform temperature, liquid metal superheating, squeezed pressure and its rate of application and die temperature. Microstructures have shown complete infiltration of Al alloy into the pores of the SiC preform forming Al composite with good interfacial bonding aided by the presence of MgAl 2 O 4 spinel. The silica coating on SiC surface have a multifunctional role of acting as a binder for the porous preform, enhances the wettability of SiC particle with molten metal during infiltration and prevention of deleterious Al 4 C 3 interfacial reaction product.
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