Nand Kumar; Dibyendu Sekhar Bag; Krishna Pratap Singh; Akansha Dixit; Shashank Mishra; Durgesh Nath Tripathi; Namburi Eswara Prasad
Abstract
Self-sealing polymers possess the virtue to seal small punctures/cracks/damages automatically whenever occurred in the materials/components during their service. This behaviour of self-sealing in polymeric materials is inspired by the biological system in which self-sealing is a usual phenomenon. There ...
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Self-sealing polymers possess the virtue to seal small punctures/cracks/damages automatically whenever occurred in the materials/components during their service. This behaviour of self-sealing in polymeric materials is inspired by the biological system in which self-sealing is a usual phenomenon. There are many self-sealing approaches demonstrated by researchers which are being applied in many polymeric components and systems to prevent them from catastrophic failure. The sealant materials in these systems are the main parts which play a crucial role in the sealing phenomenon. This review article describes self-sealing phenomenon, sealant materials and their applications in the various strategic materials and systems namely self-sealing spacecraft structures in the meteoroid environments, self-sealing fuel tank for fighter aircrafts, self-sealing hemostatic syringe to prevent bleeding, self-sealing tires to prevent punctures and concrete structures to prevent water leakages etc.

Akansha Dixit; Nand Kumar; Dibyendu S. Bag; Kavita Agarwal; Dhirendra K. Sharma; N. Eswara Prasad
Abstract
Silver nanoparticles (AgNPs) embedded double network (DN) nanocomposite hydrogels [of P(AM-co-HEMA) as second network and PVA-Borax as first network] were synthesized by in-situ reduction of silver nitrate using citric acid in presence of the fully swollen high strength DN hydrogels. The AgNPs embedded ...
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Silver nanoparticles (AgNPs) embedded double network (DN) nanocomposite hydrogels [of P(AM-co-HEMA) as second network and PVA-Borax as first network] were synthesized by in-situ reduction of silver nitrate using citric acid in presence of the fully swollen high strength DN hydrogels. The AgNPs embedded DN nanocomposites hydrogels (Ag-DNG) were characterized by FTIR, XRD and TEM analyses. Such Ag-DNG hydrogels were studied for their degree of swelling and swelling kinetics. They were also evaluated for their anti-bacterial characteristics using a Gram negative (Escherichia coli) and a Gram positive (Bacillus subtilis) bacteria. The XRD analysis revealed the presence of AgNPs in the DN nanocomposite hydrogels. The AgNPs were observed to be 20-50 nm in diameter as observed by TEM analysis. The degree of swelling of Ag-DNG hydrogels was lower than that of the virgin DN hydrogel which was because of the space of pores of the DN hydrogels occupied by AgNPs. The virgin DN hydrogels did not exhibit any antimicrobial property, whereas Ag-DNG hydrogels exhibited a significant amount of antibacterial activity towards gram positive and gram negative bacteria. Such AgNPs incorporated high strength DN nanocomposite hydrogels may find potential biomedical application.
