Umaprasana Ojha

Prof. Umaprasana Ojha


Research Focus & Metrics

Academic Career Length

17Years (2010-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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22 January 2020 in ACS Applied Polymer Materials
Verified
Journal Article
Closed access
SDSuman Debnath
Suman Debnath
SKSwaraj Kaushal
Swaraj Kaushal
Umaprasana OjhaUmaprasana Ojha
Umaprasana Ojha


6 October 2016 in Macromolecules
Verified
Journal Article
Open access
RBRanjana Baruah
Ranjana Baruah
AKAnuj Kumar
Anuj Kumar
Rewati Raman UjjwalRewati Raman Ujjwal
Rewati Raman Ujjwal
SKSoumya Kedia
Soumya Kedia
ARAmit Ranjan
Amit Ranjan
Umaprasana OjhaUmaprasana Ojha
Umaprasana Ojha
Utilizing the dynamic amidation and aza-Michael addition chemistry, a set of high strength, recyclable, and self-healable covalent adaptable networks (CANs) are synthesized by reacting the precursor and commercial oligoamine cross-linkers under mild temperature (25–50 °C) and solvent-free conditions. The amide linkages present in these CANs are readily hydrolyzable under mild acidic (pH = 5.3) conditions, whereas the aza-Michael adducts with secondary amines are thermally reversible. Utilizing the above, these CANs are depolymerized under ambient conditions in mild acidic solution and recycled with retention of original mechanical properties. The crack on the material surface is self-healed at 50 °C. The precursor, a Knoevenagel condensation product of terephthalaldehyde and diethyl malonate, is easily synthesized in a large scale. Suitable model compounds are synthesized and studied to further understand the transformations involved in the polymerization–depolymerization of these networks. These networks exhibit adequate tensile properties (ultimate tensile strength ≤35 MPa and Young’s modulus ≤3 GPa), and the properties can be tuned further by suitably changing the oligoamine cross-linker. The simplicity of synthesis, cost effectiveness, adequate mechanical property, stability in aqueous and organic media, and recyclability along with self-healability render these CANs suitable for a range of applications.

19 March 2021 in Advanced Functional Materials
Verified
Journal Article
Closed access
PDF file
SMSubhankar Mandal
Subhankar Mandal
SKSrishti Kumari
Srishti Kumari
MKMilan Kumar
Milan Kumar
Umaprasana OjhaUmaprasana Ojha
Umaprasana Ojha

30 November 2018 in Macromolecules
Verified
Journal Article
Closed access
SDSuman Debnath
Suman Debnath
Rewati Raman UjjwalRewati Raman Ujjwal
Rewati Raman Ujjwal
Umaprasana OjhaUmaprasana Ojha
Umaprasana Ojha

20 December 2019 in ACS Applied Polymer Materials
Verified
Journal Article
Closed access
SMSubhankar Mandal
Subhankar Mandal
ASAnant Seth
Anant Seth
VYVikas Yadav
Vikas Yadav
SKSrishti Kumari
Srishti Kumari
MKMilan Kumar
Milan Kumar
Umaprasana OjhaUmaprasana Ojha
Umaprasana Ojha