Research Projects

The urgent global demand for sustainable energy solutions has intensified the focus on hydrogen as a clean fuel, especially in the transportation sector. The Type IV hydrogen storage tanks, comprising carbon fiber-reinforced polymer (CFRP) composites, are widely recognized for their lightweight structure and high mechanical performance, providing a distinct advantage over metallic storage alternatives. These type IV composite pressure vessels consist of approximately 60 % carbon fibers and 40 % epoxy resin by volume. In India, a limited number of research laboratories, government institutions, and a few startup companies, along with entrepreneurs, are currently engaged in the challenging task of developing type IV hydrogen storage tanks indigenously, aiming to position our country on par with global researchers. However, the reliance on the traditional thermoset epoxy resin composites presents significant environmental challenges, particularly regarding the disposal of end-of-life materials. These composites, when incinerated or disposed of in landfills, contribute significantly to environmental pollution due to their non-recyclable nature. Furthermore, the carbon fibers, which constitute over 70% of the total cost of type IV tanks, are also non-recoverable. Traditional thermoset composite materials are characterized by permanent crosslinks that impede recycling. Attempts at recycling through mechanical processes or pyrolysis typically result in reduced quality of carbon fibers, diminishing their commercial value. Concurrent with the design and development efforts for indigenous hydrogen storage tanks, equal emphasis must be placed on researching sustainable materials and processes for the fabrication of these tanks. Strategies aimed at recovering and reusing carbon fibers could yield significant economic and environmental benefits. The escalating environmental challenges have led to the development of innovative alternative chemistries such as ‘covalent adaptable networks (CANs)’, which offer a sustainable approach to composite development through the use of dynamic covalent bonds, including imine bonds, ester bonds, disulfide bonds, acetal linkages, and carbamate linkages. In contrast to conventional thermosets, CANs exhibit thermal malleability, reprocessability, and the ability to self-heal or degrade when subjected to specific external stimuli, such as pH, heat, and UV light. The current proposal aims to strike a balance between high-performance hydrogen storage and environmentally responsible materials. Recent advances in dynamic covalent chemistry—particularly the incorporation of imine and disulfide linkages—have opened exciting avenues in the development of recyclable thermoset polymers. Our research team at CSIR NCL, Pune, has been working to develop recyclable photocurable molecules suitable for 3D printing formulations. Preliminary work has shown that these dynamic covalent bonds of imine and disulfide linkages enable dynamic reconfigurability in crosslinked polymer networks, thus introducing recyclability into traditionally irreversible thermoset systems. Building upon this foundation, the current project explores the engineering of reversible hardeners based on these chemistries, specifically to formulate high-performance, recyclable epoxy matrices. When combined with carbon fibers in Type IV hydrogen storage tanks, these recyclable epoxies offer the promise of maintaining structural and mechanical performance while enabling the extraction of the carbon fiber. The objective of the project is to fabricate type IV hydrogen storage tank of 8 to 10 liters capacity using HDPE / Nylon 6 liner and recyclable resins and carbon fibers and validate its mechanical properties. Successfully developing a recyclable, miniaturized tank opens doors for use in two-wheelers, drones, small industrial robots, and even portable power units—segments where weight, size, and safety are crucial.