Advanced experimental and modeling investigation of mass transport in polymers: Breakthroughs in CO2 transport, hydrogen storage, and separation of gas and liquid for sustainable applications.

The advancement of sustainable technologies to reduce environmental impact is a key challenge in Chemical Engineering. Polymeric materials offer an energy-efficient alternative to conventional gas separation, transport, and sequestration methods, contributing to industrial process optimization and climate change mitigation. A breakthrough in this field it is essential to develop new sustainable and efficient technologies, that can perform gas, liquid and dense-phase transportation more competently. Various polymeric materials were tested for gas, vapor, and liquid permeation and sorption using different techniques. Specifically, Aquivion was characterized for H₂S, CO₂, and NH₃ separation, while polystyrene-b-polyethylene oxide (SEO) membranes were analyzed for ethanol and water transport in block copolymers with distinct morphologies. Additionally, fluorinated polymers, elastomers, polyethylene, polyamides, and polyether were studied as candidate materials for CO₂ transport applications, including liners, sealants, and gaskets in Carbon Capture and Storage (CCS) systems. To complement the experimental approach, Lattice Fluid and Non-Equilibrium Lattice Fluid models were applied to study CO₂ sorption in commercial rubbery and glassy polymers under a wide range of temperatures (down to -50°C) and pressures (up to 100 bar). These models, validated against experimental data, provided predictive insights into solubility behavior and diffusion coefficient variations, influenced by kinetic mobility and thermodynamic factors. Furthermore, the Standard Transport Model (STM) effectively described gas permeability as a function of pressure and solubility, enabling a deeper understanding of penetrant-polymer interactions and the effects of dense-phase CO₂ under extreme operating conditions, including cryogenic environments. Additionally, similar characterization methodologies were applied to composite materials for hydrogen storage applications. This research enhances knowledge of small molecule transport in polymers and membranes for gas and liquid separation, emphasizing energy efficiency and environmental sustainability.