The increasing concerns about plastic pollution and climate change have encouraged research into bioderived and biodegradable materials. Much attention has been focused on nanocellulose due to its abundance, biodegradability, and excellent mechanical properties. Nanocellulose-based biocomposites are a viable option to fabricate functional and sustainable materials for important engineering applications. This review addresses the most recent advances in composites, with a particular focus on biopolymer matrices such as starch, chitosan, polylactic acid, and polyvinyl alcohol. Additionally, the effects of the processing methods, the influence of additives, and the outturn of nanocellulose surface modification on the biocomposite’s properties are outlined in detail. Moreover, the change in the composites’ morphological, mechanical, and other physiochemical properties due to reinforcement loading is reviewed. Further, mechanical strength, thermal resistance, and the oxygen–water vapor barrier properties are enhanced with the incorporation of nanocellulose into biopolymer matrices. Furthermore, the life cycle assessment of nanocellulose and composites were considered to analyze their environmental profile. The sustainability of this alternative material is compared through different preparation routes and options.

Plastic waste recycling remains constrained by limited cost competitiveness and energy-intensive conversion and separation. Here, we evaluate the conversion of plastic waste into refinery-compatible “poly-crude” as a pathway for plastic reintegration into existing petrochemical infrastructure, potentially eliminating the need for dedicated downstream upgrading facilities and associated capital investments. We present an early-stage, system-level sustainability assessment of poly-crude production, evaluating two hydroconversion pathways (hydrocracking and hydrogenolysis) and multiple hydrogen supply strategies. Economic performance was assessed using probabilistic technoeconomic analysis integrating process modeling, Latin hypercube uncertainty sampling, and global sensitivity analyses, while environmental performance was evaluated through scenario-based greenhouse gas (GHG) emission calculations. Results show that 20% of simulated cases achieve poly-crude minimum selling prices (MSPs) below the benchmark crude-oil price, indicating constrained profitability. Scenario analysis reveals that profitability requires hydrocracking with on-site green hydrogen production, poly-crude yields above 90%, feedstock prices below $0.3 kg−1, and capacities exceeding 250 tons day−1. GHG emissions are highly sensitive to the electricity mix and hydrogen conversion pathway, making any potential benefits relative to crude oil strongly scenario-dependent. This work provides the first probabilistic, system-level evaluation of plastic waste hydroconversion to refinery-compatible intermediates and identifies key performance targets and research priorities for improving process viability.