As the impact of climate change becomes more and more apparent, each economic sector must seek to modify its processes, in order to reduce their respective greenhouse gas emissions. The transport sector is no exception, especially considering the high percentage of CO2 emitted after burning fossil fuels during the operation of vehicles equipped with internal combustion engines. Among the many ongoing actions to remedy this situation, is the ongoing replacement of metal parts with plastic ones, in both aesthetic and functional applications. Polyphthalamide (PPA), a high-performance engineering plastic used in very specific conditions, with a high melting point, good mechanical performance and chemical resistance towards many solvents and alcohols at room temperature, is one of the many plastics currently employed in such substitutions. A literature review of the state in academic journal showed many avenues of novel research for any interested scientist. In order to help reduce the emissions, as well as increasing the sustainability of mostly oil based PPA, a number of studies have been performed in which composites and blends have been processed with biocarbon (the solid char left after a biomass has been pyrolyzed), and PA410 (polyamide 4,10, a bioplastic with a high content of renewable monomers extracted from castor beans). The results show that both biocarbon and PA410 afford a significant improvement in mechanical properties over neat PPA, at a lower density than composites filled with commercially used fillers such as talc. Optimization of the material space formed by PPA, PA410 and biocarbon (including its pyrolysis temperature) showed that the key interaction between PPA and biocarbon is responsible for the increase in mechanical properties. A durability study revealed that while the optimum biocarbon composite can compete with a talc-filled one, at least in terms of increasing stiffness and brittleness, it would require an antioxidant that would not incur in a significant decrease of the already achieved mechanical properties or would lead to an increase in density. Many future research lines remain open, especially understanding the nature of the interaction between PPA and biocarbon, as well as gaining a complete understanding of the miscibility between PPA and PA410.