Biobased polymer molecules are a goal for the future. Here, the different intermediate pathways toward renewable structural constituents, which can substitute petrochemically derived unsustainable ones, are evaluated. Various biomass resources are covered, such as cellulose, hemicellulose, lignin, lipids, and proteins, as well as their building blocks, such as sugars, glycerol, or itaconic acid. Further emphasis is put on the impact of the impurities in the biobased monomers and the possible separations steps to remove them. The kinetics of the radical polymerization process of reacting acrylic monomers, methacrylic monomers, and styrene is reviewed. Classical elementary mechanisms are briefly discussed, while focus is put on secondary chemical reactions that influence rates greatly at elevated system temperatures, starved-feed conditions, and unideal-mixed reactor units. These functional measures have now become a common standard practice in resin production manufacturing. Described breaking/forming transformations are the styrene self-initiation step, macromonomer carrier propagation, backbiting, long chain branching, β-scission, and methacrylate continuous depropagation. The effect of the copolymerization on involved occurring changes is also overviewed. Likewise, functionality now plays a much greater role than it used to, is linked to final formulation characteristics, and is thus an integral related part of this theoretical methodology. Cross-linking mechanisms are briefly discussed. Last but not least, an insight into modeling is presented with an emphasis on lumping, the method of moments, Monte Carlo applications, and simulating conversions, as well as correlated molecular mass distributions.