Nowadays, there is an increasing urge to replace fossil-based monomers with bio-based alternatives in a number of applications. Within the context of coating technology, polymeric colloidal particles, namely latexes, are in the forefront of this greener transition. Latexes can be produced primarily by emulsion polymerization, where the hydrophobic polymer is stabilized with a low molecular weight active agent, known as surfactant. Although emulsion polymerization is used extensively in the industry, it lacks control over the final particle size. Being able to control the particle size, one can tailor the film formation and surface properties depending on the end-application. A different way to synthesize latex nanoparticles is by using controlled radical polymerization (CRP) techniques, such as reversible addition−fragmentation chain-transfer (RAFT) polymerization. RAFT provides the advantage of producing “living” polymers and when combined with a process called polymerization-induced self-assembly (PISA), the latexes can be synthesized in a two-step fashion; Firstly, a hydrophilic polymer is produced which is then used to further chain extend a hydrophobic monomer in water. This results in the formation of an amphiphilic diblock copolymer which forms the aforementioned nanoparticles. The advantage of using RAFT-PISA is that the size of the final latex can be tailored depending on the number of repeating units chosen for its hydrophobic core when the hydrophilic chain remains constant. In this work, we have used the methacrylated version of sobrerol (SobMA), a terpene derived monomer in order to replace high Tg core latexes, such as PMMA. We synthesized nanosized latexes by using both emulsion polymerization where the stabilizing agent was a cationic surfactant and RAFT-PISA where a cationically charged polymer stabilized the bio-based hydrophobic core. Both approaches yielded charged nanolatexes of varying size and different kinetic profiles. Additionally, their morphology was investigated by microscopy techniques, such as AFM and FE-SEM. Their ability to adsorb on cellulose was also studied in detail by FE-SEM and their film formation mechanism was compared with commercially available sulfated PS latexes. This work expanded the scope of sobrerol in the field of coating applications while maintaining the control over the polymerization and tailoring the size of the formed nanolatexes on-demand.

Bio-based nanolatexes synthesized by emulsion and RAFT-mediated polymerization-induced self-assembly (PISA)

ACS Spring Meeting 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.