High solid content poly(butyl acrylate)/poly(methyl methacrylate) core/shell nanosized spheres synthesised by microemulsion polymerisation

Core-shell nanosized polymer particles with poly(butyl acrylate) (PBA) as core and poly(methyl methacrylate) (PMMA) as shell were synthesised via a semi-continuous two-stage microemulsion polymerisation. A series of experiments were conducted to investigate the maximum solid content of the microemulsion under different surfactant/monomer ratios, and it was found that the maximum solid content could reach around 43.73% with minimum surfactant/monomer at only 5.25 wt%. The particle samples were characterised by proton nuclear magnetic resonance (H-1-NMR), scanning electron microscopy, transmission electron microscopy (TEM) and dynamic light scattering (DLS) techniques. H-1-NMR and TEM results revealed that PBA/PMMA core/shell composite latexes were synthesised successfully by microemulsion polymerisation. DLS studies indicated that an optimal dosage of surfactant (1.29 wt% of the total amount of monomers) was found to synthesise particles with desired core-shell structure, which was consistent with the theoretical calculation. The size of nanoparticles increased with the increase in the amount of core monomer, showing an inverse relationship with surfactants.