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 (1H-NMR), scanning electron microscopy, transmission electron microscopy (TEM) and dynamic light scattering (DLS) techniques. 1H-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.