Preparation and characterization of polystryrene/poly(butylacrylate methacrylate acid) core-shell nanostructured films

Abstract

Poly(n-butyl acrylate-co-methacrylic acid) (PBA-MAA) latex series that contained polystyrene(PS) seed was prepared by seeded emulsion polymerisation. The seed-shell nanoparticles were designed with high (PS seed) and low glass transition temperature (Tg), respectively. Two types of monomer crosslinkers i.e. ethylene glycol and 1,3-butanediol dimethacrylate (1,3-BDDMA) were added into the formulation to prevent the particles from agglomeration, as well as to increase the covalent-crosslinked of polymer chains. In this study, the effects of PS content, surfactant addition mode, the degree of neutralisation, and types of monomer crosslinkers on the physical and mechanical properties of samples were investigated. Analysis using dynamics light scattering showed that the addition of PS seed increased consistency of particle size. The strains of the films were improved when surfactant was added at an initial charge compared to the feeding during polymerisation. The addition of a small percentage of ionic groups zinc oxide (ZnO) and monomeric crosslinkers increased the stress and modulus of the films. By contrast, they decreased the strain and tackiness of the films. Meanwhile, spectra from Fourier transform infrared spectroscopy confirmed that the ZnO had bonded to the carboxylic groups –RCOOH. The stress-strain data showed the neutralisation at 100n was required to increase the stress-at-break up to 0.5 MPa and to decrease strain-at-break by a factor of 2. The addition of 1,3-BDDMA crosslinker had increased the stress-at-break by the factor of 1. Meanwhile, the Tg of the films did not significantly affect by the addition of crosslinkers and ZnO, as shown by differential scanning calorimetry data.