Microstructure characterization of polyamide fibre/latex-filled plaster composites

We have investigated the microstructure of polyamide fibre/plaster and latex-filled plaster binary blends, and fibre/latex-filled plaster ternary blends. The influences of the latex (nature and concentration) and the fibres (concentration, length) were analysed in terms of the gypsum crystals morphology, the distribution of the polymer phase and the porosity of the materials. Addition of polyamide fibres and/or polymer latexes to plaster results in a coarser crystallisation, and disturbs the hydration of plaster; the porosity raises with the amount of fibres but decreases with the concentration of latex. It is shown that the presence of latex may noticeably modify the porous network of the plaster. These results are correlated to the setting of the materials.