Mechanical, rheological, and carbon dioxide barrier properties of polyvinylidene fluoride/TiO2 composites for flexible riser applications

Nanoparticles can act as a barrier to gas penetration in the polymer matrix. However, the agglomeration of nanoparticles has a negative effect on the comprehensive properties of nanocomposites. We envisioned surface modification of 25 nm TiO 2 nanoparticles with KH550 to enable better dispersion in the polyvinylidene fluoride (PVDF) matrix and prepared PVDF/TiO 2 composites by the melt blending method. The effects of adding modified nanoparticles into the matrix on the thermodynamic, mechanical, rheological, and gas barrier properties were studied. We find that the dispersion of TiO 2 in the matrix significantly improved after modification, as observed in the SEM images. As a result, the mechanical properties of composites decreased with an increase in the content of nanoparticles, and PVDF/N-TiO 2 composites showed better mechanical and CO 2 barrier properties. The permeability coefficient of PVDF/0.5% N-TiO 2 has the lowest permeability coefficient, which is 18.30% lower than primary PVDF. At a high shear rate, the viscosity of PVDF/N-TiO 2 with 0.5% and 1.0% content decreased, and the viscosity of 1.5% ratio was higher than that of primary PVDF. PVDF/0.5% N-TiO 2 has the best comprehensive performance and also possesses the advantages of simple preparation, low cost, and ease of industrial production.