Structure and properties of highly filled poly (vinyl alcohol)/talc composites prepared through thermal processing: Effects of talc size

Poly (vinyl alcohol) (PVA), a multi-hydroxyl polymer with excellent comprehensive properties, is an expected candidate to prepare high-performance polymer-based composites without using any coupling agents or compatibilisers. However, the poor thermal processability of PVA is its biggest obstacle. In this paper, by adopting polyol as a plasticiser, highly filled PVA/talc composites with good mechanical properties were successfully obtained through melt extrusion and injection, and the effects of talc size on structure and properties of the composites were studied. The results showed that talc highly filled PVA composites had satisfying melt processability, and the decrease of talc particle size increased the –OH groups on the edges of the talc layers, thus improving the compatibility between talc and PVA, and making talc particles dispersed more uniformly in PVA matrix. As a result, the composites with smaller talc particles had the higher threshold filler concentration to form the filler networks and the better flow behaviour. The smaller talc flakes also exhibited higher orientation in PVA matrix and induced more PVA molecular chains to orient along the melt flow direction, leading to the enhancement of the mechanical properties of the composites.