Production of PVAc–starch composite materials by co-grinding — Influence of the amylopectin to amylose ratio on the properties

Mixtures of polyvinyl acetate (PVAc) filled with two starch types containing different amylopectin to amylose ratios were co-ground in a laboratory tumbling ball mill. The influence of the starch nature and of the co-grinding treatment on the production mechanism and on the composite properties was studied. The thermal and mechanical properties were characterized, as well as the behavior in water. esence of starch in the mixture reduces agglomeration phenomena between matrix particles, as well as the mobility of polymeric chains. While a simple mixing of the constituents generates starch concentration points in the matrix, co-grinding favors filler dispersion and PVAc–starch interactions enabling an increase of the mixture properties without adding any chemical agent. The amylopectin to amylose ratio does not affect significantly mechanical properties while a high amylopectin rate promotes water uptake.