Plasticized starch-cellulose interactions in polysaccharide composites

This paper is focused on the interactions between leafwood cellulose fibres and a plasticized wheat starch matrix. Different plasticized starch (TPS)- based composites have been elaborated. LDPE-based composites are used as re ference materials (no fibre-matrix interactions). After extrusion and injec tion moulding, the properties of the different composites are analysed. Mec hanical properties (tensile tests), thermomechanical properties (DMTA) and morphology (SEM) are evaluated. DMTA analysis shows for TPS composites a st rong evolution of the main relaxation temperature, which can be linked to t he existence of cellulose-starch interactions resulting in a decrease of st arch chain mobility. This phenomenon is consistent with the evolution of me chanical behaviour. SEM observations correlate this hypothesis. After cryog enic fracture, TPS composites present fibres, which are embedded in the mat rix. On the composites, reinforcing effects have been observed according to the evolution of fibre length and fibre content. (C) 2001 Elsevier Science Ltd. Ah rights reserved.