FRAGMENTATION AND DISGREGATION OF SISAL FIBERS IN THERMOPLASTIC BIODEGRADABLE COMPOSITES

S. IANNACE; R. ALI; L. NICOLAIS; V. P. CYRAS; A. VAZQUEZ.; J.M. KENNY

Italia

Congreso; SAMPE 2000; 2000

Biodegradable composites based on sisal fibers and mater-bi were processed by using an internal batch mixer at different temperatures, speeds of rotation and mixing time. The fibers were then extracted from the composites by solubilizing the polymeric matrix in order to statistically evaluate length, diameter and aspect ratio l/d. Length and diameter of the initial fibers were reduced during mixing and this effect was correlated to the magnitude of the shear stress developed in the mixer. An increase of speed of rotation and/or a reduction of temperature produced fibers of smaller dimensions but with higher aspect ratio l/d. Alkaline treatment speeds up the process of fiber fragmentation and disgregation but do not affect the final dimensions after enough time of mixing.  It was found that the increase of speed of rotation and /or temperature and /or time of mixing increases tensile strength and tensile modulus and this behavior was correlated to the increase of the aspect ratio (l/d).