Short cellulosic fiber/starch acetate composites — micromechanical modeling of Young’s modulus

Abstract

This study is presented to predict the Young’s modulus of injection-molded short cellulosic fiber/plasticized starch acetate composites with variable fiber and plasticizer content. A modified rule of mixtures model is applied where the effect of porosity is included, and where the fiber weight fraction is used as the basic independent variable. The values of the input model parameters are derived from experimental studies of the configuration of the composites (volumetric composition, dimensions, and orientation of fibers), as well as the properties of the constituent fiber and matrix phases (density and Young’s modulus). The measured Young’s modulus of the composites varies in the range 1.1—8.3 GPa, and this is well predicted by the model calculations. A property diagram is presented to be used for the tailor-making of composites with Young’s modulus in the range 0.2—10 GPa.

Non-destructive automatic determination of aspect ratio and cross-sectional properties of fibres

“…In the process the original flax fibres tend to become partially fragmented such that the final composite may also contain smaller segments and pieces of fibres ('fines') with a wide distribution of size and shape. The experimental values of Young's modulus of the materials were determined by tensile tests according to ISO 527 standard [2,34]. According to the rule-of-mixtures model [33] the Young's modulus E c of a composite material is given by…”

“…Within micromechanical approach to estimating composite material performance, quantities describing the microscopic or mesoscopic structure of a composite are combined with mechanical properties of the constituents in order to estimate the macroscopic properties of the material [1][2][3][4]. For short-fibre reinforced composite materials the relevant statistical quantities describing the microstructure include, e.g., diameter, length and orientation distributions of fibres, and volume fractions of the constituents.…”

Apparent interfacial shear strength of short-flax-fiber/starch acetate composites

“…The constituents, production, morphological analysis, and testing of short-flax-fiber reinforced starch acetate composites has been described in [6,7]; below, for completeness and the ease of reference, we briefly recapitulate the relevant information.…”

“…Short-bast-fiber composites with a starch acetate matrix (with a degree of acetylation evaluated at 2.6) and different content of plasticizer were produced and characterized [6]. While the stiffness [7] and tensile strength [8] of the composites have been subjected to detailed studies, the evaluation of the fiber/matrix adhesion achieved has been addressed only via an analysis of composite strength [8].…”

Predicting stiffness and strength of birch pulp – Polylactic acid composites

“…The other is the length of the fibres. Madsen et al 11 assessed stiffness and strength of cellulosic fibre -starch acetate composites with the short fibre theory. Eitzenberger 12 and Lu 13 have written good reviews on the methods for predicting stiffness and strength of short fibre composites.…”