Micromechanical deformations in PP/lignocellulosic filler composites: Effect of matrix properties

Renner, Karl; Móczó, János; Suba, Péter; Pukánszky, Béla

doi:10.1016/j.compscitech.2010.02.029

Cited by 29 publications

(31 citation statements)

References 31 publications

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“…Three of the fibers (wood, heavy and gsoft fraction) have very similar effect on composite strength that is quite surprising since soft particle behavior dominated acoustic activity in the latter. This behavior contradicts previous experience showing close correlation between acoustic activity and tensile strength in various composites Renner et al 2010a;Renner et al 2010b). The composition dependence of the tensile strength of the composites containing the light fraction is even more difficult to explain.…”

Section: Properties and Reinforcementcontrasting

confidence: 56%

Biocomposite from polylactic acid and lignocellulosic fibers: Structure–property correlations

Faludi

Dora

Renner

et al. 2013

Carbohydrate Polymers

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PLA biocomposites were prepared using three corncob fractions and a wood fiber as reference. The composites were characterized by tensile testing, scanning electron (SEM) and polarization optical (POM) microscopy. Micromechanical deformation processes were followed by acoustic emission measurements. The different strength of the components was proved by direct measurements. Two consecutive micromechanical deformation processes were detected in composites containing the heavy fraction of corncob, which were assigned to the fracture of soft and hard particles, respectively.The fracture of soft particles does not result in the failure of the composites that is initiated either by the fracture of hard particles or by matrix cracking. Very large particles debond easily from the matrix resulting in catastrophic failure at very low stresses. At sufficiently large shear stresses large particles break easily during compounding, thus reinforcement depending on interfacial adhesion was practically the same in all composites irrespectively of initial fiber characteristics.

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Section: Properties and Reinforcementcontrasting

confidence: 56%

Biocomposite from polylactic acid and lignocellulosic fibers: Structure–property correlations

Faludi

Dora

Renner

et al. 2013

Carbohydrate Polymers

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“…It is reasonably large for the relatively stiff PLA already in the neat polymer and increases even further upon coupling. The figure also shows that and fiber fracture as the dominating local deformation process [9,18,[52][53][54]. Initiation strain and thus also initiation stress increases [39] with increasing MAPLA content indicating better stress transfer at larger amount of coupling agent.…”

Section: Properties and Reinforcementmentioning

confidence: 99%

Modification of interfacial adhesion with a functionalized polymer in PLA/wood composites

Csikós

Faludi

Domján

et al. 2015

European Polymer Journal

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Maleic anhydride (MA) grafted poly(lactic acid) (PLA) coupling agents (MAPLA) were prepared by reactive processing. The amount of peroxide initiator and MA was changed in a relatively wide range. Coupling efficiency was checked in PLA/wood composites as a function of grafting degree, coupling agent and wood content. The analysis of the results showed that chain scission takes place in PLA during reactive modification. The occurrence of grafting could not be proved by FTIR spectroscopy, but a detailed NMR analysis showed that the degree of grafting depends on the amount of both reactants; a maximum of 2.5 MA groups/PLA chain could be grafted under the conditions used in the study. The functionalized polymer proved to be an efficient coupling agent in PLA/wood composites. Efficiency increased with increasing number of functionality and coupling agent amount. Coupling resulted in increased strength and reinforcement.Acoustic emission analysis of deformation processes supported by microscopy proved that the dominating local deformation process is the fracture of the fibers, but small extent of debonding also occurs in neat, uncoupled composites. The prevention of debonding by coupling resulted in the improved performance of the composites. Local processes initiate the immediate failure of the composite irrespectively of their mechanism.

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“…the separation of the interface between the matrix and the reinforcement, several other processes including matrix yielding, the pull-out or fracture of the fibers, cavitation, etc. may also take place during the deformation of the composites (Dányádi et al 2007;Faludi et al 2013a;Imre et al 2012;Renner et al 2007;Renner et al 2010b). Some of these are burst-like processes emitting elastic waves, which can be picked up by appropriate sensors.…”

Section: Interfacial Adhesionmentioning

confidence: 99%

Thermoplastic starch/wood composites: Interfacial interactions and functional properties

Müller

Renner

Móczó

et al. 2014

Carbohydrate Polymers

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Thermoplastic starch (TPS)/wood composites were prepared from starch plasticized with 36 wt% glycerol. The components were homogenized by dry-blending, extruded and injection molded to tensile bars. Tensile properties, structure, deformation, water adsorption and shrinkage were determined as a function of wood content, which changed between 0 and 40 vol% in 7 steps. The modification of TPS with wood particles improves several properties considerably. Stiffness and strength increases, and the effect is stronger for fibers with larger aspect ratio. Wood fibers reinforce TPS considerably due to poor matrix properties and strong interfacial interactions, the latter resulting in the decreased mobility of starch molecules and in the fracture of large wood particles during deformation.Strong interfacial adhesion leads to smaller water absorption than predicted from additivity, but water uptake remains relatively large even in the presence of wood particles. The shrinkage of injection molded TPS parts is very large, around 10 %, and dimensional changes occur on a very long timescale of several hundred hours. Shrinkage decreases to a low level already at 15-20 vol% wood content rendering the composites good dimensional stability.

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Micromechanical deformations in PP/lignocellulosic filler composites: Effect of matrix properties

Cited by 29 publications

References 31 publications

Biocomposite from polylactic acid and lignocellulosic fibers: Structure–property correlations

Biocomposite from polylactic acid and lignocellulosic fibers: Structure–property correlations

Modification of interfacial adhesion with a functionalized polymer in PLA/wood composites

Thermoplastic starch/wood composites: Interfacial interactions and functional properties

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