Houževnatost PP částicového kompozitu: role interakce částice-mikrotrhlina

TOUGHNESS OF PP-BASED PARTICLE COMPOSITE: ROLE OF MICRO-CRACK PARTICLE INTERACTIONS

abstract

en

Size, shape and material properties of the particles have a significant effect on the global behaviour of the composite. Generally, the addition of rigid particles to a polymeric matrix has an embrittling effect on the composite. Using very fine isometric filler of sub-micron range with proper surface treatment and good final dispersion enable to achieve enhancement of toughness without significant reduction of its stiffness. In the contribution the role of filler size and interphase properties on micro- and macro-behaviour of particulate composites is analysed from the experimental as well theoretical point of view. The main attention is focused on fracture toughness and stiffness values. The changes in stiffness was characterised by DMTA analysis on the macroscopic level and by pulse 1H-NMR (changes in crystallinity) and DSC analysis on microscopic level. Instrumented notched Charpy impact tests were used to estimate the fracture toughness. The particle reinforced composite has been modelled as a three-phase material and numerically simulated on a microscopic scale using the finite element program ANSYS. Generally, a crack propagating in the matrix has a tendency to deflect to regions with stiffer materials (particles). If the particle is coated, this effect is shielded by the existence of the interphase. It is concluded that one of the possible sources of a toughening mechanism on micro- level is a blunting of the micro-crack caused by its interaction with coated particles. The results of numerical simulations are compared with relevant results determined experimentally.

V příspěvku je studován vliv velikosti, tvaru nebo materiálových vlastností na lomovou houževnatost částicového polymerního kompozitu.

Size, shape and material properties of the particles have a significant effect on the global behaviour of the composite. Generally, the addition of rigid particles to a polymeric matrix has an embrittling effect on the composite. Using very fine isometric filler of sub-micron range with proper surface treatment and good final dispersion enable to achieve enhancement of toughness without significant reduction of its stiffness. In the contribution the role of filler size and interphase properties on micro- and macro-behaviour of particulate composites is analysed from the experimental as well theoretical point of view. The main attention is focused on fracture toughness and stiffness values. The changes in stiffness was characterised by DMTA analysis on the macroscopic level and by pulse 1H-NMR (changes in crystallinity) and DSC analysis on microscopic level. Instrumented notched Charpy impact tests were used to estimate the fracture toughness. The particle reinforced composite has been modelled as a three-phase material and numerically simulated on a microscopic scale using the finite element program ANSYS. Generally, a crack propagating in the matrix has a tendency to deflect to regions with stiffer materials (particles). If the particle is coated, this effect is shielded by the existence of the interphase. It is concluded that one of the possible sources of a toughening mechanism on micro- level is a blunting of the micro-crack caused by its interaction with coated particles. The results of numerical simulations are compared with relevant results determined experimentally.

částicový kompozit, tuhé částice, materiálové vlastnosti

PARTICLE COMPOSITE, rigid particles, material properties

24.09.2008

Halle/Saale

978-3-940744-17-3

Properties, Processing, Modification, Application of Polymeric Materials

A36–A36

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