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FRACTURE BEHAVIOUR OF UNTREATED AND SILANE‐TREATED TALC‐FILLED POLYPROPYLENE COMPOSITES
Author(s) -
Velasco J. I.,
Saja J. A.,
Martínez A. B.
Publication year - 1997
Publication title -
fatigue and fracture of engineering materials and structures
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.887
H-Index - 84
eISSN - 1460-2695
pISSN - 8756-758X
DOI - 10.1111/j.1460-2695.1997.tb00299.x
Subject(s) - talc , materials science , composite material , polypropylene , charpy impact test , composite number , fracture toughness , fracture (geology) , silane , volume fraction , toughness
— Fracture behaviour of injection‐moulded polypropylene filled with silane‐treated talc was studied as a function of filler volume fraction (0–20%) and compared to that of polypropylene filled with untreated talc. High‐rate tests (0.57 m/s) on SENB specimens were carried out using an instrumented Charpy impact pendulum, and linear elastic fracture mechanics (LEFM) was applied to calculate the fracture parameters, K C and G C . It was found that moderate fractions of talc which were added to the polypropylene matrix increased the fracture toughness of the composite independent of the talc surface treatment. This general improvement seems to be due to the peculiar orientation of the talc platelets in the injection‐moulded specimens. The fracture behaviour of the composites was also studied at low strain rate (1 mm/min) by tests on J ‐integral type specimens with the same SENB geometry. In this case, the composites with silane‐treated talc presented poor J ‐integral values compared to those of the samples with untreated talc. This was attributed to a reduction of the plastic zone at the crack tip, since the improved coupling between the talc platelets and matrix increased the yield strength of the composite. All the results are explained on a basis of morphological and microstructural details.