http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Impact fracture behavior of model system modified polypropylene
The morphology and impact properties of polypropylene copolymer blends modified with talc and/or ethylene-propylene (EPR) or ethylene-octene (EOR) rubber were studied. Izod impact, instrumented Charpy impact, and high speed single-edge-notched three-point-bend tests were performed to obtain the values of fracture toughness. A correlation exists between the Izod impact values and the size of the damage zone after fracture. Damage analysis using the double-notch four-point-bend Charpy impact test was performed and the specific damage mechanisms that occurred during fracture were identified. The impact strength is greatly increased with the addition of EPR and EOR rubber. The specific fracture mechanisms for the rubber toughened blends include rubber particle cavitation, crazing, and shear yielding. A further increase in impact strength, with an additional increase in stiffness upon addition of talc is also found. The additional filler particle-matrix debonding dilatational mechanism is believed to provide another means to relieve the triaxial stress state ahead of the crack tip and facilitate additional shear yielding. Attempts to determine morphology differences between the EOR and EPR blends through the use of transmission electron microscopy and scanning electron microscopy were made.
"Major subject: Mechanical Engineering".
Issued also on microfiche from Lange Micrographics.
Includes bibliographical references (leaves 105-109).