Structure-property relationship in rigid-rigid polymer-toughened polypropylene blends /
The rigid-rigid polymer toughening concept is used to toughen and strengthen isotactic polypropylene (iPP). The morphology and mechanical behavior of iPP and Noryl poly(phenylene oxide)/polystyrene blends (iPP/Noryl) are studied. It is found that the fracture toughness of iPP can be significantly im...
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| Format: | Thesis Book |
| Language: | English |
| Published: |
[Place of publication not identified] :
[publisher not identified] ;
1999.
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| Subjects: | |
| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=731681751&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | The rigid-rigid polymer toughening concept is used to toughen and strengthen isotactic polypropylene (iPP). The morphology and mechanical behavior of iPP and Noryl poly(phenylene oxide)/polystyrene blends (iPP/Noryl) are studied. It is found that the fracture toughness of iPP can be significantly improved by adding rigid Noryl particles without causing any reduction in modulus. Large Noryl particles (about 10-15 []m) are formed if no compatibilities are utilized in the iPP/Noryl blend. An addition of a small amount of styrene-ethylene-propylene (SEP) compatibilizer causes a significant reduction in Noryl particle size. A noticeable improvement in particle-matrix interfacial adhesion is also observed. Also, the fracture energies required for both crack initiation and crack propagation of iPP are greatly increased. The results show that phase morphology has a great effect on the mechanical performance of these blends. The toughening mechanisms in blends of iPP/Noryl are studied using optical microscopy, scanning electron microscopy and transmission electron microscopy techniques. Crazing is found to be the dominant toughening mechanism in iPP/Noryl blend. A detailed investigation of fracture mechanisms reveals that Noryl particles help trigger and stabilize massive crazes in the iPP matrix. Crazing and shear banding mechanisms are found to operate sequentially in iPP/Noryl/SEP blends. As a result, the toughness of PP is significantly improved. |
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| Item Description: | Vita. "Major Subject: Mechanical Engineering". |
| Physical Description: | xiv, 147 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilm Inc. |
| Bibliography: | Includes bibliographical references (leaves 133-134). |