Toughening mechanisms in composites of miscible polymer blends with rigid filler particles

Fillers are often added to polymers improve stiffness at the cost of reduced toughness, but this tradeoff is not universal. Well-dispersed microscopic particles have been shown to improve toughness and stiffness simultaneously in some cases. The effect depends on interparticle distance as well as interfacial adhesion. This type of toughening has been more successful in semicrystalline than in amorphous systems. An amorphous polymer blend was chosen to elucidate the effect of matrix properties on the toughening mechanism. The ternary blend of PMMA, PVC, and DOP (a common plasticizer) was characterized using TEM, and was found to be miscible over much of the PVC-rich domain. The blend Tg's fit well to an empirical model, which was used to predict a constant-Tg ([approx.] 40°C) blend series. Mechanical testing showed a wide, systematic variation in properties among these blends, although all were brittle in tension. The blend 90% PVC / 10% DOP was mixed with barium sulfate filler and evaluated for toughness in slow tension. In general, the composites showed decreasing toughness with increasing filler content. However, several specimens at 5 vol% filler exhibited a large increase in ductility and toughness ([approx.] 19-fold).

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Chemical Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2006

Author dc:creator

• Aronow, Roger Lockwood

Advisor dc:contributor.advisor

• Robert E. Cohen.

• Chemical Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/35520

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/35520