Fracture behavior of epoxy polymers modified with core-shell rubber particles

✍ Scribed by L. Becu; A. Maazouz; H. Sautereau; J. F. Gerard

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 454 KB
• Volume: 65
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/(sici)1097-4628(19970919)65:12<2419::aid-app14>3.0.co;2-w

✦ Synopsis

Physical and thermomechanical properties of BDMA-catalyzed DGEBA/ Dicy epoxy toughened with core-shell particles were studied. Relationships between these properties and the level of toughening are reported. The blends have been made in well-defined processing conditions. In fact, the resulting properties depend on the state of dispersion of the particles in the prepolymer matrix before crosslinking and on the cure schedule. The considered core-shell particles were of two types: i) poly(butadiene-co-styrene) core/carboxy-functionalized poly(methyl methacrylate-co-styrene) shell. Such core-shell particles have been dispersed in the epoxy matrix at different volume fractions (from 9.5 to 24%); ii) poly(butyl acrylate) core/carboxy functionalized poly(methyl methacrylate-co-styrene) shell. These particles have been dispersed at a volume fraction of 24%. Static mechanical tests were performed in tension and compression modes on these core-shell polyepoxy blends. A slight decrease of Young's modulus and an increase of the ability to plastic deformation were noticed as the volume fraction of the core-shell particles increased. Using linear fracture mechanics (LEFM), an improvement of the fracture properties ( K IC ) was measured. Fatigue crack-growth studied for blends demonstrates that the Paris's law can be used to describe the behavior of the materials. Increasing the volume fraction of core-shell particles leads to an improvement of the resistance to fatigue crack-propagation. The same trend is noted on the impact behavior studied by means of high-speed tests performed in a large range of temperatures.