Thermosets thermoplastic toughening

Current Modifications of Epoxies. Particulate Toughening of Thermosets. . Rubber Toughening of Thermosets. . . Thermoplastic toughening of thermosets Epoxy Fibre Composites. ... 

Gop Gopala, A., Wu, H., Harris, F., Heiden, P. Investigation of readily processable thermoplastic-toughened thermosets. I. BMIs toughened via a reactive solvent approach. J. Appl. Polym. Sci. 69 (1998) 469 77. 

Diez-Pascual AM, Shuttleworth PS, Gdnzalez-Castillo El, Marco C, Gomez-Fatou MA, Gary Ellis G. Polymer blend nanocomposites effect of selective nanotube location on the properties of a semicrystalhne thermoplastic-toughened epoxy thermoset. Macromol Mater Eng 2014 299 1430-44 [10.1002/mame.v299.12]. 

The use of elastomeric modifiers for toughening thermoset resias generally results ia lowering the glass transition temperature, modulus, and strength of the modified system. More recendy, ductile engineering thermoplastics and functional thermoplastic oligomers have been used as modifiers for epoxy matrix resias and other thermosets (12). 

The modulus of thermosets, such as phenolic plastics, is much greater than that of thermoplastics because of the high cross-link density present in thermosets. Since these network polymers are brittle, they are usually toughened by the addition of fibrous reinforcements. 

Thermosets are generally used in advanced composites due to their excellent thermal and dimensional stability, high modulus, and good mechanical properties. Because thermoset resins are inherently brittle, however, some applications require improved fracture resistance. Toughening of thermosets has been achieved through various methods, such as incorporation of reactive liquid rubber [1-9], elastomer [10], or rigid thermoplastics [11-25], and IPN formation with ductile component [26]. 

In Secs. 13.2-13.3 the principles of toughening of thermosets by rubber particles, and the role of morphologies, interfacial adhesion, composition, and structural parameters on the toughening effect are analyzed. Section 13.4 is devoted to the use of initially miscible thermoplastics for toughening purposes. The effect of core-shell rubber particles is discussed in Sec. 13.5 and, in Sec. 13.6, miscellaneous ways of toughening thermosets (liquid crystals, hybrid composites, etc.), are analyzed. 

In the case of thermosets toughened with thermoplastics particles (Sec. 13.4), this mechanism may be of a considerable importance because of the intrinsic toughness and/or ductility of these particles. 

An improvement in the toughness of thermosets can be favored by rubber or thermoplastic particles, which operate both in crack initiation and propagation mechanisms. The different toughening mechanisms can act simultaneously and can be modeled quantitatively. 

The use of liquid reactive rubbers to toughen thermosets leads to a decrease of both T — g and the Young s modulus (see Fig. 13.7). Thermoplastics can be added to these formulations to improve thermal and mechanical properties. 

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