Resin Toughening

Using a particular reinforcement, low-velocity-impact resistance (desirable for structural applications) of a particulate or FRP composite can be greatly improved 

Modifier Concentration of modifier ( Wt%) Impact strength J/m-i GFRP Impact strength J/m-i CFRP ILSS of GFRP (MPa) 

For composites, the free energy change of the system of three components, epoxy, HBP and fibre, can be described as  

Drzal in Epoxy Resin and Composites II, Ed., K. Dusek, Advanced Polymer 

Science Series, Springer-Verlag, Berlin, Germany, 1986, p.75. 

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We conclude that (a) Shear deformations are dominant in resins toughened with small rubbery particles, (b) Crazing associated with polymer whitening and microvoid development is dominant in resins toughened with large particles, (c) Maximum toughening is obtained under conditions of combined shear and craze deformations. This condition is obtainable when both large and small particles are present. 

Rowe, E. H., Fractography of Thermoset Resins Toughened with Hycar... 

Gilbert, A.H. Bucknall, C.B. Epoxy resins toughened with thermoplastic. In Makromol. Chem. Macromol. Symp, Vol. 45, 289-298. 

Figure 1.34. Change in the phase boundary (UCST) during the cure reaction for a system of a rubber (e.g. CTBN) dissolved in an epoxy resin. Toughening requires that phase separation be achieved during the cure cycle. After Pascualt et al. (2002).

Figure 6. Comparison of experimental and predicted values of Youngs modulus of epoxy resin toughened with rubber particles. Finite-element predicted values were calculated using two values of the Poisson ratio of the rubber phase and the predicted bounds using the Ishai and Cohen model (26).

Thermal Shock Behavior and Evaluation of Epoxy Resins Toughened with Hard Particulates... 

This chapter discusses the behavior, under thermal shock conditions, of epoxy resins toughened with ceramic particulates. Alumina Al203 and silica Si02, which are usually used as filler for insulation materials, and the new ceramic materials silicon carbide SiC and silicon nitride Si3N4 are employed. For these toughened epoxy resins, the thermal shock resistance is evaluated by using fracture mechanics. The difference between experimental and calculated values of the thermal shock resistance is discussed from a fractographic point of view. 

Synthesis and Analysis of Saturated, Reactive /I-Butyl Acrylate Polymers for Use in Epoxy Resin Toughening... 

The study considered here employed materials obtained from McDonnell Aircraft Co., through Dexter Hysol, under the Air Force program Development of Ultra Lightweight Materials . They contained the Courtaulds Research Apollo 45-850, consisting of 5 pm diameter carbon fibers in Dexter Hysol s HC 9106-3 di-, tri- and tetrafunctional epoxy resin, toughened by addition of the thermoplastic polyether sulfone (PES). The thermoplastic PEIS toughening agent, present in this epoxy matrix, is presumed to phase separate out once it has cured. These panels were fabricated in an autoclave by Dexter Hysol. 

Phatomei 3215 tougheiRr, coalmgs Photom 6572 Urea-fomiddehyde resin toughener, coil coalmgs Piftlast 3m Pi ast 3192 Pi 1006 Plipol 1009 Plipol 1013 Plipol 1015 Piqrol 1017 Piqrol ... 

Wu Wu, H., Xu, J., Liu, Y., Heiden, P. Investigation of readily processable thermoplastic-toughened thermosets. V. Epoxy resin toughened with hyperbranched polyester. J. Appl. Polym. Sci. 72 (1999) 151-163. 

Jin Jin, F.-L., Park, S.-J. Improvement in fracture behaviors of epoxy resins toughened with sulfo-nated poly(ether sulfone). Polym. Degrad. Stab. 92 (2007) 509-514. 

Han Han, Y.-G., Liao, G.-X., Xu, Y.-J., Yu, G.-P., Jian, X.-G. Cure kinetics, phase behaviors, and fracture properties of bismaleimide resin toughened by poly (phthalazinone ether ketone). Polym. Eng. Sci. 46 (2009) 2301-2308. 

Pig. 2. Electron Micrograph of an OsO -Stained Microsection of Epoxy Resin Toughened with E-30... 

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