Fracture toughness of polymers

W. L. Bradley, W. Schultz, C. Corleto and S. Komatsu, The Synergistic Effect of Cross-Link Density and Rubber Additions on the Fracture Toughness of Polymers , Advances in Chemistry, 233, 317-334 (1993). 

The method has been applied to numerous ductile polymeric materials [Begley and Landes, 1972 Landes and Begley, 1974]. The critical J values obtained by using single specimen method were greater than those obtained from the standard multiple-specimen method [Westerlind et al., 1991]. Many workers have used the ASTM standards of E813-87 to characterize the fracture toughness of polymers [Chan and Williams, 1981,... 

Plati, E. and Williams, J. G. (1975b) Effect of temperature on the impact fracture toughness of polymers, Polymer Eng. Sci., 16, 915-920. 

The low fracture toughness of polymers does not mean that they are more sensitive to cracks than metals. Due to their lower strength, they are loaded less heavily than are metals so that their crack sensitivity is similar as can be seen from the critical crack length values given. 

Plati, E., Williams, J. G. (1975). Effect of Temperature on the Impact Fracture Toughness of Polymers Polymer, 16(12), 915-920. 

The multiple specimen method, first propxrsed by Landes and Begley, 1974, is the most common approach for deducing J-R curves. The basic guidelines of ESIS TC4 Protocol "J-Fracture toughness of polymers at slow speed" are applied (Hale Ramsteiner, 2001). A set of identical specimens is loaded to various displacements, unloaded, cooled at low temperatures and finally fractured. The initial and final stable crack lengths are measured physically from the broken surfaces, while J is calculated from the total energy required to extend the crack, U, which is determined from the area imder the load versus load-point displacement curve up to the line of constant displacement corresponding to the termination of the test ... 

At room temperature and under low loading rates, PPs and EPBCs present a pronounced nonlinear mechanical response. The ESIS TC4 Protocol entitled "The determination of J-fracture toughness of polymers at slow speed" (Hale Ramsteiner, 2001), was followed to achieve the J-R curves from multiple specimens of CRPPs. In turn, the guidelines given by... 

Hale, G.E. Ramsteiner, F. (2001). J-fracture toughness of polymers at slow speed. In Fracture mechanics testing methods far polymers, adhesives and composites, Moore, D.R. Pavan, A. Williams J.G., editors, pp 123-157, Elsevier Science Ltd. and ESIS, ISBN 0 08 043689 7, The Netherlands. 

Approaches to improve fracture toughness of polymer/clay nanocomposites... 

In the following sections, we shall discuss three modes of fracture and several fracture criteria. Later, we shall enumerate several major variables affecting effective fracture surface energy, fracture energy and fracture toughness of polymers. 

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