The fracture behavior of rubber‐toughened, short‐fiber composites of nylon 6,6

Abstract

This study critiques the use of both rubber particles and short-glass fibers for the improvement of polymer fracture toughness ( K ). Although dry neat nylon is brittle with only a moderate K , value (4.2 M P a g ) , additions of either second phase produce rising K,-curves and associated high K , values (8.1 M P a 6 for rubber-toughened nylon, and 10.0 M P a G for 17 vol% glass-fiber neat nylon). In the rubber-modified resin, the high K, value is associated with extensive plastic blunting at the crack tip. In the fiber-reinforced neat resin, K, is improved due to a combination of fiber-bridging and increased strength, the latter being associated with additional load carrying capacity of the fibers. When both rubber and fibers are added, however, no further increase in K, is noted ( K , = 9.3 M P a 6 for 17 vol% glass-fiber rubber-modified nylon). The extent of ductile blunting in the rubber + fiber resin is not as great as in the rubber-only resin. Furthermore, the fracture strength of the rubber + fiber resin is not as high as the fiber-only resin.The net result is a balance of properties for the rubber-toughened composite.

Fracture behavior of rubber‐modified injection molded poly(butylene terephthalate) with and without short glass fiber reinforcement

“…It is definite that the enhancement in the flexural strength is attributed to the reinforcement of glass fiber with a high aspect ratio. Percorini and Herzberg 25 and Mohd Ishak et al 4 reported similar results on rubber-toughened short glass fiber nylon 6.6 composites and short glass fiber-reinforced CSR-PBT, respectively. The inclusion of 10 wt % of either AX8900 or EXL2314 into the SGF-reinforced PBT adversely affected the flexural properties.…”

Hygrothermal aging and fracture behavior of styrene-acrylonitrile/acrylate based core-shell rubber toughened poly(butylene terephthalate)

“…15,16 The incorporation of about 20 vol % of finely dispersed ethylene propylene diene monomer rubber particles into nylon 6,6 reduced the tensile strength of the nylon 6,6 matrix from 80 to about 50 MPa. 17 As for the tensile strain, the trend shown in Figure 4 is rather unexpected. The addition of CSR modifiers did not improve the tensile strain of the PBT.…”

Effect of Impact Modifier Types on Mechanical Properties of Rubber-Toughened Glass-Fibre-Reinforced­ Nylon 66

“…Consequently, blending of both glass fi bres and rubber with thermoplastics seems to be a logical way to optimize important properties of thermoplastics. Surprisingly, though, the number of such studies conducted, mainly in the last decade, is small (see, for example, Kinloch et al, 1985;Kelnar, 1991;Nair and Shiao, 1992;Pecorini and Hertzberg, 1994;Shiao et al, 1994;Wong et al, 1995;Azari and Boss, 1996;Din and Hashemi, 1997;Nair et al, 1997a;Nair et al, 1997bNair et al, , 1998Laura et al, 2000;Cho and Paul, 2001;Sui et al, 2001). Among these studies, nylon 66 has received less attention in terms of selecting the appropriate impact modifi ers for it (Pecorini and Hertzberg, 1994;Wong et al, 1995;Nair et al, 1997a;Nair et al, 1997bNair et al, , 1998Sui et al, 2001).…”