Izod impact strength of ABS

Fig. 8-24 Izod impact strength of ABS plastic vs. stock (melt) temperature.

Figure 18.32 Variation of Izod impact strength of ABS terpolymer and toughened PS with notch tip radius and temperature. [Source Author s own files)...

Figure 7-28. Izod impact strength of ABS plastic (4 x x 3 in. specimens).

ABS usually contains about 20wt% rubber, about 25% acrylonitrile, and about 55% styrene, having a Tg value of about 105C, a tensile modulus of 2.5GPa, and an impact strength of about 4 J (12.7 mm)-1 on an Izod test. However, owing to the many variations possible, the properties can vary considerably. As an example, Super ABS can have a notched Izod impact strength of up to 8 J (25 mm)-1. Also some or all of one of the comonomers may be replaced. Methylmethacrylate may replace acrylonitrile, as in MBS and MABS, with improvement in... 

Polyamides and saturated polyesters can be toughened with ABS, ethylene-propylene copolymers/terpolymers or EPDM rubbers grafted with maleic anhydride to increase the dispersion and adhesion of the modifier. Styrene-butadiene copolymers are also effective. The notched Izod impact strength of polyamide 6-6 can be increased more than 20-fold by impact modifiers, whereas short glass fibres often reduce the impact strength, even though they increase the modulus. 

Figure 8.23 Effect of pre-blending 5% maleated EPR in maleated ABS on the notched Izod impact strength of PA6/m-ABS blends...

Fig. 3. Dependence of Izod impact strength on temperature for (-) polycarbonate, (—) ABS, and (-) polycarbonate-ABS blends. To convert J to cal,...

This action eliminates the need for a costly mechanical roughening process that most other materials require. The depositing of a metal surface on plastic parts can increase environmental resistance of the part, also its mechanical properties and appearance. As an example a plated ABS part (total thickness of plate 0.015 in.) exhibited a 16% increase in tensile strength, a 100% increase in tensile modulus, a 200% increase in flexural modulus, a 30% increase in Izod impact strength, and a 12% increase in deflection temperature. Tests on outdoor aged samples showed complete retention of physical properties after six months. 

To design a resin with the property enhancements of AN without the cross-linking problem, it was found that SMA copolymers and terpolymers could be blended with ABS resins to form miscible blends with properties of HHABS. A fundamental look at the miscibility of SMA copolymers with SAN copolymers indicated that the optimum thermodynamic interaction occurs when the AN content of the SAN is nearly equal to the MA content of the SMA [72]. Kim et al. also found low impact strengths at all modifier levels when blending SMA with SAN-g-polybutadiene (GRC = grafted rubber concentrate) [73]. Blends of SMA with SAN and GRC (SAN + GRC = emulsion ABS) exhibited ductility behavior similar to HHABS. The impact strengths of the polymers were 2-5 ft-lb/in, in a notched Izod test at ambient temperature. 

Figure 5. Izod impact strength, Y5, (kg cm/cm) as a function of ABS composition...

Figure 12.17. Influence of PVC/ABS blend composition on Izod impact strength.

Blends of polycarbonate with other styrenic resins are relatively new and therefore their current market volume is low. They have been developed primarily to upgrade the performance of such styrenic resins as styrenic-maleic anhydride (SMA), styrene-methyl methacrylate (S-MMA), acrylic-sty-rene-acylonitrile (ASA) resins primarily for impact strength and to some extent for DTUL improvement (Tables 15.7, 15.8 and 15.23). These blends uniquely combine high notched Izod impact strengths (ranging from 500 J/m to > 1000 J/m) with better UV resistance or weatherability than ABS. 

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