Izod impact strength testing

Notched Izod impact strength tests have been conducted on the effect of fiber length in a nylon 6/6 compound reinforced with 50 wt% glass fiber. It shows that impact strength of reinforced TPs (RTPs) increases significantly, as fiber length is increased. Similar effects have been measmed with other fibers, such as aramid and carbon, and with other matrices, such as polypropylene and polyphenylene sulphide. 

Charpy Impact Test. This test is conducted in a very similar manner to the Izod impact strength test. The only difference is the positioning of the specimen. Figure 2-41 illustrates one such setup. In this test the specimen is mounted horizontally and supported undamped at both ends. Only the specimens that break com-... 

Figure 13.14 Effects of glass fiber content on Izod impact strength. Test bars were molded at a mold temperature of 150 °C. Symbols represent glass fiber content in weight percent , 10 , 20 A, 30 , 40.

Trade literature can provide a wealth of information. Users should, however, bear in mind that suppliers will naturally wish to emphasise data in the best possible light. For example, if the Izod impact strength increases sharply with decrease in sample thickness, then results may be quoted for thinner section test pieces. Whilst the facts may be stated, the underlying significance may not be fully appreciated by the casual reader. 

The study on commercial HDPE samples could not provide a correlation of the izod impact test with the field performance test, i.e., drop impact resistance on moulded products [113]. It was found that the sample of highest density and lowest izod impact strength passed the drop impact test, but other samples of lower density and higher izod impact strength could not withstand shock loading by drop impact and failed in brittle manner. This may be due to the fact that velocities and modes of loading vary widely in different impact tests. It has been reported that even the qualitative agreement between the different impact tests is poor because the test bars and moulded products often have different orientation characteristics, particularly near the surface [115]. 

Nylon-6-clay nanocomposites were also prepared by melt intercalation process [49]. Mechanical and thermal testing revealed that the properties of Nylon-6-clay nanocomposites are superior to Nylon. The tensile strength, flexural strength, and notched Izod impact strength are similar for both melt intercalation and in sim polymerization methods. However, the heat distortion temperature is low (112°C) for melt intercalated Nylon-6-nanocomposite, compared to 152°C for nanocomposite prepared via in situ polymerization [33]. 

The Izod impact strength values are useful in giving a rough ranking of materials for quality control purposes, since the tests are simple and quick to carry out. The test is hardly of any use for design calculations for plastic parts. Neither has the test any physical base. 

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... 

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. 

Selected diblock polymers are provided in Table 1. Izod impact strength and flame retardancy testing are provided in Table 2. Flame retardancy was measured according to the UL-94 standard. 

However, the kind of technique used to mold these blends seems to be important in determining their mechanical properties. In fact, mechanical tests carried on injection molded samples [37] show, with respect to compression molded samples, a significant enhancement of the energy to break for all samples (Tables 20.2 and 20.3). Moreover the addition of 10wt% of SEBS to an 80 20 wt% sPS/HDPE blend involves in the injection molded samples an increase in both the energy at break and the Izod impact strength, whereas in the thermo-compressed samples no improvement is observed. Differences between compression and injection molded samples are widely acknowledged [38] and... 

Izod Impact Strength (Yr,). Izod is very likely the most common impact test for ABS resins. It is usually performed on notched specimens V - and %-inch thick, and both specimen types are simultaneously injection-molded. 

Standard test methods for the determination of Izod impact strength are listed in Table 12.10. For example, ISO R180 normalizes the notch length. The velocity of the striker on impact has been standardized at 3.5 10 per cent m/s with impact energies of 1.0, 2.75, 5.5, 11.0 and 22.0 J. Four types of test pieces are permitted. 

Table 12.10. Standard test methods for the determination of Izod impact strength...

Izod impact strength see Impact test, Izod... 

---