Testing Izod impact test

Charlie CHARMm Charpy Izod impact Charpy method Charpy test CHARTEK59 Charybdotoxin Chaser mill Chatecholates... 

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]. 

TEN-fOOT FALL —IZOD IMPACT TEST m —REFRIGERATOH ODOR-SLAM... 

The popular Izod impact tester can use different size specimens depending on the type of plastic and their method of fabrication. The specimen is usually 1/8 in. x l/2 in. x 2 in. other sizes are also used. Specimens can be notched or unnotched. A notch is cut in a specified manner on the narrow face of the specimen. The sample is clamped in the base of a pendulum testing machine so that it is cantilevered upward with the notch facing the direction of impact. The pendulum is released, and the force expended in breaking the sample is calculated from the height the pendulum reaches on the follow-through. The speed of the pendulum at impact is controlled. 

The Izod impact test may indicate the need to avoid inside sharp corners on parts made of such materials. For example, nylon and acetal-type plastics, which in molded products are among the toughest materials, are notch-sensitive and register relatively low values on the notched Izod impact test. 

Table 7-17 Example of a simplified readout for TPs toughness or fracture behavior Izod impact test results...

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]. 

Charpy Izod impact test, 19 580-581 Charts, heat-exchanger effectiveness, 13 255-256... 

Secondary Properties of Candidate Materials. In terms of maximum and minimum use temperatures, we must simply ensure that our final candidate materials meet the use temperature requirements listed in Table 8.10. This design specification is not particularly restrictive, so we will save it for last. The most common measure of impact resistance is using an Izod impact test (cf. Figure 5.79). A similar test is called the Charpy test, a schematic diagram for which is shown in Figure 8.15. We will find relevant impact resistance data for our candidate materials, if available, and ensure that this design criterion is met as well. 

IZOD impact test—method for determining the behavior of materials subjected to shock loading. Specimen supported as a cantilever beam is strack by a weight at the end of a pendulum. Impact strength is determined from the amount of energy required to fracture the specimen. The specimen may be notched or unnotched. 

Impact Test. Impact testing is of importance because adhesives, like most polymeric materials, are sensitive to high rates of application of force. The resistance of an adhesive to impact can be determined by ASTM D 950. This test is analogous to the Izod impact test method used for impact studies on materials. 

Noninstrumented Izod Testing. The impact strength, reported in joules per meter of notch, was measured at temperatures between 25° and — 30°C. The samples were cooled to the test temperature using a Lauda Kryostat and equilibrated in the Kryostat for at least one and one half hours prior to testing. Five to seven seconds were required to remove a sample from the Kryostat, mount, and perform the Izod impact test. Ten samples of each composition were tested at each temperature. 

Impact Testing (Nonins t rumen ted). Because the Izod impact is a failure test, some scatter of data is expected. Reasons for this scatter include the presence of weak domains, mechanical anisotropy, and any variability in test conditions. Extreme care was taken to maintain constant test conditions. To increase the reliability of the results, 10 test pieces of each sample were tested and the average was calculated. 

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. 

In the notched Izod impact test, with the exception of some rubber modified plastics, the fracture surface of a specimen that has failed ductilely exhibits significant inward collapsing on the sides of the impact bar near the notch, indicating that a large amount of plastic flow has... 

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