Impact properties of various types of plastics and commonly used tougheners

There are three indicators for measuring the impact strength of plastics: cantilever beam impact strength, simply supported beam impact strength and falling ball impact strength. They are not mutually convertible, and there is no mutual contrast, and sometimes even the opposite. The results, such as PA66 and PPO, PC and LDPE, etc., are shown in Table 1. Therefore, to compare the impact strength of different plastics, the same test method must be used to be comparable.

Table 1 Impact strength of commonly used plastics

The same impact strength can be divided into two types: opening gaps and not opening gaps. The gaps can be divided into V-type and square-mouth types. The impact strength of plastics at different temperatures is also very different, so the temperature value must be specified during the test. Generally, two temperatures are set, the normal temperature is 23 ° C, and the low temperature is -30 ° C. Therefore, when using the same method to test the impact strength of plastics, it is necessary to indicate the test temperature and whether to open the gap. If the temperature is not marked and the gap is not established, the default is normal temperature and there is no test condition for opening the gap. The impact strengths of different plastics vary greatly. As shown in Table 1 and Table 2, the plastic with the highest impact strength is LDPE, the impact strength is the smallest, and the impact strength of the cantilever beam is the largest and the smallest. PPO is second. The method for improving the impact strength of plastics is to add a toughening agent. There are many kinds of toughening agents that can be used for plastics. Different plastics can be applied to different toughening agents. For specific selection, please refer to Table 2 compiled by the author, which is not necessarily accurate. reference.

Table 2 Notched impact strength of different plastic cantilever beams and suitable toughener varieties