在塑料拉伸试验过程中，存在着很多对试验造成影响的 因素，例如震动影响、静电、污染、温度、湿度、辐射等因素，在这些因素中影响最大的为温度、湿度因素。GB/T2918—1982明确规定试验室的标准温度为23℃±2℃， 相对湿度 45%~55%。温度对热塑性塑料拉伸测试的影响很大， 试验曲线会随着温度上升，其拉伸的强度、弹性模量会变小，断 裂伸长率会变大。
In the process of plastic tensile test, there are many factors that affect the test, such as vibration, static electricity, pollution, temperature, humidity, radiation and so on. Among these factors, temperature and humidity are the most important. GB/T 2918-1982 clearly stipulates that the standard temperature of the laboratory is 23 +2, and the relative humidity is 45%~55%. Temperature has a great influence on the tensile test of thermoplastics. With the increase of temperature, the tensile strength, modulus of elasticity and elongation at break of thermoplastics will decrease.
试验环境的相对湿度，通常情况下对吸水率大的塑料材 料会造成较大影响。一些塑料在吸水后，内部的水分子会起 到增韧剂、偶联剂的功能，塑料的刚性和韧性将会发生改变。例如 PMMA（聚甲基丙烯酸甲酯）、乙酸纤维素这类热塑性塑 料，相对湿度对就会对其造成较大的影响，相反，湿度对吸 水率小的塑料，会产生较小的影响，因此，针对塑料拉伸性 能的测试工作，必须在处于恒温条下的试验室进行操作。
The relative humidity of the test environment usually has a great influence on the plastic materials with high water absorption. After some plastics absorb water, the internal water molecules will play the role of toughening agent and coupling agent, and the rigidity and toughness of plastics will change. For example, PMMA (polymethyl methacrylate), cellulose acetate and other thermoplastic plastics, relative humidity will have a greater impact on it, on the contrary, humidity will have a smaller impact on plastic with low water absorption. Therefore, for testing the tensile properties of plastics, it is necessary to enter the laboratory under the constant temperature strip. Line operation.