Nylon molecular formula contains amido group, amido group can form hydrogen bond with water molecule, so it has great water absorption. The various properties of nylon will vary depending on the amount of water absorbed. When the moisture absorption increases, the yield strength of nylon will decrease, but the yield elongation and impact strength will increase. Elevated temperature also enhances nylon’s impact strength and toughness
The main advantages of nylon are as follows:
- High mechanical strength, good toughness, high tensile and compressive strength. The specific tensile strength of nylon is higher than that of metal; the specific compressive strength of nylon is comparable to that of metal, but its rigidity is not as good as that of metal. The tensile strength is close to the yield strength, more than double that of ABS. The ability to absorb shock and stress vibration is strong, and the impact strength is much higher than that of ordinary plastics, and is better than that of acetal resin.
- Outstanding fatigue resistance, the parts can still maintain the original mechanical strength after repeated inflections for many times. Common escalator handrails, new bicycle plastic rims and other occasions where the periodic fatigue effect is very obvious are often used PA.
- High softening point and heat resistance (such as nylon 46, the heat distortion temperature of high crystalline nylon is high, and it can be used for a long time at 150 degrees. After PA66 is reinforced with glass fiber, its heat distortion temperature reaches more than 250 degrees).
The main disadvantages of nylon are as follows:
- Easy to absorb water. High water absorption. Its saturated water can reach more than 3%, which to a certain extent, affects dimensional stability and electrical properties, especially the thickening of thin-walled parts; water absorption will also greatly reduce the mechanical strength of plastics. When selecting materials, the influence of the use environment and the matching accuracy with other components should be considered.
- Poor light resistance. In a long-term high temperature environment, it will oxidize with oxygen in the air, and the color will turn brown at the beginning, and then the surface will be broken and cracked.
- Strict technical requirements for injection molding: the presence of trace moisture will cause great damage to the molding quality; the dimensional stability of the product is difficult to control due to thermal expansion; the existence of sharp corners in the product will lead to stress concentration and reduce mechanical strength; Uneven thickness will lead to distortion and deformation of the workpiece; high precision equipment is required during processing.
Laizhou Kaihui Machinery Co., Ltd. is manufacturer of plastic extrusion lines for PP, PE, PA, PET & PVC. With about 30 year’s manufacturing experience, KHMC has become one of the leader manufacturers in this industry and its quality is among the top. Our machineries have been exported to over 50 countries and gained good reputation.
Post time: Aug-01-2022