Mehdi Kheirabadi - Iran Polymer and Petrochemical Institute, P.O. Box: 14965/115, Tehran, Iran
Jalil Morshedian - Iran Polymer and Petrochemical Institute, P.O. Box: 14965/115, Tehran, Iran
Shervin Ahmadi - Iran Polymer and Petrochemical Institute, P.O. Box: 14965/115, Tehran, Iran

An increasing use of plastics in various applications requires the production of new types of polymers and improving the properties of the existing ones. Polyoxymethylene (POM), an excellent engineering plastic, can be a substitute for metals in many applications because of its excellent mechanical properties and good chemical stability. POM has been successfully used as the polymeric layer in the three-layer (polymer/copper-powder/steel) self-lubrication bearing materials. Polyoxymethylene polymers are also one of the renowned high performance plastics used in industry, such as automobile, electronics, medical devices etc.The mechanical properties of POM is due to its high crystallinity ratio (about 50% to 95%). This crystallinity shows itself in local arrangements in lamellas that are gathered in the forms of spherolites.In order to improve mechanical properties such as tensile strength, shear strength and modulus, Some investigations have been done via introducing various fillers and reinforcing agents into POM.