Polyoxymethylene copolymer (POM) is considered a high performance engineering polymer with many applications due to its good chemical resistance and very good mechanical properties. It is known that mechanical properties of polymers are greatly influenced by their average molecular weight (Mw). This paper presents the shear creep compliance of new POM copolymers with a broad range of average molecular weights (10240 to 204400 g/mol). Master curves of creep compliance were constructed using the time-temperature superposition principle. It was observed that at short time (t = 0.25 s), creep compliance is independent of Mw. As the time increases (t = 3.16x108 s ~ 10 years) shear compliance decreases as a power function of Mw, but only up to a critical Mw of a aproximately 92300 g/mol. After this critical Mw creep compliance becomes again independent of Mw. These results in combination with finite element analysis could be used for selecting a specific Mw according to suit the require ments of certain application.
B.04 Guest lecture
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