POM Mechanical Properties
Résumé
Thanks to its high degree of crystallinity, polyoxymethylene (POM) homopolymer
exhibits high mechanical properties of strength, stiff ness and creep. In the case of
POM copolymer, the strength and stiff ness are slightly lower because of its lower
degree of crystallinity. Furthermore, the use domain ranges from -30°C to 150°C
which allows various applications. More specifi cally to the POM, friction properties
are excellent due to oxygen contained in the POM monomer.
Th e major drawback of POM homopolymer is its brittleness at RT compare to
polyolefi ns, typically nominal strain at break values are close to 20%. To improve
mechanical properties at failure, diff erent strategies can be adopted as POM copolymer
have lower crystallinity degree (strain at break close 70%) or added polyurethane
in POM matrix (100ST from DuPont for instance). However, we will see
that these strategies lead to a decrease in the material’s stiff ness. Lastly, another
possible way is the use of specific processing conditions to induce oriented morphology.
We will review all these aspects.
This chapter is divided in two major parts: the first part is devoted to shortterm
mechanical properties as elastic properties as a function of temperature and
morphology aspects, failure properties and the diff erent strategies to improve
them. The second part aims to present long-term properties such as creep behavior
and modifi cations induced by aging, leading to an embrittlement of the POM
limiting its lifetime.
Domaines
Matériaux
Origine : Fichiers produits par l'(les) auteur(s)
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