Young modulus and degree of crystallization of highly‐elongated polyoxymethylene

Abstract

ABSTRACT:The physical structure of polyoxymethylene (POM) drawn into two steps by a press and a simultaneous biaxial drawing machine was studied and the drawing dependency on the degree of the crystallization, the orientation, and the modulus were analyzed. The stretching ratio by the press reached 6.0 and the tensile modulus of elasticity increased from 2.5 to 4.5 GPa. However, the degree of crystallization decreased slightly. The rupture elongation increased in the lower drawing region and it peaked when the drawing ratio was 1.7. The film stretched by 2 times was drawn by the biaxial drawing machine. The high tensile modulus of elasticity was obtained and the maximum value was 11.5 GPa at 14 times of the drawing ratio. The lamella structure of POM was supposed to loosen and become oriented to the drawing axis ambiguously by the first drawing. The lamella was highly oriented by the second stretching procedure. The tensile strength and the elongation as well as the modulus were analyzed as a function of the degree of the stretching and the crystallization.

Formation of a large‐scale shish‐kebab structure of polyoxymethylene in the melt spinning and the crystalline morphology evolution after hot stretching

“…Although the melt spinning of POM fiber was reported in literature, these studies mainly covered the relationship of the orientation degree, take‐up speed, and mechanical properties. For instance, several studies have reported that the orientation degree of lamellar stacks of POM is proportional to the take‐up speed . In the present study, the POM fiber is produced by melt spinning with a high take‐up speed.…”

“…For instance, several studies have reported that the orientation degree of lamellar stacks of POM is proportional to the take-up speed. [45,46] In the present study, the POM fiber is produced by melt spinning with a high takeup speed. A strong shear flow field and orientation on the monofilament during crystallization are imposed.…”

Polyoxymethylene Processing

“…By applying the press drawing followed by subsequent simultaneous biaxial drawing, the tensile modulus reached 11 GPa when the draw ratio was 14 times, and the degree of crystallinity increased from 71% to 76-80%. Additionally, the high tensile modulus of elasticity was obtained and the maximum value was 11.5 GPa at 14 times of the drawing ratio [141].…”

The Influence of Nanohydroxyapatite on the Thermal, Mechanical, and Tribological Properties of Polyoxymethylene Nanocomposites

“…Polyoxymethylene (POM) is one of the major thermoplastic engineering polymers and it is mainly applied in mechanical parts due to excellent performance against wear, high strength, stiffness, and excellent chemical resistance [1][2][3]. POM is also attractive material for use in biomedical applications such as bone tissue replacement especially in hip prosthesis [4], dentistry [5], and cardiology [6].…”