Annular expansion for enhanced orientation and mechanical properties of extruded amorphous PPESK/PES pipes

• Published in: Journal of applied polymer science Vol. 141; no. 18
• Main Authors: Pan, Xiaotong, Pan, Yuxi, Zhao, Haiyang, Liu, Cheng, Zeng, Wenguang, Guo, Yujie, Song, Ce, Jian, Xigao
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 10.05.2024; Wiley Subscription Services, Inc
• Subjects: Axial stress; blends; Bursting strength; Carbon fibers; copolymers; Corrosion products; Corrosion resistance; cross‐linking; crystallization; Extrusion; Ketones; Mechanical properties; Molecular chains; Oil fields; Pipes; polyamides; Polyethersulfones; Tensile strength
• ISSN: 0021-8995; 1097-4628
• DOI: 10.1002/app.55326

With the discovery of deeper oil fields, conventional metal pumping pipes have been proven to be ineffective in meeting the requirements for deep well oil production due to their high weights and limited corrosion resistance. Therefore, in this study, a composite of Poly(phthalazinone ether sulfone ketone) (PPESK) and polyethersulfone (PES) was used to fabricate nonmetal pipes. To enhance the mechanical properties of the PPESK/PES pipes, a self‐designed annular expansion pipe extruder head was used. The circumferential burst stress and axial tensile strength of the PPESK/PES pipes subjected to 30° expansion were 73.0% and 48.9% higher than those of the unexpanded sample, respectively. When annular expansion was integrated into the extrusion of PPESK/PES/carbon fiber pipes, the axial tensile strength and circumferential burst stress were 45.9% and 88.8% higher than those of the unexpanded sample, respectively. Results of polarized infrared testing and metallographic microscopic examinations demonstrated that molecular chains present a regular orientation at a certain angle to the extrusion direction, under the effect of annular expansion extrusion. These findings highlight the efficiency of annular expansion in promoting the large‐scale production of pipes. The extrusion molding process of annular expansion orientation enhancement pipe has a positive effect on the molecular chain forming the oriented structure of amorphous polymers. This method is also suitable for shortcut carbon fiber reinforced pipes, which can make the carbon fibers have good regular orientation, and improve the overall mechanical properties of the pipe through physical means during processing.