Improved toughness of phthalonitrile composites through synergistic toughening methods. (August 2021)

• Record Type: Journal Article
• Authors: Sun, Jinsong; Han, Yue; Zhao, Zehua; Wang, Guangxing; Zhan, Shuyi; Ding, Jiangnan; Liu, Xiang; Guo, Ying; Zhou, Heng; Zhao, Tong
• Is Part Of: Composites communications. Volume 26(2021)
• Publication Date: 2021-08
• Subjects: Phthalonitrile composites -- Synergistic toughening -- Fracture toughness
• DOI: 10.1016/j.coco.2021.100779
• Languages: English
• ISSNs: 2452-2139

Abstract

Abstract: Brittleness has long been a trouble for the application of phthalonitrile polymers in high temperature structural composites. In this work, crosslinkable poly(aryl ether nitrile) and insoluble polyimide particles were first selected as binary toughening modifiers for synergistic toughening of phthalonitrile composites, respectively. Various mechanical measurements and thermal tests were adopted to systematically evaluate the toughening effects as well as heat resistance. The optimized composites exhibited GIC of 659.7 J/m 2 and GIIC of 907.1 J/m 2, while ILSS increased to 78.6 MPa. More importantly, its glass transition temperature was 449 °C, which was only slightly lower than the blank contrast. Later, the mechanism for this synergistic toughening was proposed and discussed. Graphical abstract: Image 1 Highlights: Crosslinkable PEN and insoluble PI synergistically improve the PN composites toughness. GIC and GIIC values with toughening are 125% and 114% higher than the blank contrast. Mechanism between 'matrix toughening' of PEN and 'interlaminar toughening' of PI is clearly characterized. Very limited loss in heat resistance of PN composites with toughening.