A tailor-made method to recycle slow-curing thermoset of phthalonitrile by constructing self-composite with the improved properties. (August 2021)

• Record Type: Journal Article
• Authors: Yang, Xulin; Lei, Wenwu; Liu, Qiancheng; Li, Ying; Li, Kui; Wang, Pan; Feng, Wei
• Is Part Of: Composites communications. Volume 26(2021)
• Publication Date: 2021-08
• Subjects: Thermoset recycling -- Self-composite -- Phthalonitrile -- Compatibility
• DOI: 10.1016/j.coco.2021.100791
• Languages: English
• ISSNs: 2452-2139

Abstract

Abstract: Considering the excellent comprehensive properties and high cost of slow-curing thermoset phthalonitrile (PN) resin, discarding of PN materials increases the burden on the environment, but also is a waste of resources. The current study proposed a tailor-made method to recycle PN products by constructing the self-composite (PNSC). Based on the curing gradient, the infusible PN polymer (PPNP) was crushed, graded and directly reused as the reinforcement for its prepolymer (PNP). Due to the co-curing of PNP and PPNP, a transform from a heterogeneous phase-separation to a continuous structure indicated PN self-composite was successfully formed after 320 °C/4 h curing. Thanks to the self-composite structure, PNSC exhibited the parallel or superior mechanical and thermal properties than those heterogeneous PN/filler composites. This research has demonstrated a close-to-commercial, effective and efficient recycling method for PN materials, but also proposed a new concept of self-composite that can be used for the construction and regulation of other thermosetting resin. Graphical abstract: Image 1 Highlights: To recycle PN products, a tailor-made method by constructing the self-composites (PNSC) was proposed. PN polymer (PPNP) was crushed, graded and directly reused as the reinforcement for its prepolymer (PNP). Chemical compatibility between matrix and reinforcement was realized intrinsically in PPNP/PNP via the structural similarity. A transform from phase-separation to continuous structure indicated the formation of PN self-composite (PNSC) after 320 ℃/4 h. PNSC exhibited the parallel or superior mechanical and thermal properties to those heterogeneous PN/filler composites.