A study of the thermal cure of a phenylethynyl-terminated imide model compound and a phenylethynyl-terminated imide oligomer (PETI-5)

Epoxy resins with high heat resistance and flame retardancy via a new process

“…These results suggest that the curing reaction of the phenylethynylcarbonyl groups progressed upon heating, giving the alkene CC structure as shown in Figure 7 10 . Previous reports 12‐16 have shown that the reaction of the phenylethynyl groups first forms a polyene structure. Although several studies on the curing of phenylethynyl end‐capped model compounds and oligomers have been reported, the mechanism for thermal curing has not been fully elucidated 15 .…”

Processable PMR-Type Polyimides: Process-Property Relationships, Curing Kinetics, and Thermooxidative Stability

“…The lower activation for TAB10 is consistent with the faster cure observed in the rheological studies. The similarity of the E a values for the TAB samples to those for a phenylethynyl-terminated imide oligomer, PETI-5 (156 kJ mol 21 , by DSC) and a 3,4 1 -bis[(4-phenylethynyl) phthalimido] diphenyl ether, PEPAODA [4], suggest that the cure behavior is similar, which is reasonable, since the TAB materials also contain phenylethynyl endcaps. Although the exact cure mechanism for phenylethynyl-terminated systems is still being investigated, it is presumed to occur via chain extension, crosslinking and branching [9].…”

Polyimide Hybrid Nanocomposites with Controlled Polymer Filling and Polymer–Matrix Interaction

“…Using Raman spectroscopy (Figure ), we confirmed that the cross-linking of PAO under confinement was complete. During thermal curing, the CC groups in the terminal phenylethynyl cross-link moieties (end-caps) of PAO (and AFRL-PETI) molecules act as reactive sites for free radical addition, poly­(acetylene) and aromatic formation reactions by which cross-links form between polymer molecules. − Note that the balance of polyalkylene and aromatics might be affected by confinement effects; however, the characteristic Raman peak of these CC groups at ∼2215 cm –1 is likely to provide insights for the degree of the cross-linking reaction. − Such CC peak in the Raman spectrum of PAO remained unchanged after polymer filling, but was completely absent after cross-linking, providing strong evidence that the confined cross-linking reaction of PAO was indeed complete under confinement.…”