N-(2-biphenylenyl)-4-[2′-phenylethynyl]phthalimide—new monomer synthesis, cure and thermal properties of resulting high temperature polymer

N‐(2‐biphenylenyl)‐4‐[2′‐phenylethynyl] phthalimide: 2. Detailed study of the monomer cure and properties of the resulting polymer

“…As noted previously,17 DSC of BPP monomer showed a sharp melting endotherm at about 280 °C and an exothermic polymerisation peak between 330 and 430 °C. A DSC rescan of the cured BPP demonstrated the absence of any residual melting or polymerisation events, but also failed to reveal an obvious T g .…”

“…In a recent publication,17 we described the synthesis of N ‐(2‐biphenylenyl)‐4‐[2′‐phenylethynyl]phthalimide (BPP), a monomer which showed promise for applications where the resulting polymer could experience use temperatures in excess of 300 °C. Following these initial encouraging results, more detailed studies have been undertaken on the cure of the BPP monomer and the thermal properties of the resulting homopolymer.…”

“…Table 1 lists the T g s, recorded by TMA, of BPP cured at 370 and 400 • C for times ranging from 1 to 16 h. From the results it is clear that BPP exhibits higher T g values when cured at 400 • C rather than 370 • C. In both cases, the T g increases with curing time, reaching the highest value after 16 h. This implies that even after 16 h of curing, further crosslinks are formed. This is unsurprising since, although the ethynyl groups in BPP are completely consumed after only 1 h at 370 • C, 17 further crosslinking is possible through any polyene structures formed in the initial polymer. 6 An ultimate T g of 451 • C is extremely high for an organic polymer and confirms the promise of BPP as a potential monomer precursor to ultrahigh-temperature polymers.…”

“…When the curing behaviour of acetylene and biphenylene end‐capped polyimide blends was examined, however, the products were found to have similar thermal properties to those of the individual acetylene and biphenylene end‐capped polyimides,15, which was attributed to the phenanthrene ring formation leading to chain extension rather than crosslinking. As part of our work on the development of new high‐temperature polymers, we recently reported the synthesis and thermal cure of a novel monomer, N ‐(2‐biphenylenyl)‐4‐[2′‐phenylethynyl]phthalimide (BPP), along with preliminary thermal properties of the resulting polymer 17. In comparison with the PETI resins, the cured BPP has a T g value about 100 °C higher.…”

Crystal structure of dimethyl 4-(phenylethynyl)phthalate, C18H14O4

“…To balance the high temperature performance, high hydrolytic resistance and the processing ease of these materials, the exploration of new compositions and new processing methods for polyimides are developing rapidly. Many researchers have demonstrated that termination of various imide oligomers with phenylethynylg roups can lead to dramatic improvements in hydrothermal durability, toughness and processability [3][4][5][6]. The commonly used terminated agent was 4-(phenylethynyl)phthalic anhydride.…”