Highly soluble phenylethynyl‐terminated imides derived from mellophanic dianhydride (MPDA)

Abstract

Novel highly soluble phenylethynyl‐endcapped oligoimides with different calculated molecular weights were prepared by using mellophanic dianhydride and bis(4‐amino‐2‐trifluoromethylphenyl)ether in the presence of 4‐phenylethynyl phthalic anhydride as the reactive endcapping agent. The effect of molecular weights of the aromatic oligoimides on their solubility and processability as well as the thermal and mechanical properties of the thermal‐cured polyimides was fully investigated. This kind of phenylethynyl‐terminated imides exhibited excellent comprehensive properties. Most importantly, a big progress has been made in the solubility of the oligoimides in this paper. Most of the oligoimides showed excellent solubility (more than 33 wt%) even in acetone, which was reported for the first time. And oligoimides with appropriate molecular weights also showed very good processability with minimum melt viscosities no higher than 120 Pa·s by the rheological study. After thermally curing at 370°C for 1 hour, the cured flexible films showed very high glass transition temperatures up to 392°C by dynamic mechanical analysis, and the temperature of 5% weight loss was higher than 500°C in both air and N2 atmosphere by thermogravimetric analysis. The cured films also exhibited very good toughness with elongation up to 9%.

Novel acetylene‐terminated thermosetting polyisoimides with excellent solubility and performed as efficient heat shields composites

“…Benefiting from its low melt viscosity and better processing window, PMR‐15 composites have been widely used in airplanes, automobiles, and off‐shore oil‐drilling platforms 3,19 . However, the poor thermo‐oxidative and storage stability, harsh curing conditions (600 K, 200–500 psi) as well as the brittleness of cured PIs limited the applications of norbornene (NE) end‐capped prepolymers 14,20 . Due to forming aromatic cross‐linking structure introduced phenylethynyl terminated imide, the thermo‐oxidative stability and toughness of PIs were effectively improved.…”

1,4‐Bis(2,3‐dicarboxyl‐phenoxy)benzene dianhydride‐based phenylethynyl terminated thermoset oligoimides for resin transfer molding applications

“…First, the dianhydrides should be asymmetric, because they can decrease the melt viscosity of the oligomers and enhance the T g after cured. That is why asymmetric dianhydrides have been widely investigated lately . Second, there should be flexible segments in molecular chains (like 1,3,4‐APB, 3,4′‐ODA, and 1,4,4‐6FAPB), because they can enhance the processability of the oligomers.…”

Phenylethynyl-terminated oligoimides with ultra-low melt viscosity derived from 1,4-bis(3,4-dicarboxy phenoxy)benzene dianhydride

“…5 Therefore, PETIs have received sustained attention over these years. [6][7][8][9][10][11] In recent years, it was found that oligomers with calculated molecular weight of 750 g mol À1 showed good features for resin transfer molding (RTM) processing. RTM is more desirable for composite fabrication than conventional autoclave techniques because of its relatively low manufacturing cost and the solvent-free feature.…”