A Novel Thermo‐Polymerizable Aromatic Diamine: Synthesis and Application in Enhancement of the Properties of Conventional Polyimides

Abstract

Owing to their important application in the production of high performance materials, aromatic diamines have received interest in many areas for several years. However, most of the polymers derivated from diamines show poor processability due to their rigid backbone. Although much effort has been made, a balance between the solvent (or heat)-resistance and processability of the polymers still needs to be achieved. In this contribution, a new aromatic diamine is reported, which has both reactive amine groups and thermo-polymerizable benzocyclobutene moieties. Starting from the diamine can not only give the corresponding polymers, such as polyamides, polyimides, and polyurethanes, but can also provide new structural materials through the post-polymerization of the polymers. It is found that adding diamine into a conventional polyimide system can greatly improve the properties of the polyimide, such as T g , coeffi cient of thermal expansion, tensile strength, and storage modulus. When the content of the diamine is in the range ≈ 5-10 mol%, the tensile strength of the conventional polyimide is increased by up to 30%. The highest T g (> 400 °C) is observed when the content of the diamine is 40 mol%. the polymers derivated from diamines show poor processability, mainly due to the inherent rigid backbone of the diamine. For example, polyamides [ 1 ] based on aromatic diamines are insoluble in common organic solvents. Moreover, polyimides [2][3][4][5] derived from rigid diamines are infusible and partly soluble in solvents with strong polarity. In order to reduce the rigidity of aromatic diamines, a general strategy is to attach side chains to the backbone of the diamines [ 6 ] or introduce fl exible ether bonds to the molecules. [ 7 ] Nevertheless, an improvement in rigidity is usually accompanied by a decrease in the solvent resistance and heat resistance of the polymers. Hence, exploration and development of new aromatic diamines with excellent properties is necessary.Recently, we have found that postpolymerization is an effi cient and simple way to realize the balance

Synthesis and characterization of high fluorine‐containing polyimides with low‐dielectric constant

“…After stirring for 12 h, a viscous solution of PAA was obtained. Then the PIs were prepared by chemical imidization according to literature 38 . The PIs films were prepared by casting PI solutions in DMAc with 10 wt% onto a clean glass plate and dried in vacuum for 2 h. Then the polymer films (thickness: 50 um) were obtained by a stepped thermal sequence (150°C/1 h, 250°C/1 h, and 310°C/1 h).…”

Synthesis and properties of novel colorless and thermostable polyimides containing cross‐linkable bulky tetrafluorostyrol pendant group and organosoluble triphenylmethane backbone structure

“…In many cases, attaching cross‐linkable pendant group is an efficient and simple strategy to realize the balance between processability and solvent resistance, and which could also be capable of effectively enhancing numerous properties of polymers involving a higher T g , thermal stability, dimensional stability, mechanical property, chemical solvent resistance, and so forth. Benzocyclobutene, trifluorovinylether, terminal phenylethynyl, poly(maleic anhydride), and styryl groups are both frequently used cross‐linking groups, 25–32 and in which the styryl‐based thermal cross‐linking reaction is readily accomplished by heating at a relative low temperature in the presence of any initiator 33–35 . Moreover, triphenylmethane and its derivative PIs have excellent solubility in high polar aprotic solvents, such as N‐methyl pyrrolidone (NMP), N,N‐dimethylacetamide (DMAc), and N,N‐dimethylformamide (DMF), due to their special twisted pyramid configuration, and have become worthy of attention in recent years.…”

Microwave-assisted synthesis of high thermal stability and colourless polyimides containing pyridine

“…PI composed of TPM and pyromellitic dianhydride (PMDA) (TPM-PMDA) shows T g of 365°C. Subsequently, people explored a series of TPM derivatives (as shown in scheme 1) by introducing various aromatic units into R 1 position and aliphatic units into the R 2 and R 3 positions of the diamine [15–24]. R 1 groups were found to have great effect on the T g s of the final polymers.…”