New Heat-Resistant and Soluble Aramids Synthesized by Palladium-Catalyzed Carbonylation-Polycondensation

Abstract

As a candidate for the alternate of conventional, insoluble thermosetting resins that are matrix components of fiber reinforced plastics (FRP), soluble and heat-resistant aramids (wholly aromatic polyamides) were synthesized. To obtain rigid biphenyl-containing aramid, one-step procedure from dihalobiphenyl and aromatic diamine by palladium-catalyzed carbonylation-polycondensation was successfully applied. Reaction parameters, such as base, solvent, palladium-phosphine catalyst and CO pressure in the reaction of 2,7-dibromo-9,10-dihydrophenanthrene (1) and 4,4 -diaminodipheyl ether (2a), were very important for successful synthesis. They affected the molecular weight of resulting aramid significantly. Under optimum conditions, poly[amino-1,4-phenyleneoxy-1,4-phenyleneaminocarbonyl(9,10-dihydro-2,7-phenanthrenediyl)carbonyl] (3a) was obtained in 99% yield with high molecular weight (polystyrene equivalent M w = 128100). The procedure was applied to some other diamines. The aramid 3a was heat-resistant and soluble in polar organic solvent. On the basis of thermal analysis, 10% weight loss temperature (T 10 ) of the aramid was 461 • C. The tensile strength and tensile modulus were 48 MPa and 1.6 GPa, respectively; these properties are roughly in the same level as those of conventional unsaturated polyester resin. Judging from the data, aramid 3a is applicable for matrix of FRP. Some other aramids exhibited similar properties.

Highly Selective and Efficient Catalyst for Carbonylation of Aryl Iodides:Dimeric Palladium Complex Containing Carbon-Palladium Covalent Bond

“…Furthermore, the activation of less reactive and less expensive aryl, vinyl bromides and chlorides for the carbonylation reaction with alcohols and amines to achieve high turnover numbers and frequencies is in progress, which is of potential importance in industrial applications for the synthesis of organic soluble polyesters and polyamides. 12 In a typical procedure, aryl iodide (2.5 mmol), alcohol (2.5-3.0 mmol), 1,8-diazabicyclo [5.4.0] undec-7-ene (DBU, 3.0 mmol) and catalyst (0.01 mmol) in benzene (5 mL) were taken in autoclave (50 mL), flushed with nitrogen 3 times and pressurized with carbon monoxide (0.5 MPa). The autoclave was placed in oil bath heated at 120°C and the whole mixture was stirred for 3 h. After the reaction, the autoclave was cooled, excess carbon monoxide was purged, and benzene was evaporated in vacuo.…”

Critical Issues in Promotion of Environmentally Benign Manufacturing and Materials Processing

“…Hence, as reported in Ref. 15), separable interface must be equipped into an assembly technology in manufacturing. That is, adequate inclusion infiltrated into an interface drastically reduces the interfacial strength to the level, where it breaks away from itself by the thermal stress or the thermal shock.…”