Polyaramides with Reactive Phenylethynyl Pendants
Abstract
2,5-Bis(phenylethynyl)terephthaloyl chloride and 4,6-bis(phenylethynyl)isophthaloyl chloride were synthesized in a multistep reaction scheme from 2,5-dibromoterephthaldehyde and 4,6-dibromoisophtahldehyde, respectively. Low temperature solution polycondensation of these novel monomers and tolane-2,4'-dicarbonyl chloride with aromatic diamines yielded polyaramides containing phenylethynyl moieties. Inherent viscosities of 0.20-0.51 d1/g were recorded. Attempts to carry out the homopolymerization of 2-(3-aminophenylethynyl)-benzoyl chloride hydrochloride under similar conditions led to low molecular weight polyamide. Under differential scanning calorimetry and thermal mechanical analysis, the polyamides exhibited strong exotherms with onset occurring in the 185-225 C range. The exotherms were attributable to intramolecular cycloaddition of phenylethynyl moieties with amide groups to give polybenzalphthalimidine structures. Curing of a pressed pellet specimen for 16 hours at 250 C under a nitrogen atmosphere resulted in partial conversion to a polybenzalphthalimidine structure with a concomitant increase in the polymer glass transition temperature. Keywords: Matrix resins, Polyaramides, Polyamides, Thermooxidative stability, Thermal reactivity.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 1988
- Accession Number
- ADA196746
Entities
People
- George J. Moore
- Robert C. Evers
- Tonson Abraham
Organizations
- Wright Laboratory