Transitions and Relaxations in Aromatic Polymers,
Abstract
Transition and relaxation phenomena in twenty-six structurally related polyquinoxalines and other aromatic polymers were studied over a temperature range from 70 to 770K by means of calorimetric, dilatometric, dynamic mechanical and dielectric techniques. Differential thermal analysis and X-ray data showed these polymers to be essentially amorphous. Calorimetric measurements gave discontinuities in heat capacities ranging from 12 to 54 cal/C per mole of repeat unit structures and provided unambiguous assignments of glass transition temperatures of these polymers. Viscoelastic properties were obtained by means of torsional braid analysis and using a longitudinal vibrational apparatus. In a typical case, the dynamic mechanical relaxation spectrum contained three loss maxima. Major mechanical relaxations occurring in the glass transition interval of these polymers are proposed to result from translational motions. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1971
- Accession Number
- AD0718834
Entities
People
- Wolfgang Wrasidlo
Organizations
- Boeing