Polymer Structures and Properties. Part II. Thermally Stable Polymers.
Abstract
Viscoelastic studies on BBB to elucidate the mechanism by which deformation occurs and the relation between supramolecular structure and deformation are described. A tensile creep apparatus suitable for studies on films in vacuum from -20 to 500 C is described. The 'instantaneous' creep deformation in BBB is followed by creep in which the deformation is proportional to the cube root of time (Andrade Creep). Creep recovery is complete, although the rate of recovery is not in accord with the laws of linear viscoelasticity. Dilute solution properties (light scattering and viscometry) on fractions of BBL in methane sulfonic acid gives the molecular weight and the dimensions of BBL fractions are described. Fractionation was achieved by preparative scale chromatography. Light scattering studies of the supramolecular films of BBB prepared by several techniques are described. The scattering enveloped films of BBB usually reveal a rod-like segment correlation. Data are compared with theoretical scattering envelopes. Rheometry on concentrated solutions of BBB in methane sulfonic acid providing information on the properties of BBB solutions at concentrations employed in fiber spinning. Several theoretical models for peak migration in gel permeation chromatography are compared. Calculations based on these models find use in the interpretation of chromatographic data in terms of molecular weight distribution. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1972
- Accession Number
- AD0903773
Entities
People
- C. P. Wong
- E. F. Casassa
- G. C. Berry
- K. D. Goebel
- S. M. Liwak
Organizations
- Carnegie Mellon University