Off-campus UMass Amherst users: To download dissertations, please use the following link to log into our proxy server with your UMass Amherst user name and password.
Non-UMass Amherst users, please click the view more button below to purchase a copy of this dissertation from Proquest.
(Some titles may also be available free of charge in our Open Access Dissertation Collection, so please check there first.)
Characterization of structural transformations with vibrational spectroscopy
The work presented in this thesis applies primarily the techniques of Raman and infrared spectroscopy to characterize the structural transformations in polymers. An overview of the problems studied is given in Chapter 1. Particular emphasis is given to mainly syndiotactic polypropylene structural transformations influenced by configurational defects (Chapter 2), and thermal history and mechanical deformation (Chapter 3). In Chapter 4, the influence of a confining surface in the structural transformation of poly(dimethyl siloxane) Langmuir films at the air-water interface is characterized. ^ Using a combination of Raman spectroscopy, and normal coordinate analysis of both ordered and disordered chains, it was possible to relate the Raman spectrum to the amorphous phase and ordered phase structures. With this relationship, it was possible to directly relate the Raman spectrum to the population of meso(isotactic) defects in mainly syndiotactic polypropylene. In addition, time, temperature, and mechanical stretching-dependent transformations were characterized. ^ With external reflectance infrared spectroscopy, it was possible to characterize chain conformation and the local environment of the polymer backbone. Dependence of band intensity and frequency was related to the average segmental orientation and the proximity of the water surface. ^
Chemistry, Physical|Chemistry, Polymer
Thomas D Hahn,
"Characterization of structural transformations with vibrational spectroscopy"
(January 1, 1999).
Electronic Doctoral Dissertations for UMass Amherst.