Spin Relaxation and Local Motion in a Dissolved Aromatic Polyformal

Jeppson Laboratory, Department of Chemistry, Clark University, Worcester, M A 01610 R T INGLEFIELD 

Department of Chemistry, College of the Holy Cross, Worcester, MA 01610 

In addition, the formal unit itself offers a new opportunity for monitoring chain motion relative to the polycarbonates since the carbonate unit contains no protons. The spin-lattice relaxation times, T s of all protons and all carbons with directly bonded protons are reported for the polyformal. Also the carbon and proton Tj s are measured at two different Larmor frequencies to expand the frequency range covered by the study. 

In addition to determining the time scales for several local motions in polyformal, two different interpretational models for segmental motion will be employed. An older model by Jones and Stockmayer (7 ), based on the action of a three bond jump on a tetrahedral lattice is compared with a new model by Weber and Hel-fand ( ), based on computer simulations of polyethylene type chains. These two models for segmental motion have been compared before ( ) for two polycarbonates but somewhat different results are seen in the polyformal Interpretation. 

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Spin Relaxation and Local Motion in a Dissolved Aromatic Polyformal... 

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