th - 1988 - 51st ENC Conference
th - 1988 - 51st ENC Conference
th - 1988 - 51st ENC Conference
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--194<br />
I CPMAS ANALYSIS OF A POLYIMIDE/GLASS CIRCUIT BOARD:<br />
B. L. Myers-Acosta*, S. J . Selover, Lockheed Missiles & Space Company,<br />
Inc., Sunnyvale, California 94088-3504.<br />
The effects of starting material chemistry and processing on <strong>th</strong>e final<br />
properties of cured polyimide/glass composites has been investigated<br />
using CPMAS spectroscopy. We have found <strong>th</strong>at bo<strong>th</strong> changes in<br />
stoichiometry and processing can be detected using <strong>th</strong>is technique.<br />
Previously, only starting material chemistry could be readily<br />
investigated making it difficult or impossible to evaluate <strong>th</strong>e effects<br />
of processing on <strong>th</strong>e material chemistry. We have found <strong>th</strong>at several<br />
features of <strong>th</strong>e performance of <strong>th</strong>ese polyimide materials, after<br />
processing into circuit boards, are a function of <strong>th</strong>e interaction<br />
between material chemistry and processing. CPMAS spectroscopy<br />
provided a unique way to evaluate <strong>th</strong>e chemistry of <strong>th</strong>e cured composite<br />
in finished parts to establish <strong>th</strong>e processing requirements of specific<br />
materials. Fur<strong>th</strong>er, processing latitude could be evaluated by<br />
examining <strong>th</strong>e chemical state in cured composites from various<br />
lamination schedules. Spectroscopic details will be presented.<br />
--195 I A STUDY ON 3',5'-AMP BY TWO-DIMENSIONAL DOUBLE QUANTUM<br />
SPECTROSCOPY IN 'H NMR, Gang Wu*, Wei Gun, Y. Huang, Shouping Jiang, Shaohui LJan,<br />
Physics Department, East China Normal University, Shanghai 200062, People's<br />
Repub]ic of China.<br />
The results of two-dimensional double quantum spectroscopy on 3',5'-AMP will be<br />
presented. The resonances of H(2) and H(8) are resolved in <strong>th</strong>e spectrum, which are<br />
partially overlapped in ttle 1D spectrum, and <strong>th</strong>e coupling of H(1')-H(8) is revealed<br />
from which we are able to deduce <strong>th</strong>at <strong>th</strong>e glycosyl bond conformation of 3',5'-AMP<br />
in solution (ph 7, O.04M, 23°C) is in <strong>th</strong>e form of syn conformation wi<strong>th</strong> <strong>th</strong>e<br />
dihedral angle ~ in a range of 79 ° ~ 90 ° . The spectrum also shows<br />
<strong>th</strong>e direct coupling between H(2) and H(8) by Type I signals, which coupling is<br />
unresnlvable in ID spectr.m because of its small value.<br />
c,.,<br />
C,+ o~<br />
¢8<br />
~o-P=o q'Hl~ H /1 It<br />
*Present address: Department of Chemistry, York University, 4700<br />
Keele St., Nor<strong>th</strong> York, Ontario M3J 1P3 Canada.<br />
196
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