Accession Number : ADA313876

Title :   Cure and Water Monitoring in Selected Polymers.

Descriptive Note : Final rept. 1 Jul 92-31 Dec 95,

Corporate Author : CONNECTICUT UNIV STORRS INST OF MATERIALS SCIENCE

Personal Author(s) : Sung, C. S. ; Sung, N. H.

PDF Url : ADA313876

Report Date : 29 MAR 1996

Pagination or Media Count : 11

Abstract : The objective of the research under this contract was to develop in-situ monitoring technique for cure and water in selected polymers. The techniques explored are intrinsic fluorescence, phosphorescence and UV reflection The polymers studied are epoxy, polyimide and vinyl polymers (MMA and styrene). These techniques were also used to probe fiber/resin interphase. The intrinsic fluorescence spectral shift (25 nm) due to the cure of epoxy with the main curing agent, p,p'-diamino diphenyl sulfone (DDS) was related to the extent of cure and implemented by fiber-optic fluorimeter for in-situ cure characterization of epoxy/graphite composites. The phosphorescence lifetime due to DDS was found to be useful to measure the extent of cure in the prepregs. The external UV reflection technique was developed as an intrinsic cure monitoring technique for polymers such as polyimides exhibiting weak fluorescence. A bifurcated multifiber probe for UV reflection technique has been implemented for in-situ imidization studies. Polymerization of styrene and methyl methacrylate (MMA) were successfully monitored by UV and in-situ fluorescence techniques via fiber-optics. For water-uptake monitoring, the fluorescence intensity of DDS which shows sensitive decrease was correlated to the water-uptake measured by gravimetry in neat epoxy as well as in epoxy composites. The characterization of cure reactions in epoxy/fiber interphase has been probed by evanescent fluorescence due to an extrinsic cure sensor, p,p'-diamino azobenzene by using sapphire fiber due to its high refractive index of 1.78 in comparison to that of epoxy of 1.61.

Descriptors :   *MONITORING, *WATER, *POLYMERS, *CURING AGENTS, FIBER OPTICS, PROBES, FLUORESCENCE, ULTRAVIOLET RADIATION, METHYL RADICALS, COMPOSITE MATERIALS, POLYMERIZATION, STYRENES, REFRACTIVE INDEX, PHASE STUDIES, REFLECTION, SAPPHIRE, GRAVIMETRY, METHACRYLATES, EPOXY COMPOUNDS, EPOXY COMPOSITES, PREPREGS, GRAPHITED MATERIALS, LOW STRENGTH, VINYL PLASTICS, POLYIMIDE RESINS, PHOSPHORESCENCE.

Subject Categories : Polymer Chemistry
      Organic Chemistry
      Physical Chemistry
      Laminates and Composite Materials

Distribution Statement : APPROVED FOR PUBLIC RELEASE