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Application of analytical instruments in epoxy resin characterization
Abstract
Advanced fiber reinforced plastics are increasingly being used to replace metals in applications such as aircraft structures, missile casings, rocket motor cases, pressure vessels, automotive components, and others. Advantages of composites over their metallic counterparts are higher strength to weight ratios, higher resistance to corrosion, and lower cost. Structural fibers such as graphite, glass, and polyaramids combined with resin are often used to fabricate these durable goods. Epoxy resins are commonly used in composite industries. In most composite work, the resin is normally impregnated in the fiber. Reaction of the resin starts immediately even when stored at cold temperature. Therefore, the curing mechanism of the resin must be known to prevent wasting expensive preimpregnated fiber due to aging. Other important manufacturing factors that influence composite cost and quality are cure profile, laminate thickness, time to apply pressure and vacuum, thermal oxidation stability, and shrinkage. Most of these manufacturing problems depend very much on the resin used. The differential scanning calorimeter (DSC), gel permeation chromatograph (GPC), dynamic mechanical analyzer (DMA), infrared spectroscopy (IR), elevated temperature viscometer (ETV), and the universal testing machine were used in this study to develop cure models for an amine cured epoxy. In this study, new methods based on differential analysis and least squares regression of DSC data are developed. This new method was found to be more accurate than other methods proposed prior to this study. In addition, DMA, GPC, IR, and ETV were used in conjunction with a universal testing machine to evaluate the curing mechanism of an amine cured epoxy. Several models capable of predicting the degree of cure of an amine cured epoxy are proposed. The aging characteristic of the epoxy was also explored. An equation that relates the extent of reaction using the GPC to the glass transition temperature from the DSC was developed. A comparison of results from each instrument was also presented. Good agreement was found between the DSC and other analytical instruments.
Subject Area
Chemical engineering|Materials science
Recommended Citation
Ayorinde, Ayodeji John, "Application of analytical instruments in epoxy resin characterization" (1990). ETD collection for University of Nebraska-Lincoln. AAI9030103.
https://digitalcommons.unl.edu/dissertations/AAI9030103