Location

Snowbird, UT, USA

Start Date

1-1-1999 12:00 AM

Description

The motivation behind this work was a requirement to optimise the cure cycles of adhesive used in the construction of automotive body shells and to establish the tolerance of the adhesive to uneven heating during cure, and to variation in the ratio of resin to hardener in the adhesive mixture. The rationale was that ultrasonic compression wave (CW) measurements on curing epoxy were relatively easy [1,2], and that increases in CW propagation velocity during cure corresponded to the development of mechanical moduli, given only small changes in the density of the adhesive during cure. Of interest was the way in which CW measurements relate to the evolving chemistry and structure in the adhesive, how they relate to the development of shear strength, and whether CW absorption measurements could be useful in tracking the cure cycle. In this work we have compared wide bandwidth measurements of absorption for both compression and shear (SW) waves. CW measurements were also compared to wide angle x-ray scattering (WAXS) measurements and to low resolution nuclear magnetic resonance (NMR) measurements in order to relate what was observable by ultrasound to the evolving structure in the adhesive and to the progress of the cure reaction. In a parallel study, not reported here, we have also made comparisons between CW and dielectric spectroscopy.

Book Title

Review of Progress in Quantitative Nondestructive Evaluation

Volume

18B

Chapter

Chapter 8: Process Control, Reliability, and Training

Section

Process Control

Pages

2185-2189

DOI

10.1007/978-1-4615-4791-4_280

Language

en

File Format

application/pdf

Share

COinS
 
Jan 1st, 12:00 AM

Epoxy Cure Observed by Ultrasound, NMR and WAXS

Snowbird, UT, USA

The motivation behind this work was a requirement to optimise the cure cycles of adhesive used in the construction of automotive body shells and to establish the tolerance of the adhesive to uneven heating during cure, and to variation in the ratio of resin to hardener in the adhesive mixture. The rationale was that ultrasonic compression wave (CW) measurements on curing epoxy were relatively easy [1,2], and that increases in CW propagation velocity during cure corresponded to the development of mechanical moduli, given only small changes in the density of the adhesive during cure. Of interest was the way in which CW measurements relate to the evolving chemistry and structure in the adhesive, how they relate to the development of shear strength, and whether CW absorption measurements could be useful in tracking the cure cycle. In this work we have compared wide bandwidth measurements of absorption for both compression and shear (SW) waves. CW measurements were also compared to wide angle x-ray scattering (WAXS) measurements and to low resolution nuclear magnetic resonance (NMR) measurements in order to relate what was observable by ultrasound to the evolving structure in the adhesive and to the progress of the cure reaction. In a parallel study, not reported here, we have also made comparisons between CW and dielectric spectroscopy.