Date of Award

12-2014

Document Type

Thesis

Degree Name

Master of Science (MS)

Legacy Department

Packaging Science

Advisor

Dr. Duncan Darby

Committee Member

Dr. Robert Kimmel

Committee Member

Dr. Patrick Gerard

Abstract

Heat sealing is an integral method for the closure and protection of packaging. Previous work has shown that seal strength is developed by the interdiffusion of polymer chains within heat seals. Heat seals were made between two dissimilar materials. Poly(ethylene-co-acrylic acid) (EAA) was heat sealed to ionomer. Diffusion within the EAA-ionomer heat seals was estimated. The diffusion estimates were then related to resulting seal strength in the EAA-ionomer sealant system. Heated tooling sealing was utilized to make heat seals at 40 psi (275.79 kPa), 0.5 seconds, and a range of temperatures between 180˚F (82.22˚C) and 300˚F (148.89˚C). Scanning electron microscopy and energy dispersive x-ray spectroscopy was employed to measure the diffusion of polymer chains within the heat seals. Two estimators for polymer chain diffusion were made for each heat seal. The results of this study agree with previous theories and computations on heat sealing. Polymer chain diffusion was measured in two ways. It was found that heat energy drives polymer chain diffusion. Diffusion consistently increased as the heat seal temperature was increased. Greater polymer chain diffusion distances resulted in heat seals with greater seal strength.

Share

COinS