Date of Award

8-2012

Document Type

Thesis

Degree Name

Master of Science (MS)

Legacy Department

Packaging Science

Advisor

Darby, Duncan O

Committee Member

Whiteside , William S

Committee Member

Rieck , James R

Abstract

This work was aimed at studying the relationship between burst pressure and seal peel strength. Past researchers developed a force balance equation based on the analysis of a force diagram to relate burst pressure to seal strength. The theoretical formula S=P(D/2) (S=Seal Strength, P=Burst Pressure, D=Restraining Plate Gap) has been studied by past researchers with contrasting results.
The theoretical formula was tested by varying dwell time to produce seals of varying strength. Pouches were burst tested at each of these dwell times to obtain burst pressures, burst peeling times, and burst locations. Corresponding peel tests were performed with crosshead speeds that were adjusted to match the peeling time of the burst tests. The peel tests were also performed with adjusted gauge lengths to match the plate gap used in inflation burst testing and compression burst testing.
The data was analyzed by treating the obtained burst pressures as proxy variables for the unobtainable true burst pressures associated with the pouches that were destroyed during peel testing. Dwell time was used as an instrumental variable, and the two-stage least squares method for parameter estimation was used to estimate the slope of the regression.
The estimated slopes of the regressions were compared to the theoretical slope (D/2) for each plate gap using analysis of variance. The results showed that the theoretical relationship suggested by past researchers only worked for a restrained burst test with a plate gap of 0.25in.
Empirical equations were developed from the parameter analysis. The empirical equations were used to calculate predicted burst pressures which were then compared to the burst pressures obtained from testing. The percent difference between the two values ranged from 0% to 28%.

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