The effect of repeated microwave heating, fill level and temperature on the impact resistance of a polypropylene syrup bottle

The effect of repeated microwave heating, fill level/and storage temperatur e on the impact resistance of microwavable polypropylene bottles containing syrup was studied. Bottles filled with syrup at 100%, 75%, 50%, and 25% le vels were subjected to drop tests after storage at 8 degreesC, 20 degreesC/ and 40 degreesC and after several reheatings in a conventional microwave ov ert following the label directions. The degree of crystallinity of the poly propylene was also evaluated using modulated DSC. A decrease in impact resi stance and art increase in the degree of crystallinity of the package mater ial was observed after the bottles were repeatedly heated in the microwave oven. Impact orientation, product fill level and storage temperature also s ignificantly affected the impact resistance of the bottles. The bottle impa ct resistance may be insufficient for the intended use. Copyright (C) 2000 John Wiley & Sons, Ltd.