Measuring Thermal Crystallinity in PET
The mechanical properties of poly (ethylene terephthalate) (PET) depend on the degree of crystallinity. PET crystallizes from both thermal and strain-induced process paths. Strain-induced crystallization occurs under uniaxial or biaxial stretching, the latter is common in stretch blow molding. Thermal crystallization takes place when cooling from the melt or under sustained elevated temperature which are both common during injection and blow molding. The current work focuses on comparing methods used to quantify the percent thermal crystallinity in injection molded water bottle preforms. An injection molded preform with a gradient of induced thermal crystallinity was examined using Differential Scanning Calorimetry (DSC), Micro X-ray Diffraction (μXRD), and Raman Spectroscopy. Correlating these three techniques for percent thermal crystallinity, helps with the development of nondestructive crystallinity measurement methods to aid with process optimization and part quality.
Modelling capping of 28 mm beverage closures using finite element analysis
Understanding the performance of packaging on production lines is of course extremely important to the packaging industry. Computer simulation techniques have improved vastly in recent years, and modelling the complex interaction of three‐dimensional threaded shapes, like closures, is now a reality. This paper outlines the work undertaken in understanding the possible mechanisms relating to the capping of 28  mm beverage closures and the use of experimental and computer simulations in order to establish that understanding. Copyright © 2007 John Wiley & Sons, Ltd.
Chromatographic analysis of elastomer antidegradants and accelerators
Summary The use of various chromatographic methods in the analysis of all classes of elastomer antidegradants and accelerators is reviewed. The review of extraction methods is also included.