Use of Migration Modelling for food contact materials :
Exercises
Download SML Exercises : Use of Migration Modelling for food contact materials (pdf, 6.7 MB)
Application of Finite Element Analysis (FEA) for the simulation of release of additives from multilayer polymeric packaging structures
1AKTS AG – Advanced Kinetics and Technology Solutions, TECHNOArk 1, Siders, Switzerland, and
2Swiss Federal Office of Public Health, Division of Food Science, Bern, Switzerland
Abstract
Computer programmes are available to predict, for consumer protection purposes, the migration of additives from a polymeric package during its contact with food. However most of these programs were developed to estimate migration only from single layer polymeric packaging under isothermal conditions. In this work a diffusion model was developed to simulate the migration from multilayer packaging and under non-isothermal temperature conditions, too. Finite Element Analysis (FEA) is used as a numerical approximation method to solve the diffusion equations describing such processes. The possibilities and limitations of the FEA method are presented and the correlation between experimental and computed results is discussed.
Simulation of Deterrent Diffusion in Double Base Propellant Under Different Temperature Profiles
1AKTS AG, http://www.akts.com, TECHNOArk 1, 3960 Siders, Switzerland, b.roduit@akts.com
2MDCTec Systems GmbH, Gutenbergstrasse 5, 82205 Gilching, Germany
3armasuisse, Science and Technology Centre, 3602 Thun, Switzerland
4Nitrochemie Wimmis AG, 3752 Wimmis, Switzerland
5Royal Military Academy, Avenue de la Renaissance 30, 1000 Bruxelles, Belgium
6PB Clermont s.a., Rue de Clermont 176, 4480 Engis, Belgium
Abstract
Propellants can burn so rapidly that the initial rise of pressure in weapons may be faster than desired. To avoid this unwanted effect, burning rate of the propellants is moderated by applying a surface coating. Coating agents are usually deterrents (moderants), substances that gelatinize or plasticise the nitrocellulose matrix of the propellants decreasing its initial burning rate, therefore, in turn, the rate of gaseous phase formation. The knowledge of the diffusion rate of deterrents helps therefore in developing propellants with superior ballistic performance. Another parameter, namely the rate of the migration of deterrent into the propellant matrix during ageing / storing is also important as it influences the ballistic shelf-life i.e. the period of time during which the ballistic requirements are fulfilled. As migration measurements are often difficult, expensive and timeconsuming the development of the simulation tools of above processes seems to be of a great importance. The present paper describes the simulation method for deterrent and blasting oil diffusion in double base propellant applying the temperature dependence of the diffusion coefficients D determined in isothermal experiments and taking into account the influence of the swelling effect of the propellant matrix. The simulations were done using the AKTS-SML software [1], which allowed considering the migration of both, deterrent and nitroglycerine through the swollen matrix of the propellant. Furthermore, after determination of the temperature dependence of the diffusion coefficient D, it was possible to predict the deterrent migration under any, arbitrarily chosen temperature profile such as oscillatory temperature mode, real atmospheric temperature profiles or under temperature mode corresponding to atmospheric changes according to STANAG 2895 [2].
Download: Simulation of Deterrent Diffusion in Double Base Propellant Under Different Temperature Profiles (pdf, 239 KB)
Diffusion Coefficients of Antimony Catalyst in Polyethylene Therephthalate (PET) materials :
Download: Diffusion Coefficients of Antimony Catalyst in Polyethylene Therephthalate (PET) materials (pdf, 75 KB)
Food Contact Materials Compliance Database :
Risk assessment and management tool
Download: Food Contact Materials Compliance Database (pdf, 564 KB)
Presentation and Exercises