Modelling of the melting point shift in semi-crystalline thermoplastics dependent on prior cooling rate and heating rate. (21st July 2022)

• Record Type: Journal Article
• Authors: Bölle, Simon; Alms, Jonathan; Weihermüller, Max; Robisch, Meike; Wipperfürth, Jens; Hopmann, Christian; Dahlmann, Rainer
• Is Part Of: Polymer. Volume 254(2022)
• Publication Date: 2022-07-21
• Subjects: Differential scanning calorimetry -- Material model -- Melting temperature -- Polyamide 6.6 -- Polypropylene -- Degree of crystsallisation; Polymers -- Periodicals; Polymerization -- Periodicals; Polymères -- Périodiques; Polymérisation -- Périodiques; 547.7
• DOI: 10.1016/j.polymer.2022.125100
• Languages: English
• ISSNs: 0032-3861

Abstract

Abstract: The different local properties of plastic parts are highly dependent on local thermal histories. In DSC measurements a shift in peak melting temperature was detected in semi-crystalline thermoplastics (Polypropylene and Polyamide) dependent on the heating rate and prior treatment conditions of the samples. To investigate such phenomena, the shift in peak melting temperature depending on a prior cooling and subsequent heating for polyamide 6.6 and isotactic polypropylene is examined using Flash-DSC measurements. Due to crystallisation and heat conduction effects the temperature shows a dependence on the cooling and heating rate. From the observations, a model was developed that is able to predict the measured peak melting temperature as a function of the cooling and heating rate. A phenomenological model is developed uniting the effect of cooling rate prior and the melting rate in order to predict the main melting point. Graphical abstract: Image 1 Highlights: Modelling the melting temperature of the welding of injection moulded parts. Semi-crystalline polymers: isotactic polypropylene and polyamide 6.6. Analysis of thermal effects of iPP and PA6.6 representing industrial polymers. Correlation of both cooling history and heating rate on melting temperature. Thermal analysis at high cooling and heating rates using the Flash-DSC 2+.