Detection of Inclusions and Degradation in Injection-Molded Thermoplastics
DOI:
https://doi.org/10.12974/2311-8717.2019.07.3Keywords:
Forensics, injection molding, inclusion, degradation.Abstract
This work suggests a formal procedure to identify inclusions and anomalies in injection molded specimens. To find a suitable procedure, experiments with actual molded specimens have been tested. The specimens were injection molded blow preform of PET with inclusions and the PET preform degraded intentionally by controlling the residence time. By microtoming the inclusions have been exposed to the surface and then they have been analyzed by XRD, XRF, FTIR and DSC. Based on the results, this study have proposed a simple protocol for identifying visually observable foreign or unwanted substances. It starts with optical microscopy followed by SEM/EDS. Based on the result and amount of the inclusions, the procedure move onto conventional FTIR or micro-IR test. The XRF can be of aid especially when the inclusion is inorganic.
References
Rosato DV, Rosato Marlene G. Injection Molding Handbook, Springer New York 2000. https://doi.org/10.1007/978-1-4615-4597-2
Kerkstra R, Brammer S. Injection Molding: Advanced Troubleshooting Guide: The 4M Approach, Hanser 2018. https://doi.org/10.3139/9781569906460.fm
Chaves ML, Vizán A, Márquez JJ, Ríos J. Inspection model and correlation functions to assist in the correction of qualitative defects of injected parts Polymer Engineering & Science 2010; 50(6): 1268-1279. https://doi.org/10.1002/pen.21647
Lewis PR, Gagg C. Forensic polymer engineering, Cambridge: Woodhead Pub. Ltd. 2010. https://doi.org/10.1533/9781845697808
Griffiths ER, de Haseth JA. Fourier Transform Infrared Spectrometry. Wiley, New York 1986.
Skoog DA, Holler FJ, Crouch SR. Principles of Instrumental Analysis 6th Edition, Thomson Brooks/Cole 2008.
Turi EA, Khanna YP, in: Turi EA, (Ed.), Thermal Analysis in Polymer Characterization. Heyden & Son, Philadelphia 1981.
Hellmiss G. Thermal Analysis Methods in Forensic Science. In: Maehly A, Williams RL, (Eds.,) Forensic Science Progress. Forensic Science Progress, vol 2. Springer, Berlin, Heidelberg 1988. https://doi.org/10.1007/978-3-642-69403-5_1
Kosky RG, McDonald RS, Guggenheim EA. Determination of end‐group concentrations and molecular weight of poly(butylene terephthalate) by solid‐state fourier transform infrared spectroscopy. Polym Eng Sci 1985; 25: 389. https://doi.org/10.1002/pen.760250703
Antoon MK, Koenig JL. Crosslinking mechanism of an anhydride‐cured epoxy resin as studied by fourier transform infrared spectroscopy. J Polym Sci Part A: Polym Chem 1981; 19: 549. https://doi.org/10.1002/pol.1981.170190228
Antoon MK, Zehner BE, Koenig JL. Spectroscopic determination of the in‐situ composition of epoxy matrices in glass fiber‐reinforced composites. Polym Compos 1981; 2: 81. https://doi.org/10.1002/pc.750020207
Blom H, Yeh R, Wojnarowski R, Ling M. Detection of degradation of ABS materials via DSC, Therm Anal Calorim 2006; 83: 113. https://doi.org/10.1007/s10973-005-6977-0
Li J, Stoliarov SI. Measurement of kinetics and thermodynamics of the thermal degradation for charring polymers, Polymer Degradation and Stability 2014; 106: 2- 15. https://doi.org/10.1016/j.polymdegradstab.2013.09.022
Caron AGM, Thomas CR, Berry KLE, Mottia CA, Ariel E, Jon Brodie E. Validation of an optimised protocol for quantification of microplastics in heterogenous samples: A case study using green turtle chime, MethodsX 2018; 5: 812- 823. https://doi.org/10.1016/j.mex.2018.07.009
Emma Strömberg Sigbritt Karlsson. The design of a test protocol to model the degradation of polyolefins during recycling and service life, Applied Polymer Science 2009; 112: 1835-1844. https://doi.org/10.1002/app.29724