Thermochemical Transition in Non-Hydrogen-Bonded Polymers and Theory of Latent Decomposition
Although thermosets and various biopolymers cannot be softened without being decomposed, the vast majority of thermoplastics are believed to exhibit thermal transitions solely related to physical alterations of their structure—a behavior typical of low molecular weight substances. In this study, Dif...
| Main Author: | |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2022-11-01
|
| Series: | Polymers |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2073-4360/14/23/5054 |
| _version_ | 1797462352347529216 |
|---|---|
| author | Costas Tsioptsias |
| author_facet | Costas Tsioptsias |
| author_sort | Costas Tsioptsias |
| collection | DOAJ |
| description | Although thermosets and various biopolymers cannot be softened without being decomposed, the vast majority of thermoplastics are believed to exhibit thermal transitions solely related to physical alterations of their structure—a behavior typical of low molecular weight substances. In this study, Differential Scanning Calorimetry (DSC), Fourier Transform Infrared Spectroscopy (FTIR) and Thermogravimetry (TGA) were used to study the softening of four common non-hydrogen-bonded thermoplastic polymers (polypropylene, polypropylene-grafted-maleic anhydride, poly(vinyl chloride) and polystyrene) along with a hydrogen-bonded polymer as a reference, namely, poly(vinyl alcohol). It is shown that the softening of these polymers is a thermochemical transition. Based on fundamental concepts of statistical thermodynamics, it is proposed that the thermal transition behavior of all kinds of polymers is qualitatively the same: polymers cannot be softened without being decomposed (in resemblance with their incapability to boil) and the only difference between the various types of polymers is quantitative and lies in the extent of decomposition during softening. Decomposition seems to reach a local maximum during softening; however, it is predicted that polymers constantly decompose even at room temperature and, by heating, (sensible) decomposition is not initiated but simply accelerated. The term “<i>latent decomposition</i>” is proposed to describe this concept. |
| first_indexed | 2024-03-09T17:35:18Z |
| format | Article |
| id | doaj.art-e8de862f72324af99d2b2f621fb194f2 |
| institution | Directory Open Access Journal |
| issn | 2073-4360 |
| language | English |
| last_indexed | 2024-03-09T17:35:18Z |
| publishDate | 2022-11-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Polymers |
| spelling | doaj.art-e8de862f72324af99d2b2f621fb194f22023-11-24T11:57:30ZengMDPI AGPolymers2073-43602022-11-011423505410.3390/polym14235054Thermochemical Transition in Non-Hydrogen-Bonded Polymers and Theory of Latent DecompositionCostas Tsioptsias0Laboratory of Physical Chemistry, Department of Chemical Engineering, Aristotle University of Thessaloniki, University Campus, 54124 Thessaloniki, GreeceAlthough thermosets and various biopolymers cannot be softened without being decomposed, the vast majority of thermoplastics are believed to exhibit thermal transitions solely related to physical alterations of their structure—a behavior typical of low molecular weight substances. In this study, Differential Scanning Calorimetry (DSC), Fourier Transform Infrared Spectroscopy (FTIR) and Thermogravimetry (TGA) were used to study the softening of four common non-hydrogen-bonded thermoplastic polymers (polypropylene, polypropylene-grafted-maleic anhydride, poly(vinyl chloride) and polystyrene) along with a hydrogen-bonded polymer as a reference, namely, poly(vinyl alcohol). It is shown that the softening of these polymers is a thermochemical transition. Based on fundamental concepts of statistical thermodynamics, it is proposed that the thermal transition behavior of all kinds of polymers is qualitatively the same: polymers cannot be softened without being decomposed (in resemblance with their incapability to boil) and the only difference between the various types of polymers is quantitative and lies in the extent of decomposition during softening. Decomposition seems to reach a local maximum during softening; however, it is predicted that polymers constantly decompose even at room temperature and, by heating, (sensible) decomposition is not initiated but simply accelerated. The term “<i>latent decomposition</i>” is proposed to describe this concept.https://www.mdpi.com/2073-4360/14/23/5054simultaneousdecompositionsofteninglatentmeltingglass transition |
| spellingShingle | Costas Tsioptsias Thermochemical Transition in Non-Hydrogen-Bonded Polymers and Theory of Latent Decomposition Polymers simultaneous decomposition softening latent melting glass transition |
| title | Thermochemical Transition in Non-Hydrogen-Bonded Polymers and Theory of Latent Decomposition |
| title_full | Thermochemical Transition in Non-Hydrogen-Bonded Polymers and Theory of Latent Decomposition |
| title_fullStr | Thermochemical Transition in Non-Hydrogen-Bonded Polymers and Theory of Latent Decomposition |
| title_full_unstemmed | Thermochemical Transition in Non-Hydrogen-Bonded Polymers and Theory of Latent Decomposition |
| title_short | Thermochemical Transition in Non-Hydrogen-Bonded Polymers and Theory of Latent Decomposition |
| title_sort | thermochemical transition in non hydrogen bonded polymers and theory of latent decomposition |
| topic | simultaneous decomposition softening latent melting glass transition |
| url | https://www.mdpi.com/2073-4360/14/23/5054 |
| work_keys_str_mv | AT costastsioptsias thermochemicaltransitioninnonhydrogenbondedpolymersandtheoryoflatentdecomposition |