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Vyazovkin S. "Nothing Can Hide Itself from Thy Heat": Understanding Polymers via Unconventional Applications of Thermal Analysis. Macromol Rapid Commun 2018; 40:e1800334. [PMID: 30033550 DOI: 10.1002/marc.201800334] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 05/26/2018] [Indexed: 11/06/2022]
Abstract
This article surveys some exciting possibilities and results offered by less common, yet essential applications of differential scanning calorimetry and thermogravimetric analysis (TGA). The applications are concerned with the most commonly studied processes of the glass transition, crystallization, melting, polymerization, and degradation. Issues related to the glass transition include the non-Arrhenius temperature dependence and fragility, kinetic complexity of physical aging, evaluation of cooperatively rearranging regions, and rigid amorphous fraction. Discussion of crystallization covers separation of heterogeneous and homogeneous nucleation, crystallization controlled by physical aging, and the use of isoconversional methods for determining the Hoffman-Lauritzen parameters. For melting, the role of reorganization and nucleation control is emphasized. For the thermal degradation and polymerization, advanced kinetic treatments as a way of obtaining mechanistic insights are discussed, and the possibility of studying both processes during continuous cooling is stressed. The possibility of using TGA for monitoring polycondensation is also highlighted.
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Affiliation(s)
- Sergey Vyazovkin
- Department of Chemistry, University of Alabama at Birmingham, 901 S. 14th Street, Birmingham, AL, 35294, USA
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Pin JM, Behazin E, Misra M, Mohanty A. Stereodynamic insight into the thermal history effects on poly(vinyl chloride) calorimetric sub-glass and glass transitions as a fragile glass model. Phys Chem Chem Phys 2018; 20:16333-16346. [PMID: 29717310 DOI: 10.1039/c8cp00755a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The dynamic thermal history impact of poly(vinyl chloride) (PVC) has been explored for a wide range of pre-cooling rates, from 1 to 30 °C min-1. A first macroscopic insight into the dynamic thermal history influence has been highlighted through a decrease in the apparent activation energy (Eapp) in the first stage of the glass transition. The overall glass transition Eapp surface was successfully modeled in a polynomial fashion regarding the pre-cooling range. Raman scattering was used to associate the Eapp variations along the glass transition conversion with the stereochemistry evolution during the polymeric relaxation. Herein, the selection of atactic PVC as the polymer model permits us to monitor the glassy polymer segment stereodynamics during the heating ramp through the C-Cl stretching. The intermolecular H-Cl dipole interactions, as well as intramolecular conformational reorganizations among syndiotactic, isotactic and heterotactic polymer sequences, have been associated with non-cooperative and cooperative motions, i.e. the β- and α-process, respectively. The fruitful comparison of the two extreme values of the pre-cooling rates permits us to propose a thermokinetic scenario that explains the occurrence, intensity, and inter-dependence of β- and α-processes in the glassy state and during the glass transition. This scenario could potentially be generalized to all the other polymeric glass-formers.
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Affiliation(s)
- Jean-Mathieu Pin
- Bioproducts Discovery and Development Centre, Department of Plant Agriculture, Crop Science Building, University of Guelph, Guelph, N1G 2W1, Ontario, Canada.
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Vyazovkin S. Modern Isoconversional Kinetics: From Misconceptions to Advances. RECENT ADVANCES, TECHNIQUES AND APPLICATIONS 2018. [DOI: 10.1016/b978-0-444-64062-8.00008-5] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
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Vyazovkin S. Isoconversional Kinetics of Polymers: The Decade Past. Macromol Rapid Commun 2016; 38. [PMID: 28009078 DOI: 10.1002/marc.201600615] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 11/02/2016] [Indexed: 01/17/2023]
Abstract
This article surveys the decade of progress accomplished in the application of isoconversional methods to thermally stimulated processes in polymers. The processes of interest include: crystallization and melting of polymers, gelation of polymer solutions and gel melting, denaturation (unfolding) of proteins, glass transition, polymerization and crosslinking (curing), and thermal and thermo-oxidative degradation. Special attention is paid to the kinetics of polymeric nanomaterials. The article discusses basic principles for understanding the variations in the activation energy and emphasizes the possibility of using models for linking such variations to the parameters of individual kinetic steps. It is stressed that many kinetic effects are not linked to a change in the activation energy alone and may arise from changes in the preexponential factor and reaction model. Also noted is that some isoconversional methods are inapplicable to processes taking place on cooling and cannot be used to study such processes as the melt crystallization.
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Affiliation(s)
- Sergey Vyazovkin
- Department of Chemistry, University of Alabama at Birmingham, 901 S. 14th Street, Birmingham, AL, 35294, USA
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Lu S, Zhang R, Wang X, Sun P, Lv W, Liu Q, Jia N. Effect of PEO molecular weight on the miscibility and dynamics in epoxy/PEO blends. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2015; 38:118. [PMID: 26577817 DOI: 10.1140/epje/i2015-15118-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Accepted: 10/23/2015] [Indexed: 06/05/2023]
Abstract
In this work, the effect of poly(ethylene oxide) (PEO) molecular weight in blends of epoxy (ER) and PEO on the miscibility, inter-chain weak interactions and local dynamics were systematically investigated by multi-frequency temperature modulation DSC and solid-state NMR techniques. We found that the molecular weight (M(w)) of PEO was a crucial factor in controlling the miscibility, chain dynamics and hydrogen bonding interactions between PEO and ER. A critical PEO molecular weight (M(crit)) around 4.5k was found. PEO was well miscible with ER when the molecular weight was below M(crit), where the chain motion of PEO was restricted due to strong inter-chain hydrogen bonding interactions. However, for the blends with high molecular weight PEO (M(w) > M(crit)), the miscibility between PEO and ER was poor, and most of PEO chains were considerably mobile. Finally, polarization inversion spin exchange at magic angle (PISEMA) solid-state NMR experiment further revealed the different mobility of the PEO in ER/PEO blends with different molecular weight of PEO at molecular level. Based on the DSC and NMR results, a tentative model was proposed to illustrate the miscibility in ER/PEO blends.
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Affiliation(s)
- Shoudong Lu
- Patent Examination Cooperation Center of the Patent Office, SIPO, Beijing, P. R. China
| | - Rongchun Zhang
- Key Laboratory of Functional Polymer Materials, Ministry of Education; College of Chemistry and School of Physics, Nankai University, 300071, Tianjin, P. R. China
| | - Xiaoliang Wang
- Key Laboratory of High Performance Polymer Materials and Technology, Ministry of Education, Department of Polymer Science and Engineering, School of Chemistry and Chemical Engineering, Nanjing University, 210093, Nanjing, P. R. China.
| | - Pingchuan Sun
- Key Laboratory of Functional Polymer Materials, Ministry of Education; College of Chemistry and School of Physics, Nankai University, 300071, Tianjin, P. R. China.
| | - Weifeng Lv
- Research Institute of Petroleum Exploration & Development, PetroChina, 100083, Beijing, P. R. China
| | - Qingjie Liu
- Research Institute of Petroleum Exploration & Development, PetroChina, 100083, Beijing, P. R. China
| | - Ninghong Jia
- Research Institute of Petroleum Exploration & Development, PetroChina, 100083, Beijing, P. R. China
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Unique evolution of spatial and dynamic heterogeneities on the glass transition behavior of PVPh/PEO blends. CHINESE JOURNAL OF POLYMER SCIENCE 2012. [DOI: 10.1007/s10118-012-1182-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Fraga I, Montserrat S, Hutchinson JM. Vitrification and Devitrification during the Non-Isothermal Cure of a Thermoset. Theoretical Model and Comparison with Calorimetric Experiments. MACROMOL CHEM PHYS 2009. [DOI: 10.1002/macp.200900322] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Affiliation(s)
- Kai Chen
- Department of Chemistry, University of Alabama at Birmingham, 901 South 14th Street, Birmingham, Alabama 35294
| | - Sergey Vyazovkin
- Department of Chemistry, University of Alabama at Birmingham, 901 South 14th Street, Birmingham, Alabama 35294
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Chen K, Baker AN, Vyazovkin S. Concentration Effect on Temperature Dependence of Gelation Rate in Aqueous Solutions of Methylcellulose. MACROMOL CHEM PHYS 2009. [DOI: 10.1002/macp.200800518] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Guigo N, Mija A, Vincent L, Sbirrazzuoli N. Molecular mobility and relaxation process of isolated lignin studied by multifrequency calorimetric experiments. Phys Chem Chem Phys 2009; 11:1227-36. [PMID: 19209367 DOI: 10.1039/b812512k] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The glass transition of lignin has been studied by multifrequency calorimetric measurements in order to highlight the morphological changes and the dynamic aspects associated to this relaxation process. Influences of water sorption and thermal annealing on molecular mobility have been considered. Additional investigations by thermogravimetry, infra-red spectroscopy and rheometry have been performed to corroborate the claims. The relaxation process of annealed lignin shows a different behaviour as the consequence of micro-structural modifications of lignin. These are explained by redistribution of secondary bonds as well as formation of new interunit linkages. Concerning the dynamic aspects, apparent activation energy, E, and sizes of cooperatively rearranging region, V(crr), have been evaluated respectively from the frequency dependence and heat capacity measurements of the glass transition. Compared to dried lignin, both E and V(crr) significantly decrease in a water-sorbed matrix indicating that the three-dimensional structure presents a higher mobility and is less confined.
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Affiliation(s)
- Nathanael Guigo
- Thermokinetic Group, Laboratory of Chemistry of Organic and Metallic Materials C.M.O.M., Institute of Chemistry of Nice (CNRS FR3037), University of Nice-Sophia Antipolis, 06108, Nice Cedex 2, France
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Chen K, Vyazovkin S. Temperature Dependence of Sol-Gel Conversion Kinetics in Gelatin-Water System. Macromol Biosci 2008; 9:383-92. [DOI: 10.1002/mabi.200800214] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Affiliation(s)
- Sergey Vyazovkin
- Department of Chemistry, University of Alabama at Birmingham, 901 14th Street South, Birmingham, Alabama 35294, USA.
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