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Thermodynamics of Polymerization
TLDR
In this article, three possible conditions for free energy change of polymerization may be summarized as follows: at the ceiling temperature, Tc, ΔG is zero, so that where ΔHp and ΔSp are the enthalpy and entropy changes per monomer unit.Abstract:
I. THE CHILING TEMPERATURE CONCEPT A. Thermodynamic Approach The Gibbs free energy of a system at temperature T is defined as were H is the enthalpy and S the entropy of the system. The free energy change for any polymerization will be, therefore, When the polymer has a lower free energy than the initial monomer, a polymerization can occur spontaneously, and the sign of ΔG is negative. A positive sign for ΔG signifies, therefore, that the polymerization is not spontaneous. When the system is in equilibrium at a certain critical temperature, there is no tendency for polymerization, and, hence, ΔG = 0 [1–3]. This temperature is known as the ceiling temperature. These three possible conditions for free energy change of polymerization may be summarized as follows: At the ceiling temperature, Tc, ΔG is zero, so that where ΔHp and ΔSp are the enthalpy and entropy changes per monomer unit.read more
Citations
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Book ChapterDOI
Principles of Polymerization
TL;DR: In this paper, all syntheses that proceed from low-molecular-weight compounds (monomers) to produce high-molescular weight compounds (polymers) are termed polymerizations (i.e., polyreactions).
Journal ArticleDOI
Chemically recyclable polymers: a circular economy approach to sustainability
Miao Hong,Eugene Y.-X. Chen +1 more
TL;DR: In this paper, a critical review article captures some selected highlights of the emerging area of recyclable "green polymers" by focusing on the major progress made and the technical and environmental benefits obtained in the development of repurposing and depolymerization processes for chemical recycling of polymers at the end of their useful life.
Journal ArticleDOI
Completely recyclable biopolymers with linear and cyclic topologies via ring-opening polymerization of γ-butyrolactone
Miao Hong,Eugene Y.-X. Chen +1 more
TL;DR: It is reported that the ROP of γ-BL can, with a suitable catalyst, proceed smoothly to high conversions under ambient pressure to produce PγBL materials with a number-average molecular weight up to 30 kg mol(-1) and with controlled linear and/or cyclic topologies.
Book ChapterDOI
Structure and elasticity of non-crystalline polymer networks
Karel Dušek,W. Prins +1 more
Journal ArticleDOI
Free-Radical Frontal Polymerization: Self-Propagating Thermal Reaction Waves
TL;DR: In this paper, the physicochemical properties of monomers are classified in connection with complications arising in the experiments, including low conversion, convection and bubbles, and the necessary conditions for the existence of the free-radical frontal polymerization regime are considered.
References
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Book
Encyclopedia of polymer science and technology
TL;DR: In this article, the authors present a survey of the properties of polymers and their application in the field of chemical engineering, including the following: Coextrusion, Injection Molding, Flexible Packaging, Fibers, Polymer-Clay, and Plasticizers.