Ceiling temperature of α‐methylstyrene

McCormick, H. W.

doi:10.1002/pol.1957.1202511112

Cited by 155 publications

(71 citation statements)

References 2 publications

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“…[43][44][45][46] Examples of reversible ROP processes are also known for organic cyclic species, for example THF in the presence of Lewis acids and cyclopentene in the presence of certain metal alkylidene complexes. 41,47,48 Most of the known reversible polymerizations are characterized by small, favourable (negative) values of ΔH and unfavourable (negative) values of ΔS.…”

Section: Resultsmentioning

confidence: 99%

Main-chain metallopolymers at the static–dynamic boundary based on nickelocene

et al. 2017

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General rightsThis document is made available in accordance with publisher policies. Please cite only the published version using the reference above. AbstractInteractions between metal ions and ligands in metal-containing polymers involve two bonding extremes: persistent covalent bonding, where the polymers are essentially static in nature, or labile coordination bonding, which leads to dynamic supramolecular materials.Main chain polymetallocenes based on ferrocene and cobaltocene fall into the former category due to the presence of strong metal-cyclopentadienyl bonds. Herein we describe a main chain polynickelocene formed by ring-opening polymerization of a moderately strained[3]nickelocenophane monomer, that can be switched between static and dynamic states as a result of the relatively weak Ni-cyclopentadienyl ligand interactions. This is illustrated by the observation that, at low concentration or at elevated temperature in a coordinating or polar solvent, depolymerization of the polynickelocene occurs. A study of this dynamic polymermonomer equilibrium by 1 H NMR spectroscopy allowed for determination of the associated thermodynamic parameters. Microrheology data, however, indicated that under similar conditions the polynickelocene is considered to be static on the shorter, rheological timescale.2

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Section: Resultsmentioning

confidence: 99%

Main-chain metallopolymers at the static–dynamic boundary based on nickelocene

et al. 2017

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“…Normally, this equilibrium monomer concentration is very low. A notable exception is a-methylstyrene whose T c for 100% monomer concentration is 61 C, and the equilibrium monomer concentration at 25 C is 2.2 mol/L [20]. In a strict sense, the propagation rate constant k p changes with chain length.…”

Section: Propagationmentioning

confidence: 99%

Polymerization Processes, 1. Fundamentals

Tobita

2015

Ullmann's Encyclopedia of Industrial Chemistry

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The article contains sections titled: 1. Introduction 2. Polymerization Mechanisms and Kinetics 3. Kinetics of Step Polymerization 4. Basic Concepts of Molecular Mass Distribution 5. Chain Polymerization 6. Free‐Radical Polymerization 6.1. Elementary Reactions 6.1.1. Initiation 6.1.2. Propagation 6.1.3. Termination 6.1.4. Chain Transfer to Small Molecules 6.2. Kinetics of Free‐Radical Polymerization 6.2.1. Polymerization Rate 6.2.2. Molecular Mass Distribution 6.3. Effect of Temperature 7. Copolymerization 7.1. Copolymer Composition 7.2. Kinetics of Free‐Radical Copolymerization 8. Living Polymerization 8.1. Ideal Living Polymerization 8.2. Reversible‐Deactivation Radical Polymerization 8.2.1. Polymerization Rate 8.2.2. Molecular Mass Distribution 9. Polymers with Branches and Crosslinks 9.1. Crosslinked Polymers 9.2. Branched Polymers 9.3. Note on Nonlinear Polymerization

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“…In the cases of copolymers containing AMS units, polymerization of compositions rich in this monomer was limited to lower temperature to achieve high molecular weights owing to the low ceiling temperature for AMS (618C [22]). However, when the polymerization temperatures are low, free-radical polymerization rates are exceedingly slow.…”

Section: Methodsmentioning

confidence: 99%

Effect of monomer architecture on segmental interaction parameters of binary blends involving copolymers of cyclohexyl methacrylate, methyl methacrylate and styrene derivatives

Múgica¹,

Barral²,

Pomposo

et al. 1999

Acta Polym.

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The phase behavior of binary blends of poly(cyclohexyl methacrylate‐co‐methyl methacrylate) (P(CHMA‐co‐MMA)) copolymers with poly(α‐methylstyrene) (PAMS) and poly(p‐methylstyrene) (PPMS) has been determined experimentally and compared to that of the P(CHMA‐co‐MMA)/PS system. The enthalpic and entropic parts of the segmental interaction parameter for each binary monomer pair involved have been determined from a fit of the lower critical solution temperature (LCST) behavior of these systems, with the aid of Flory‐Huggins (FH) theory which incorporates temperature dependent interaction parameters. The results reveal that the strength of the interaction with the copolymer P(CHMA‐co‐MMA) decreases in the following order: PAMS > PS > PPMS. These differences are also illustrated in the glass transition (Tg)‐composition curves of the above systems as well as in analog calorimetry results and scanning electron microscopy (SEM) studies. Good agreement is obtained when various theoretical miscibility windows for binary blends of copolymers involving CHMA, MMA and styrene derivatives are compared to experimental data. Thus it is shown that the subtle difference of monomer structures is captured to a good degree by the segmental interaction parameters derived from phase behavior.

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Ceiling temperature of α‐methylstyrene

Cited by 155 publications

References 2 publications

Main-chain metallopolymers at the static–dynamic boundary based on nickelocene

Main-chain metallopolymers at the static–dynamic boundary based on nickelocene

Polymerization Processes, 1. Fundamentals

Effect of monomer architecture on segmental interaction parameters of binary blends involving copolymers of cyclohexyl methacrylate, methyl methacrylate and styrene derivatives

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