Free‐radical polymerization of phenylacetylene

Amdur, S.; Cheng, A. T. Y.; Wong, Chop; Ehrlich, P.; Allendoerfer, Robert D.

doi:10.1002/pol.1978.170160211

Cited by 41 publications

(22 citation statements)

References 10 publications

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“…From l H and 13 C NMR data, the same research group (11 ) proposed that the polymeric products were polyenic systems with a trans-cisoid structure. It was also pointed out (3,12) that the reactivity decreases as the average molecular weight of products increases.…”

Section: Gandon Et Almentioning

confidence: 97%

Mechanism of Step-Growth Thermal Polymerization of Arylacetylene

Gandon¹,

Mison²,

Sillion³

1996

Step-Growth Polymers for High-Performance Materials

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The reaction mechanism of arylacetylene thermal polymerization has been studied on 4-(1-hexyloxy)-phenylacetylene 1, used as a monofunctional model compound. Its linear dimers 2-5 [a diyne and 3 enyne isomers] were also synthetized and their thermal behavior investigated. Reaction products were analyzed by chromatography (HPLC, SEC), spectroscopy ( 1 H and 13 C NMR) and spectrometry (SIMS) techniques. The lowest molecular weight components were isolated and their structure established. There are naphthalenic dimers (2 isomers) and benzenic trimers (3 isomers) and they represented 30% in weight of the overall thermal reaction product of 1. We have shown that linear dimers 2-5 are not reaction intermediates of the thermal polymerization of 1. Moreover, under prolonged curing, a depolymerization process was pointed out, indicating that the highest polymerization steps could give termination by intramolecular reactions inducing chain cleavage leading to lower molecular weight entities. A bimolecular reaction mechanism generating diradical intermediate species is proposed and its implications are discussed.Many acetylene terminated resins have been described (1,2). Although some α,ω-diethynylimide oligomers were commercialized in the seventies, the reaction mechanism of the thermal polymerization of the arylacetylene group is not yet well established. The polymerization takes place above 130°C, without catalyst (1,2). The properties of the resulting networks are dependent on the length and the nature of the aromatic or heterocyclic moieties, as well as on polymerization and post-cure conditions. Different assumptions concerning the polymerization mechanism were based on kinetic data, electron spin resonance (ESR) analyses, structures determination of low molecular weight species and nuclear magnetic resonance (NMR) studies of the oligomeric products.

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Section: Gandon Et Almentioning

confidence: 97%

Mechanism of Step-Growth Thermal Polymerization of Arylacetylene

Gandon¹,

Mison²,

Sillion³

1996

Step-Growth Polymers for High-Performance Materials

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“…Kovar et al 18 and Admur et al 19 have discussed the mechanism of the thermal polymerization of phenylacetylenes with and without radical initiators. In the absence of initiators, in general, the observed polymerizations were predominantly initiated by the thermal homolysis of impurities, including peroxides or hydroperoxides formed due to oxygen, present in the monomer.…”

Section: Proposed Cured Structurementioning

confidence: 99%

Thermal cure behavior and pyrolysis of methyl‐tri(phenylethynyl)silane resin

Zhou

2009

J of Applied Polymer Sci

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A polyfunctional organic-inorganic hybrid monomer, methyl-tri(phenylethynyl)silane (MTPES) could be thermally polymerized by a free radical mechanism to a highly crosslinked structure of interest as a high temperature composite matrix resin. The structural changes during thermal cure process were characterized by fourier transform infrared spectrum and 13 C-CP-MAS-NMR spectrum. The disappearance of secondary acetylene stretching band at 2166 cm À1 was used successfully to monitor cure reaction accompanied with the formation of cis-polyene structure at 1600 and 754 cm À1 . The possible cure mechanism of MTPES was also proposed. The pyrolysis of cured MTPES under a stream of argon to 1450 C gave a ceramic in high yield (81%). Thermal conversion of polymer to ceramic was studied by means of X-ray diffraction, Raman spectrum, and energy dispersive spectrometer analysis. The results showed that pyrolytic products were made up of b-SiC, graphite, and glassy carbon. V

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“…At the same time, we could see that the peak temperature of polymerization (T p ) of VTPES was 316°C, which was 47°C lower than that of PTPES (Table 1), and the reactive activation energy of VTPES (114.25 kJ/mol) was also 40 kJ/mol lower than that of PTPES. It is well known that thermal polymerization of phenylethylene monomers is a radical mechanism [24,25]. Thus, it was theoretically possible to deduce that radicals formed by VTPES would be stabilized to a greater extent and more active than those formed by PTPES, and the coordination role reduced the reactive energy barrier at the unitary level between double bonds and acetylenic bonds.…”

Section: Cure Reactivity Of the Two Monomersmentioning

confidence: 99%

Synthesis, characterization, and non-isothermal curing kinetics of two silicon-containing arylacetylenic monomers

Tan

Shi

2011

Res Chem Intermed

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Vinyltri(phenylethynyl)silane ((ph-C:C) 3 -Si-C=CH 2 ; VTPES) and phenyltri(phenylethynyl)silane ((ph-C:C) 3 -Si-ph; PTPES) were synthesized by Grignard reaction. Their molecular structures were characterized by means of 1 H NMR, 13 C NMR, 29 Si NMR, and FT-IR spectroscopy. Their nonisothermal thermal curing processes were characterized by DSC, and the corresponding kinetic data, for example activation energy (E), pre-exponential factor (A), and the order of the reaction (n), were obtained by the Kissinger method. The results showed that the melting points of VTPES and PTPES were 84 and 116°C, respectively. Their curing reaction rates were consistent with first-order kinetic equations. VTPES monomer had a lower activation energy and curing temperature as a result of coordination between reactive groups.

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Free‐radical polymerization of phenylacetylene

Cited by 41 publications

References 10 publications

Mechanism of Step-Growth Thermal Polymerization of Arylacetylene

Mechanism of Step-Growth Thermal Polymerization of Arylacetylene

Thermal cure behavior and pyrolysis of methyl‐tri(phenylethynyl)silane resin

Synthesis, characterization, and non-isothermal curing kinetics of two silicon-containing arylacetylenic monomers

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