Preparation and properties of elastomers based on a cycloaliphatic diepoxide and poly(tetrahydrofuran)

Hartwig, Andreas; Sebald, Monika

doi:10.1016/s0014-3057(03)00125-3

Cited by 29 publications

(19 citation statements)

References 13 publications

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“…It was shown in an earlier paper that such polymers decompose by the acid catalysed decomposition of the PTHF forming THF. [8] TGA shows that this first step of the decomposition does not take place in the case of the nanocomposites examined here. Therefore, we conclude that the HSbF 6 is adsorbed on the surface of the clay used for the modification and is not available for reactions.…”

Section: Discussionmentioning

confidence: 67%

“…The thermal decomposition of these materials was recently reported. [8] The cationic polymerisation was thermally initiated with the latent initiator benzyltetrahydrothiophenium hexafluoroantimonate. [9] Experimental Part…”

Section: à2mentioning

confidence: 99%

“…The diol is incorporated into the polymer network by a chain transfer mechanism. [7,8] The two different nanofillers were mixed into the resin mixture with a dissolver. 4.7 wt.-% organobentonite were used in both cases.…”

Section: Preparation and Properties Of The Nanocompositesmentioning

confidence: 99%

“…It is proposed that ordered domains are present in the pure polymer due to the PTHF. [8] One may speculate that the interaction between the PTHF chains is interrupted by the clay particles and that the reinforcement by the clay particles is lower than the effect caused by the interruption of the interactions between the polyether chains.…”

Section: Preparation and Properties Of The Nanocompositesmentioning

confidence: 99%

“…The low temperature step found in the TGA measurements of the pure polymer, under aerobic as well as anaerobic conditions, corresponds to the acid catalysed decomposition of the PTHF fixed within the polymer network. [8] Tetrahydrofuran is formed due to this reaction as volatile decomposition product and it is known that during a short time thermal exposure the PTHF is not decomposed completely. As this reaction is much less pronounced in the nanocomposite containing the ammonium bentonite and does not take place in the nanocomposite containing the phosphonium bentonite, one can conclude that the acid present in the samples is buffered or in any other way fixed by the bentonites.…”

Section: Decomposition and Combustion Properties Of The Nanocompositesmentioning

confidence: 99%

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Combustion Behaviour of Epoxide Based Nanocomposites with Ammonium and Phosphonium Bentonites

Hartwig

Pütz

Schartel

et al. 2003

Macro Chemistry & Physics

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The influence of different organobentonites on the decomposition and the combustion behaviour of an epoxy resin were examined. The epoxy resin is a cationically polymerised cycloaliphatic epoxy resin flexibilised with poly(tetrahydrofuran) (PTHF), with hydroxyl endgroups. The bentonite was modified with either an ammonium or a phosphonium salt. The thermal decomposition of the PTHF induced by the initiator, used for the cationic polymerisation, did neither take place for the nanocomposite based on the ammonium bentonite nor for that based on the phosphonium bentonite. This improved decomposition characteristic lead to a larger time to ignition for both kinds of nanocomposites compared to the not modified polymer, which is not the case for other polymer/clay nanocomposites described in the literature. The fire behaviour was investigated using limiting oxygen index (LOI), a horizontal burner test and a cone calorimeter. The forced flaming conditions in the cone calorimeter were varied using different external heat fluxes between 30 and 70 kW · m−2. The fire behaviour of the nanocomposites was improved in comparison to the polymer, and phosphonium bentonite was superior to ammonium bentonite. The main mechanism is a barrier formation resulting in a reduction of the fire growth rate, which was more pronounced in the case of high external heat fluxes. magnified image

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Section: Discussionmentioning

confidence: 67%

Section: à2mentioning

confidence: 99%

Section: Preparation and Properties Of The Nanocompositesmentioning

confidence: 99%

Section: Preparation and Properties Of The Nanocompositesmentioning

confidence: 99%

Section: Decomposition and Combustion Properties Of The Nanocompositesmentioning

confidence: 99%

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Combustion Behaviour of Epoxide Based Nanocomposites with Ammonium and Phosphonium Bentonites

Hartwig

Pütz

Schartel

et al. 2003

Macro Chemistry & Physics

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Influence of Proton Donors on the Cationic Polymerization of Epoxides

2005

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The cationic polymerization of epoxy resins becomes more and more important in adhesive bonding technology. Most often a cationic photopolymerization is applied, but occasionally thermally induced cationic polymerization of epoxides is also used. The polymerization is strongly influenced by water, namely the humidity of the surrounding atmosphere in which the adhesives are cured. Traces of water or other proton donors are required as co-catalyst for the initiation of the polymerization. On the other side the cation as well as the anion of the latent initiators is hydrolyzed by the long term influence of moisture. But water does not only influence the initiation reaction of the polymerization but also the chain growth reaction. Depending on the kind of epoxide the polymerisation is strongly accelerated by the water or strongly retarded. These extreme differences are explained by differences in the mechanism of the chain transfer reaction carried out by the water. In any case the water reduces the mechanical strength of the cured epoxides by the formation of unbound chain-ends in the polymer network and therefore lower cross-link density. Also alcohols lead to chain transfer reactions during polymerization of the epoxides and consequently they have an influence on the polymerization kinetics as well as on the mechanical properties of the epoxides Different polymeric and oligomeric alcohols (polyols) are applied to adjust the mechanical properties of cationically curing adhesives. It could for example be shown that the addition of polytetrahydrofuran leads to polymers with rubber elastic behaviour. But also the polymerization kinetics is strongly influenced by polyols. In the case of polyethers based on 1,2-diols the protons required to progress the polymerization can be fixed within five-membered rings. The polymerization rate is decelerated in the presence of such polyols, therefore. The formed structures have some similarity with crownethers complexing a proton. And it is therefore not surprising that crown-ethers inhibit the cationic polymerisation very efficiently. On the other hand no retardation of the reaction rate is observed if 1,4-diol based polyethers are used to modify the properties of the materials. 205 208 Scheme 14.1 Synthesis of (9-oxo-9H-fluoren-2-yl)phenyliodonium hexafluoroantimonate.

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Industrial Applications

Kaiho¹,

Zhdankin

2018

Patai's Chemistry of Functional Groups

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This chapter provides a summary of industrial applications of organic and inorganic hypervalent iodine compounds. Potassium iodate has found some applications as a dietary supplement and a food additive. Iodine pentafluoride is used as an industrial fluorinating reagent, and iodine pentoxide is a powerful and selective oxidant that is particularly useful in analytical chemistry. Common hypervalent iodine reagents such as (dichloroiodo)benzene and (diacetoxyiodo)benzene are occasionally used in the chemical industry as reagents for the production of important pharmaceutical intermediates. Diaryliodonium salts have found industrial application as photoinitiators for cationic photopolymerizations. Hypervalent polyiodide compounds have numerous industrial applications including their use as disinfectants and intermediates in iodine production.

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Preparation and properties of elastomers based on a cycloaliphatic diepoxide and poly(tetrahydrofuran)

Cited by 29 publications

References 13 publications

Combustion Behaviour of Epoxide Based Nanocomposites with Ammonium and Phosphonium Bentonites

Combustion Behaviour of Epoxide Based Nanocomposites with Ammonium and Phosphonium Bentonites

Influence of Proton Donors on the Cationic Polymerization of Epoxides

Industrial Applications

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