Study of the structure of phenolcarborane formaldehyde oligomers and polymers

Abramova, T.M.; Alekseyeva, S.G.; Valetskii, P. M.; Golubenkova, L. I.; Makarova, I.M.; Slonim, I.Ya.; Urman, Ya.G.; Shabadash, A. N.

doi:10.1016/0032-3950(80)90065-9

Cited by 3 publications

(3 citation statements)

References 5 publications

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“…7 and 8). Similar result was also obtained by Russian scientists and the low molecular weight was attributed to the strong steric hindrance of o-carborane bisphenol [29] . Scheme 1 Synthetic route to o-carborane bisphenol resol phenolic resin (P1) As a yellow solid, the obtained P1 could be solved in common organic solvents such as acetone, THF, and DMSO.…”

Section: Synthesis Of O-carborane Bisphenol Resol Phenolic Resin (P1)supporting

confidence: 88%

Synthesis and characterization of carborane bisphenol resol phenolic resins with ultrahigh char yield

Han

Wang

et al. 2015

Chin J Polym Sci

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Two carborane-containing resol phenolic resins (P1 and P2) with high boron content were synthesized via the reaction of carborane bisphenols (1 and 2) with formaldehyde in the presence of alkaline. HRMS results indicate that P1 is mainly composed of hydroxymethylated o-carborane bisphenols, the M w of which was restrained around 500 due to the strong steric hindrance of o-carborane bisphenol. In contrast, the molecular weight of P2 was well regulated under various reaction conditions. The obtained resins were characterized with spectroscopic techniques including FTIR, 1 H-NMR, 13 C-NMR, and 11 B-NMR, which gave satisfactory results. TGA studies show that P2 shows char yield of 88.9% and 92.9% at 900 C under nitrogen and air respectively. The imported carborane cage endows phenolic resin with ultrahigh char yield. Particularly, the char yield of the obtained carborane-containing phenolic resin under air is higher than that under nitrogen. FTIR and XRD confirm that the carborane cage could react with oxygen to form B 2 O 3 at elevated temperatures, which postpones the thermal decomposition of phenolic resin and accounts for the high char yield.

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Section: Synthesis Of O-carborane Bisphenol Resol Phenolic Resin (P1)supporting

confidence: 88%

Synthesis and characterization of carborane bisphenol resol phenolic resins with ultrahigh char yield

Han

Wang

et al. 2015

Chin J Polym Sci

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“…Owing to these distinctive properties, carboranes have been regarded as one of the most excellent organic groups to improve performance of organic polymers with remarkable thermal stability . Therefore, carboranes were incorporated into many traditional polymers to improve their thermal stability including epoxy resins, phenolic resins, polyurethanes, organic silicone polymers, benzoxazine resins, polyimides, and so forth.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and characterization of carborane‐containing polyester with excellent thermal and ultrahigh char yield

Zeng

et al. 2016

J of Applied Polymer Sci

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A series of wholly carborane‐containing polyesters with high thermostability were successfully synthesized by the catalytic polycondensation of carborane diol monomers with carborane diacid chlorides. They can be used for the preparation of materials of high temperature resistant coatings and adhesive. The influence of solvent, reaction temperature, and reaction time on the molecular weight and yield of the polymers were studied. In comparison with the carborane‐free polyester, the carborane‐containing polyesters showed higher degradation temperature and char yield and lower degradation rate. The thermal gravimetric analyzer (TGA) curves indicate that the carborane group could effectively reduce the degradation rate of carborane‐containing polyesters, which give a char yield of exceeding 64% under air (47% under N2) at 700 °C. Such data are superior to the carborane‐free polyester, which showed a low char yield of around 0.3% under air (5% under N2) at the same condition. Moreover, the thermal transition mechanism of carborane‐containing polyesters was also studied. The FTIR spectra and TG‐FTIR analysis indicate that the carborane cage could react with oxygen to form BOB and BC linkages at elevated temperatures, which postpones the thermal decomposition of polyester and accounts for the high char yield. The newly prepared kind of high temperature polyesters have enormous technical and economic value, especially in the high temperature fields. They can be widely used as raw materials to prepare the high temperature resistant coatings or adhesives for automotive engine, aircraft and other equipments worked in high‐temperature environments. Under high environmental temperature, the good thermal stability is capable of keeping polyesters stable and expanding their service lives. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44202.

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“…Besides, the large volume of three‐dimensional cage endows carboranes with strong shielding effect on adjacent segments. Therefore, carboranes were incorporated into many traditional polymers to improve their thermal stability including polysiloxanes, epoxy resins, phenolic resins, aromatic polymers, etc. With the increasing appearance of new polymers, carboranes expanded their application fields such as dendrimers and conjugated polymers with light‐emission property …”

Section: Introductionmentioning

confidence: 99%

Synthesis, characterization, and curing behavior of carborane‐containing benzoxazine resins with excellent thermal and thermo‐oxidative stability

Wang

Han

et al. 2016

J of Applied Polymer Sci

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Two benzoxazine precursors bearing carborane moiety (1 and 2) were designed and synthesized successfully by the Mannich reaction of corresponding carborane bisphenol (3 and 4) with aniline and formaldehyde in 1,4-dioxane. The obtained precursors were characterized by using multiple spectroscopic techniques including GPC, FTIR, 1 H NMR, 13 C NMR, and 11 B NMR. Nonisothermal DSC studies showed that precursor 1 owned lower apparent activation energies (E a ) than 2. The optimum curing processes of benzoxazine precursors were also obtained on the basis of DSC data. TGA analyses manifested that the incorporation of carborane moiety endowed the obtained benzoxazine resins (cured 1 and 2) with excellent thermal stability and unique thermo-oxidative stability. The T d data showed that the initial degradation of both cured 1 and 2 under nitrogen and air was postponed to some extent owing to the shielding effect of carborane moiety on adjacent organic fragments. At higher temperature three-dimensional polymer networks with B-O-B and B-C linkages were formed as chars by the reaction of carborane cage with atmospheric moisture, degradation products such as phenolic hydroxyl, and oxygen (under air). Under nitrogen this network hindered the motion of radicals formed at elevated temperature and thus inhibited further polymer degradation processes. While under air, the formed boron-rich networks could hardly be further oxidized into carbon dioxide so that the carborane-containing benzoxazine resins also showed very high char yields.Closo-carboranes (C 2 B 10 H 12 ), with an icosahedral geometry, are excellent building blocks for thermally stable polymers. 17 Carboranes could absorb energy like a kind of "power gauge" at high temperature owing to its "superaromatic" electronic structure. Besides, the large volume of three-dimensional cage endows carboranes with strong shielding effect on adjacent segments. Therefore, carboranes were incorporated into many traditional polymers to improve their thermal stability including polysiloxanes, 18-26 epoxy resins, 27,28 phenolic resins, 29,30 aromatic polymers, 31 etc. With the increasing appearance of new polymers, carboranes expanded their application fields such as dendrimers [32][33][34][35][36][37][38] and conjugated polymers with light-emission property. [39][40][41][42][43][44] Additional Supporting Information may be found in the online version of this article.

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Study of the structure of phenolcarborane formaldehyde oligomers and polymers

Cited by 3 publications

References 5 publications

Synthesis and characterization of carborane bisphenol resol phenolic resins with ultrahigh char yield

Synthesis and characterization of carborane bisphenol resol phenolic resins with ultrahigh char yield

Synthesis and characterization of carborane‐containing polyester with excellent thermal and ultrahigh char yield

Synthesis, characterization, and curing behavior of carborane‐containing benzoxazine resins with excellent thermal and thermo‐oxidative stability

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