Well-defined organic–inorganic hybrid benzoxazine monomers based on cyclotriphosphazene: Synthesis, properties of the monomers and polybenzoxazines

Wu, Xuqiang; Liu, Shuzheng; Tian, Di; Qiu, Jian; Liu, Chengmei

doi:10.1016/j.polymer.2011.07.037

Cited by 34 publications

(33 citation statements)

References 52 publications

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“…Undoubtedly, fluorinated benzoxazines have attracted many attentions and gradually become a research focus [51][52][53]. Recently, our group focused on preparing organicinorganic hybrid polybenzoxazines based on cyclotriphosphazene core, and this kind of resins exhibited excellent thermal stability and easy preparation [54][55][56][57]. Though these monomers have higher molecular weights (>1490 g/mol) compared that with traditithe onal bisphenol-A based benzoxazine monomer, but some of them showed relatively low melting point (32-84°C) [57] and have the potential to be used as a matrix resin for composite preparation.…”

Section: Introductionmentioning

confidence: 99%

Low melting point, high thermal stable branched benzoxazines resin derived from mixed-substituted phosphazene core

Ma¹,

Qiu²,

Liu³

2020

Express Polym. Lett.

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Six fluorine-containing, mix-substituted phosphazene-based branched benzoxazine monomers with a low melting point were successfully prepared and their chemical structures were verified by 1 H, 13 C, 31 P and 19 F nuclear magnetic resonance (NMR). These branched benzoxazine resins underwent thermal ring-opening polymerization to form cured polymers with high thermal stability both in N 2 atmosphere and in air. The co-substituents, both m-CF 3 PhOH and p-CF 3 PhOH, imposed significant effects on processing, thermal, and surface properties of corresponding polybenzoxazines. Non-isothermal differential scanning calorimetry (DSC) under diverse heating rates was adopted to investigate the curing kinetics and determine the activation energy of polymerization. DSC results indicate that the m-CF 3 PhO-/p-CF 3 PhO-groups have the potential to lower ring-opening polymerization temperature. Glass transition temperatures (T g s) of polybenzoxazines derived from p-CF 3 PhOH are higher than that of polymers derived from m-CF 3 PhOH due to different steric hindrance and crosslinking density. More interesting, all polybenzoxazines show relatively high dielectric constant but exhibit low dielectric loss at ambient temperature.

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Section: Introductionmentioning

confidence: 99%

Low melting point, high thermal stable branched benzoxazines resin derived from mixed-substituted phosphazene core

Ma¹,

Qiu²,

Liu³

2020

Express Polym. Lett.

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“…Endo and coworkers also applied a similar approach to prepare poly(allylamine)‐based benzoxazine 19. Liu and coworkers used the same approach to prepare phosphazine‐containing benzoxazines 20, 21. Although the approach is time consuming, it can be applied in preparing various diamine or multifunctional amine‐based benzoxazines.…”

Section: Introductionmentioning

confidence: 99%

Salvage radiation in men after prostate‐specific antigen failure and the risk of death

Cotter

Chen

Moul

et al. 2011

Cancer

101

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BACKGROUND: A survival benefit has been observed with salvage radiation therapy (RT) for prostate-specific antigen (PSA) failure after radical prostatectomy (RP) in men with rapid rises in PSA doubling time (DT, <6 months). Whether such a benefit exits in men with a protracted PSA rise in DT (6 months) is unclear and was examined in the current study. METHODS: Of 4036 men who underwent RP at Duke University between 1988 and 2008, 519 experienced a PSA failure, had complete data, and were the subjects of this study. Univariate and multivariate Cox regression analyses were performed to evaluate whether salvage RT in men with either a rapid (<6 months) or a protracted (6 months) PSA DT was associated with the risk of all-cause mortality adjusting for age at the time of PSA failure, known prostate cancer prognostic factors, and cardiac comorbidity. RESULTS: After a median follow-up of 11.3 years after PSA failure, 195 men died. Salvage RT was associated with a significant reduction in all-cause mortality for men with either a PSA DT of <6 months (adjusted hazard ratio [AHR], 0.53; P ¼ .02) or a PSA DT of 6 months (AHR, 0.52; P ¼ .003). In a subset of patients with comorbidity data at the time of PSA failure, salvage RT remained associated with a significant reduction in all-cause mortality for both men with a PSA DT of <6 months (AHR, 0.35; P ¼ .042) or a PSA DT of 6 months (AHR, 0.60; P ¼ .04). CONCLUSIONS: Salvage RT for PSA DTs less than or in excess of 6 months is associated with a decreased risk in all-cause mortality. Cancer 2011;117:3925-32.

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“…It is clear that the onset and maximum temperatures of the exotherm of these four monomers show little difference, which means that the polymerization temperature of benzoxazine monomers depends mainly on its chemical structure, not on the content of benzoxazine group in one molecular unit. Our previous results showed that a benzoxazine monomer with the same chemical structure as monomer IV possessed a low polymerization temperature (onset and maximum temperatures of the exotherm were 177 °C and 225 °C, respectively) . The difference is due to purity variation in these two monomers.…”

Section: Resultsmentioning

confidence: 97%

“…Our research focuses on preparing phosphorus‐containing polybenzoxazines, and previous results have proved that combining the cyclotriphosphazene core with benzoxazine moiety through chemical bonding is an effective route to obtain high‐performance polybenzoxazines . These compounds demonstrated enhanced flame retardancy from the synergistic effect of phosphorus and nitrogen atoms .…”

Section: Introductionmentioning

confidence: 99%

Synthesis of branched benzoxazine monomers with high molecular mass, wide processing window, and properties of corresponding polybenzoxazines

Zhao

Qiu

Liu

et al. 2016

J of Applied Polymer Sci

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Four cyclotriphosphazene-based benzoxazine monomers (I, II, III, and IV) with relatively high molecular weight were synthesized by a nucleophilic substitution reaction, and their chemical structures were confirmed by 1 H-NMR and 31 P-NMR. A new term, oxazine value (OV, similar to epoxy value), was first proposed to explain the structure-property relationship of the cured polymers. The polymerization behaviors of the four monomers were studied by differential scanning calorimetry and Fourier transform infrared spectroscopy. The maximum exothermic peaks of the four monomers are in the range 244-248 8C. All monomers possess a wide processing window despite their high molecular weight. The thermal stability, glass-transition temperature (T g ), and mechanical properties of each cured polymer were studied by thermogravimetric analysis and dynamic mechanical thermal analysis. The char yield at 850 8C, T g , and storage moduli of PIV (polybenzoxazine obtained from monomer IV) are 60.0%, 218 8C, and 9.0 GPa, respectively. The surface property and humidity absorption character of the cured polybenzoxazines were also studied. V C 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44453.

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Well-defined organic–inorganic hybrid benzoxazine monomers based on cyclotriphosphazene: Synthesis, properties of the monomers and polybenzoxazines

Cited by 34 publications

References 52 publications

Low melting point, high thermal stable branched benzoxazines resin derived from mixed-substituted phosphazene core

Low melting point, high thermal stable branched benzoxazines resin derived from mixed-substituted phosphazene core

Salvage radiation in men after prostate‐specific antigen failure and the risk of death

Synthesis of branched benzoxazine monomers with high molecular mass, wide processing window, and properties of corresponding polybenzoxazines

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