Studies on structurally different benzoxazines

Rishwana, S. Shamim; Mahendran, Arunjunai Raj; Vijayakumar, Chinnaswamy Thangavel

doi:10.1177/0954008314561806

Cited by 10 publications

(5 citation statements)

References 47 publications

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“…Considering the polymerization mechanisms and the intimate structures of poly(FAEN-Bz), the thermal decomposition processes can be concluded as follows (shown in Scheme 3): firstly, the Mannich bridge was broken and the long molecular structures of poly(FAEN-Bz) turn into aromatic ester nitrile segments, which possessed outstanding thermal stability (Scheme 3a) [9]. At the elevated temperatures, the segments began to collapse along with the fracture of chemical bonds (Scheme 3b) [27].…”

Section: Resultsmentioning

confidence: 99%

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Benzoxazine Containing Fluorinated Aromatic Ether Nitrile Linkage: Preparation, Curing Kinetics and Dielectric Properties

Chen

Ren

et al. 2019

Polymers

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Benzoxazine containing fluorinated aromatic ether nitrile linkage (FAEN-Bz) had been synthesized from 2,6-dichlorobenzonitrile, 4,4’-(hexafluoroisopropylidene)diphenol (bisphenol AF), 3-Aminophenol, formaldehyde, phenol by condensation polymerization and Mannich ring-forming reaction. Structures of the monomer were verified by Proton NMR spectrum (1H-NMR) and Fourier transform infrared spectroscopy (FTIR). Curing behaviors and curing kinetics of designed monomers were investigated and discussed. The activation energy was calculated and possible polymerization mechanisms were also proposed. Then, properties of cured polymers including crosslinking degrees, thermal decomposition, surface wettability and energy, and dielectric properties were studied and discussed. Additionally, programmed integral decomposition temperature (IPDT) was also used to evaluate the thermal stability of final polymers. Results indicated that the incorporation of benzoxazine and nitrile resulted in increased thermal stability and char yields. Moreover, the surface wettability and dielectric properties of poly(FAEN-Bz) can be easily controlled by tuning the curing temperatures and time.

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Section: Resultsmentioning

confidence: 99%

“…It has been widely used in construction, electronics, aerospace and other fields [8]. However, traditional phenolic resin often releases volatiles which corrode the processing equipment during the curing process [9]. It will lead to the formation of micro-voids, and damage the performance of final materials.…”

Section: Introductionmentioning

confidence: 99%

Benzoxazine Containing Fluorinated Aromatic Ether Nitrile Linkage: Preparation, Curing Kinetics and Dielectric Properties

Chen

Ren

et al. 2019

Polymers

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“…This restricts the motion of oxazine rings, leading to less involvement of oxazine rings in polymerization and, therefore, resulting in lower ∆H values [192]. Incorporation of rigid spacer units, trimethylphenyl indane and tetramethyl spirobiindane between the reactive benzoxazine units, leads to mobility restriction imposed on the reactive sites by the increasing viscosity of the polymerizing medium, affecting the polymerization rate [401]. The effect of intermolecular H-bonding between the urea linkages allowed close proximity of oxazine rings, which in turn, lead to accelerated polymerization at much lower temperature [225].…”

Section: Acceleration Of the Rate Of Polymerization Via Intramolecular Interaction 41 Modification Of Monomer Structures By Electron-donamentioning

confidence: 99%

Review on the Accelerated and Low-Temperature Polymerization of Benzoxazine Resins: Addition Polymerizable Sustainable Polymers

et al. 2021

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Due to their outstanding and versatile properties, polybenzoxazines have quickly occupied a great niche of applications. Developing the ability to polymerize benzoxazine resin at lower temperatures than the current capability is essential in taking advantage of these exceptional properties and remains to be most challenging subject in the field. The current review is classified into several parts to achieve this goal. In this review, fundamentals on the synthesis and evolution of structure, which led to classification of PBz in different generations, are discussed. Classifications of PBzs are defined depending on building block as well as how structure is evolved and property obtained. Progress on the utility of biobased feedstocks from various bio-/waste-mass is also discussed and compared, wherever possible. The second part of review discusses the probable polymerization mechanism proposed for the ring-opening reactions. This is complementary to the third section, where the effect of catalysts/initiators has on triggering polymerization at low temperature is discussed extensively. The role of additional functionalities in influencing the temperature of polymerization is also discussed. There has been a shift in paradigm beyond the lowering of ring-opening polymerization (ROP) temperature and other areas of interest, such as adaptation of molecular functionality with simultaneous improvement of properties.

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“…This increase in E a and the increase in conversion rate for stages 1 and 2 have already been described by researchers. Shamim Rishwana et al 52 have observed that the CN bond, with its relatively low energy of 305 kJ/mol in contrast to the CC bond (346 kJ/mol), undergoes its degradation during the early phases of degradation, specifically at lower conversion degrees. Consequently, Schiff base products are generated as a result.…”

Section: Resultsmentioning

confidence: 99%

Thermal stability and decomposition kinetics of polybenzoxazine and oligomeric polyhedral octaphenyl silsesquioxane nanocomposites

Faghihi,

Azar,

Khonakdar

et al. 2024

Polymers for Advanced Techs

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In this study, the impact of octaphenyl polyhedral oligomeric silsesquioxane (POSS) on the thermal stability of polybenzoxazine resin at 1, 3, and 5 wt% POSS loading through dynamic thermogravimetric analysis (TGA) at heating rates of 10, 20, 30 and 40°C min−1 was investigated. Besides, the decomposition kinetics of polybenzoxazine resin (PBZ) and various nanocomposites were studied using Kissinger, Friedman, Flynn‐Wall‐Ozawa (FWO) and Coats‐Redfern (CR) models and also, the activation energies of samples were calculated. At first, benzoxazine monomer was synthesized and then nanocomposites were prepared via solution mixing method. The qualitative dispersion of nanoparticles in benzoxazine resin was examined through the utilization of scanning electron microscopy and x‐ray diffraction experiments. The results showed that the addition of nanoparticles improved the thermal stability of PBZ resin specially at 1 wt% POSS loading and at higher POSS content the thermal stability of the resin decreased. As determined by TGA, the char yield of resin was enhanced by 2.6% upon the addition of 1 wt% nanoparticles. In addition, in 1 weight percent of nanoparticles, as the heating rate rose from 10 to 40°C min−1, the Integral Program Decomposition Temperature (IPDT) has increased by about 260°C, and this increase is about 183°C compared to the resin, and also elevating the heating rate, Td (5%) and Td (10%) weight loss of samples shifted to higher temperatures. The degradation mechanism of the resin and nanocomposites was evaluated through Kissinger, Friedman, FWO and CR models. The results displayed that the addition of 1 wt% nanoparticles increased the activation energy (Ea) values of the nanocomposites compared to that of neat resin and above this filler content, the Ea values decreased. The findings derived from the FWO model indicated that the inclusion of a 1 wt% filler raised the Ea values of the first and second stages of PBZ resin decomposition from 136–200 and 151–214 kJ mol−1 to 148–210 and 180–228 kJ mol−1, respectively.

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Studies on structurally different benzoxazines

Cited by 10 publications

References 47 publications

Benzoxazine Containing Fluorinated Aromatic Ether Nitrile Linkage: Preparation, Curing Kinetics and Dielectric Properties

Benzoxazine Containing Fluorinated Aromatic Ether Nitrile Linkage: Preparation, Curing Kinetics and Dielectric Properties

Review on the Accelerated and Low-Temperature Polymerization of Benzoxazine Resins: Addition Polymerizable Sustainable Polymers

Thermal stability and decomposition kinetics of polybenzoxazine and oligomeric polyhedral octaphenyl silsesquioxane nanocomposites

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