scholarly journals Design of High-Performance Polybenzoxazines with Tunable Extended Networks Based on Resveratrol and Allyl Functional Benzoxazine

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2794
Author(s):  
Yunliang Xing ◽  
Xianru He ◽  
Rui Yang ◽  
Kan Zhang ◽  
Shengfu Yang

A novel resveratrol-based bio-benzoxazine monomer (RES-al) containing an allyl group has been synthesized using resveratrol, allylamine, and paraformaldehyde via Mannich condensation reaction, and its chemical structures have been characterized by FT-IR spectroscopy and NMR techniques. The polymerization behavior of this benzoxazine resin has been investigated using in situ FT-IR and differential scanning calorimeter (DSC) measurements, and the thermal-mechanical properties of its corresponding polybenzoxazines are evaluated by DMA and TGA. We show that by controlling the curing process of the oxazine ring, the C=C bond in resveratrol, and the allyl group in RES-al, the cross-linking network of the polybenzoxazine can be manipulated, giving rise to tunable performance of thermosets. As all curable functionalities in RES-al are polymerized, the resulted polybenzoxazine exhibits a good thermal stability with a Tg temperature of 313 °C, a Td5 value of 352 °C, and char yield of 53% at 800 °C under N2.

Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 2995
Author(s):  
Artur Jamrozik ◽  
Mateusz Barczewski ◽  
Grzegorz Framski ◽  
Daniel Baranowski ◽  
Paulina Jakubowska ◽  
...  

A series of cresol-based benzoxazines were synthesized for potential application as a polymer matrix in abrasive composites. The chemical structures of the obtained benzoxazine resins were investigated in detail using Fourier transform infrared spectroscopy (FTIR) and hydrogen-1 as well as carbon-13 nuclear magnetic resonance spectroscopy (1H NMR, 13C NMR) with an additional analysis using two-dimensional NMR techniques (2D NMR 1H-1H COSY, 1H-13C gHSQC and gHMBC). Structural analysis confirmed the presence of vibrations of -O-C-N- at ~950 cm−1 wavenumber, characteristic for an oxazine ring. The thermal properties of benzoxazine monomers were examined using differential scanning calorimetry (DSC) analysis. The polymerization enthalpy varied from 143.2 J/g to 287.8 J/g. Thermal stability of cresol-based benzoxazines was determined using thermogravimetry (TGA) analysis with additional analysis of the amount of volatile organic compounds (VOC) emitted from the synthesized benzoxazines during their crosslinking by static headspace coupled with gas chromatography technique (HS-GC). The amount of residual mass significantly differed between all synthesized polybenzoxazines in the range from 8.4% to 21.2%. The total VOC emission for benzoxazines decreased by 46–77% in reference to a conventional phenolic binder. The efficiency of abrasive composites with the benzoxazine matrix was evaluated based on abrasion tests. Performed analyses confirmed successful synthesis and proper chemical structure of cresol-based benzoxazines. All the experiments indicated that benzoxazines based on different cresol isomers significantly differ from each other. Good thermal performance and stability of the abrasive composites with the polybenzoxazine matrix and significantly lower VOC emission allow us to state that benzoxazines can be a promising and valuable alternative to the phenolics and a new path for the development of modern, eco-friendly abrasives.


RSC Advances ◽  
2015 ◽  
Vol 5 (42) ◽  
pp. 33623-33631 ◽  
Author(s):  
Tong Zhang ◽  
Jun Wang ◽  
Tiantian Feng ◽  
Hui Wang ◽  
Noureddine Ramdani ◽  
...  

A novel tetrafunctional oxazine monomer containing benzoxazine and fluorene-oxazine was prepared for the first time using a Mannich condensation reaction of 2,7-dihydroxy-9,9-bis-(4-hydroxyphenyl)fluorene with paraformaldehyde and n-butylamine.


2011 ◽  
Vol 217-218 ◽  
pp. 1159-1164
Author(s):  
Guan Jun Chang ◽  
Lin Zhang ◽  
Run Xiong Lin

Poly(aryl imino sulphone)s (PAIS) as novel high-performance polymers have been obtained by the condensation polymerization of 4,4'-dibromodiphenyl solfone with different primary aromatic diamines via Palladium-catalyzed aryl amination reaction. The structure of polymers synthesized was characterized by means of FT-IR, NMR spectroscopy and elemental analysis, the results showed an agreement with the proposed structure. Differential scanning calorimetry (DSC) and thermal analysis (TG) measurements showed that polymers possessed high glass transition temperature (Tg>145°C) and good thermal stability with high decomposition temperatures (TD>450°C). These novel polymers also exhibited good mechanical behaviors and good solubility.


2017 ◽  
Vol 70 (6) ◽  
pp. 669
Author(s):  
Chongling Yang ◽  
Shouzai Tan ◽  
Gengen Chen ◽  
Litao Guan

A copolymer of PA6 (polyamide 6) and PEG (polyethylene glycol) was synthesized by a condensation reaction. The optimal reaction conditions were determined as the following: a reaction temperature of 255°C, –0.04 MPa vacuum, and a condensation time of 40 min. A series of novel PA6-PEG/Li composites were developed by melt blending the PA6-PEG copolymer (10 wt-% PEG) with three different kinds of colourless lithium salts (LiCl, C18H35LiO2, LiAc). FT-IR, NMR, thermogravimetric (TGA), electronic universal testing, and resistivity analyses were employed to investigate the comprehensive properties of the copolymers and composites. The results of FT-IR and 1H NMR analyses revealed that the PEG was copolymerized with PA6 successfully. TGA results indicated that the decomposition temperature of the PA6-PEG copolymer was above 350°C. Resistivity testing revealed that the surface resistivity (Rs) of the copolymer decreased from 1 × 1014 to 5.67 × 109 Ω square–1 with an increase of the content of PEG. The PA6-PEG/LiCl composite showed an excellent static dissipation performance of 2.71 × 108 Ω square–1.


Coatings ◽  
2018 ◽  
Vol 8 (3) ◽  
pp. 88 ◽  
Author(s):  
Jinyue Dai ◽  
Shimin Yang ◽  
Na Teng ◽  
Yuan Liu ◽  
Xiaoqing Liu ◽  
...  

In this work, several bio-based main-chain type benzoxazine oligomers (MCBO) were synthesized from eugenol derivatives via polycondensation reaction with paraformaldehyde and different diamine. Afterwards, their chemical structures were confirmed by Fourier Transform Infrared Spectroscopy (FT-IR) and Nuclear Magnetic Resonance Spectroscopy (1H-NMR). The curing reaction was monitored by Differential Scanning Calorimetry (DSC) and FT-IR. The polybenzoxazine films were prepared via thermal ring-opening reaction of benzoxazine groups without solvent, and their thermodynamic properties, thermal stability, and coating properties were investigated in detail. Results indicated that the cured films exhibited good thermal stability and mechanical properties, showing 10% thermal weight loss (Td10%) temperature as high as 408 °C and modulus at a room temperature of 2100 MPa as well as the glass transition temperature of 123 °C. In addition, the related coatings exhibited high hardness, excellent adhesion, good flexibility, low moisture absorption, and outstanding solvent resistance.


2015 ◽  
Vol 14 (05n06) ◽  
pp. 1550021
Author(s):  
S. G. Gunasekaran ◽  
K. Rajakumar ◽  
M. Dharmendirakumar

A new series of multi-walled carbon nanotube reinforced polybenzoxazine (MWCNT/PBZ) nanocomposites was successfully designed and developed. Three different maleimido terminal benzoxazine monomers (MI-BZs) were synthesized using N-(4-hydroxyphenyl) maleimide (HPM) and formaldehyde solution through Mannich condensation reaction and were characterized by FT-IR and NMR spectroscopy. Varying weight percentages (0 wt.%, 0.5 wt.%, 1.0 wt.% and 1.5 wt.%) of glycidyl-MWCNT were then incorporated into benzoxazine matrices to prepare MWCNT/PBZ nanocomposites. The nanocomposites having higher weight percentage of MWCNT were found to possess excellent thermal properties than those of neat PBZs. The developed nanocomposites exhibited better flame retardancy and higher dielectric constant. The optical properties ascertained from the UV-Vis absorption bands at the region of 300–350 nm and strong fluorescent emissions were observed in the wavelength range of 300–550 nm from Photoluminescence analysis. The intensity of characteristic diffraction peaks corresponding to g-MWCNT confirmed the reinforcement of MWCNT in the benzoxazine matrices, which indicated the successful formation of nanocomposites. The morphological studies ascertain the compatibility and uniform dispersion of MWCNT in the PBZ network.


2018 ◽  
Vol 913 ◽  
pp. 746-751
Author(s):  
Peng Yang ◽  
Jun Xiao Yang ◽  
Guan Jun Chang

N-substituted crosslinking polybenzimidazole pyridine sulfone, as novel high performance functional polymers, was prepared by the coordination of N-substituted polybenzimidazole pyridine sulfone (Py-N-PBIS) ligand with varying content of metallic ion (Co2+, Ni2+, Zn2+). The structures of the polymers were characterized by means of FT-IR and 1H NMR spectroscopy, and the results showed a good agreement with the proposed structures. TGA measurements exhibited that the crosslinking polymers possessed good thermal stability with high thermal decomposition temperatures (thermally stable up to 405-510 °C). Additionally, the thermal stability of the coordination polymers was improved constantly with the increasing of the content of Co2+, Ni2+ or Zn2+. The metal coordination crosslinking N-substituted polybenzimidazole pyridine sulfone could be considered as a novel high performance thermoset.


2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Davi Rabelo de Oliveira ◽  
Selma Elaine Mazzetto ◽  
Diego Lomonaco

Naphthoxazines are a class of compounds with potential application in obtaining high-performance polymeric materials. Such application of these compounds, however, is still scarcely explored in the literature. Combined with the search for new high-performance materials, the development of biobased polymers has gained a lot of attention. In this sense, the inclusion of furan groups in polymers has been explored as a strategy that combines the search for high-performance materials with the search for the development of biobased materials. In this work, novel naphthoxazine monomers containing furan groups were synthetized. The syntheses were carried out in a single step, without the use of solvents and catalysts, obtaining the products in satisfactory yields and high purity. The naphthoxazines had their chemical structures completely characterized by FTIR, 1H NMR, and 13C NMR techniques. The thermal analyses (DSC and TGA) showed that all naphthoxazines exhibit exothermic typical polymerization events, making these compounds suitable for obtention of poly(naphthoxazines) resins, but suffer significant mass losses at temperatures below the onset polymerization temperature. In this way, a catalyst (1 mol% MgCl2) was used in order to allow the polymerization of the compounds before the mass loss events. The FTIR analysis showed strong evidences of the formation of poly(naphthoxazines), and TGA analyses showed that the resins have high thermal stability, with high flame resistance and self-extinguishing properties (LOI > 28), which makes these compounds attractive in the development of biobased and high-performance materials.


2019 ◽  
Vol 2019 ◽  
pp. 1-6 ◽  
Author(s):  
Alver A. Castillo-Aguirre ◽  
Zuly Jenny Rivera Monroy ◽  
Mauricio Maldonado

A method for the separation of stereoisomer mixture of the octol C-tetra(p-hydroxyphenyl)calix[4]resorcinarene that was obtained by an acid cyclocondensation reaction between resorcinol and benzaldehyde is reported in this paper. A crude product from octol formation reaction was analyzed by reverse-phase high-performance liquid chromatography (RP-HPLC), and two well-resolved signals corresponding to the crown and chair isomers were found. A reverse phase in solid-phase extraction (RP-SPE) protocol allowed the separation of the two stereoisomers with high purity of each isomer. Finally, the crude and purified stereoisomers were characterized by using FT-IR, 1H-NMR, and 13C-NMR techniques, confirming the chemical identity of the two isomers and the efficiency in the separation process.


2020 ◽  
Vol 981 ◽  
pp. 121-126
Author(s):  
Nurfatin Farhanah Rohimi ◽  
Rasidi Roslan ◽  
Nurjannah Salim ◽  
Siti Noor Hidayah Mustapha ◽  
Sarani Zakaria ◽  
...  

In this study, a renewable phenolic component was synthesized using empty fruit bunch fibers via microwave-assisted liquefaction known as Liquefied Empty Fruit Bunch (LEFB). LEFB can be used as phenolic derivative to replace petroleum-based phenol as it contains aromatic group in lignin that can be used as starting materials to synthesis polybenzoxazine resins. A Lignin-based benzoxazine (L-PBz) has been synthesized using a solventless approach from the reaction of LEFB, furfurylamine as the amine component and paraformaldehyde via Mannich condensation reaction. Two different ratios of LEFB:furfurylamine:paraformaldehyde which are 1:1:1 and 1:1:2 were investigated. The thermal properties and polymerization behavior of the L-PBz were analyzed using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), respectively. In addition, cured-polybenzoxazine composites were also prepared by hot-pressing the uncured L-PBz at 250 °C for 4 hours, and the mechanical properties of the composites were assessed through Izod impact strength test. TGA analysis showed that, L-PBz with ratio of 1:1:1 exhibit a high char yield compared to 1:1:2 which is 47% vs 43%, respectively, after being heated until 900 °C. However, L-PBz with ratio of 1:1:2 showed good polymerization behavior compared to 1:1:1 which indicated by the curing temperature 215 °C vs 238 °C. L-PBz composites, which added with cellulose nanocrystal (CNC) fillers have better strength compared with the absence of fillers. As a conclusion, the aromatic structure of lignin in empty fruit bunch fibers has presented a promising alternative to replace petroleum-based phenol in polybenzoxazine synthesis.


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