A new pathway for the preparation of polysiloxane oligomers bearing benzoxazine side groups were reported via the hydrolysis and co-polycondensation of benzoxazinyl siloxane (SBZ) with dimethyldiethoxysilane (DEDMS). The structures of SBZ and oligomers were characterized by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR) spectroscopy. The average molecular weights of the obtained oligomers were estimated from size exclusion chromatography and ¹H-NMR to be in the range of 2000–4000. The oligomers gave transparent films by casting in THF solution. The films were further thermally treated to produce crosslinked films via the ring opening polymerization of benzoxazine side group. The effects of siloxane content on polymerization behavior, glass transition temperature, and mechanical properties of the polybenzoxazine thermosets were investigated. Tensile test of the films revealed that the elongation at break increased with increasing siloxane content. The elongation at break of poly(I-50) was up to 12.1%. Dynamic mechanical analysis of the thermosets showed that the T_gs were in the range of 119–165°C. Thermogravimetic analysis also revealed a better thermal stability as evidenced by the 5% weight loss temperatures in the range of 363–390°C. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40960.

A novel high-performance resin blend composed of nitrile functionalized benzoxazine (CNBZ) and bismaleimide (4,4′-bismaleimidodiphenyl methane) (BMI) was prepared via solvent method. Its curing behaviors, thermal properties, and mechanical properties were studied by differential scanning calorimetry (DSC), fourier transform infrared spectroscopy (FTIR), dynamic mechanical analysis (DMA), thermogravimetric analysis (TGA), and universal testing machine, respectively. The results showed that the addition reaction between phenolic hydroxyl group and the double bond occurred except for the homopolymerization of CNBZ and BMI. When BMI content was more than 40%, the cured CNBZ/BMI blends exhibited higher glass transition temperatures (T_gs) than CNBZ and BMI homopolymers, which reached up to 334°C. Meanwhile, when BMI content was 40%, the tensile strength, flexural strength, and shearing strength reached up to 69, 235, and 12.9 MPa, respectively, which exhibited the comparable mechanical properties with BT resin. Furthermore, the glass cloth (GF) reinforced laminates based on these blends were prepared. The results showed that when BMI content was 40%, their tensile strength, flexural strength, and impact strength reached up to 334 MPa, 593 MPa, and 145 KJ m⁻², respectively. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41072.

A new synthetic route was designed to significantly increase the content of triazine structure in benzoxazine resin. 2,4,6-Tri(4-hydroxylphenyl)-13,5-s-triazine (TP) was synthesized by cyclotrimerization of 4-cyanolphenol and then benzoxazine monomer-containing triazine [2,4,6-tri(3-phenyl-3,4-dihydro-2H-1,3-benzoxazin-6-yl)-1,3,5-s-triazine (BZ-ta)] was synthesized via Mannich reaction from TP. Finally, the cross-linked polymer P(BZ-ta) was produced by thermal polymerization of BZ-ta. BZ-ta was characterized by nuclear magnetic resonance spectroscopy (NMR), fourier transform infrared spectroscopy (FTIR), mass spectrum, elemental analysis, and viscosity measurement. Curing behavior of BZ-ta was studied by differential scanning calorimetry, FTIR, and gel permeation chromatography. The structure and properties of P(BZ-ta) were investigated by powder X-ray diffraction, dynamic mechanical analysis, and thermogravimetric analysis. The results showed that the P(BZ-ta) had high glass temperature (T_g = 322°C), excellent thermal oxidation stability (5 and 10% weight loss temperatures in air up to 403 and 453°C, respectively), high char yield (64%, 800°C in nitrogen), and high flame-retardance (limiting oxygen index, 39.7). © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Water-soluble polyphenol-graft-poly(ethylene oxide) (PPH-g-PEO) copolymers were prepared using grafting-through methodology. Polyphenol chains were synthesized via enzymatic polymerization of phenols, and the graft chains were synthesized via living anionic polymerization of ethylene oxides. The polymers were characterized using gel permeation chromatography, static light scattering and ¹H NMR, infrared and ultraviolet spectroscopies. The PPH-g-PEO graft copolymers are soluble in several common solvents, such as water, ethanol, N,N-dimethylformamide, tetrahydrofuran and methylene dichloride. The solubility of the PPH-g-PEO graft copolymers is improved significantly compared with that of polyphenol. Copyright © 2009 Society of Chemical Industry

A novel benzoxazine precursor containing phenol hydroxyl groups was synthesized from bisphenol A, 4,4′-diaminodiphenyl methane, and formaldehyde with a molar ratio of 2:1:4. The benzoxazine precursor was characterized with Fourier transform infrared, proton nuclear magnetic resonance, and size exclusion chromatography. The curing reaction was monitored by the gel time, differential scanning calorimetry, and Fourier transform infrared. The obtained polybenzoxazine showed high thermal stability and a high glass-transition temperature. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008