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Indexed by:期刊论文

Date of Publication:2018-12-01

Journal:POLYMER TESTING

Included Journals:SCIE、Scopus

Volume:72

Page Number:232-237

ISSN No.:0142-9418

Key Words:Benzoxazine resin; Alkynyl; Curing mechanism; Isothermal infrared method; Glass transition temperature

Abstract:Alkynyl-functionalized benzoxazine (A-BZ) resin containing phthalide side group with excellent heat resistance has been successfully synthesized with phenolphthalein, meta-aminophenylacetylene and formaldehyde solution as starting materials. Its chemical structure was characterized and analyzed by Fourier transform infrared (FT-IR) spectroscopy and hydrogen nuclear magnetic resonance (H-1-NMR) spectroscopy. A-BZ can easily dissolve in the common organic solvents including ethanol, acetone et al. The gelation time under different temperature of A-BZ resin was measured by dynamic mechanical analysis (DMA) according to the intersection time of the isothermal curves of the storage modulus and loss modulus. The gelation activation energy was determined by Arrhenius formula (E-a = 48.51 kJ/mol). The optimal curing procedure was established by combing non-isothermal differential scanning calorimetry (DSC) and isothermal DMA. The curing mechanism was analyzed in in situ FT-IR method by monitoring the change of characteristic peaks under different temperature. The reaction temperatures of ring-opening reaction of benzoxazine (170 degrees C) and trimerization cyclization of alkynyl groups (170-200 degrees C) were determined. The glass transition temperature (T-g) of A-BZ cured product tested by DMA equals to 382 degrees C, which is much larger than those of counterparts (251-259 degrees C).