Competing Narratives: The Struggle for the Soul of Egypt

Mansouri, Ahmed El

doi:10.15760/etd.7236

Cited by 1 publication

(1 citation statement)

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“…It can substitute for petrolbased chemical compounds in polymer formulations, dispersant agents, emulsifiers, chelating agents, or adsorbents, and phenolic resins. [3][4][5][6][7][8][9] Phenolic resins are considered to have potential for the application of lignin polymers. They are widely used in industry because of their good heat resistance, electrical insulation, dimensional stability, low flammability, and low smoke generation.…”

Section: Introductionmentioning

confidence: 99%

Investigation of curing and thermal behavior of benzoxazine and lignin mixtures

Mansouri

Yuan

Huang

2012

J of Applied Polymer Sci

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This article describes the synthesis and characterization of two types of benzoxazine monomers based on phenol or bisphenol, aniline, and formaldehyde. Their characterization was achieved by Fourier transform infrared, 1H‐nuclear magnetic resonance, differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). Lignin polymer was characterized by infrared, DSC, and TGA. The curing behavior of mixtures of benzoxazine monomers and lignin was investigated by DSC. The mass ratios of benzoxazine monomers/lignin of a series of samples were 100 : 0, 95 : 05, 90 : 10, 85 : 15, 80 : 20, 75 : 25, and 70 : 30. The results indicate that the maximum curing temperatures of the mixtures were lower than that of the pure benzoxazine monomers, and that they decreased with increasing contents of lignin in the mixture. The heat of polymerization (ΔH) of the benzoxazine monomers and lignin mixtures as a function of the mass ratio and the structure of the benzoxazine monomers shows no definite trend. The samples were cured according to the following conditions: 170°C/2h + 200°C/2h and analyzed by DSC and TGA. In all the samples, the glass transition temperature of the benzoxazines increased upon mixing with increasing amounts of lignin. The changes may be due to the formation of a more compact network structure in the mixtures. The thermal stability of the isothermally cured resins is found to be dependent on the mass ratio of benzoxazine/lignin and structure of the benzoxazine monomers. The more lignin in the mixture, the higher is the char yield in the mixture. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

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