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Cure Path Dependency on Meta-Alkyl Substituted Aniline Based Polybenzoxazine Thermosets


Title: Cure Path Dependency on Meta-Alkyl Substituted Aniline Based Polybenzoxazine Thermosets

Authors: Bernardo Barea-López, Benjamin L.G. Morasch, Otoniel Durán, and Dr. Jeffrey S. Wiggins

DOI: 10.33599/nasampe/s.22.0758

Abstract: Polybenzoxazine chemistry is an attractive alternative to more traditional matrices used in the aerospace industry due to the high glass transition temperature, UV resistance, low coefficient of thermal expansion and low water absorption. Ishida et al. proposed that meta-alkyl substituted aniline based polybenzoxazines exhibit two different crosslinking mechanisms shown in Scheme 1.[1] In route A, the opening of the oxazine ring leads to the formation of a phenolic Mannich bridge. In route B, meta-alkyl substituted aniline based polybenzoxazine can undergo the formation of an arylamine Mannich bridge. It has been reported that both mechanisms have dissimilar activation energies.[2] However, it is still unknown how different cure protocols would affect the network architecture of meta-alkyl substituted aniline based polybenzoxazines thermosets. Herein, chemorheological and thermomechanical characterizations were performed to study the benzoxazine network formation of the same monomer (BA-35mt) that was cured from 150 °C to 250 °C at four different ramp rates: 0.1 °C/min, 0.5 °C/min, 1.0 °C/min, and 2.0 °C/min. Dynamic Mechanical Analysis (DMA) , Thermogravimetric Analysis (TGA) and moisture uptake tests were employed to analyze the properties of the four fully cured BA-35mt networks. Furthermore, gelation tests were performed to understand the kinetics of the crosslink reaction. This research seeks to establish the effect of different cure protocols on the network formation of meta-substituted aniline based polybenzoxazine thermosets.

References: [1] Ishida, H.; Sanders, D. P. Improved Thermal and Mechanical Properties of Polybenzoxazines Based on Alkyl-Substituted Aromatic Amines. J. Polym. Sci. Part B Polym. Phys., 2000, 38 (24), 3289–3301.<3271::AID-POLB80>3.0.CO;2-6. [2] Song, Y.; Zhang, S.; Yang, P. Effect of Methyl Substituent on the Curing of Bisphenol-Arylamine-Based Benzoxazines. Thermochim. Acta, 2018, 662 (February), 55–63. [3] Ishida, H.; Ning, X. Phenolic Materials via Ring-Opening Polymerization: Synthesis and Characterization. J. Polym. Sci. Part A Polym. Chem., 1994, 32, 1121–1129. [4] Ran, Q.; Gu, Y.; Ishida, H. Thermal Degradation Mechanism of Polybenzoxazines; 2017. [5] Ishida, H.; Low, H. Y. A Study on the Volumetric Expansion of Benzoxazine-Based Phenolic Resin. Macromolecules, 1997, 30 (4), 1099–1106. [6] Wang, Y. X.; Ishida, H. Development of Low-Viscosity Benzoxazine Resins and Their Polymers. J. Appl. Polym. Sci., 2002. [7] Ohashi, S.; Ishida, H. Various Synthetic Methods of Benzoxazine Monomers; Elsevier Inc., 2017. [8] Ishida, H.; Allen, D. J. Physical and Mechanical Characterization of Near-Zero Shrinkage Polybenzoxazines. J. Polym. Sci. Part B Polym. Phys., 1996, 34 (6), 1019–1030.<1019::AID-POLB1>3.0.CO;2-T. [9] Ishida, H.; Sanders, D. P. Regioselectivity and Network Structure of Difunctional Alkyl-Substituted Aromatic Amine-Based Polybenzoxazines. Macromolecules, 2000, 33 (22), 8149–8157. [10] Jubsilp, C.; Damrongsakkul, S.; Takeichi, T.; Rimdusit, S. Curing Kinetics of Arylamine-Based Polyfunctional Benzoxazine Resins by Dynamic Differential Scanning Calorimetry. Thermochim. Acta, 2006, 447 (2), 131–140. [11] Situ, Y.; Zhu, Z.; Huang, H. Catalytic Effect of Trifluoroacetamido Group on Thermally Induced Ring-Opening Polymerization of 1,3-Benzoxazine and Formation of Arylamine Mannich Bridge Structure. High Perform. Polym., 2016, 28 (3), 271–280. [12] Jackson, M.; Kaushik, M.; Nazarenko, S.; Ward, S.; Maskell, R.; Wiggins, J. Effect of Free Volume Hole-Size on Fluid Ingress of Glassy Epoxy Networks. Polymer 2011, 52, 4528–4535.

Conference: SAMPE 2022

Publication Date: 2022/05/23

SKU: TP22-0000000758

Pages: 10

Price: $20.00

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