There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

Natural-sourced benzoxazine resins, homopolymers, blends and composites: A review of their synthesis, manufacturing and applications

/pdf/a-comprehensive-review-on-mechanical-electromagnetic-101zclstxk.pdf

A comprehensive review on mechanical, electromagnetic radiation shielding, and thermal conductivity of fibers/inorganic fillers reinforced hybrid polymer composites

Five commercially available amines: m-phenylenediamine (A1), m-xylylenediamine (A2), isophorone diamine (A3), trimethylhexamethylenediamine (A4), and 4,4′-diaminodiphenyl sulfone (A5), were examined as nucleophilic hardeners for bis-benzoxazine monomers based on aniline paired with bisphenol-A (BA-a) or bisphenol-F (BF-a). The reactivities and reaction mechanisms of their mixtures with BA-a were investigated using FTIR and NMR spectroscopy, DSC, and HPLC techniques. It was found that BA-a rapidly cured with the amines upon heating at 120 °C or 150 °C. The cure rate was similar to the amine/epoxy curing process in practical uses, and significantly faster than the ring-opening polymerization of bulk BA-a. The possible reaction mechanism was supported by the experimental results and includes three successive steps: (i) nucleophilic substitution at the carbon atom (O–C–N) in the oxazine ring by the amine, (ii) thermal decomposition of the resulting aminomethanaminium structure, and (iii) electrophilic addition of the newly formed iminium ion with the aromatic ring to form stable aminomethylphenol structures. These findings are helpful to improve the thermosetting resins in terms of their chemical structure, material properties, and processability.

/pdf/a-curing-system-of-benzoxazine-with-amine-reactivity-1lhcqo4puk.pdf

A curing system of benzoxazine with amine: reactivity, reaction mechanism and material properties

Polymer/Inorganic nanocomposite coatings with superior corrosion protection performance: A review

This book summarizes recent advances in the fabrication methods, properties, and applications of various ceramic-filled polymer matrix composites. Surface-modification methods and chemical functionalization of the ceramic fillers are explored in detail, and the outstanding thermal and mechanical properties of polymer–ceramic composites, the modeling of some of their thermal and mechanical parameters, and their major potential applications are discussed along with detailed examples. 
Aimed at researchers, industry professionals, and advanced students working in materials science and engineering, this work offering a review of a vast number of references in the polymer–ceramic field, this work helps readers easily advance their research and understanding of the field.

Polymer and Ceramic Composite Materials: Emergent Properties and Applications

In situ Al-based composites with different SiO2/C/Al molar ratios were fabricated by reaction hot pressing. Differential scanning calorimetry (DSC) was used to investigate the reaction mechanisms in the Al-SiO2-C system. X-ray diffraction results revealed that no new resultant phase was observed below the melting temperature of aluminum except the SiO2, C and Al phases. Heating at different synthesis temperatures showed that, up to 1000°C with a holding time of 1 h, the reactions in the Al-SiO2-C system took place completely, where the final products were Al2O3, SiC, Al4C3 and Si. Microstructural observation showed that the in situ synthesized Al2O3, SiC, Al4C3, and Si were dispersed uniformly and had fine sizes less than 2 µm. The formed interfaces between the reinforcements and Al matrix are clean and free from any interfacial phase. During cooling, the synthesized Si formed a multilayer growth in the (111) direction. When the SiO2/C/Al molar ratio was (6/3/9), more Al2O3 and Si were produced along with the complete prevention of Al4C3 in the Al-SiO2-C system. The yield strength, ultimate tensile strength and Brinell hardness of the in situ fabricated composites are significantly higher than those of pure aluminum matrix, with a decrease of ductility. Mechanisms governing the tensile fracture process are also discussed.

In Situ Al Based Composites Fabricated in Al-SiO 2 -C System by Reaction Sintering

Benzoxazine containing phthalonitrile, as one of the most advanced high performance thermosetting resin, has gained a lot of attention in the last decades. Indeed, the combination of the thermally activated ring-opening polymerization of the benzoxazine and the cyano addition reaction of the phthalonitrile allows the development of robust polymeric networks. Following this path, a renewable natural resource, vanillin, was used to develop a new benzoxazine containing phthalonitrile thermosetting system. The newly developed monomers present the advantage of a simple synthesis process along with an autocatalytic polymerization mechanism. The molecular structures of the synthesized monomers were characterized by Fourier transform infrared spectroscopy and proton nuclear magnetic resonance spectroscopy . Thermal properties were also characterized by differential scanning calorimetry and thermogravimetric analysis . Typically, the newly developed monomers showed excellent thermal stability with starting decomposition temperatures over 496.4°C with a char yield at 800°C of about 80.7%. The thermomechanical properties were investigated by dynamic mechanical analyzer and the fractured surfaces were studied by scanning electron microscopy Globally, the newly developed partially bio polymer showed outstanding thermal resistance along with excellent thermomechanical properties.

Novel vanillin-based benzoxazine containing phthalonitrile thermosetting system: Simple synthesis, autocatalytic polymerization and high thermomechanical properties

This chapter focuses on the preparation methods and evaluation of the morphological, thermal, and mechanical properties of some natural fillers and biopolymers-reinforced polybenzoxazine materials using different structural, mechanical, and thermal techniques. In addition, reinforcement mechanisms of the typical polybenzoxazine thermoset by these bio-fillers are discussed in detail. Furthermore, the interaction and relationship between these modifiers and the different mechanical and thermal property improvements in their polybenzoxazine blends and composites are scrutinized.

Chitin- and Shell-Based Benzoxazines

In a vision to develop new synthetic routes for the preparation of energetic materials, two new energetic benzoxazine monomers were synthesized via a two-step Mannich reaction process involving the incorporation of nitrogen–nitrogen bonds and explosophore groups (NO2) into the monomer backbone. The molecular structures of the synthesized monomers were confirmed by 1H NMR, Fourier transform infrared and elemental analysis techniques. The curing behavior and the degradation phenomena were evaluated by differential scanning calorimetry-thermogravimetric analysis analyses. The two monomers showed two distinct exothermic peaks related to the polymerization and degradation phases. The energetic performances were evaluated by determining the heat of combustion and formation using a bomb calorimeter, in an oxygen atmosphere. The results indicated that the 2,4 dinitrophenylhydrazine–based benzoxazine has better energetic properties than the phenylsemicarbazide-based benzoxazine, and the two developed polymers showed comparable performances with nitrocellulose and glycid azide polymer. Overall, this study has demonstrated that the ease of synthesis of the benzoxazine resins via Mannich reaction can be further extended to the energetic field and further research is undergoing to fully unravel the potential of these exceptional materials.

https://journals.sagepub.com/doi/pdf/10.1177/09540083211073654

Noureddine Ramdani

Papers

Polymer and Ceramic Composite Materials: Emergent Properties and Applications

In Situ Al Based Composites Fabricated in Al-SiO 2 -C System by Reaction Sintering

Novel vanillin-based benzoxazine containing phthalonitrile thermosetting system: Simple synthesis, autocatalytic polymerization and high thermomechanical properties

Chitin- and Shell-Based Benzoxazines

Synthesis and characterization of nitrogen-rich polybenzoxazines for energetic applications