Noureddine Ramdani

Synthesis of novel furan-containing tetrafunctional fluorene-based benzoxazine monomer and its high performance thermoset

A novel furan-containing tetrafunctional fluorene-based benzoxazine monomer with bisphenol- and diamine-type oxazine rings was successfully prepared. The resulting polybenzoxazine exhibits extremely higher glass transition temperature (440 °C) and better thermal stability than difunctional furan-containing fluorene-based and traditional multifunctional benzoxazine resins.

A novel high performance oxazine derivative: design of tetrafunctional monomer, step-wise ring-opening polymerization, improved thermal property and broadened processing window

A novel tetraphenol fluorene, 2,7-dihydroxy-9,9-bis-(4-hydroxyphenyl)fluorene (THPF), was synthesized via the condensation reaction of 2,7-dihydroxy-9-fluorenone and phenol in the presence of a strong acidic cation exchange resin and 3-mercaptopropionic acid. Thus, a novel tetrafunctional oxazine monomer containing benzoxazine and fluorene-oxazine (t-BF-b) was prepared for the first time using a Mannich condensation reaction of THPF with paraformaldehyde and n-butylamine. The chemical structures of THPF and t-BF-b were characterized by Fourier transform infrared (FTIR) spectroscopy, elemental analysis, 1H and 13C nuclear magnetic resonance (NMR). The viscosity–temperature properties and the polymerization behavior of t-BF-b as well as the thermal and mechanical properties of its cured polymer (poly(t-BF-b)) were studied by rheometry, FTIR, 1H NMR, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and dynamic mechanical analysis (DMA). The results show that poly(t-BF-b) displays a lower melting point and wider processing window. The oxazine rings of fluorene-oxazine possess higher reactivity and lower polymerization temperature than those of benzoxazine. Also, its cured poly(t-BF-b) exhibits a higher glass transition temperature than its corresponding bifunctional polybenzoxazines without sacrificing any thermal properties in spite of the introduction of more flexible aliphatic groups into polymer chains.

Preparation and properties of chitosan particle-reinforced polybenzoxazine blends

This study investigates the effects of chitosan particles (CTS) on the curing behavior, thermal and thermomechanical properties of polybenzoxazine matrix. The morphological, thermomechanical, and thermal properties of the blends are analyzed using scanning electron microscopy (SEM), dynamic scanning calorimetry (DSC), dynamical mechanical analyzer (DMA), and thermogravimetric analysis (TGA). The results show that the −NH2 groups on the chitosan can act as an active crosslinking position and hydrogen bonding. The SEM micrographs reveal good compatibility between the blend components. Furthermore, the values of glass transition temperatures, char yields, and storage moduli of the cured blends are found to be increased with the increase of CTS contents to reach 191℃, 34%, 4.3 GPa, respectively, at 10% of CTS content.

Preparation and Thermal Properties of Polybenzoxazine/TiC Hybrids

In this work, typical polybenzoxazine, as new class of phenolic resin, has been used as a matrix for preparing a series of high performance hybrid materials using various amounts of titanium carbide (TiC) ranging between 0-10 wt% as fillers, via a solution blending technique. The thermal properties of bisphenol A-aniline base benzoxazine monomers (BA-a) and TiC mixtures have been studied by differential scanning calorimetry (DSC). The thermal stability of their cured hybrids has been tested by means of thermogravimetric analysis (TGA). The result showed that the glass transition temperature of the prepared composites increased with increasing the amount of TiC to reach a higher value at 194°C. Also, the incorporation of TiC nanoparticles has considerably improved the thermal stability of the hybrids including the char yield which increase by 50 % at 10 wt% TiC content.

New oligomeric containing aliphatic moiety phthalonitrile resins: their mechanical and thermal properties in presence of silane surface-modified zirconia nanoparticles

This study deals with the influences of both the length of the aliphatic spacer within the phthalonitrile monomers backbones, and the amount of the silane surface modified zirconia nanoparticles on the mechanical and thermal properties of the so-called second generation phthalonitrile resins. Investigation on the curing behavior under differential scanning calorimeter outlined an important gain in the processability as the aliphatic spacer became longer. Results from the mechanical tests revealed that changing the length of the aliphatic spacer affects the mechanical properties in different ways. For instance, as the aliphatic spacer became longer, the toughness state was enhanced. At the same time, the tensile modulus and stress as well as the microhardness values were slightly reduced. It was also noticed that the introduction of the reinforcing phase caused an increase in all the tested mechanical properties. Furthermore, results from the thermogravimetric analysis and dynamic mechanical analysis revealed that reducing the length of the aliphatic spacer and adding nanofillers caused an increase in the thermal stability, storage modulus, and glass transition temperature. Moreover, a morphological study has been conducted under scanning electron microscope and transmission electron microscope to put in light the mechanisms of enhancements. Finally, this study demonstrated that the excellent properties of the phthalonitrile resins can be tailored by two ways either by monomers design or by inorganic nanoparticles reinforcement.

Effects of aluminium nitride silane-treatment on the mechanical and thermal properties of polybenzoxazine matrix

A new kind of polymer composite, produced from the typical polybenzoxazine and 0–30 wt-% native and silane-treated aluminium nitride (T-AlN), was investigated. The mechanical tests revealed a significant increase in the microhardness and flexural properties upon adding the T-AlN particles compared to that obtained from the untreated ones. By adding 0–30 wt-% T-AlN, the tensile moduli were accurately reproduced by the Halpin-Tsai and Nielsen models. At 30 wt-% T-AlN, dynamic mechanical analysis showed a significant increase in the storage moduli and the glass transition temperature (Tg), reaching 3.2 GPa and 217°C, respectively. The thermal stability of these materials was significantly improved upon the addition of the T-AlN fillers. These improvements are attributed to the high thermal and mechanical properties of the fillers and their good dispersion and adhesion in and to the matrix as revealed by a morphological analysis.

Chapter 41 – Ceramic-Based Polybenzoxazine Micro- and Nanocomposites

This chapter studies the effects of adding various micro- and nanoceramic fillers on the structure, thermal, and mechanical properties of polybenzoxazine resins. The effects of particle contents, particle sizes, and surface treatment are discussed. In addition, the mechanisms of reinforcement for these kinds of micro- and nanocomposites are also investigated and some mechanical parameters are reproduced using some theoretical and semiempirical models. The application of these materials in the coating, anticorrosion, and electronic-packaging areas are evaluated. The presented results of this chapter provide a basis for understanding the improvements that result during the filling of polybenzoxazines matrices with ceramic fillers.

Chapter 26 – Chitin- and Shell-Based Benzoxazines

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.

In situ (α-Al2O3+ZrB2)/Al composites with network distribution fabricated by reaction hot pressing

In situ (α-Al2O3+ZrB2)/Al composites with network distribution were fabricated using low-energy ball milling and reaction hot pressing. Differential thermal analysis (DTA) was used to study the reaction mechanisms in the Al–ZrO2–B system. X-ray diffraction (XRD) and scanning electron microscopy (SEM) in conjunction with energy-dispersive X-ray spectroscopy (EDX) were used to investigate the composite phases, morphology, and microstructure of the composites. The effect of matrix network size on the microstructure and mechanical properties was investigated. The results show that the optimum sintering parameters to complete reactions in the Al–ZrO2–B system are 850°C and 60 min. In situ-synthesized α-Al2O3 and ZrB2 particles are dispersed uniformly around Al particles, forming a network microstructure; the diameters of the α-Al2O3 and ZrB2 particles are approximately 1–3 μm. When the size of Al powder increases from 60–110 μm to 150–300 μm, the overall surface contact between Al powders and reactants decreases, thereby increasing the local volume fraction of reinforcements from 12% to 21%. This increase of the local volume leads to a significant increase in microhardness of the in situ (α-Al2O3–ZrB2)/Al composites from Hv 163 to Hv 251.