Polybenzoxazine

In recent years there have been comparatively few developments in phenolic resin technology apart from the so-called Friedel-Crafts polymers introduced in the 1960s and the polybenzoxazines announced in 1998 which are discussed briefly at the end of the chapter. 

The polybenzoxazines (PBZs) provide a new class of phenolic resins that were first described by Ishida in 1998 (Ref. 15). Synthesis of the resins involves three components a phenol, a primary amine and formaldehyde. The first stage involves the formation of a multifunctional benzoxazine monomer Figure 23.30 a)). The monomer can then be ring-opened at elevated temperatures (160-220 C) to yield a polymeric stmcture (Figure 23.30(b)). 

Figure 18.22. Differential mechanical analysis scans of polybenzoxazine. Reproduced from Ishida and Lee (2001), by permission of Elsevier, Ltd.

Ishida, H., and I.cc, Y.-H. (2001). Synergism observed in polybenzoxazine and poly(e-caprolactone) blends by dynamic mechanical and thermogravimetric analysis. Polymer 42(16), 6971-6979. 

Hydroxylamine glycoside linkage Walker 1994 Lecithin lipids Stouch 1991 Polybenzoxazine Kim 1998... 

These dimers are of interest because they serve as model compounds for a new class of phenolic materials, the polybenzoxazines, whose synthesis and characterization has been described by Ishida and coworkers.146-149 These polybenzoxazine resins were found to have a number of unusual, but commercially favorable, properties, in particular a near-zero shrinkage or volumetric expansion upon curing (polymerization) as well as low water absorption. In addition, the resins have high glass-transition temperatures even though they have been shown to have low crosslink densities. Explanations for these properties have been hypothesised in terms of favorable hydrogenbonding interactions.150... 

Ishida. H., and Low, H.. Polybenzoxazines Expanding phenolic resin with structural applications. ACS PMSE. Fall. 115 116 (1996). 

Ertas, Y., Uyar, T., 2014. Main-chain polybenzoxazine nanofibers via electrospinning. Polymer 55 (2), 556—564. Available from http //dx.doi.0rg/lO.lOl6/j. 

Erden, N. 2009. Polyurethane-polybenzoxazine based shape memory jxjlymers,... 

Zheng S, Lu H (2003) Miscibility and phase behavior in thermosetting blends of polybenzoxazine and poly(ethylene oxide). Polymer 44 4689-4698... 

The quantity of the hterature in the field of the nanocomposite polymeric materials has grown multiple times in recent years. The possibility to use almost all polymeric and polycondensated materials as a matrix is shown The nanocomposites from various organoclays and polymers have been synthesized. Here is just a small part of the compounds for being the matrix referenced in literature polyacrylate [83], polyamides [82,84,85], polybenzoxazine [86], polybutylene terephtalate [11,82,87], polyimides [88], polycarbonate [89], polymethylmetaciylate [90], polypropylene [91,92], poly-... 

Erden, N. and Jana, S.C. (2013) Synthesis and characterization of shape-memory polyurethane-polybenzoxazine compounds. Macromol. Chem. Phys., 214 (11), 1225-1237. 

Polybenzoxazine-Silica Hybrid Surface with Environmentally Responsive Wettability Behavior... 

Polybenzoxazine, sihca nanoparticle, superhydrophobic surface, hydrophilic... 

In our previous study [11], we discovered a new class of low surface free energy materials, polybenzoxazines, which can have surface free energies even lower than... 

Figure 1. Responsive wettability for polybenzoxazine-silica hybrid films, (a) Idealized representation of the transition between dry state and wet state, (b) Change of water drop profile when dried in vacuum oven (120°C, 3 h) and immersed in selective solvent (H20/EtOH 70°C for 1 h).

Figure 2. AFM images of different polymer surfaces, (a) Film prepared from pure BA-a polybenzox-azine. (b), (c) Polybenzoxazine-silica hybrid surface with 50 and 120 phr silica nanoparticle contents, respectively.

These silica nanoparticles generate surface roughness on the polybenzoxazine nanocomposite film, possessing both micro- and nanoscale binary structures. In addition, its appropriate chemical structure allows for reversible wettability operation. The as-prepared superhydrophobic surface is not wettable by pure water. Mohammad et al. [13] reported that aqueous solutions of various surfactants were able to wet a superhydrophobic surface since these surfactants reduced the siuface tension of the solutions. Soeno and co-workers [14] also reported wetting of their superhydrophobic surfaces with a water/ethanol mixture. In this study, ethanol was chosen to reduce the surface tension of the solvent and shift the superhydrophobic polymer film into wettable film through a relatively milder condition. 

Figure 4. Reversible wettability transition of polybenzoxazine-silica hybrid films with 50 phr (circle) and 120 phr (triangle) silica nanoparticle contents.

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