Preparation and Properties of Polybenzoxazinepoly(dimethylsiloxane-co-diphenylsiloxane) Hybrids as High Performance Polymers

Abstract

Polybenzoxazine, poly(B-a), was hybridized with polysiloxanes by synchronizing two reactions1 ring-opening polymerization of benzoxazine (B-a) and the sol-gel process of diethoxysilanes. As diethoxysilanes, mixtures of diethoxydimethylsilane and diethoxydiphenylsilane in various ratios were used to prepare polysiloxane copolymers, poly(dimethylsiloxane-co-diphenylsiloxane), P(DMS/DPS). The effect of diphenylsiloxane (DPS) content of polysiloxane copolymer on the optical, mechanical, and thermal properties of the hybrids was studied. The progress of the sol-gel process was confirmed by IR, 1 H-NMR and size exclusion chromatography. Opaque poly(B-a)-P(DMS/DPS) hybrid films were obtained at high dimethylsiloxane (DMS) content corresponding to the phase separation. The domain size of the polysiloxane was evaluated from the scanning electron microscope. Meanwhile, transparent hybrid films were obtained at high DPS content, corresponding to the homogeneous phase as observed from the scanning electron microscope. The hybrid films revealed higher tensile strength and elongation at break than pristine poly(B-a) as a function of DPS content. Dynamic viscoelastic analyses of the hybrids at high DMS content revealed two glass transition temperatures (T g ) corresponding to polysiloxane and poly(B-a) components, while one T g was observed at high DPS content. Thermogravimetric analysis of the hybrids revealed that the thermal stability of the poly(B-a)-polysiloxane hybrids was higher than pristine poly(B-a) depending on the DPS content.

Nanosized Silica-Reinforced Maleimido Terminal Triaryl Pyridine Core Polybenzoxazine (nSiO2/PBZ) Nanocomposites

“…The characteristic absorption band at around 1260 cm À1 corresponding to the stretching of -Si-C was shown, after thermal imidization. The absorption bands at 1387 cm À1 (symmetric C-N) and a peak at 1018 cm À1 confirms the incorporation of nSiO 2 in the benzoxazine matrix [6,7,29] .…”

“…Agag et al synthesized a polybenzoxazine-titania based hybrid, with improved thermal properties [6] . Recently, Ardhyananta have prepared polybenzoxazine poly (dimethylsiloxane-co-diphenyl siloxane) hybrids and polybenzoxazine-polydimethylsiloxane (PBa-PDMS) hybrids and studied their thermal properties [7] . Further nanofiller reinforcement with benzoxazine improved the properties to an appreciable extent [8,9] .…”

Silane‐functional benzoxazine: synthesis, polymerization kinetics and thermal stability

“…Several investigations on polybenzoxazines containing polysilsesquioxanes have been described by using, in most cases, the sol − gel technology as an effective and inexpensive method . The sol − gel process involves two different stages: hydrolysis and polycondensation reactions of the alkoxy groups that lead to the formation of the Si–O–Si network.…”

“…Thus, introducing the sulfone moiety into benzoxazine can enhance the rigidity, modulus and thermal stability of the corresponding cured resins . Another important way of enhancing the performance is to fabricate inorganic − organic hybrids of polybenzoxazine with polysiloxane, which could improve its flexibility, thermal stability (in terms of initial decomposition temperature and char/ceramic yields) and flame retardancy and increase its glass transition temperature . Moreover, the hydrogen bonds formed in the benzoxazine ring‐opening process favour the arrangements of organic fragments of the polysilsesquioxanes .…”

Preparation and properties of polymer alloys consisting of high-molecular-weight benzoxazine and bismaleimide

“…[36][37][38][39][40][41][42] Previously, we succeeded in synthesizing high-molecular-weight benzoxazines (HMWBs) having benzoxazine units in the main chain by the reaction of bisphenol A, diamines, and paraformaldehyde. 22,26 HMWBs were easily soluble in various common solvents and the thermally cured films were much more flexible and tough, had higher T g s, and higher thermal stability than PB-a.…”