Synthesis of a phosphinated tetracyanate ester and its miscible blend with 4,4′-oxydianiline/phenol-based benzoxazine

Abstract

A phosphinated tetracyanate ester (4) was prepared by a three-step procedure, including nucleophilic addition of DOPO on 5,5 0 -methylenebis(2-hydroxybenzaldehyde), electrophilic substitution of phenol, and nucleophilic substitution with cyanobromide. Tetracyanate ester (4) was applied to copolymerize with a 4,4 0 -oxydianiline/phenol-based benzoxazine (P-oda) to enhance the properties of P-oda thermoset. We discussed the miscibility, microstructure, as well as the thermal and dielectric properties of the reactive blends of (4) with a P-oda. A miscible blend can be achieved in all compositions, as judged by thermal analysis. The co-reactions between (4) and P-oda, as observed in the IR analysis, explain the single-T g phenomenon. The experimental data show that the thermal, dielectric and flame retardant properties of polybenzoxazine are enhanced through the reactive blends.

Function of chitosan in aDOPO‐based flame retardant modified epoxy resin

“…PDE‐CS composites had a low phosphorous content, only 0.48 wt%, beneficial for the environment‐protection considerations 8–11,14,15 . In addition, EP/9% PDE‐CS not only kept a certain level of transparency, but also owned an ability to filter the ultraviolet, which can protect it from the damage of ultraviolet radiation.…”

“…During the synthesis process, ethanol acted as both a green solvent and a reactant, while protocatechualdehyde is plant extract, derived from the root of Salvia 12 . The reaction between DOPO and protocatechualdehyde was carried out in ethanol solution, which was more environmentally friendly than the similar reactions reported to be performed in toxic solvents such as toluene or tetrahydrofuran 13–16 …”

Halogen-free flame-retardant rigid polyurethane foam with a nitrogen–phosphorus flame retardant

“…To compare the effectiveness of flame retardants in polymer composites, the reduction in PHRR is the most important parameter obtained from cone calorimeter, which can give a general indication on the size of the fire and how fast it grows. 12,13,[35][36][37] The results of cone calorimeter of the flame-retardant composites at an incident heat flux of 50 kW m 22 is shown in Figure 8 and corresponding data are presented in Tables 5 and 6.…”

Multistructural Network Design Enables Polybenzoxazine to Achieve Low-Loss-Grade Super-High-Frequency Dielectric Properties and High Glass Transition Temperatures

“…Owing to good mechanical strength, thermal stability, flame retardance, adhesion and dielectric properties, chemical and water resistance, and near-zero shrinkage during polymerization, polybenzoxazines (PBZs) have been industrialized in the field of CCLs. − However, k (about 3.5) and f (about 0.02) values of most commercial PBZs are still high, which are not suitable for super-high-frequency circuit applications. , Generally, for dielectric performance enhancement of PBZs, there are four main ways to lower k and/or f values of PBZs. The preparations of less polar fluorinated monomers, − cured resins with bulky and low polar groups, − inorganic–organic composites, − and binary, ternary, and tetra copolymer systems − have been reported. However, until now high-performance PBZs with both super-high-frequency low dielectric properties ( k < 3, f ≤ 0.008) and high T g (about 240 °C) have rarely been reported.…”