Yajie Lei

Effect of polyarylene ether nitrile on the curing behaviors and properties of bisphthalonitrile

Abstract The 2,2-bis[4-(3,4)-dicyanophenoxy phenyl]propane (BAPh)/polyarylene ether nitrile (PEN-OH) prepolymers and polymers were prepared by heat polymerization. Firstly, BAPh/PEN-OH systems were characterized using differential scanning calorimetry, dynamic rheological analysis, and thermal gravimetric analysis. The results revealed that the polymerization reaction can be controlled by various concentrations of PEN-OH and postcuring temperatures, and BAPh/PEN-OH prepolymers had low curing temperatures (229.3–300.4°C), large processing windows (∼106.5°C) with low melt viscosities, and excellent thermal stabilities. Then, the polymerization reaction and surface structures of BAPh/PEN-OH systems were investigated using Fourier transform infrared and scanning electron microscopy, respectively. The interpenetrating polymer networks were found in BAPh/PEN-OH polymers, suggesting that the addition of PEN-OH can not only promote the curing behaviors of BAPh but also increase the toughness of the polymers. The flexure strength and modulus of BAPh/PEN-OH polymers increased with the introduction of PEN-OH. The dielectric properties of BAPh/PEN-OH polymers were investigated, which had little dependence on the frequency. BAPh/PEN-OH systems can be used as a good candidate for high-performance polymeric materials.

Preparation and thermal properties of flame retardant phthalonitrile/epoxy blends

Abstract The blends were successfully prepared by the copolymerization of 2,2-bis [4-(3, 4-dicyanophenoxy) phenyl] propane (BAPh) and epoxy resins E-44 (EP) in the presence of 4,4′-diaminodiphenyl sulfone (DDS) as curing additive. With the loading of BAPh in blends increasing from 10% to 50%, the excellent flame retardancy properties of the copolymers with the weight ratio of 20:80 of BAPh/EP achieved over 30 according to the limiting oxygen index test (LOI) values and V-0 grade of UL-94 measurement compared with the pure EP. The temperatures at weight loss 5% (T5%) of the pure EP were improved 16.4°C in nitrogen and 64.6°C in air when the ratio was 20:80. In addition, the gelation time was shortened to 3 min when the prepolymerization temperature was 190°C.