Study of polyarylene ether nitrile terminated with phthalonitrile/hybrid Fe3O4nanospheres composites by orthogonal experiments

Novel phthalonitrile-based composites with excellent processing, thermal, and mechanical properties

Phthalonitrile resins exhibit excellent thermostability and mechanical strength after curing. However, poor processability made them difficult to fabricate fiber-reinforced composites with desirable integrated performance. In this article, a novel mixed phthalonitrile resin was developed to be used as the matrix for glass fiber–reinforced laminates. Poly (aryl ether nitrile phthalazinone) oligomer end-capped by phthalonitrile units (PPEN-PN) was firstly designed and blended with bisphenol-based phthalonitrile monomers (BP-PN) (Figure 1), which were obtained according to the literature procedure. A novel mixed curing agent (zinc chloride and 4,4-diamine-diphenylsulfone) was also exploited to accelerate curing rate of the resins. Solubility tests, differential scanning calorimetry and rheological studies revealed that the mixed resins exhibited good processability with low processing viscosity. Thermal gravimetric analysis indicated that the cured resins were stable below 530 to approximately 570 °C in nitrogen atmosphere after low-cost curing procedure. In air, char yields of the resins were between 30 to approximately 40% when heated to 800 °C. The laminates reinforced by E-glass fiber cloth possessed a bending strength of 668 MPa with interlaminar shear strength of 84.6 MPa at room temperature. 50% of the strength and modulus was maintained when heated to 400 °C. Consequently, this type of laminates may be potential candidates for aerospace applications.

MWCNT-reinforced polyarylene ether nitrile nanocomposites

In this study, we investigated the effect of surface roughness of acidulated multi-walled carbon nanotube (MWCNT) on the physical performances of MWCNT/polyarylene ether nitrile (MWCNT/PEN) nanocomposites. Acidulated MWCNTs with different surface roughnesses were prepared by ultrasonicating and refluxing of MWCNTs in the mixture solvent of sulfuric acid/nitric acid and characterized by atomic force microscopy. With longer acidulating time, more and more oxygen functional groups including carboxyl and hydroxyl groups which result in the coarser surface of the obtained MWCNT, were generated. MWCNT/PEN composites were fabricated by using the solution-casting method with the acidulated MWCNTs and PEN. SEM observation showed that the acidulated MWCNTs are well-embedded in the polymer matrix without aggregation. differential scanning calorimetry and thermogravimetric analysis results showed that the incorporation of acidulated MWCNTs can improve the thermal behavior of the resulted polymer composites. The coarser the surface of the acidulated MWCNT, the better the mechanical performances of the obtained composites, while opposite results were observed for the dielectric properties of the nanocomposites. The dynamical rheological results showed that a better compatibility between the MWCNT and PEN is achieved when the coarser MWCNT is used.