Blending And Filling Modification Of Poly (Phthalazinone Ether Sulfone Ketone)

Poly(phthalazinone ether sulfone ketone)(PPESK), a novel high performance polymer developed by our research group, has much better thermal resistance and solubility than some well known commercial high performance polymers. These characteristics permit it to be used in many engineering applications. However, PPESK is very difficult to process in common methods, such as extruding and injecting, owing to its high melting viscosity. Moreover, pure PPESK resin shows high friction coefficient and wear rate. All those are limited its extensive application. Therefore, blending and filling modification of PPESK were adopted in order to improve its processability and wear resistance. In this paper, different kinds of modified PPESK were prepared by meltingly mixing method, and their structures and properties were studied systematically, which is attempted to make foundations in their industrialization and application.Bisphenol-A polysulfone (PSF) was used to modify the processability of PPESK and the blends with different compositions were prepared by meltingly extruding on a twin-screw extruder. Phase behaviors of the blends were investigated firstly by soluble parameter, interface tension, differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and FT-IR. The blends should show a better miscibility, evaluated by the low soluble parameter difference (Δδ= 0.25 (J/ml)^1/2), interface tension (0.86 mN·m^-1) and high adhesion strength (69.33 mN·m^-1). The further studies using of the differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and FT-IR indicated that PPESK/PSF blends are partially miscible over the studied composition range. The processability and rheology of the blends were studied by a capillary rheometer. The results showed that the melt processability of PPESK were improved obviously with the addition of PSF into PPESK. PPESK/PSF blends were non-Newton pseudoplastic fluid when PSF content was lower, and the viscosity of melt decrease clearly with the increasing of PSF content and the melt were inclined to Newtonian fluid. The blends were injected easily as the PSF additions were above 20 wt%. The results of thermogravimetric analysis exhibited that the heat resistance decreased slightly. The heat temperature and T_5% (temperature for 5% weight loss) of PPESK/PSF blends were 195℃and 481℃, and the T_5%of the blends declined about 10℃compared to PPESK. The mechanical strength of PPESK/PSF blends decreased a little as the contents of PSF were below 40 wt% (the tensile strength and flexural strength were 80 MPa and 117 MPa), however, declined clearly when the PSF compositions were above 40 wt%. Different composition PPESK/Poly(aryl ether nitrile) (PEN) blends were prepared by melt blending. The miseibility of PPESK/PEN forecasted by solubility parameter indicated that the blends should show a better miseibility because of similarity solubility parameter (Δδ= 0.34 (J/ml)^1/2). The results of DSC showed that PPESK/PEN were partially miscible, and the two T_g were drawn close to each other. Interface tension and high adhesion strength were about 0.12 mN·m^-1 and 67.93 mN·m^-1, which illustrated a better interface properties between PPESN and PEN. The results of processabilities and mechanical properties indicated that the blends showed a higher melt viscosity, and some defect were found in the sample with a lower addition of PEN (20 wt%). This reason resulted in the descending mechanical strength , and the tensile strength was about 72 MPa. As the addition of PEN reached 40 wt%, the technological conditions of PPESK/PEN were improved obviously and the blends maintained a higher mechanical strength. Furthermore, thermogravimetric analyses of PPESK/PEN blends were investigated. The results exhibited that PPESK/PEN blends have excellent high-temperature resistance and all the T_5% of the blends were above 484℃.The PPESK/PTFE composites were prepared in twin-screw extruder and injection moulding machine based on the modification of the PPESK melt processabilities. The mechanical properties and thermal stability properties of the composites were investigated. The results showed that the mechanical properties of the PPESK/PTFE composites decreased slightly as the content of PTFE were below 15 wt%. The thermal stabilities of the composites were similar to PPESK, and the heat deforming temperatures were about 185℃. The tribological results showed that the composites tribological properties could be remarkably improved because of the addition of PTFE, and as the PTFE content was 25 wt%, the friction coefficient and wear rate of the composites reduced to 0.14 and 1.80×10^-5 mm³(N·m)^-1. The SEM morphology of worn surface indicated that the wear mechanism of PPESK/PTFE mainly included the prior main particle abrasion wear and later main adhesive wear.PPESK/Graphite composites were manufactured by twin-screw extruder and injection moulding machine. The mechanical properties, thermal stability properties and tribological properties of the composites were investigated. The results showed that the mechanical properties of the PPESK/Graphite composites decreased slightly as the content of graphite was below 20 wt%, and the tensile strength were above 65 MPa. The thermal stabilities of the composites were not decreased with the increasing graphite content, but increased about 10℃compared to PPESK. The tribological properties of the composites could be remarkably improved with the increasing content of graphite. Friction coefficients decreased to 0.11 and the specific wear rate reduced to 1.25×10^-5 mm³(N·m)^-1 two orders of magnitude compared to PPESK. The SEM morphology of worn surface indicated that the wear mechanism of PPESK/Graphite mainly included the particle abrasion as the graphite low content and adhesive wear play a dominant role as the graphite content was relatively higher.