Blends And Short Glass Fiber Reinforced Composites Of Poly(arylether)s Containing Phthalazinone Moieties

Glass fiber reinforced high performance thermoplastic composites were well-known for their outstanding comprehensive properties such as excellent heat-resistance, light-weight, high specific strength, low cost to preserve, easy for general design, good resistance against for chemic corrosion. These attracting properties make them good candidates for wide-spread applications in aerospace, airplane, automobile, mechanism, electronics, and also an essential and important research topic for development of high performance materials. As a major field of advanced composites, the research and development of glass fiber reinforced high temperature thermoplastic composites appear to be a very interesting topic of research. The syntheses of phthalazinone-based poly(arylene ether)s were disclosed with high thermal stabilities and acceptable mechanical properties as well as reasonable solubility. Therefore, the phthalazinone-based poly(arylene ether)s are supposed to be novel candidates as matrix resins for high-performance composites. However, the melt process of phthalazinone-based poly(arylene ether)s frequently suffer many handle problems, such as high melt viscosity, hard to extrusion and injection. Here this paper, therefore, demonstrates the blends of the poly(phthalazinone ether sulfone)s by introduction of PEEK to improve the melt processabilities. On this basis, high performance thermoplastic composites were developed by using inexpensive glass fiber(SH4 and HP3786) as reinforced materials. The influence of melt processing flow properties, phase structure, fiber content, interface interaction and production procedure on the composite performance was investigated.Phthalazinone-based poly(arylene ether sulfone ketone)s (PPESK) and PEEK blends were prepared by melt coextrusion using twin screw extruder. The compatibility and thermal stability were investigated by DSC, SEM and TGA measurements. The primary results indicated a co-continuous two phase system did exist for the blends with a wide range of compositions, and phase inversion were exhibited when PEEK increased to some extent. Base on studies on current for extrusion and exit pressure, the final melt viscosity of the blends was decreased due to the introduction of PEEK. Short glass fiber reinforced PPESK/PEEK(7:3, w/w) composites were prepared by using melt blending, and the interface, mechanical properties and average length of glass fiber in matrix were also investigated by applying SEM and ignition measurements. The obtained results indicated PPESK was the major component of interface layer, the average length of short glass fiber was 100μm under normal distribution. The addition of certain glass fiber was found to be effective in promoting the mechanical properties of the blends including tensile strength, flexural strength and impact strength. For example, the tensile strength of SH4 glass fiber (30wt%) reinforced PPESK/PEEK composite at 150℃was 89MPa, which was increased by 24%relative to that of short glass fiber (30wt%) reinforced PEEK composite.PPBES/PEEK blends were readily prepared by melt extrusion. By using DSC and SEM measurements, their phase structure and morphology were investigated. The DSC results indicated two Tg did exist for the blends with a wide range of compositions, and between Tg of PPBES and PEEK. Results indicated PPBES/PEEK blends were partially compatible. A co-continuous two phase system was found for each blend.5%weight loss temperature of PPBES/PEEK was 508℃. Preliminary results from extrusion current and exit pressure studies indicated the final melt viscosity of the blends was decreased due to the introduction of PEEK. On this basis, glass fiber reinforced PPBES/PEEK(7:3,w/w) composites were prepared by using melt blending, the influence of fiber content, fiber length and interface interaction on the tensile strength, flexural strength and impact strength of composite were investigated. A preliminary investigation demonstrated that mechanical property of composite was increased due to the introduction of glass fiber. The tensile strength, flexural strength and impact strength of glass fiber reinforced PPBES/PEEK composites were effectively improved with the increase of glass fiber content. For example, the tensile strength of HP3786 glass fiber (30wt%) reinforced PPBES/PEEK composite at 150℃was 98MPa, which was increased by 36% relative to that of glass fiber (30wt%) reinforced PEEK composite. the residual ratio of tensile strengh was 66% at 150℃.In this article, a new class of biphenyl-containing PPESK, namely PPBESK, was matrix, and then their composites with glass fibers were obtained by melt coextrusion. Firstly, the processing flow properties and thermal stability of PPBESK matrix were investigated, current for extrusion and exit pressure were decreased relative to that of PPBES/PEEK and PPESK/PEEK, the processing temperature was decreased from 340℃to 330℃. The results indicated a good processing flow propertie for PPBESK.5% weight loss temperature of PPBESK was 502℃. Secondly, the influence of average weight molecular weight on mechanical properties of glass fiber reinforced PPBESK composite was investigated. The results indicated perfect mechanical properties were found at the average-weight molecular weight 44000 of PPBESK. Finally, glass fiber reinforced composites were prepared by using PPBESK (Mw for 44000), The influence of fiber content, fiber average length on mechanical properties was investigated. A investigation demonstrated that mechanical properties of composites were effectively improved with the increase of glass fiber content. For example, the tensile strength of HP3786 glass fiber (30wt%) reinforced PPBESK composite at 150℃was 105MPa, which was increased by 46% relative to that of glass fiber (30wt%) reinforced PEEK composite, the residual ratio of tensile strengh was 66% at 150℃. The SEM Photographs of tensile fracture specimens indicated a perfect interfacial adhesive strength between glass fiber and the PPBESK matrix. The average length of glass fibers in HP3786/PPBESK composites were also investigated by ignition measurements, the results indicated the average length of glass fiber in composite was 126μm.