Improved Melt Processabilities of Thermosetting Polyimide Matrix Resins for High Temperature Carbon Fiber Composite Applications

Abstract

With the goal of improving processability of imide oligomers and achieving of high temperature carbon fiber composite, a series of Thermosetting Matrix Resin solutions (TMR) were prepared by polycondensation of aromatic diamine (3,4′-oxybisbenzenamine, 3,4-ODA) and diester of biphenylene diacid (BPDE) using monoester of 4-phenylethynylphthalic acid (PEPE) as end-capping agent in ethyl alcohol as solvent to afford phenylethynyl-endcapped poly(amic ester) resins with calculated molecular weight (Calc’d Mw) of 1500–10,000. Meanwhile, a series of reactive diluent solutions (RDm) with Calc’d Mw of 600–2100 were also prepared derived from aromatic diamine (4,4′-oxybisbenzenamine, 4,4-ODA), diester of asymmetrical biphenylene diacid (α-BPDE) and monoester of 4-phenylethynylphthalic acid (PEPE) in ethyl alcohol. Then, the TMR solution was mixed with the RDm solution at different weight ratios to afford a series of A-staged thermosetting blend resin (TMR/RDm) solutions for carbon fiber composites. Experimental results demonstrated that the thermosetting blend resins exhibited improved melt processability and excellent thermal stability. After being thermally treated at 200 °C/1 h, the B-staged TMR/RDm showed very low melt viscosities and wider processing window. The minimum melt viscosities of ≤50 Pa·s was measured at ≤368 °C and the temperature scale at melt viscosities of ≤100 Pa·s were detected at 310–390 °C, respectively. The thermally cured neat resins at 380 °C/2 h showed a great combination of mechanical and thermal properties, including tensile strength of 84.0 MPa, elongation at breakage of 4.1%, and glass transition temperature (Tg) of 423 °C, successively. The carbon fiber reinforced polyimide composite processed by autoclave technique exhibited excellent mechanical properties both at room temperature and 370 °C. This study paved the way for the development of high-temperature resistant carbon fiber resin composites for use in complicated aeronautical structures.

Consolidation of continuous-carbon-fiber-reinforced PAEK composites: a review

“…For many decades, thermoset based composites such as carbon fiber (CF)/polyimide, CF/phtanolonitrile or CF/bismaleimide were used in the aerospace sector due to their ease of processing (e.g. low viscosities and long pot-life [1,2]), high service temperatures [3][4][5] and excellent mechanical properties [2]. However, the sometimes-consequent curation times under energy-intensive process devices and limited shelf life [6] coupled with an increase in industrial demands are gradually making thermoset-based composites less competitive than high-performance thermoplastic ones.…”

Вязкоупругие Свойства Углепластиков На Основе Порошковых Полиимидных Связующих

“…Известной проблемой при создании ВКМ, в том числе углепластиков на основе полиимидных связующих, является преодоление объективно существующего противоречия между высокой теплостойкостью и трещиностойкостью. Большинство применяемых в настоящее время полиимидных полимерных матриц для ВКМ относится к реактивным связующим [2,3]. Обладая высокой термостойкостью, полиимиды на основе реактивных связующих относятся к хрупким материалам с невысокими значениями трещиностойкости (трещиностойкость G 1C не превышает 500 J/m 2 ).…”

Viscoelastic properties of carbon plastics based on powdered polyimide binders

“…One known problem in the design of FCMs (including carbon plastics based on polyimide binders) consists in overcoming a natural discrepancy between a high thermal resistance and crack resistance. The majority of presently used polyimide polymer matrices for FCMs belong to the class of reactive binders [2,3]. While polyimides based on reactive binders feature a fine thermal resistance, they are brittle materials with modest crack resistance values (their crack resistance G 1C does not exceed 500 J/m 2 ).…”