Study on aromatic nitrile-based resins containing both phthalonitrile and dicyanoimidazole groups

The development of lightweight composites with desirable thermo‐mechanical properties is progressively increasing. Phthalonitrile (PN) based composites have shown great potential in this regard. However, the basic thermal properties of PN composites required for engineering design are not yet fully understood. In this work, we investigated the thermal stability, thermal expansion behavior and thermal conductivity of PN composites reinforced with carbon fiber (CF) and high silicon fiberglass (HSF) via combined experimental studies and numerical simulations. The results indicated that CF/PN performs better in thermostability than HSF/PN at temperatures below 500°C. Moreover, the incorporation of CF and HSF lowered the coefficient of thermal expansion (CTE) and thermal insulation of PN. At room temperature, the in‐plane CTE of CF/PN and HSF/PN were 1.97E‐6 and 9.24E‐6°C−1, respectively, while the out‐plane thermal conductivities of CF/PN and HSF/PN were 0.65 and 0.34 W/(m K). It is worth noting that an excessively high fiber volume fraction would lead to poor thermal insulation and lightweight properties of the PN composites, while a low fiber volume fraction would result in poor stiffness and thermal dimensional stability. Determined via TOPSIS model, a fiber volume fraction range of 50%–60% was ideal for both composites with comprehensive optimal properties, respectively.

Section: Fea Simulationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Optimizing the thermal properties of fiber reinforced phthalonitrile composites

Feng,

Wang,

et al. 2023

“…36 Finally, absorptions observed at 1359 and 1524 cm À136 are characteristic of a triazine ring and the peak at 1724 cm À1 was attributed to an isoindoline ring. 37…”

Section: Synthesis and Structural Analysis Of Pekk-pn Resinsmentioning

confidence: 99%

Preparation and properties of bisphenol A polyetherketoneketone based phthalonitrile resins

Brown,

Richardson,

Lusk

et al. 2023

A promising high temperature phthalonitrile (PN) resin composed of a polyetherketoneketone (PEKK) core bridged by two bisphenol A linkers and end capped with PN groups is presented. This PEKK‐PN resin was characterized via differential scanning calorimetry, thermogravimetric analysis, proton nuclear magnetic resonance spectroscopy, scanning electron microscopy, dynamic mechanical analysis, attenuated total reflection Fourier transform infrared, and rheometry. The PEKK‐PN resin was evaluated with two different compositions containing 1) 70:30 PEKK‐PN to bisphenol A PN (n = 0) and 2) pure PEKK‐PN. The 70:30 PEKK‐PN resin was mixed with bis[4‐(3‐aminophenoxy)phenyl]sulfone and exhibited a melt viscosity of 271 cP, much lower than the 657 cP viscosity of the pure PEKK‐PN mixture. Void‐free PEKK‐PN polymers were easily prepared by degassing and curing up to 380°C, resulting in fully crosslinked networks exhibiting thermal stability above 500°C and a 75% char yield. Additionally, the cured PEKK‐PN polymer samples displayed good mechanical integrity retaining 50% stiffness at 300°C. This combination of properties suggests these new PEKK‐PN resins are excellent materials for high temperature thermosets in composite applications.

“…13,14 The introduction of flexible structures like aromatic ether, novolac segments, and siloxanes can decrease the melting temperatures of phthalonitrile resins. [15][16][17][18][19][20] The effect of crosslinking density on the properties of the resins has also aroused a lot of interest. Jiao et al 21 prepared novel polyimides containing chlorine atoms in which the interchain crosslinking produced by chlorine atom decomposition could occur.…”

Section: Introductionmentioning

confidence: 99%

“…For example, flexible phenyl ether structures were introduced into the backbone of thermosetting polyimides to improve the processability 13,14 . The introduction of flexible structures like aromatic ether, novolac segments, and siloxanes can decrease the melting temperatures of phthalonitrile resins 15–20 . The effect of crosslinking density on the properties of the resins has also aroused a lot of interest.…”

Section: Introductionmentioning

confidence: 99%

High‐performance poly(methylsilane arylether arylacetylene) resins with low curing temperatures and weak secondary relaxations

Li,

Gong,

et al. 2023

A series of poly(methylsilane arylether arylacetylene) (PSEA‐H) resins were synthesized from methyldichlorosilane and isomeric arylether arylacetylenes, and characterized by 1H‐NMR and FT‐IR spectroscopies. The effect of reactive Si‐H groups and the linking positions of benzene rings in the arylether arylacetylene units on the properties of the resins were investigated. The results show that PSEA‐H resins possess good processability with processing windows of over 80°C. The introduction of Si‐H groups reduces the curing temperatures for PSEA‐H resins and weakens the secondary relaxation for the cured PSEA‐H resins. The cured resins and T300 carbon fiber (T300CF) reinforced composites display high mechanical properties. The flexural strengths of a cured PSEA‐H resin and its T300CF composite at room temperature reach 64.2 and 426.5 MPa, respectively. The flexural properties depend on the linking positions of benzene rings. The cured PSEA‐H resins show excellent heat resistance with a temperature of 5% weight loss (Td5) above 500°C.