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Phthalonitrile resin is a potential high-performance composite matrix, its brittleness and weak interaction with fiber are the main obstacles to its wide application. High-performance thermoplastic poly(phthalazinone ether nitrile)s (PPEN) and poly(phthalazinone ether nitrile ketone)s (PPENK) have been used to toughen basalt fiber (BF) reinforced 4,4′-bis(3,4-dicyanophenoxy)biphenyl (BPh) composite. The curing kinetics for the BPh/PPEN and BPh/PPENK blends have been investigated using DSC. The structures and thermal properties of the cured BPh blends have been studied in detail. The effects of PPEN and PPENK on the mechanical properties of the modified BF/BPh composite have been assessed. The non-notched impact strength of BF/BPh/PPENK laminate can be up to 107.7 kJ/m2, which is 64.2% higher than that of the BF/BPh laminate. And the interlaminar shear strength of BF/BPh/PPEN laminate can reach 42.5 MPa, 134.8% higher than that of the BF/BPh laminate. Simultaneously, the fracture surface of the laminate showed that the thermoplastic PPEN and PPENK can significantly inhibit the delamination between the layers and the fiber pullout and debonding. [Display omitted] • The mechanical properties of BF/BPh were significantly improved by the introduction of PPEN(K) with pendant cyano groups. • The properties of modified BF/BPh composites can be tuned by the pendant cyano content on thermoplastic resin. • The introducing of high-performance thermoplastic PPEN(K) remains the excellent thermal properties of BF/BPh composites. [ABSTRACT FROM AUTHOR]

Bismaleimide resin has poor toughness, limiting its wide application potential. High-performance thermoplastic amino-terminated poly(phthalazinone ether nitrile sulfone)s (PPENS-DA) with different cyano group content, have been prepared and used to toughen blends of 4,4′-bismaleimidodiphenyl-methane (BDM)/diallyl bisphenol A (DABPA). The rheological properties and curing kinetics for the PPENS-DA/BDM/DABPA blends have been investigated using rotational rheometry and DSC. The mechanical and thermal properties of the cured BMI blends have been studied in detail. The effects of level of loading and the cyano group content of PPENS-DA on the mechanical properties of cured blends have been assessed. The notched impact strength of PPENS-DA/BDM/DABPA blends can be up to 3.98 MPa, which is 65.15% higher than that of the pristine BDM/DABPA blend. Simultaneously, the thermal properties of blends have been improved with T g increasing from 237 °C to 265 °C. Furthermore, an isothermal rheological model was established, and the model curve was verified to be consistent with the experimental value. Image 1 • The amino-terminated poly(phthalazinone ether nitrile sulfone)s (PPENS-DA) was introduced into the BDM/DABPA blend system. • The impact toughness of BDM was significantly improved by the participating of PPENS-DA in the crosslinking reaction. • The introduction of high-performance thermoplastic PPENS-DA improved the glass transition temperature of BDM/DABPA blend. • The isothermal rheological model of PPENS-DA/BDM/DABPA blends was established. [ABSTRACT FROM AUTHOR]

Basalt fiber (BF) reinforced heat-resistant thermoplastic engineering plastic composites exhibit excellent toughness, strength, corrosion resistance, and high- and low-temperature resistance. However, the BF and resin exhibit poor interfacial compatibility resulting in low interfacial strength. Here, mono-, di- and tri-amino silane coupling agents (3-aminopropyltrimethoxysilane, SATMS; N -(2-aminoethyl)-3-aminopropyltrimethoxysilane, DATMS and (3-trimethoxysilylpropyl)-diethylenetriamine, TATMS) were used to treat BF, and composites were then prepared using the modified BF and high-performance thermoplastic poly(phthalazinone ether nitrile ketone) (PPENK). The chemical structures, surface morphologies, roughness and hydrophilicity of the modified BF surface were characterized. In addition, the flexural strength, tensile strength and interlaminar shear strength of BF-DATMS/PPENK composite increased to 1127 MPa, 633 MPa and 55 MPa, which are 18%, 30% and 25% higher than the desized-BF/PPENK, respectively. And the BF-DATMS/PPENK composite exhibited a glass transition temperature (T g) of 293 °C higher than those of PPENK (280 °C) and desized-BF/PPENK (285 °C). Results indicated that the interfacial adhesion between BF and PPENK were improved by the amino-silane modified BF, which in turn enhanced the mechanical properties of the corresponding BF/PPENK composites. [Display omitted] • Mono-, di-, and tri-aminosilane coupling agents (ASCAs) were used to modify BF. • ASCAs possess excellent potential for enhancing interfacial adhesion of BF/PPENK. • The BF/PPENK composites exhibit great mechanical and thermo-resistant properties. • Di-aminosilne is the best one to increase combination properties of BF/PPENK. [ABSTRACT FROM AUTHOR]

This paper used phthalazinone-based copoly(biphenyl ether nitrile) (co-PPEN) to improve the low-temperature toughness of epoxy resin E51. The effects of co-PPEN content on the normal/low-temperature mechanical properties, thermomechanical properties, and thermal stability of epoxy resins were studied. Results showed that co-PPEN significantly improved the normal/low-temperature mechanical properties of E51. At room temperature, the impact strength, flexural strength, and tensile strength of co-PPEN/E51 blends increased by 144.0%, 12.8%, and 28.1%, respectively; at low temperature, the impact strength, flexural strength, and tensile strength of co-PPEN/E51 blends increased by 87.9%, 43.6%, and 18.5%, respectively. From the cross-sectional analysis, the crack deflection and crack bridging of co-PPEN are the main toughening mechanisms of the blends. The blend system has high thermal property, and the glass transition temperature of the co-PPEN/E51 blend increased by about 50 °C. Simultaneously, all blends exhibited better thermal stability. [Display omitted] • High-performance thermoplastic co-PPEN engineering plastic toughened epoxy resin. • Modified co-PPEN/E51 composites have good low-temperature properties (−183 °C). • Modified co-PPEN/E51 composites have good thermal properties. [ABSTRACT FROM AUTHOR]