Phthalonitrile Blends: Simple Way to Improve Physical Properties by Increasing Crosslinking Density

Abstract

A method to improve the mechanical properties of phthalonitrile (PN) resins at lower postcure temperatures is achieved by blending a second‐generation oligomeric aromatic ether ketone‐based PN resin with 1,1,1‐tris‐[4‐(3,4‐dicyanophenoxy)phenyl]ethane in varying concentrations. Most of the mixtures exhibit a single softening temperature indicating that the two resins are miscibile in one another at the respective concentrations. After various blends are thermally cured to several postcure temperatures yielding crosslinked polymers, the polymers demonstrate superb mechanical properties and thermooxidative stability at lower overall postcure temperatures.

Investigation on curing reaction of phthalonitrile resin with nanosilica and the properties of their glass fiber‐reinforced composites

“…Then, a platform was observed at above 315°C and BA‐ph/CE/GF composites exhibited the lowest storage modulus. Results indicated that BA‐ph/CE matrix exhibited excellent thermomechanical properties and could maintain good mechanical properties under higher temperature after being cured at 200–210°C for 4 h 20,31,35 …”

“…As temperature increased, all the composite laminates maintained stable storage modulus before 220 C and gradually decreased between 220 and 315 C. Then, a platform was observed at above 315 C and BA-ph/CE/GF composites exhibited the lowest storage modulus. Results indicated that BA-ph/CE matrix exhibited excellent thermomechanical properties and could maintain good mechanical properties under higher temperature after being cured at 200-210 C for 4 h. 20,31,35 Glass transition temperature (T g ) can be defined as the temperature at the maximum peak of tan δ plots. As shown in Figure 4(b), a single loss peak of composites appeared as well as the T g for each composite laminates was 314.3, 314.1, 306.6, and 308.2 C, respectively.…”

“…Phthalonitrile resin was a kind of high performance thermosetting resin, due to the high stability of resulted triazine and phthalocyanine rings generated from ring‐formation polymerization of nitrile groups. These high stable units contributed to phthalonitrile resin with outstanding thermal stabilities, high T g , good flame retardancy and high mechanical properties, which could be applied as advanced structural materials 20–22 . However, pure phthalocyanine also showed high melting points and slow curing reactions without curing agents 23 .…”

“…These high stable units contributed to phthalonitrile resin with outstanding thermal stabilities, high T g , good flame retardancy and high mechanical properties, which could be applied as advanced structural materials. [20][21][22] However, pure phthalocyanine also showed high melting points and slow curing reactions without curing agents. 23 In order to improve the problems of pure phthalonitrile resin, phthalonitrile containing benzoxazine (BA-ph) was synthesized in our previous researches with low melting point, wide processing window and self-catalysis properties.…”

Oligomeric phthalonitriles and tetrakis(phenylethynyl)benzene blends with improved processing and thermal properties

“…Different types of blended PN resins have been explored including mixing PNs with thermoplastic polymers to improve thermal and mechanical properties. More commonly, PNs have been mixed with other thermosetting polymers including phenolic, epoxy, and other PN resins . For example, Xu et al recently combined allyl phenolic moieties with PN resins in order to broaden their processing window while also producing cured oligomeric resins with char yields of 74% at 1000 °C—thereby demonstrating the enhanced thermal stability compared to their base components.…”