Morphology and thermal behavior of dicyanate ester-polyetherimide semi-IPNS cured at different conditions

Abstract

A high-temperature thermosetting bisphenol-A dicyanate, BADCy was modified with polyetherimide, PEI, at various compositions. Phase separation and rheokinetics through curing were studied by optical microscopy, dynamic and isothermal differential scanning calorimetry, and rheological measurements. The PEI phase separated at the early stages of curing, well before gelation, and did not affect the polycyclotrimerization kinetics. The phase structure and thermal properties of the final network were investigated as a function of the PEI content and cure temperature. For this purpose, dynamic mechanical analysis, scanning electron microscopy studies, and thermogravimetrical analysis were carried out. The morphological changes were interpreted in terms of a spinodal decomposition mechanism in the composition range studied.

Cyanate Esters

“…Cyanate ester resins are very often used in combination with numerous other high-performance polymers [66,67,68,69], the most important being duroplastic systems such as epoxy [3,4,21,69,70À78] or bismaleimide resins [6À8,79À81,81a], or rubber [82] of various thermoplastics [82] for improved toughness.…”

Evaluation of fiber surface treatment and toughening of thermoset matrix on the interfacial behaviour of carbon fiber-reinforced cyanate matrix composites

“…The catalyst system used was a mixture of 360 ppm of copper (II) acetylacetonate, Cu(AcAc) 2 , with a 2% of nonylphenol, NP, both from Aldrich [18]. For toughening of DCBA matrix a polyether imide, PEI, Ultem 1000, from General Electric, with the following properties: M n ¼ 12; 000 and M w ¼ 30; 000, q 25°C = 1.27 g/cm 3 , and T g = 220°C was used.…”

“…Nevertheless, although cyanate ester resins are known to be relatively tough compared with other thermosetting matrices, some applications require improved fracture resistance [4]. Thus, several attempts have been made to improve the toughness of cyanate ester by adding elastomers or thermoplastics [5][6][7][8][9][10][11][12]. Traditionally, the most successful method has been the addition of a suitable elastomer to the uncured resin [2,[5][6][7][8].…”

“…Traditionally, the most successful method has been the addition of a suitable elastomer to the uncured resin [2,[5][6][7][8]. However, in the last years, the modification with high-performance thermoplastics has been more investigated because of the advantage, as compared to rubber modification, that there is no reduction in thermal and mechanical properties of the cyanate matrix [5][6][7][9][10][11][12]. The properties of these types of materials are closely related to the generated morphologies, which are controlled by the thermoplastic content and the curing conditions [6][7][8][9][10][11][12].…”

The Effect of Particle Matrix Adhesion on the Mechanical Properties of Silica Filled Cyanate Ester Composites

“…This requires the use of additives such as inorganic fillers 2–5. Whilst there has been considerable interest in the toughening of cyanate esters,6–13 little has been done to evaluate the properties of moderately/highly filled cyanate ester composites 14…”