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

Abstract

Blended resins were prepared from the resorcinol-based PEEK-like oligomeric phthalonitrile resin (RES) and tetrakis(phenylethynyl)benzene (TPEB), a high char yield arylacetylene resin. Initial probing of curing properties using differential scanning calorimetry, indicated that TPEB and RES co-cure when heated. Characterization of thermal properties using thermogravimetric analysis indicated that a 1:1 TPEB-RES blend (by weight) exhibited a char yield of 80% which was 6% larger compared to pure RES (74%). According to FTIR characterization, the enhanced thermal properties of TPEB-RES were the result of increased crosslinking density. Rheological studies of TPEB, RES, and TPEB-RES blends indicated that blended systems exhibit similar processing characteristics as RES resin. For example, resins display ideal viscosities and relatively large processing windows when cured at 175 C. Alternatively, pure TPEB resin exhibits low viscosities when melted, which are not suitable for preparing composite materials. This study indicates that preparing TPEB-RES blends is an effect strategy for improving thermal performance of potential RES composites while still maintaining the required processability for fabrication of dense polymer composites.Additional supporting information may be found in the online version of this article.

Influence of molecular weight on thermal and mechanical properties of bisphenol A‐based phthalonitrile resins

“…Smaller samples were then cut from the n = 25 square monolith for testing. The samples were then removed from their respective molds and post‐cured in a tube furnace by slowly heating to 380°C using a previously described procedure 16 …”

Chemical structure and curing dynamics of bisphenol S, PEEKTM‐like, and resveratrol phthalonitrile thermoset resins

“…To that end, as they are subjected to rising temperatures, the polymers soften, melt (undergo a T g ), gel, and, eventually, rapidly cross-link and form stable thermosets. 25 Prior measurement efforts had identified the 75-150 C temperature range during which T g and softening occur, 26 and these materials typically cure at 175-250 C. 27 The specific values for each polymer vary and depend on: (1) the specific chemistry (its functional groups) of each PN; (2) the molecular weight of each given material (which may differ between different batches and strongly depends on the manufacturing techniques); (3) chemical purity of the resin; (4) environmental conditions of the curing process, including gas flow and any applied pressure. Furthermore, the processes of softening, melting, gelation, and curing are highly dynamic.…”

Preparation of hybrid cyanate ester resin in the presence of polysilazane and its properties

“…Bisphenol-A dicyanate ester is an important high-performance thermosetting polymer with excellent dimensional stability, high heat resistance, low dielectric constant, strong adhesion and good mechanical properties. 1 –7 It is usually used as a resin matrix for advanced composites, adhesives and coatings used in the electronics, aerospace and military industries. 8 –10 To meet the process requirements of these practical applications, it is necessary for bisphenol-A dicyanate ester to have good processability, including film-forming properties, melting fluidity and a wide processing window.…”