Cyanate ester resins, recent developments

The search for advanced, high performance, high temperature resistant polym ers is on the rise in view of the growing demand for polymer matrix composi tes that are to meet stringent functional requirements for use in the rapid ly evolving high-tech area of aerospace. Cyanate esters (CEs) form a family of new generation thermosetting resins whose performance characteristics m ake them attractive competitors to many current commercial polymer material s for such applications. The chemistry and technology of CEs are relatively new and continue to evolve and enthuse researchers. The CEs are gifted wit h many attractive physical, electrical, thermal, and processing properties required of an ideal matrix resin. These properties are further tunable thr ough backbone structure and by blending with other polymer systems. The str ucture-property correlation is quite well established. Several new monomers have been reported while some are commercially available. The synthesis of new monomers has come to a stage of stagnation and the present attention i s on evolving new formulations and processing techniques. The blends with e poxy and bismaleimide have attracted a lot of research attention and achiev ed commercial success. While the latter is now known to form an IPN, the re action mechanism with epoxy is still intriguing. Extensive research in blen ding with conventional and high performance thermoplastics has led to the g eneration of key information on morphological features and toughening mecha nisms, to the extent that even simulation of morphology and property has no w become possible. Despite the fact that the resin and its technology are n early two decades old, the fundamental aspects related to curing, cure kine tics, reaction modeling, etc. still evince immense research interest and ne w hypotheses continue to emerge. The system enjoys unprecedented success fo r applications in microelectronics, aerospace, and related areas. CEs tends to be the resin of choice in advanced composites for aerospace and high-sp eed electronics. The objective of the present article is to analyze recent developments in the chemistry, technology, and applications of cyanate este rs. It mainly focuses on the advancements in research and development relat ed to fundamental and applied aspects of cyanate esters during the last few years. It also gives a brief account of the overall scenario of the develo pments in this area, prior to discussing recent trends in detail.