Synthesis And Thermal Properties Of Thermosetting Calixarene Resins Containing Nanopores

The purpose of this paper is to synthesize calixarene resins containing nanopores, which is of excellent quality and excellent heat resistance and is expected to be used in high performance aerospace materials and military materials.The synthesis conditions of calixarenes are comparatively harsh, and the higher synthesis temperature and longer synthesis time restrict its application. In order to solve the above problems, the following research is mainly carried out in this paper: (1) The influence of experimental conditions on the species of calixarenes is researched, which make us figure out the optimal condition; (2) P-tert-butylcalix[4]arene cyanate resin was synthesized and it was also modified by copolymerizing with epoxy, diallyl bisphenol A, polysilazane, 2,2-bis-(4-cyanatophenyl)propane, which decreases its curing temperature efficiently; (3) allylic p-tert-butylcalix[4]arene has been synthesized. However, the porosity of calix[4]arene has vanished after allylic p-tert-butylcalix[4]arene is cured. To save its porosity, the influence of parent calixarenes' para-orienting group and curing temperature on allylic p-tert-butylcalix[4]arenes'porosity have been studied respectively.In this research, we synthesize p-tert-butylcalixarene and 4- methyl-calixarene, and probe the influence of synthesis conditions on the species of calixarenes we synthesized by controlling the temperature and time of reaction. The result demonstrates that, with the increasing of temperature and time, the synthesized calixarenes transform from calix[8]arene to calix[6]arene and to calix[4]arene eventually. During the process, the annular cavity of calixarenes is becoming smaller and smaller. Moreover, as a result of steric effect, 4- methyl-calixarene having the smaller substituent can be synthesized easier than P-tert-butylcalixarene.P-tert-butylcalix[4,6,8]arenes and p-tert-butylcalix[4]arene cyanate resins were synthesized. Calixarene cyanate resins' curing properties were researched by DSC, which demonstrates its curing temperature is comparatively high and it is not able to melt as a whole,making it fail to meet the demands of high performance composite materials' liquid formation.In this work, p-tert-butylcalix[4]arene cyanate resins were modified by copolymerizing with bisphenol A, polysilazane, 2,2-Bis-(4-cyanatophenyl)propane, which decreases its curing temperature efficiently and makes it able to melt as a whole to meet the demand of being used as materials. In addition, Calixarene cyanate resins' superior heat resistance is maintained after being modified.Allylic p-tert-butylcalix[4]arene has been synthesized when hydrogen on the hydroxyl group is substituted for allyl. Its curing temperature is lower than p-tert-butylcalix[4]arene cyanate.However, the porosity of allylic p-tert-butylcalix[4]arene has vanished after it is cured. There are two methods to save its porosity: (1) The p-tert-butyl calixarene is reacted with 1,6-hexamethylene diisocyanate to synthesize isocyanated calixarene resin which can be cured at a lower temperature (80?). And the porosity of the resinized calixarene can be retained after cured at 80?; (2) The calixarene, which has a larger para-substituent, can be used as the parent calixarene (such as p-phenyl calixarene) to synthesize resinized calixarene. Due to the strong steric hindrance effect of the para-orienting group, it is difficult to flip the inside of the calixarene molecule, which makes the resinized calixarenes retain their inherent porosity after curing.