The evolution of nanopores in allylated calixarene resin during thermal cure

Abstract

In this paper one kind of new thermosetting resin, allyl etherified calixarene (allylated calixarene), was prepared and investigated. Claisen rearrangement reaction could not occurred due to the existence of para-positioned substituent in allylated calixarenes, and thermal cure proceeded at comparably low curing temperature (210–230 °C, lower than the curing temperature of allylated Bisphenol-A and allylated phenol-formaldehyde prepolymer at 330 °C). Allylated p-methylcalixarene cannot remain its nanopore conformation (i.e., cone conformation) even before its thermal cure. Allylated p-tert-butylcalixarene can keep its cone conformation at room temperature and low curing temperature (e.g., <130 °C), however its nanopores will be destroyed upon heating at high temperature (the gradually level-off and quietly weak diffraction peak in the Small Angle X-ray Diffraction profile). Allylated p-phenylcalixarene can preserve its nanopore conformation at room temperature and high curing temperature (e.g., 200 °C). The results indicated that the larger para-substituent will hinder the inversion of phenolic ring, and the higher curing temperature will promote the rotation of phenolic ring.