Clixarene, as a class of special cyclic hindered phenols, have displayed good performance in polymer stabilization towards light, heat, oxygen and radiation. In the present paper, two new calixarene derivatives----unsymmetrically hindered phenol-substituted calix[n] arene 4a(n=4) and were 4b(n=6) were synthesized with p-tert- butylphenol and aqueous formaldehyde as starting materials via cyclic condensation, de-tert-butylation, chloromethyllation, and nucleophilic substitution with 2-tert-bytyl-6-methylphenol. Their structures were established by IR, MS, UV, and ^1H NMR spectra oscopy, and elemental analysis 4a was assigned to be in the cone conformation. Introduction of unsymmetrical structure into the calixarene results in decrease in melting point to ca. 100℃. This is advantageous to the polymer processing and provides a new way to design calixarene stabilizers. Preliminary results of the antioxidant activities show that unsymmetrically hindered phenols-substituted calix[n]arenes exhibit a higher stoichiometric factor (4.8) compared to calixarene with symmetrical phenol stricture (4.2) and a much higher factor to small phenol compound such as 2-tert-bytyl-6-methylphenol(1.4) and 2, 6-di-tert-butyl-6-methyl phenol(2.0).

Key words: ASYMMETRY, CONES, CONFORMATION, HINDERED PHENOL, CALIXARENE, STRUCTURE CHARACTERISTICS