Rare earth (Nd, Y, La) p-tert-butylcalix[n]arene (n = 4, 6, and 8) complexes alone have been developed to catalyze random and block copolymerizations of trimethylene carbonate (TMC) and 2,2-dimethyltrimethylene carbonate (DTC). The random or block structure and thermal behavior of the copolymers have been characterized by SEC, NMR, DSC, XRD and PLM. Random copolymer with M-W of 14, 100 and M-W/M-n of 1.36 was prepared by neodymium, p-tert-butylcalix[6]arene complex under the conditions: [TMC + DTC](0)/[Nd] = 400, 80 degrees C, 8 It. The reactivity ratios of TMC and DTC are measured to be r(TMC) = 4.68 and r(DTC) = 0.163, respectively. Random copolymerization could be well designed by the feeding ratio to prepare copolymers with controlled T-m and T-g. Only 8% TMC units in the polymer chain destroyed the crystallization of PDTC showing no Tm of the copolymer in the DSC analysis. (c) 2005 Elsevier Ltd. All rights reserved.