No abstract

Transmission electron microscopy (TEM) pictures show that the intramolecularly cross-linked macromlecules (ICMs) have two kinds of networks:  the “chemical network” and the “mechanical network”. The “chemical network” depends on the reactants and the feed ratio; the “mechanical network” is formed by the globules that are formed in the earlier stage of polymerization. The TEM pictures show that the morphologies of ICMs differ greatly from each other; the molecular size reaches hundreds of nanometers. It was found that the size of ICM with a high degree of cross-linking almost remains constant after the sample was dissolved, based on which we calculated the number-averaged molecular weight (M n) of sample 1568EA-0.25, M n = 2.91 × 108.

No abstract

In the presence of acetic anhydride, the catalyst containing protons makes the polymerization complex.1,2 Thus, whether the living center, during the polymerization process of THF, transfers to the acetic anhydride is a difficult problem to answer. In this article, CH3COSbCl6 is used as the catalyst to avoid the interference of the protons. It is found that acetic anhydride is an effective chain transfer agent, by the experiment at different temperatures for two systems in the presence or absence of acetic anhydride, and by the comparison of kinetic behavior. In the system without acetic anhydride at the temperature of 7, 15, and 22°C, the propagation rate constants of THF, kp are 7.90, 14.23, and 23.35 10−3L/Mol.S, respectively. In the presence of acetic anhydride, kp are 1.51, 2.85, and 4.98 10−3L/Mol.S; and ktr are 2.04, 3.59, and 6.49 10−4L/Mol.S, respectively. © 1994 John Wiley & Sons, Inc.