Thermal polymerization of DL‐α‐lipoic acid (LPA) in bulk without any initiator proceeded easily above the melting point of LPA. The molecular weight polymer determined by GPC was high. From the 1H NMR spectra of polymers, poly(LPA) obtained from polymerization of high purity LPA was to consist of cyclic structures, which was confirmed by ESI‐MS. Interlocked polymer consisting of poly(LPA) and dibenzo‐30‐crown‐10 entangled with each other was synthesized by the polymerization of LPA in the presence of dibenzo‐30‐crown‐10. From the DSC analysis of the polymers, glass transition temperature was estimated to be about −11 °C, but melting point was not observed, indicating that poly(LPA) is an amorphous polymer. By photodecomposition of poly(LPA), Mn was rapidly decreased at the early stage of the decomposition. After that, the Mn of the polymer kept and then was almost constant even for a prolonged reaction time. On the basis of the results, it would be presumed that poly (LPA) obtained form polymerization of high purity LPA includes an interlocked structure. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010

Typical Ziegler‐type catalysts derived from AIR3 and TiCl4 were found to be effective in the syndiotactic polymerization of methyl methacrylate at low temperatures. The influences of polymerization variables on the polymer yield, the molecular weight of the polymer produced, and the syndiotactic regulating capacity of the catalysts were investigated. In general AlEt3/TiCl4 molar ratios of 3:10 mixing of both the catalyst components and aging of the catalyst system in the temperature range of −30 to 30°C. using aromatic hydrocarbon solvents such as toluene as a polymerization medium, and low polymerization temperature, such as −78°C. are the preferred conditions for the formation of syndiotactic, high molecular weight poly(methyl methacrylate) in high yield. From the results of testing catalyst activities of the separated catalyst systems it was concluded that some cooperation between AIR3 and the insoluble Ti halide compound obtained by the reduction of TiCl4 with AIR3 is essential for the formation of syndiotactic poly(methyl methacrylate).

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