Tactic heat resistant polymer was prepared by free radical polymerization of lactic acid-based monomers, i.e. chiral
2-isopropyl-5-methylene-1,3-dioxolan-4-ones (1). The polymerization of 1 proceeded smoothly without ring-opening
to give a polymer with high isotacticity (mm) of 29.7~100% and glass transition temperature (T<sub>g</sub>) of 172~213°C. 1 also showed high reactivity in the copolymerization with styrene and methyl methacrylate, and the incorporation of 1 unit in the copolymer structure increased T<sub>g</sub> of each polymer. In addition, hydrolysis of poly(1) produced a new type of water soluble poly(lactic acid), i.e. poly(α-hydroxy acrylate), and poly(α-hydroxy acrylate-co-divinyl benzene) hydrogel absorbed water as high as 1000 times of the original polymer weight.