@article{oai:kyutech.repo.nii.ac.jp:00005532,
 author = {Fan,  Yujiang and Nishida, Haruo and 西田, 治男 and Shirai, Yoshihito and 白井, 義人 and Endo, Takeshi and 遠藤, 剛},
 issue = {3},
 journal = {Polymer Degradation and Stability},
 month = {Mar},
 note = {Poly(L-lactide) with calcium salt end structure (PLLA-Ca) is a promising material for PLLA recycling because of the ease of lactide recovery through the unzipping depolymerization process. However, the pyrolysis of PLLA-Ca also causes meso-lactide to form. In this article, the racemization in PLLA-Ca pyrolysis was analyzed in detail with Py-MS, Py-GC/MS, and a glass tube oven. The results suggested that at a temperature lower than 250°C, nucleophilic attack by a carboxylate anion end on an asymmetrical methyne carbon in a penultimate lactate unit occurred, resulting in the predominant formation of meso-lactide. On the other hand, also at temperatures over 320°C, by-reactions, such as enolization reactions, caused the meso-lactide to form, but not dominantly. In the temperature range of 250-320°C, L,L-lactide was produced exclusively, because unzipping depolymerization proceeded as the main reaction. This is a very significant result for PLLA recycling, because PLLA-Ca is an easily recyclable material, which depolymerizes based on the 1st-order weight loss process.},
 pages = {503--511},
 title = {Racemization on Thermal Degradation of Poly(L-lactide) with Calcium Salt End Structure},
 volume = {80},
 year = {2003},
 yomi = {ニシダ, ハルオ and シライ, ヨシヒト and エンドウ, タケシ}
}