@article{oai:kyutech.repo.nii.ac.jp:00005551,
 author = {Tsukegi,  Takayuki and Motoyama,  Toru and Shirai, Yoshihito and 白井, 義人 and Nishida, Haruo and 西田, 治男 and Endo, Takeshi and 遠藤, 剛},
 issue = {4},
 journal = {Polymer Degradation and Stability},
 month = {Jan},
 note = {To control the depolymerization process of poly (L-lactic acid) into L,L-lactide for feedstock recycling, the racemization of L,L-lactide as a post-depolymerization reaction was investigated. In the absence of a catalyst, the conversion to meso-lactide increased with increase in the heating temperature and time at a higher rate than the conversion into oligomers. The resulting high composition of meso-lactide suggests that the direct racemization of L,L-lactide had occurred in addition to the known racemization mechanism that occurs on the oligomer chains. In the presence of MgO, the oligomerization rapidly proceeded to reach an equilibrium state between monomers and oligomers. The equilibrium among L,L-, meso-, and D,D-lactides was found to be a convergent composition ratio: L,L-:meso-:D,D-lactides = 1:1.22:0.99 (wt/wt/wt) after 120 min at 300 °C. This composition ratio also indicates that, in addition to the known racemization reaction on the oligomer chains, direct racemization among the lactides is also a frequent occurrence.},
 pages = {552--559},
 title = {Racemization Behavior of L,L-Lactide during Heating},
 volume = {92},
 year = {2007},
 yomi = {シライ, ヨシヒト and ニシダ, ハルオ and エンドウ, タケシ}
}