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Tytuł :
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Racemization Behavior of L,L-Lactide during Heating
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Index Terms :
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Poly(L-lactic acid)
L,L-lactide
Chemical recycling
Racemization
Ester–semiacetal tautomerization
Journal Article
Journal Article
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Wydawca :
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Elsevier 2018-05-15
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Dodane szczegóły :
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Molecular Engineering Institute, Kinki University 11-6 Kayanomori, Iizuka, Fukuoka 820-8555 Japan, Kyushu Institute of Technology 2-4 Hibikino, Wakamatsu-ku, Kitakyushu-shi, Fukuoka, 808-0196, Japan
Kyushu Institute of Technology 2-4 Hibikino, Wakamatsu-ku, Kitakyushu-shi, Fukuoka, 808-0196, Japan
Kyushu Institute of Technology 2-4 Hibikino, Wakamatsu-ku, Kitakyushu-shi, Fukuoka, 808-0196, Japan
Molecular Engineering Institute, Kinki University 11-6 Kayanomori, Iizuka, Fukuoka 820-8555 Japan
Molecular Engineering Institute, Kinki University 11-6 Kayanomori, Iizuka, Fukuoka 820-8555 Japan
Tsukegi, Takayuki
Motoyama, Toru
Shirai, Yoshihito
Nishida, Haruo
Endo, Takeshi
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Typ dokumentu :
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Zasób elektroniczny
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URL :
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http://jairo.nii.ac.jp/0054/00006036">http://jairo.nii.ac.jp/0054/00006036
info:doi/10.1016/j.polymdegradstab.2007.01.009
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Dostępność :
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Open access content. Open access content
Elsevier Ltd.
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Pozostałe numery :
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JPNII oai:irdb.nii.ac.jp:0054/00006036
https://kyutech.repo.nii.ac.jp/?action=repository_action_common_download&item_id=5551&item_no=1&attribute_id=17&file_no=1
0141-3910
Polymer Degradation and Stability
92
4
552
559
2007-01-14
1060414168
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Źródło wspomagające :
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NATIONAL INST OF INFO
From OAIster®, provided by the OCLC Cooperative.
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Numer akcesji :
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edsoai.on1060414168
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Zasób elektroniczny
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.