TY - JOUR
T1 - Crystallizability of substituted poly(lactic acid)s
T2 - Effects of alkyl side-chain structure
AU - Marubayashi, Hironori
AU - Mizukami, Ryo
AU - Hamada, Yuji
AU - Nojima, Shuichi
N1 - Funding Information:
This work was financially supported by the ”Planting Seeds for Research” program from Tokyo Institute of Technology (H.M., 2014–2015), Mizuho Foundation for the Promotion of Sciences (H.M., 2015–2017), and JSPS KAKENHI Grant-in-Aid for Young Scientists (B) 17K12836 (H.M., 2017–2019). We thank Prof. T. Takata and Dr. H. Sogawa (Tokyo Institute of Technology, Japan) for letting us use polarimeter and thermogravimetric analyzer.
Publisher Copyright:
© 2018 Elsevier Ltd
PY - 2018/7
Y1 - 2018/7
N2 - The side-chain-substituted poly(lactic acid)s (SPLAs) having C3–C4 alkyl side chains (Pr, iPr, n-Bu, iBu, and s-Bu for propyl, isopropyl, n-butyl, isobutyl, and sec-butyl groups, respectively) were synthesized from L-amino acids, and their crystallizability was systematically investigated (unknown for Pr, n-Bu, and s-Bu but already known for iPr and iBu). s-Bu was found to be a crystalline polymer like iPr, whereas Pr and n-Bu had no or very little crystallizability like iBu. The crystal structure, melting behavior, and crystallization rate of s-Bu were examined in detail. The crystal structure and crystallinity (ca. 60%) of s-Bu were not affected at all by the crystallization temperature and casting solvent. The melting temperature and spherulite growth rate of s-Bu were compared with those of iPr and referenced data of SPLA with methyl side chains (Me) [i.e., poly(L-lactic acid)] and that with ethyl side chains (Et) [i.e., poly(L-2-hydroxybutanoic acid)]. The magnitude relation among melting temperatures of SPLAs would be iPr > s-Bu > Me > Et, and that among spherulite growth rates iPr > Me ≈ s-Bu > Et.
AB - The side-chain-substituted poly(lactic acid)s (SPLAs) having C3–C4 alkyl side chains (Pr, iPr, n-Bu, iBu, and s-Bu for propyl, isopropyl, n-butyl, isobutyl, and sec-butyl groups, respectively) were synthesized from L-amino acids, and their crystallizability was systematically investigated (unknown for Pr, n-Bu, and s-Bu but already known for iPr and iBu). s-Bu was found to be a crystalline polymer like iPr, whereas Pr and n-Bu had no or very little crystallizability like iBu. The crystal structure, melting behavior, and crystallization rate of s-Bu were examined in detail. The crystal structure and crystallinity (ca. 60%) of s-Bu were not affected at all by the crystallization temperature and casting solvent. The melting temperature and spherulite growth rate of s-Bu were compared with those of iPr and referenced data of SPLA with methyl side chains (Me) [i.e., poly(L-lactic acid)] and that with ethyl side chains (Et) [i.e., poly(L-2-hydroxybutanoic acid)]. The magnitude relation among melting temperatures of SPLAs would be iPr > s-Bu > Me > Et, and that among spherulite growth rates iPr > Me ≈ s-Bu > Et.
KW - Crystal structure
KW - Crystallinity
KW - Crystallizability
KW - Crystallization
KW - Crystallization rate
KW - Melting temperature
KW - Sec-butyl group
KW - Side chain
KW - Substituent effect
KW - Substituted poly(lactic acid)
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U2 - 10.1016/j.polymdegradstab.2018.04.033
DO - 10.1016/j.polymdegradstab.2018.04.033
M3 - Article
AN - SCOPUS:85047262874
SN - 0141-3910
VL - 153
SP - 318
EP - 324
JO - Polymer Degradation and Stability
JF - Polymer Degradation and Stability
ER -