Next Article in Journal
Improved Aging Stability of Ethylene-Norbornene Composites Filled with Lawsone-Based Hybrid Pigment
Previous Article in Journal
Erratum: Electrostatic-Interaction-Driven Assembly of Binary Hybrids towards Fire-Safe Epoxy Resin Nanocomposites. Polymers 2019, 11, 229.
Previous Article in Special Issue
Rubber-Filler Interactions in Polyisoprene Filled with In Situ Generated Silica: A Solid State NMR Study
Open AccessArticle

NMR Analysis of Poly(Lactic Acid) via Statistical Models

Material Analysis Research Center, Teijin Ltd, Hino, Tokyo 191-8512, Japan
Department of Biotechnology, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588, Japan
Department of Applied Chemistry, Tokushima University, 2-1 Minamijosanjima, Tokushima 770-8506, Japan
Southern Regional Research Center, USDA Agricultural Research Service, 1100 Robert E. Lee Blvd., New Orleans, LA 70124, USA
Authors to whom correspondence should be addressed.
Polymers 2019, 11(4), 725;
Received: 20 March 2019 / Revised: 15 April 2019 / Accepted: 16 April 2019 / Published: 19 April 2019
(This article belongs to the Special Issue NMR in Polymer Science)
The physical properties of poly(lactic acid) (PLA) are influenced by its stereoregularity and stereosequence distribution, and its polymer stereochemistry can be effectively studied by NMR spectroscopy. In previously published NMR studies of PLA tacticity, the NMR data were fitted to pair-addition Bernoullian models. In this work, we prepared several PLA samples with a tin catalyst at different L,L-lactide and D,D-lactide ratios. Upon analysis of the tetrad intensities with the pair-addition Bernoullian model, we found substantial deviations between observed and calculated intensities due to the presence of transesterification and racemization during the polymerization processes. We formulated a two-state (pair-addition Bernoullian and single-addition Bernoullian) model, and it gave a better fit to the observed data. The use of the two-state model provides a quantitative measure of the extent of transesterification and racemization, and potentially yields useful information on the polymerization mechanism. View Full-Text
Keywords: Bernoullian; NMR; poly(lactic acid); statistical model; stereosequences; tacticity Bernoullian; NMR; poly(lactic acid); statistical model; stereosequences; tacticity
Show Figures

Figure 1

MDPI and ACS Style

Suganuma, K.; Asakura, T.; Oshimura, M.; Hirano, T.; Ute, K.; Cheng, H.N. NMR Analysis of Poly(Lactic Acid) via Statistical Models. Polymers 2019, 11, 725.

AMA Style

Suganuma K, Asakura T, Oshimura M, Hirano T, Ute K, Cheng HN. NMR Analysis of Poly(Lactic Acid) via Statistical Models. Polymers. 2019; 11(4):725.

Chicago/Turabian Style

Suganuma, Koto; Asakura, Tetsuo; Oshimura, Miyuki; Hirano, Tomohiro; Ute, Koichi; Cheng, H. N. 2019. "NMR Analysis of Poly(Lactic Acid) via Statistical Models" Polymers 11, no. 4: 725.

Find Other Styles
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

Search more from Scilit
Back to TopTop