Morphology and molecular mobility of plasticized polylactic acid studied using solid‐state 13 C‐ and 1 H‐NMR spectroscopy

• Published in: Journal of applied polymer science 2016-06, Vol.133 (23)
• Main Authors: Koval'aková, Mária, Olčák, Dušan, Hronský, Viktor, Vrábel, Peter, Fričová, Oľga, Chodák, Ivan, Alexy, Pavel, Sučik, Gabriel
• Format: Article
• Language: English
• ISSN: 0021-8995; 1097-4628
• DOI: 10.1002/app.43517

MAS 13 C‐NMR measurements were used for the study of morphology and molecular mobility in amorphous quenched and triacetine‐plasticized PLA samples and PLA samples which underwent cold crystallization during annealing at 80 and 100 °C. The single pulse MAS 13 C‐NMR spectra indicate that plasticizer promotes cold crystallization which results in the decrease of the temperature of crystallization and formation of more perfect crystalline domains. The T 1 ( 13 C) spin‐lattice relaxation times show that the presence of plasticizer molecules leads to an increase of local mobility in PLA chains but plasticized PLA after annealing at 100 °C shows more rigid structure. The series of broad line 1 H‐NMR spectra performed at temperatures up to 100 °C provided information on the changes in relaxation processes and morphology of the studied samples. The interpretation of the results obtained using the techniques of NMR spectroscopy were supported by WAXD and DSC measurements. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133 , 43517.