TY - JOUR
T1 - Molecular simulation and experimental studies of the miscibility of PLA/PLAx-PEGy-PLAx blends
AU - Takhulee, Adisak
AU - Takahashi, Yoshiaki
AU - Vao-soongnern, Visit
N1 - Funding Information:
This work is the second report following our previous publication on simulation of PLA/PEG system supported by experiments at selected conditions [17]. The organization of this paper is as follows: First, MD and DPD simulations are employed to predict the miscibility and morphology of PLAx-PEGy-PLAx systems. Then, preparation and characterization of PLAx-PEGy-PLAx block copolymer and PLA/ PLAx-PEGy-PLAx blends are reported. The characteristics of PLAx-PEGy-PLAx triblock copolymer were evaluated by NMR spectroscopy and gel permeation chromatography (GPC). Thermal and rheological properties of PLA/PEG and PLA/PLAx-PEGy-PLAx blends are then investigated to evaluate the miscibility of the blends.
Funding Information:
Acknowledgements The financial support for A.T. by the Commission on Higher Education, Ministry of Education (Thailand) for supporting the grant fund under the program Strategic Scholarships for Frontier Research Network for the Ph.D. Program is gratefully acknowledged. All molecular simulation works were done at Suranaree University of Technology (SUT), Thailand, and most of the experimental part was performed at Kyushu University, Japan. A.T. and V.V. would like to thank National Nanotechnology Center, Thailand, for their permission to use Material Studio software.
Publisher Copyright:
© 2017, Springer Science+Business Media B.V.
PY - 2017/10/1
Y1 - 2017/10/1
N2 - To design a more efficient plasticizer for PLA based on PEG derivative, the miscibility enhancement of PLA/PLAx-PEGy-PLAx blends were investigated by both atomistic and mesoscale simulations. Flory-Huggins interaction parameters (χij) of PLAx-PEGy-PLAx blends, with PLA block fractions = 0.1–0.5, were calculated using molecular dynamic (MD) simulation to determine the miscibility of PLA/PLAx-PEGy-PLAx blends and compared with PLA/PEG blends (Takhulee et al. J Polym Res 24:8, 2017). Based on the calculated χij and radial distribution functions, PLA/PLAx-PEGy-PLAx showed better miscibility compared to PLA/PEG. The values of χij for PLA/PLAx-PEGy-PLAx blends are always lower than those for PLA/PEG blends at the same PEG composition. For PLA/PLAx-PEGy-PLAx blends, χij increased as a function of PLA block fractions. Mesoscale properties of PLA/ PLAx-PEGy-PLAx blends were then determined using dissipative particle dynamic (DPD) simulation. Smaller PEG domain in PLA/PLAx-PEGy-PLAx blends was observed, compared to that in PLA/PEG blend. Miscibility behavior of PLA/PLAx-PEGy-PLAx blends was investigated by experiments at selected conditions based on the simulation results. By differential scanning calorimetry measurements, acceleration of the crystallization of PLA matrix by blending PLAx-PEGy-PLAx was observed. Although PLA/PEG 70/30 (wt/wt) blend was phase separated when slowly cooled from the melt, due to the crystallization of PEG component, this phenomenon was not observed in PLA/PLAx-PEGy-PLAx blends. The melting temperature (Tm) depression of PLA/PLAx-PEGy-PLAx blends was also more pronounced. From dynamic mechanical analysis, the storage (G′) and loss moduli (G′′) curves in terminal region were determined. The slope of G′ curves for PLA/PEG 75/25 and 70/30 (wt/wt) was less than 2 while this deviation was found only at 70/30 (wt/wt) for PLA/PLAx-PEGy-PLAx. These results indicate that PLAx-PEGy-PLAx is better miscible with PLA.
AB - To design a more efficient plasticizer for PLA based on PEG derivative, the miscibility enhancement of PLA/PLAx-PEGy-PLAx blends were investigated by both atomistic and mesoscale simulations. Flory-Huggins interaction parameters (χij) of PLAx-PEGy-PLAx blends, with PLA block fractions = 0.1–0.5, were calculated using molecular dynamic (MD) simulation to determine the miscibility of PLA/PLAx-PEGy-PLAx blends and compared with PLA/PEG blends (Takhulee et al. J Polym Res 24:8, 2017). Based on the calculated χij and radial distribution functions, PLA/PLAx-PEGy-PLAx showed better miscibility compared to PLA/PEG. The values of χij for PLA/PLAx-PEGy-PLAx blends are always lower than those for PLA/PEG blends at the same PEG composition. For PLA/PLAx-PEGy-PLAx blends, χij increased as a function of PLA block fractions. Mesoscale properties of PLA/ PLAx-PEGy-PLAx blends were then determined using dissipative particle dynamic (DPD) simulation. Smaller PEG domain in PLA/PLAx-PEGy-PLAx blends was observed, compared to that in PLA/PEG blend. Miscibility behavior of PLA/PLAx-PEGy-PLAx blends was investigated by experiments at selected conditions based on the simulation results. By differential scanning calorimetry measurements, acceleration of the crystallization of PLA matrix by blending PLAx-PEGy-PLAx was observed. Although PLA/PEG 70/30 (wt/wt) blend was phase separated when slowly cooled from the melt, due to the crystallization of PEG component, this phenomenon was not observed in PLA/PLAx-PEGy-PLAx blends. The melting temperature (Tm) depression of PLA/PLAx-PEGy-PLAx blends was also more pronounced. From dynamic mechanical analysis, the storage (G′) and loss moduli (G′′) curves in terminal region were determined. The slope of G′ curves for PLA/PEG 75/25 and 70/30 (wt/wt) was less than 2 while this deviation was found only at 70/30 (wt/wt) for PLA/PLAx-PEGy-PLAx. These results indicate that PLAx-PEGy-PLAx is better miscible with PLA.
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U2 - 10.1007/s10965-017-1344-y
DO - 10.1007/s10965-017-1344-y
M3 - Article
AN - SCOPUS:85030707417
SN - 1022-9760
VL - 24
JO - Journal of Polymer Research
JF - Journal of Polymer Research
IS - 11
M1 - 178
ER -