TY - JOUR
T1 - Improving Processing, Crystallization, and Performance of Poly-L-lactide with an Amide-Based Organic Compound as Both Plasticizer and Nucleating Agent
AU - Leone, Nils
AU - Roy, Manta
AU - Saidi, Sarah
AU - de Kort, Gijs
AU - Hermida-Merino, Daniel
AU - Wilsens, Carolus H. R. M.
N1 - Funding Information:
NWO (Nederlandse Organisatie voor Wetenschappelijk Onderzoek) is acknowledged for providing beam time at the ESRF. The staff of both the DUBLLE (Dutch Belgian beamline, ESRF) and the NCD station (Alba synchrotron) are acknowledged for supporting the X-ray experiments. Enabling Technologies B.V. is acknowledged for providing access to equipment for SAXS analysis. This project has received funding from the INTERREG V program Flanders-Netherlands (Puur Natuur: 100% biobased), the cross-border collaboration program financially supported by the European fund for regional development.
Publisher Copyright:
© 2019 American Chemical Society.
PY - 2019/6
Y1 - 2019/6
N2 - In this work, we report on a novel hydrogen-bonding compound, N,N'-bis(2-hydroxyethyl)-terephthalamide (BHET), and its potential as additive in poly-L-lactide (PLA). Although the hydroxyl groups of BHET can participate in transesterification with the PLA matrix, we demonstrate through gel permeation chromatography that extrusion at 200 degrees C does not result in a drastic decrease in molecular weight. When dissolved in the PLA matrix, BHET facilitates a plasticizing effect, indicated by a suppression in both melt viscosity and glass-transition temperature. Additionally, BHET can crystallize from the PLA melt during cooling, where the generated BHET crystals facilitate heterogeneous nucleation of the PLA matrix. In general, BHET crystallization is favored at high undercooling/superstaturation, as this yields BHET crystals with a high surface area-to-volume ratio. However, rapid cooling to temperatures below the glass-transition temperature prevents the crystallization of the BHET, effectively yielding samples where only the plasticizing effect of BHET is evident. A suppression in yield point is observed during mechanical analysis of samples with increasing BHET concentration, a characteristic feature for samples with decreasing glass-transition temperatures. In contrast, when allowed to crystallize during processing, BHET can be used to generate PLA crystals oriented along the flow direction, effectively enhancing the tensile modulus. Overall, the combined plasticizing and nucleating effect of BHET makes it a verstaile additive for controlled processing and performance of PLA.
AB - In this work, we report on a novel hydrogen-bonding compound, N,N'-bis(2-hydroxyethyl)-terephthalamide (BHET), and its potential as additive in poly-L-lactide (PLA). Although the hydroxyl groups of BHET can participate in transesterification with the PLA matrix, we demonstrate through gel permeation chromatography that extrusion at 200 degrees C does not result in a drastic decrease in molecular weight. When dissolved in the PLA matrix, BHET facilitates a plasticizing effect, indicated by a suppression in both melt viscosity and glass-transition temperature. Additionally, BHET can crystallize from the PLA melt during cooling, where the generated BHET crystals facilitate heterogeneous nucleation of the PLA matrix. In general, BHET crystallization is favored at high undercooling/superstaturation, as this yields BHET crystals with a high surface area-to-volume ratio. However, rapid cooling to temperatures below the glass-transition temperature prevents the crystallization of the BHET, effectively yielding samples where only the plasticizing effect of BHET is evident. A suppression in yield point is observed during mechanical analysis of samples with increasing BHET concentration, a characteristic feature for samples with decreasing glass-transition temperatures. In contrast, when allowed to crystallize during processing, BHET can be used to generate PLA crystals oriented along the flow direction, effectively enhancing the tensile modulus. Overall, the combined plasticizing and nucleating effect of BHET makes it a verstaile additive for controlled processing and performance of PLA.
KW - POLY(LACTIC ACID)
KW - ISOTACTIC-POLYPROPYLENE
KW - MECHANICAL-PROPERTIES
KW - POLY(L-LACTIC ACID)
KW - OXALAMIDE COMPOUNDS
KW - HYDRAZIDE COMPOUND
KW - BEHAVIOR
KW - TRANSITION
KW - MELT
KW - ORIENTATION
U2 - 10.1021/acsomega.9b00848
DO - 10.1021/acsomega.9b00848
M3 - Article
SN - 2470-1343
VL - 4
SP - 10376
EP - 10387
JO - Acs omega
JF - Acs omega
IS - 6
ER -