Heating-induced dimensional changes in crystal lattice and lamellar thickness of isothermally crystallized poly(butylene 2,5-furandicarboxylate) (PBF)

abstract

Poly(butylene 2,5-furandicarboxylate) (PBF), one of the most promising biobased polyesters, was isothermally crystallized from the melt at Tc= 70, 140 and 160 degrees C and subsequently quenched to room temperature. For the first time, the different structural evolution of these thermally treated samples during heating was investigated in situ by synchrotron Wide-Angle and Small-Angle X-ray Scattering (WAXS and SAXS) and interpreted as a function of the amorphous chain mobility at different temperatures. A structural change in the crystal lattice of the PBF crystals grown at Tc= 70 degrees C was detected by WAXS during heating beyond 110 degrees C. Coincidently, SAXS evidenced an increase in lamellar thickness during heating at temperatures close to 110 degrees C for all samples, regardless of their crystallization conditions. This crystal improvement could be due to the significant mobilization of the methylene sequences within the polymer chains at that limiting temperature. Thanks to less restricted and easier conformational rearrangements, the reorganization of the crystals through a melting/recrystallization mechanism could be favored. On the other hand, a different mechanism involving the rigid amorphous fraction (RAF), i. e. the constrained interphase located at the amorphous/crystal boundary, is proposed to explain the increase in the lamellar thickness observed at around 90 degrees C after crystallization at Tc= 70 degrees C. The temperature limit for the presence of the RAF in PBF was indeed identified around 85-90 degrees C. Complete mobilization of the amorphous chains at temperatures above 90 degrees C could favor the rearrangements necessary to form thicker lamellae.

keywords

RIGID AMORPHOUS FRACTION; X-RAY-SCATTERING; SEMICRYSTALLINE POLYMERS; RENEWABLE RESOURCES; MELTING BEHAVIOR; STRUCTURAL-CHANGES; GLASS-TRANSITION; ETHER KETONE); TEMPERATURE; POLYESTERS

subject category

Polymer Science

authors

Righetti, MC; Matxinandiarena, E; Sousa, AF; Müller, AJ

Groups

G4 - Renewable Materials and Circular Economy

Projects

European network of FURan based chemicals and materials FOR a Sustainable development (FUR4Sustain)

CICECO - Aveiro Institute of Materials (UIDB/50011/2020)

CICECO - Aveiro Institute of Materials (UIDP/50011/2020)

Associated Laboratory CICECO-Aveiro Institute of Materials (LA/P/0006/2020)

acknowledgements

This study was supported by the COST Action FUR4Sustain-European network of FURan based chemicals and materials FOR a Sustainable development, CA18220. A.F.S. declares that her contribution to this work was developedwithin the scope of the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020 (DOI 10.54499/UIDB/50011/2020) , UIDP/50011/2020 (DOI 10.54499/UIDP/50011/2020) & LA/P/0006/2020 (DOI 10.54499/LA/P/0006/2020) , financed by national funds through the FCT/MCTES (PIDDAC) . A.F.S. also acknowledges the FCT for her research contract (CEECINSTLA/00002/2022) . E.M and A.J.M. acknowledge support from the ALBA synchrotron through granted proposal number AV-2024028078 (September 2024) and for their staff's help during the experiments.