Study of the chain microstructure effects on the resulting thermal properties of poly(L-lactide)/poly(N-isopropylacrylamide) biomedical materials.
The development of thermally-sensitive poly(N-isopropylacrylamide) (PNIPAAm) and biocompatible/biodegradable poly(L-lactide) (PLLA) blends offers us an efficient strategy in order to obtain materials with improved functional properties to be used in the emerging field of biomedicine. In this sense, thermal properties of PLLA and PNIPAAm have been investigated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and wide angle X-ray diffraction (WAXD) were conducted to shed more light on the obtained results. For a better understanding of PLLA/PNIPAAm system, both low and high molecular weight PLLA and PNIPAAm have been synthesized by ring opening polymerization and aqueous redox polymerization respectively. Obtained results are interpreted from the viewpoint of chain microstructure of each homopolymer and the ratio between two constituent materials. DSC, SEM and WAXD results show a phase separation over the entire composition range irrespectively of the molecular weight of both homopolymers. Additionally, it was found a nucleating agent behavior of low molecular weight PNIPAAm, while high molecular weight PNIPAAm hinders the crystallization of PLLA. FTIR results suggest that the strong autoassociation present in PNIPAAm plays a key role impairing the miscibility of the whole system. Thermogravimetric analysis reveals that thermodegradation process of PLLA could be continuously delayed with the addition of PNIPAAm due to the increased thermal stability of N-isopropylacrylamide in regard to L-lactide sequences.
Macromolecular Chemistry Research Group (LABQUIMAC), Dept. of Physical Chemistry, Faculty of Science and Technology, University of the Basque Country (UPV/EHU), Spain. Electronic address: erlantz.liizundia@ehu.es.
E
E
Lizundia
Department of Mining-Metallurgy and Materials Science and BERC POLYMAT, School of Engineering, University of the Basque Country (UPV/EHU), Spain. Electronic address: emiliano.meaurio@ehu.es.
E
E
Meaurio
Macromolecular Chemistry Research Group (LABQUIMAC), Dept. of Physical Chemistry, Faculty of Science and Technology, University of the Basque Country (UPV/EHU), Spain. Electronic address: josemanuel.laza@ehu.es.
J M
JM
Laza
Basque Center for Materials, Applications and Nanostructures (BCMaterials), Parque Tecnológico de Bizkaia, Ed. 500, Derio 48160, Spain. Electronic address: joseluis.vilas@bcmaterials.net.
J L
JL
Vilas
Macromolecular Chemistry Research Group (LABQUIMAC), Dept. of Physical Chemistry, Faculty of Science and Technology, University of the Basque Country (UPV/EHU), Spain; Basque Center for Materials, Applications and Nanostructures (BCMaterials), Parque Tecnológico de Bizkaia, Ed. 500, Derio 48160, Spain. Electronic address: luismanuel.leon@ehu.es.
L M
LM
León Isidro
D000180:Acrylic Resins / Q000737:chemistry*; D001672:Biocompatible Materials / Q000737:chemistry*; D002152:Calorimetry, Differential Scanning; D003460:Crystallization; D008970:Molecular Weight; D011091:Polyesters / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature; D013818:Thermogravimetry; D014961:X-Ray Diffraction
D000180:Acrylic Resins; D001672:Biocompatible Materials; D011091:Polyesters; C052970:poly-N-isopropylacrylamide; C033616:poly(lactide)
Biomedical material; Glass transition temperature; Poly(N-isopropylacrylamide); Poly(l-lactide); Thermally induced crystallization; Thermodegradation