Monday, March 12, 2018

PLLA from PolySciTech used in fundamental research project on polymer processing conditions and crystallinity formation


One of the key parameters controlling polymer mechanical and optical behavior is how the polymer chains arrange or ‘stack’ relative to each other. Chemically, polymers with regular, repeating structures tend to stack more closely into crystalline forms than polymers which have irregular structures where steric hindrance prevent the chains from getting to close to one another. Additionally, the speed and conditions at which the polymers solidify (either from solvent or melt) as well as any mechanical drawing force play a role in crystalline domain formation. The more time the chains have to rearrange, the more they tend to crystallize and, if there is an applied force, they tend to crystallize parallel to the direction of the force. Recently, researchers from Université d’Orléans (France) utilized PLLA (PolyVivo AP006 and PolyVivo AP050) from PolySciTech (www.polyscitech.com) to perform fundamental research on the effect processing conditions have on crystalline PLLA film formation. This research holds promise for the development of mechanically robust or optically clear components for use in biomedical applications. Read more: Vayer, Marylène, Alain Pineau, Fabienne Warmont, Marjorie Roulet, and Christophe Sinturel. "Constrained crystallization of poly (L-lactic acid) in thin films prepared by dip coating." European Polymer Journal (2018)., https://www.sciencedirect.com/science/article/pii/S0014305717322413

“Abstract: Dip coating process used at various withdrawing speeds showed a great ability to control the crystalline structure of thin films of poly(L-lactic acid) which can be of great importance for applications where mechanical or optical properties are involved. Thin films were studied by Atomic Force Microscopy and Grazing Incidence Angle X-ray Diffraction. Withdrawing the silicon substrate in the draining regime (at high speed) led to amorphous films with flat surface whatever the solvent and the molar mass. At low speeds (capillary regime), AFM demonstrated the presence of spherulites or hedrites in the films depending on the solvent and the molar mass. GIXRD showed that spherulites were less crystallized than hedrites. This difference was attributed to solvent evaporation rate. Highlights: PLLA thin films were prepared by dip coating solutions. The thin films were investigated using AFM and GIXRD. Withdrawal at high speed led to amorphous films. Withdrawal at low speed led to partially crystallized films. The nature of solvent and molecular mass influenced the crystalline structure of the films.”

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