Publié le 03/02/2023 par Brinkmann Martin
PLA is a biosourced polymer of high interest for various applications including packaging and medical use. The properties of this polymer depend strongly on its crystallinity. The sycommor group has demonstrated that high-temperature rubbing at a temperature above the Tg of the polymer is able to induce polymer alignement and crystallization. The rubbing temperature is a key parameter, that allows to prepare PLLA films with different structures including the alignment mesophase, the oriented alpha' structure and the stable alpha form of PLLA. Interestingly, equimolar blends of PLLA and PDLA can also be crystallized and oriented in the form of pure films of the stereo-complex (SC-PLA) without traces of homo-crystals of PLLA and PDLA. These results were published in J. Appl. Polym. Sci. (https://doi.org/10.1002/app.53532).
In a second step, we demonstrated that it is possible to reduce the presence of pin-holes and scratches in the rubbed films by combining rubbing at a moderate temperature (100°C) and a thermal annealing. Again, this methodology helps form highly crystalline and oriented PLLA and SC-PLA thin films. This second approach was published in J. Polymer Science (https://doi.org/10.1002/pol.20220740).