One-pot preparation of thermosensitive polylactic acid materials by modifying with N-Isopropyl acrylamide

Abstract

Polylactic acid (PLA) is highly attractive polyester in biomedical application, and its thermosensitive materials can achieve multiple functions due to their being sensitive to the temperature. In this work, based on lactic acid (LA), maleic anhydride (MAH), and N-isopropyl acrylamide (NIPAM), a thermosensitive modifier, the thermosensitive PLA material PLAMN is directly synthesized via one-pot preparation of melt polymerization and radical polymerization. The molecular structure, thermosensitive characteristics, and micellization behavior of the serial PLAMNs with different molar feed ratios are well characterized with FTIR, 1H NMR, GPC, DLS, TEM and other characterization techniques. The results show that, as anticipated, the obtained products have the ability to self-assemble. The specific physical and chemical properties can be controllable by the molar feed ratio n(LA)/n(MAH)/n(NIPAM). When the ratio is 20/1/7, the obtained PLAMN7 has the minimum critical micelle concentration (only 4.17 mg L−1), and its critical phase transition temperature is 30.6 °C. This new synthetic strategy can effectively simplify the preparation of the thermosensitive PLA polymeric material, which is beneficial to realize the loading of the hydrophobic drugs.