Synthesis of L-lactid dimer via reactive distillation and synthesis and processing of poly (L-lactic acid) (PLLA)

• Grant number: 23/00691-5
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• Start date: May 01, 2023
• End date: November 30, 2023
• Field of knowledge: Engineering - Chemical Engineering - Chemical Technology
• Principal Investigator: Rubens Maciel Filho
• Grantee: Sara Crivellin
• Host Institution: Faculdade de Engenharia Química (FEQ). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil

Abstract

This Project deals with the study of the poly(L-lactic acid) (PLLA) polymer, in particular in an L-lactide (LLT) reaction intermediate, produced by the synthesis of the ring-opening polymerization (ROP) that is used for the production of the polymer with high molar mass. There is another reaction synthesis for producing the polymer, direct polycondensation that permits to product PLLA with a lower molecular weight. The most important goal is the production of LLT in a single step, and consequently trying to skip the part of the oligopolymerization which normally includes the synthesis through the ROP. After this step, the focus is concentrated to produce PLLA with high molecular mass. The main objective is to develop a strategy to obtain LLT using reactive distillation, integrating the synthesis reaction of LLT and its separation in a one-step and continuous and has a comparison with the synthesis route of polycondensation. One-step process permit to increase the productivity of the process, the selectivity for the product of interest, and the optimization of the synthesis process of this product about the industrial processes known up to now, completing the route of polymerization and processing of PLLA to validate the quality of the product obtained. The main application, up to now, is to obtain membranes through electrospinning with specific proprieties, to be used in the medical field. According to the bibliography, it has been observed a large number of publications refer both to the production of lactic acid (LA) and its isomers, such as L-lactic acid (LLA), and the synthesis of poly(lactic acid) (PLA) and his isomers (PLLA, PDLA, PLDLA), and little has been demonstrated about the synthesis of the cyclic dimer, lactide (LT). For this reason, the continuous increase in the market has increased the interest and the study of this material and in particular of LLT. The purity of the dimer and the synthesis of the polymer are the characteristics that influence the physical and chemical characteristics of the final polymer (PLLA). PLLA is very important thanks to its condition like biodegradability, biocompatibility. The absence of available technologies on the synthesis of LT leaves a gap that allows the evaluation of different technologies to obtain this product. To this end, the reaction kinetics, phase equilibrium, and the influence of thermodynamic properties will be evaluated to reach an adequate process design. The LLT and PLLA are characterized by gel permeation chromatography (GPC), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). (AU)