Obtenção e caracterização do compósito poliácido láctico e microcelulose cristalina (PLA/ MCC) obtido por impressão 3D LCD (Liquid crystal display

Abstract

The excessive use of non-biodegradable polymers has generated significant environmental impacts. Additive Manufacturing has driven research into sustainable composites for 3D printing, such as polylactic acid matrix (PLA), due to their biodegradability and good mechanical properties. The incorporation of Crystalline Microcellulose (MCC), which has a high Modulus of Elasticity, can enhance these characteristics. Thus, this study aims to obtain and characterize PLA and MCC composites via Liquid Crystal Display (LCD) Additive Manufacturing and determine the ideal percentage of MCC to evaluate its influence on polymer properties. CCM has been characterized by Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS), Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Diffraction (XRD). Then, it was incorporated into the polymeric matrix in different concentrations (1, 3, 5 and 10%) and the composites were obtained through Additive Manufacturing. Pure PLA and composites were characterized by Thermogravimetry (TGA), Differential Scanning Calorimetry (DSC), Tensile Mechanical Test, Shore D Hardness, SEM morphological analysis, Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Diffraction (XRD). In addition, pure PLA and composites were subjected to thermal aging in an incubator for 15 days and to water absorption tests, with the objective of evaluating the influence of MCC on the structural and mechanical properties of the samples. The characterization results indicated that the incorporation of MCC led to an increase in Shore D hardness, tensile strength and modulus of elasticity compared to pure PLA. The analysis of SEM fractures showed that pure PLA presented a homogeneous surface, characteristic of fragile polymers, while composites exhibited greater heterogeneity as the percentage of MCC increased. The thermal analyses showed that while the addition of MCC can lead to variations in the thermal stability of the composites, in some cases it also causes increased degradation as observed in the C1 sample (1% MCC). With thermal aging, a reduction in the mechanical and thermal performance of the samples was observed. In addition, the composites showed more damaged fracture regions after the test, suggesting that the presence of MCC influenced the degradative processes. However, the sample with 10% MCC demonstrated greater stability after thermal aging. In the water absorption test, an increase in absorption proportional to the MCC content was verified, which can impact the durability and stability of composites in humid environments.