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The main objective of the presented work is to evaluate the thermal behavior of Poly-lactic acid (PLA) parts made with a Fused Deposition Modelling (FDM) process. By using a robust framework for the testing sequence of PLA parts, with the aim of establishing a standard testing cycle for the optimization of the part performance and quality. The research involves study the materials before and after 3D printing. Two biodegradable PLA polymers are investigated, characterized by different colors (one black and the other transparent). The study starts with the examination of each polymeric material and measurements of its main thermal properties. [ABSTRACT FROM AUTHOR]

Poly(lactic acid) (PLA) is biodegradable bioplastic with reasonably high tensile strength and modulus. However, its brittleness and low crystallinity led to low thermal stability and limited applications. This research aims to enhance crystallization of PLA by using talc and to improve toughness of PLA by compounding with silicone rubber (SR). Films of PLA/talc and PLA/SR were prepared by using a twin screw extruder with film blowing facility. Mechanical, thermal and physical properties of both PLA/talc and PLA/SR films were investigated. DSC thermograms revealed that the addition of talc raised the degree of crystallinity from 1.4% of the neat PLA to 4.7% for the PLA films with 10 wt% talc. The cold crystallization temperature (Tcc) of PLA also decreased with increasing talc content. The ductility of PLA was significantly improved by blending with SR; the addition of only 3 wt% SR enhanced the elongation at break of the PLA/SR film by about 24 folds to 179.4% compared with 7.4% observed in the neat PLA. Under tension, the PLA/SR film yielded more easily at lower stress than those nucleated with talc. In addition, the increase of talc and SR content led to enhancement of impact strength. Significant surge of impact strength to 732 J/m was found in the PLA film with 3 wt% SR while that of neat PLA film was 328 J/m. Microscopic study revealed talc and SR dispersed and adhered well to the PLA matrix. [ABSTRACT FROM AUTHOR]

Polylactid acid seems to be an appropriate replacement of conventional non-biodegradable synthetic polymer primarily due to comparable mechanical, thermal and processing properties in its high molecular weight form. Biodegradation of high molecular PLA was studied in compost for various forms differing in their specific surface area. The material proved its good biodegradability under composting conditions and all investigated forms showed to be acceptable for industrial composting. Despite expectations, no significant differences in resulting mineralizations were observed for fiber, film and powder sample forms with different specific surface areas. The clearly faster biodegradation was detected only for the thin coating on porous material with high specific surface area. [ABSTRACT FROM AUTHOR]