Abstract
Multiscale structured polymers have been considered as a promising category of functional materials with unique properties. We combined rapid prototyping and gas foaming technologies to fabricate multiscale functional materials of superior mechanical and thermal insulation properties. Through scanning electron microscope based morphological characterization, formation of multiscale porous structure with nanoscale cellular pores was confirmed. Improvement in mechanical strength is attributed to rearrangement of crystals within CO2 saturated grid sample. It is also shown that a post-foaming temperature higher than the glass transition temperature deteriorates mechanical strength, providing process guidelines. Thermal decomposition of filament material sets the upper limit of temperature for 3D printed features, characterized by simultaneous differential scanning calorimetry and thermogravimetric analysis. Porosity of the fabricated 3D structured polylactic acid (PLA) foam is controllable by suitable tuning of foaming conditions. The fabricated multiscale 3D structures have potential for thermal insulation applications with lightweight and reasonable mechanical strength.
Highlights
Polylactic acid (PLA) is a thermoplastic aliphatic polyester polymer that is derived from renewable resources
To understand the mechanical properties of 3D structures fabricated by 3D printing, representative compressive and bending test results are displayed in Figure 7
A new type of polylactic acid (PLA) based 3D structures has been fabricated by integrating 3D printing and gas foaming technologies
Summary
Polylactic acid (PLA) is a thermoplastic aliphatic polyester polymer that is derived from renewable resources. It has received increased attention as a potential environmentally friendly substitute for petroleum-based counterparts. Senatov et al [10] made porous scaffold with pre-modeled PLA structure by fused filament fabrication and investigated the mechanical properties and shape memory effect. Formation of rigid structural nano-foams is of critical importance for the structure with further improved thermal insulation performance with acceptable mechanical strength. In this study, we fabricate PLA based multiscale 3D freeform structures by combining 3D printing technology, and subsequent two-step gas foaming process to form nano-cellular foams within the 3D printed features towards the potential application for thermal insulation. The main focus of this research is to mainly evaluate the mechanical effect of nano-foams implemented within 3D printed structures as a first step
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