Study of Shape Memory and Tensile Property of 3D Printed Sinusoidal Sample/Nylon Composite Focused on Various Thicknesses and Shape Memory Cycles

Abstract

This study evaluated the shape memory and tensile property of 3D-printed sinusoidal sample/nylon composite for various thickness and cycles. Sinusoidal pattern of five thicknesses: 0.2 mm, 0.4 mm, 0.6 mm, 0.8 mm, and 1.0 mm were 3D-printed on nylon fabric by the fused deposition modeling (FDM) 3D printer using shape memory thermoplastic polyurethane (SMTPU). Afterward, shape memory and tensile property was investigated up to 50 shape memory cycles. The study found that 3D-printed sinusoidal sample/nylon composite had a 100% shape recovery ratio for various thicknesses up to 50 cycles. The average shape recovery rate gradually decreased from 3.0°/s to 0.7°/s whereas the response time gradually increased with the increase of a 3D-printed pattern thickness. The stress and initial modulus gradually increased with the increase of the cycle’s number. Thus, the shape memory property had a similar tendency for various cycles whereas the tensile property gradually increased with the increase of the cycle number. Moreover, this study demonstrated that this 3D-printed sinusoidal sample/nylon composite can go through more than 50 cycles without losing its tensile or shape memory property. This 3D-printed sinusoidal sample/nylon composite has vast potential as smart, reinforced, and protective clothing that requires complex three-dimensional shapes.

Investigation of the Shape-Memory Properties of 3D Printed PLA Structures with Different Infills

“…It should be mentioned that PLA is not the only 3D printable shape memory polymer (SMP). Other SMPs which can be 3D printed are, e.g., polyurethane [ 25 , 26 ], poly(ε-caprolactone) [ 27 ], poly(vinyl alcohol) [ 28 ] or poly cyclooctene [ 29 ].…”

Pressure Orientation-Dependent Recovery of 3D-Printed PLA Objects with Varying Infill Degree

“…This means that a 3D-printed object from PLA can be deformed to a certain degree and subsequently regenerated into its original shape through heat treatment, typically in the temperature range of 60–100 °C [ 15 , 16 , 17 , 18 ]. While other 3D printing polymers, such as poly(vinyl alcohol), poly(ε-caprolactone) or polyurethane, also show shape-memory properties [ 19 , 20 , 21 , 22 ], PLA is often advantageous due to its ease of printing, the relatively low price, and especially its biocompatibility.…”

Mechanical Properties of FDM Printed PLA Parts before and after Thermal Treatment

“…It should also be mentioned that PLA is not the only shape-memory polymer that can be 3D-printed [ 31 , 32 ] and that it can be assumed that polyurethane or PVA could be used similarly. However, polyurethane shows two glass transition temperatures, the higher of which is—depending on the exact composition—higher than that of PLA, making it more complicated to fit an orthosis of this material to the human body, while PVA is water-soluble and thus not suitable to serve as an orthosis.…”

“…However, this works only as long as no connections are broken, leading in reality to the necessity to construct such objects carefully to avoid breaks and thus to optimize regeneration properties [ 29 , 30 ]. Other FDM printing materials may also show shape-memory properties, such as polyurethane or poly(vinyl alcohol) (PVA) [ 31 , 32 ], but they are less common in the FDM process.…”