4D printing of polyurethane paint-based composites

Abstract

In recent studies, polyurethane has shown multiple properties that make it an excellent candidate material in 4D printing. In this study, we present a simple and inexpensive additive method to print waterborne polyurethane paint-based composites by adding carboxymethyl cellulose (CMC) and silicon oxide (SiO 2) nanoparticles to the paint. The first function of CMC and SiO 2 is to improve rheological properties of the polyurethane paint for making a printable precursor, which improves the printing resolution and enhances additive manufacturability. Second, the composite precursors improve the curing rate of the polyurethane paint without changing its inherited shape memory properties. Third, the printed composite parts shown enhanced mechanical strength compared with that of the parts printed with pure polyurethane. Finally, the 3D printed polyurethane-CMC and SiO 2 parts exhibit time-resolved shape transformation upon heat stimulation. To the best of our knowledge, this is the first study of using the polyurethane paint as the precursor for 4D printing, which would open new possibilities in future applications in biomedical engineering, soft robotics and so on.

Two-Way and Multiple-Way Shape Memory Polymers for Soft Robotics: An Overview

“…It is also important to highlight that thermo-responsive SMPs may exhibit high variations in the elastic modulus over the operational temperature range (being softer above the transition temperature and harder below the transition temperature) [3,33]. Several fillers, such as carbon nanotubes (CNTs), carbon black, polypyrrole, and nickel powders, or additives, such as plasticizer molecules, have been used to increase thermal and electrical conductivity or functionalities, mechanical strength, and recovery stresses, and to tune shape memory behavior (see [3,[160][161][162] and references therein).…”

Smart polymers and nanocomposites for 3D and 4D printing

“…Increasing the temperature above Tt triggers restoration of the configurational entropy and in turn the primary shape is recovered (recovery step) [191], [192], [195]. Remarkable advances in 3D printing techniques allow printing of various SMPs such as polycaprolactone (PCL) [196]- [198], polyurethane (PU) [199]- [201], polylactic acid (PLA) [202]- [204], acrylate-based and epoxy-based resins [205]- [209] to develop intelligent structures such as actuators, robots and medical devices. Zarek et al [196] 3D printed several models with complex structures and submillimeter thickness with methacrylated PCL using a commercial SLA 3D printer (Fig.…”

Polymer 4D printing: Advanced shape‐change and beyond

“…The Tango™ and Vero™ series of commercial SMPs from Stratasys® are especially popular 12,51,65,66,68–70,75,77,78,81,83–91 . Common 4D printable polymers which have shown shape memory effects include polylactic acid (PLA), 55,57,63,82,92–113 polycaprolactone (PCL), 57,59,64,79,80,106,114,115 polyurethane (PU), 54,116–125 polyester (PE), 126,127 polystyrene (PS), 113,128 acrylonitrile butadiene styrene (ABS), 113,129 high impact polystyrene (HIPS), 113 polyamide, 130 and polyvinyl alcohol (PVA) 56,131 . There are also many acrylate monomers which have been polymerized during the 3D printing process to make SMPs such as butyl acrylate, 122 tert ‐butyl acrylate, 132–135 benzyl methacrylate, 136,137 lauryl acrylate, 138 methyl acrylate, 139 isobornyl acrylate (IBOA), 123,139–143 acrylic acid, 52 bisphenol‐A glycerolate dimethacrylate, 72 bisphenol A diglycidyl ether diacrylate, 123,144 trimethylolpropane triacrylate, 140 ethylene glycol phenyl ether acrylate, 141 2‐ethyl hexyl acrylate, 143 2‐phenoxyethyl acrylate, 142 and soybean oil epoxidized acrylate, 60 as well as acrylate crosslinkers such as di(ethylene glycol) diacrylate, 133–137 bisphenol A ethoxylate dimethacrylat...…”