Smart Magnetorheological Elastomer Based Filament for Potential 4D Printing Technology

Magnetorheological elastomers (MREs) are smart materials that exhibit tunable rheological and mechanical properties in response to external magnetic fields. While traditional fabrication methods for MREs are time-consuming and involve complex curing processes, this study explores the potential of additive manufacturing (AM), specifically fused filament fabrication (FFF), as a sustainable alternative. This research investigates the use of MRE filaments as a novel material in 4D printing technology, with a focus on the previously understudied effect of carbonyl iron particle (CIP) content on filament fabrication. The primary objective was to develop an optimized MRE filament with enhanced mechanical properties suitable for AM processes. MRE filaments with varying CIP contents (50, 60, 70, and 80 wt.%) were prepared by mixing with thermoplastic polyurethane (TPU) and extruded into filament spools. The mechanical properties of the 4D printed MRE samples were evaluated using dynamic mechanical analysis (DMA), with a particular focus on Young’s modulus. Results revealed that MRE filaments containing 60 wt.% CIP exhibited the highest Young’s modulus of 48.06 MPa among the tested compositions. This optimal CIP content provides a promising foundation for fabricating MRE filaments suitable for printing a wide range of MRE products in future applications. The successful implementation of AM techniques for MRE production offers potential advantages in terms of reduced material wastage, faster production times, and cleaner manufacturing processes compared to conventional methods.