Experimental Investigations into 4 D Printing of Barium Titanate and Graphene Reinforced PVDF Matrix Composites

Abstract

3D printing of smart materials is one of the disruptive innovations in the field of advanced manufacturing. From the past one decade significant advancements have been reported in this sector with respect to printers, materials, and processes. Fused deposition modelling (FDM) (one of the low cost 3D printing technologies) has entered into the field of smart manufacturing, in which active materials are being used particularly for dynamic 4D applications. FDM has been widely explored for different range of thermoplastics and thermosetting composites. Researchers have worked on the in-house development of thermoplastic composite based feedstock filaments by using various polymers such as polyvinyl chloride (PVC), poly lactic acid (PLA), polypropylene (PP), acrylonitrile butadiene styrene (ABS) etc. for numerous applications. But, hitherto little has been reported on the preparation of smart polymer based feedstock filament for 3D printing of functional prototypes having 4D properties. In this research work an electro-active polymer, polyvinylidene fluoride (PVDF) was reinforced with graphene (Gr), and barium titanate (BTO) for the preparation of composite. newlineTwo different methods of blending have been explored for the development of smart polymer based composite (i) mechanical blending (MB) of materials and (ii) chemical assisted mechanical blending (CAMB). In the first stage, based upon the melt flow index (MFI), different proportions/compositions of PVDF-Gr-BTO were selected for extrusion with twin screw extruder (TSE). Further to optimize the process parameters of TSE three input parameters (a) extruder temperature, (b) rotational speed (rpm) and (c) composition were selected. The prepared feed stock filaments of MB based composites were subjected to mechanical, thermal dimensional and morphological analysis. The analysis of variance (ANOVA), suggested the optimised settings of TSE for fabrication of MB based composite feedstock filament as: extruder temperature 200°C, rotation speed 40 rpm with composi