This work investigates the effects of modification of polylactide (PLA) using dicumyl peroxide (DCP) as a crosslinker and Joncryl as a chain extender on boehmite distribution. The PLA/boehmite (PLA/BA) composites at various concentrations were prepared via a twin-screw extruder. Transmission electron microscopy showed more agglomerations of BA particles when Joncryl and DCP were added individually to the PLA matrix, with lesser agglomeration upon simultaneous addition of DCP and Joncryl, which led to an enhancement of 10.7% of the heat distortion temperature and 8.8% of the modulus. The existence of fine dispersed BA particles in the BA3 sample improved the cold crystallization by 4 °C. Moreover, the maximum reinforcing effect in increasing the storage modulus of the prepared system was observed upon concurrent addition of DCP and Joncryl, with minimum reinforcing effect upon individual addition of DCP and Joncryl. In general, a bio-based PLA composite base BA with enhanced properties was successfully prepared for various applications.

The technology of 4DP utilizes shape memory materials (SMMs). Among the SMMs, SMP is the material that has potential and is ideal for this technology. However, due to their restrictions, fillers are incorporated to produce a novel shape memory polymer composite (SMPC). The objective of the present work was to investigate how the modification of PLA via the incorporation of boehmite alumina and thermochromic dye, and the use of 3DP on polyester fabric to make smart material textiles (SMT), influenced the shape-memory properties of printed objects. SMPCs with 3 wt% BA particles were prepared by means of the fused deposition modelling (FDM) process, with heat used as an actuation. It was demonstrated that sample thickness and the method of PLA modification affected the shape recovery of 3D-printed objects. All neat PLA samples recovered their angle fully for all thicknesses, while modified PLA incorporated with BA particles and dye recovered its initial angle fully at 1 mm thickness and showed less recovery for 1.5- and 2 mm-thicknesses. The 1 mm-thick sample was then chosen for printing onto the textile material for all samples. When printed onto the fabric, the neat PLA and SMPCs recovered their initial shapes fully, while samples with the dye added into the PLA and SMPC did not recover their initial shape fully due to the presence of the dye, which hindered the movement of the polymer chains. SEM revealed good layer bonding for the SMPCs compared to the neat PLA, which led to improved mechanical properties. The thermal stability of PLA was improved by the BA particles; furthermore, the dye and BA particles nucleated the crystallization of PLA, resulting in an enhanced storage modulus. Overall, a biodegradable 3D-printed object of 1 mm in thickness with improved thermal and mechanical properties was produced, with and without the use of the textile.