Printability, shape‐memory, and mechanical properties of PHB/PCL/CNFs composites

Abstract

Shape‐memory polymers have attracted attention as smart implant materials in recent years because they are lightweight, low‐cost, easily processable, and because they undergo large deformation. Here, cellulose nanofibers (CNFs) were used as a reinforcement for polyhydroxybutyrate (PHB)/polycaprolactone (PCL) composites to improve mechanical properties. The composites were investigated by rheological tests, differential scanning calorimetry, dynamic mechanical analysis, mechanical property tests, and shape‐memory tests. The printability of PHB/PCL/CNFs composites was demonstrated by using them to print interconnected porous structures with a gyroid surface. The results showed that the PHB/PCL (80:20) composites with 1 wt% CNF displayed the best comprehensive mechanical and shape‐memory properties. As a functional verification, a model of the self‐opening hand was fabricated by 3D printing, and its deformation and recovery capabilities were evaluated.

Effects of polycaprolactone viscosity on morphology, mechanical properties, water uptake, and cellular viability in poly(3‐hydroxybutyrate)/polycaprolactone blends for tissue engineering

“…The blends showed a sea‐island morphology in which the droplets dispersed are from the PCL phase while PHB is the matrix. The presence of two phases confirms the blends immiscibility which has already been reported 17,21,23,27,32 …”

“…The first heating runs of the pure polymers and polymer blends in different compositions are shown in Figure 3. The PHB presented a crystalline melting event ( T m ) around 173°C, while PCLH and PCLL presented melting events around 53 and 60°C, respectively (Figure 3A,B), as reported in the literature 21,31,32,61 . PCLH presented a more heterogeneous melting event when compared to the PCLL, indicating a greater heterogeneity of the crystalline population, reflecting a lower degree of crystallinity (Table 3).…”

“…It was verified that the experimental T g values deviate from the ones calculated, confirming the immiscibility of this system already observed in other works in the literature. 22,23,32 When comparing the same ratios with the different PCLs (Figure 5), no significant influence was observed for the two molar masses of PCL investigated in this study. The behavior indicates that there was no increase in the mobility of the amorphous phase of PHB.…”

“…Some studies have already reported the preparation and characterization, 21‐23 compatibilization, 24‐26 and composites 27‐33 of PHB/PCL blends.…”

Fabrication of Nanostructured Polycaprolactone (PCL) Film Using a Thermal Imprinting Technique and Assessment of Antibacterial Function for Its Application

“…When the demolding temperature was lower, the releasing force and the stretching tension at the interface between the mold and the replica seem to be reduced [43], and the deformation of the nanopillars was negligible at a low temperature. However, as the release temperature increased, the mechanical properties, yield strength or stiffness could decrease because the melting temperature of PCL was approximately 60 • C [44,45]. Therefore, the PCL nanopillars were more elongated as the temperature increased.…”