Fig. 4
From: Compatible composites filaments based on PHB/starch for 3d printing via fused deposition modeling
SEM images of the cross-section and surface morphology of PHB and PHB/GUM composite filaments. (a, b) PHB; (c, d) PHB/GUM 1; (e, f) PHB/GUM 5; (g, h) PHB/GUM 20. High-magnification images (f, h) reveal micron-sized particles, likely starch agglomerates