(a) Microspheres

(b) SBO PU foam without fillers

(c) SBO PU foam with 1% microspheres

(d) SBO PU foam with 3% microspheres

(e) SBO PU foam with 5% microspheres

(f) SBO PU foam with 7% microspheres

Figure 3: Scanning electron micrographs of SBO PU foams modified with microspheres.