The mechanical properties of the pure PBS elastomers and blends were assessed by rheology using 20 mm parallel plates at 25 °C. Strain amplitude experiments on the pure PBS samples were initially carried out as to assess the critical strain (Figure ). This was done in order to ensure the oscillation sweep measurements on the blends are within the linear viscoelastic region (LVR). The LVR is the range in which measurements can be carried out without destroying the structure of the sample and the critical strain signifies this maximum strain. At a constant frequency of 1 Hz against increasing strain, the elastic modulus (G') of LPBS deviates from the plateau at a strain of ~25%. HPBS, however, starts to show a decrease in G' at a strain in excess of ~40%. The absolute value of the critical strain was then taken to be 24 and 41 % for LPBS and HPBS respectively, with a standard deviation of ±5 % in G'. The G' of LPBS within the LVR was ~125 kPa whereas HPBS showed a much lower G' within the LVR of only ~21 kPa. The differences in critical strain and G' between the two PBS samples are inferred due to the number of chain end crosslinks, agreeing with the increase in intensity of the SiO-B stretch for LPBS from the FTIR measurements. The small amplitude oscillatory shear (SAOS) experiments across all samples were performed at a constant strain of 10 % assumed to be well within the LVR of the different PBS samples. The G' and G'' of the pure PBS, PDMS-OH precursors, and blends at increasing angular frequency (0.01 to 50 Hz) and constant strain (10%) were extracted from the SAOS experiments (Figure and Figure and). When comparing the SAOS results for PDMS-OH and PBS samples, PDMS-OH shows a linear increase in G' and G'' with respect to increasing frequency whereas PBS shows a cross over of G' and G''. Previous literature report on PBS rheology showed that PBS acts as a liquid at low oscillating frequencies, whereas adopting more solidlike properties at higher frequencies above the cross over point. Using the Maxwell model very low frequencies in the terminal region before the G' and G'' crossover, both G' and G'' increase linearly on a double log plot with increasing frequency. According to the Maxwell model, and at a constant temperature, G' and G'' can be expressed as equation 1 and 2