The weightings of the PC3 function, which accounts for 1.29% of the PCA, are positive for 0, 15 and 100 wt% samples and negative for the other composites. PC3 is a repository for parts of the PDFs that are not fully accounted for by PC1 and PC2. These can be additional real interactions in the composites as well as indicators of deficiencies in the overall analysis method. Taking the latter first, PC3 includes correlations at higher r-values that mimic the PDF from Ti-MOF in this r-region (Figure ). The weightings in (Figure .b) show that PC3 acts to diminish the contribution from PC2 (~Ti-MOF D(r)) for the 0 and 15 wt% samples' PDFs while increasing the Ti-MOF D(r) content in the 100 wt% sample's D(r). It acts in a similar, but less obvious, manner to increase the glass-like features present at low-r in PC1 for the D(r) from 0 and 15 wt% samples. Of more interest is whether PC3 contains features not associated with either Ti-MOF or IG D(r). The two main negative peaks in PC3 (Figure .a, b, note that the PC3 weighting is negative for all but one of the composite samples) are located at 1.90 and 3.25 Å and might be related to a Ti-O shorter distance because of the thermal treatment and a Ti-O-P correlation likely related to an interaction at the interface (Figure ).