Solid-state NMR studies of polysaccharide systems

Two polysaccharide systems were studied by solid-state NMR methods: (i) Chitin/glucan complexes. The C-13 NMR spectra have shown that in samples isolated from the mushroom Pleurotus sp., the glucan content was always higher in stems than in pilei. While carbonyl lineshape in complex isolated from Aspergillus niger mycelium shows similar hydrogen bonding as in neat chitin, a significantly higher amounts of hydrogen bonding between carbonyl groups of chitin and hydroxy groups of glucan was found in complexes isolated from Pleurotus sp. (ii) Biodegradable starch/polycaprolactone (PCL) blends. From the relaxation times T-1(H) and T-1 rho(H) it follows that blends starch/PCL, starch/ester oligomers and starch formate/ester oligomers are phase-separated even on the scale 20-110 nm. on the contrary, starch formate/PCL blend is phase-separated on the scale 1-9 nm but homogeneously mixed on the scale 20-90 nm. Therefore formylation of starch significantly improves its miscibility with PCL.