Nanocomposites of polyhydroxybutyrate (PHB) and poly­(hydroxybutyrate-co-hydroxyvalerate) (PHBV) with cellulose nanocrystals (CNCs) were prepared by dispersion of CNCs into (aqueous) poly­(vinyl acetate) (PVAc) emulsion or poly­(ethylene glycol) (PEG) solution, followed by melt mixing of dried PVAc/CNC and PEG/CNC masterbatches with neat polyesters. Ternary nanocomposites PHB/PVAc/CNC, PHB/PEG/CNC, PHBV/PVAc/CNC, and PHBV/PEG/CNC were obtained with CNC contents of 2.4 and 4.8 wt %, designed for potential applications in the field of biodegradable packaging, as well as in the biomedical sector. Binary blends of PHB and PHBV with PVAc and PEG, obtained by melt mixing, were also analyzed to investigate the polymer miscibility and crystallization behavior. The results of microscopic, wide-angle X-ray scattering, Fourier-transform infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis, and mechanical analyses of nanocomposites indicated that the polymer blending procedure of PHB and PHBV enhanced the CNC dispersion into the polymer matrices and modified the phase morphology and properties. For both PHB and PHBV nanocomposites, the addition of PVAc resulted in higher tensile strength and elongation at break by increasing the CNC content.

In azidic binders for solid propellants, the N3 functionality is introduced by substitution of a halogen or tosyl group, but recently the mesyl group has been suggested as an alternative. The mesylate group has two advantages, mainly related to its small dimensions and low cost. Poly(glycidyl azide) and poly 3-azidomethyl-3-methyl oxetane were prepared by using both tosylate and mesylate precursors. The azidation kinetics were studied at three different temperatures while keeping all other operating parameters the same. The results confirmed the good potential of the mesylate precursors for the production of azidic binders

Polymeric binders for solid propellants are usually based on hydroxyl-terminated polybutadiene (HTPB), which does not contribute to the overall energy output. Azidic polyethers represent an interesting alternative but may have poorer mechanical properties. Polybutadiene–polyether copolymers may combine the advantages of both. Four different ether-butadiene-ether triblock copolymers were prepared and azidated starting from halogenated and/or tosylated monomers using HTPB as initiator. The presence of the butadiene block complicates the azidation step and reduces the storage stability of the azidic polymer. Nevertheless, the procedure allows modifying the binder properties by varying the type and lengths of the energetic blocks