Synthesis and Characterization of Azido Esters as Green Energetic Plasticizers

Three azido-esters based green energetic plasticizers were synthesized from their chlorides including DEGBAA (diethyleneglycol bis(azidoacetate)), DPGBAA (dipropyleneglycol bis(azidoacetate)) and HETTAA (hexanetriol tris(azidoacetate)). The syntheses were carried out in a two-step process: the first step was esterification of glycol or triol using chloroacetyl chloride, and the second step was substitution of chloracetate with sodium azide that yields corresponding azido derivatives. The parameters of synthesis such as molar ratio of hydroxyl and acyl groups, and amount and type of solvent (dimethyl sulfoxide and dimethyl formamide) were optimized to achieve maximal conversion and purity of the products. The obtained products were characterized by elemental analysis, nuclear magnetic resonance (NMR), and infrared vibrational spectroscopy (IR). Thermal and rheological properties were determined using DSC and Modular Compact Rheometer. Condensed phase heat of formation and several properties important for high-energy materials were predicted from quantum chemical calculations using CBS-4M method. Detonation and combustion performance of energetic compounds were calculated with the thermochemical computer code EXPLO5V06.05. using the predicted heats of formation and experimentally determined densities as input. The energetic and physical properties of the synthesized compounds were compared to the literature data for common plasticizers

Reuse potential of functionalized thermoplastic waste as reinforcement for thermoset polymers: Mechanical properties and erosion resistance

Two types of polymer waste materials, poly(ethylene terephthalate) (PET) and polycarbonate based Colombian Resin (CR-39), were used for the designing of fully recycled composite materials. Waste PET was employed for the synthesis of thermoset unsaturated polyester resin (UPR), while CR-39 was used as reinforcement in the UPR matrix. Prior to mixing, CR-39 particles were subjected to oxidation and chemical activation using acids/base and ethanol amine, respectively. The effect of the modifier type and variable loading of the activated CR-39 particles on mechanical and dynamic-mechanical properties of the corresponding composites was investigated. The greatest improvement in the tensile and flexural strength of UPR resin was achieved with the composite containing 0.5 wt% of amine activated filler particles, 96.0% and 62.2%, respectively. The Arrhenius equation was used to calculate the activation energy for glass transition from dynamic mechanical properties measured at various frequencies. The activation energy of the main transition for UPR resin and composites were calculated to be 173 and 350 kJ center dot mol(-1) indicating that reinforcement results in an increase in the energy barrier to macromolecules viscoelastic relaxation. In addition, erosion resistance was studied during exposure of samples to cavitation tests. According to the obtained results, these materials can be applied in construction and mining industry