Superior improvement in thermo-mechanical properties of polyurethane based on glycidyl azide polymer/polyethylene adipat
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Superior improvement in thermo‑mechanical properties of polyurethane based on glycidyl azide polymer/ polyethylene adipate Yadollah Bayat1 · Hasan Kashef Shandi1 · Tayebe Khanlari1 Received: 16 June 2020 / Revised: 20 October 2020 / Accepted: 23 October 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract In this study, to improve the thermo-mechanical properties of glycidyl azide polymer (GAP)-based elastomers, polyethylene adipate (PEA) with different molecular weights was successfully synthesized using a solvent-free method. GAP was synthesized by cationic ring-opening polymerization of epichlorohydrin and then azidation. The structure of PEA and GAP was characterized by FTIR, 1HNMR, and GPC. The compatibility of GAP/PEA at various weight ratio blends was investigated by differential scanning calorimetry. The result indicated GAP/PEA is compatible, and addition of PEA to GAP leads to the decrease in glass transition temperature. The copolyurethane elastomers were prepared by cross-linking GAP and PEA at various weight ratios using isophorone diisocyanate and N100 as curing agent. The thermomechanical properties were evaluated by dynamic mechanical analysis and tensile test. Based on the results, with increasing weight ratios of PEA, the copolyurethane elastomers displayed an increase in tensile strength (6.97 MPa) and elongation (792%) in comparison with GAP. Keywords Glycidyl azide polymer (GAP) · Polyethylene adipate (PEA) · Blending · Copolyurethane elastomer · Mechanical properties
Introduction Solid composite propellants consist of oxidizers, metallic fuels, binders, plasticizer, and other additives [1–3]. Among these components, the binder plays an important role in binding the components of the propellant [4–6]. In the last decades, the use of polymeric binders including energetic functional groups in polymer backbones (such as nitro, azido, and difluoramine) [7, 8] instead of usual and inert binders * Yadollah Bayat [email protected] 1
Faculty of Chemistry and Chemical Engineering, Malek Ashtar University of Technology, P.O. Box16765‑3454, Tehran, Iran
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such as hydroxyl-terminated polyether (HTPE), hydroxyl-terminated polybutadiene (HTPB), hydroxy‐terminated polyisoprene (HTPI), etc. [9, 10], to improve highperformance propellants is a novel field in energetic material [11–13]. Energetic polymeric binders improve the performance of the propellants by increasing the total energy of the formulations [14–16]. Among the energetic polymeric binders, azide polymers are considered in the solid composite propellant formulation. Glycidyl azide polymer (GAP) is a unique binder used in the propellant industry due to high density with positive heat of formation (+ 117.2 kcal/mol), a low tendency for detonation, and good compatibility with all high-energy oxidizers [17–20]. The usage of this binder in formulation leads to an increase in specific impulse, burning rate, decrease releases gas in combustion, and the best candidate polymer for chl
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