Rheological and thermal properties of glycidyl azide polyol‐based energetic thermoplastic polyurethane elastomers

Abstract

The purpose of this study was to investigate the effects of polyol on glycidyl azide polyol (GAP)‐based energetic thermoplastic polyurethane elastomers (ETPEs). Briefly, a series of GAP/polyol‐based ETPEs (GAP/polyol ETPEs) with different copolyol ratios and hard segment contents were synthesized using GAP‐diol with common polyol and 4,4‐methylenebis(phenylisocyanate)‐extended 1,5‐pentanediol as soft and hard segments, respectively, by solution polymerization in dimethylformamide. The three types of polyols used were poly(tetramethylene ether) glycol (PTMG), polycarbonate‐diol (PCL‐diol) and polycaprolactone‐diol (PCD‐diol). The synthesized GAP/polyol ETPEs were identified and characterized using Fourier transform infrared and 1H NMR spectroscopy, differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and rheometric mechanical spectrometry. For GAP/PCL ETPEs with lower hard segment content, DSC results showed that the GAP segment failed to interact with either the PCL segment or PCL melting. In addition, the results of DMA showed that the presence of PCL segments in ETPEs improved the storage modulus below the melting temperature of the PCL block. Further, the crystalline PCL segments were attributed to reinforcing the ETPEs in a manner similar to that of the hard domain. As the hard segment content increased in the GAP/polyol ETPEs, both GAP/PTMG ETPEs and GAP/PCL ETPEs exhibited microphase separation transitions, while rheological experiments demonstrated a sudden decrease in complex viscosity in neighboring microphase separation transitions. © 2012 Society of Chemical Industry

Synthesis of Propargyl‐Terminated Polybutadiene and Properties of Polytriazole Elastomers

“…It can be seen from the diagram that a maximum value occurs around À 62°C in the tanδ-T curves of the elastomers, which corresponds to the glass transition temperature of the elastomer. At the same time, in the DMA curves of S4 and S5, a broad peak appears around 0°C, corresponding to azide curing agent [31]. In the curve of S1, the absence of a peak at 0°C shows that most of the GAPa is involved in the reaction with an alkynyl group.…”

Azidated Ether-Butadiene-Ether Block Copolymers as Binders for Solid Propellants

“…N,N dimethylacetamide (99%), toluene (99,8%), dimethyl sulfoxide (DMSO) (99.7%), dimethylformamide (DMF) (99.8%), methanol (99.9%), ethanol (99.9%), sodium azide (>99.5%), boron trifluoride tetrahydrofuranate (BTF THF), triethylamine (TEA) (≥99%), 3hydroxy-methyl-3-methyloxetane (HMMO) (98%), glycidol (G) (96%), toluene-4-sulfonyl chloride (TsCl) (≥99%), sodium chloride (>99%), sodium hydroxide (>98%), sodium carbonate anhydrous, sodium bicarbonate (>99.7%), magnesium sulfate (>99.5%), phosphorus pentoxide, hydrochloric acid, potassium hydroxide were used as received. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 11…”

“…In the case of azidic functionalities, there is a slightly longer list of candidates, but the most studied one is glycidyl azide polymer (GAP). GAP has been employed also as a plasticizer [4] and several publications may be found concerning its 4 synthesis as well as its thermal behavior and explosive properties [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25]. The GAP synthesis was first described in a patent filed in 1972 by Vandenburg [26] who did azidation of polyepichlorohydrin (PECH) by using sodium azide in dimethylformamide.…”

Structure and mechanical properties of novel composites based on glycidyl azide polymer and propargyl‐terminated polybutadiene as potential binder of solid propellant

“…1 Moreover, glycidyl azide polymer (GAP) and hydroxyl-terminated polybutadiene (HTPB) are the most common polymers for propellant binders, and generally crosslinked by diisocyanate according to the traditional isocyanate curing system. 5,6 As a result, the polyurethane-type binder systems based on GAP and/or HTPB have been explored, and the crucial crosslinked structure and mechanical performances were optimized by changing the diisocyanate categories, 7-9 applying chain extender and/or crosslinker of small molecular polyols, 10 regulating the molar ratio of isocyanate group versus hydroxyl group, 7,10 incorporating other polymer component, [11][12][13][14] and so on. Furthermore, GAP shows a good compatibility with advanced oxidizer like ammonium dinitramide.…”

“…4 At the same time, HTPB exhibits other excellent properties for the application of rocket propellant, such as low glass transition temperature, high flexibility, hydrolytic stability, and resistance to solvents. 5,6 As a result, the polyurethane-type binder systems based on GAP and/or HTPB have been explored, and the crucial crosslinked structure and mechanical performances were optimized by changing the diisocyanate categories, [7][8][9] applying chain extender and/or crosslinker of small molecular polyols, 10 regulating the molar ratio of isocyanate group versus hydroxyl group, 7,10 incorporating other polymer component, [11][12][13][14] and so on. To make full use of the advantages of GAP and HTPB, the composites of GAP and HTPB had been attempted to develop.…”