Thermoset polyurethane elastomers made from poly(3,3-bis(azidomethyl) oxetane with tetrahydrofuran) and various multifunctional isocyanate cross-linkers were compared to uncover a new mechanism of modulating the mechanical properties. Extra hydrogen bonding motifs, such as urethane or urea, built in proved essentially determine stiffness toughness elastomers, while covalent cross-linking densities both networks controlled strictly at same level. The impact interchain H-bonding on properties...

Here, we report a dual-stage polymerization system based on thermally cured polyurethane formation and subsequent UV-activated cross-link reactions, applicable to the fabrication of programmable 3D structures high-resolution features. Glycidyl azide polymer (GAP) can react with isocyanate cross-linkers obtain relatively soft intermediate polymer, upon UV exposure, nitrene species are subsequently generated induce highly cross-linked network. The photoreaction at second stage increases...

With significant progress in space technology, waste propellant is expected to be generated large quantities, and technology for recovering ingredients from this offers economic benefits, energy conservation, ecological advantages. In study, recyclable polyether propellants were produced using thiourethane covalent-adaptable networks (CANs). Isocyanate-terminated crosslinkers synthesized by reacting trifunctional thiol TMPTMP with HDI or TDI, then cured hydroxyl-terminated (HTPE) form...

In this paper, highly spherical and porous ammonium dinitramide (ADN) crystals were prepared by using solvent-antisolvent crystallization method. To explore the growth mechanism of ADN in different solvent environments,...

Abstract Thermoset materials, known for their stable topology structure, have garnered significant interest in recent years applications coatings, foam, adhesives, and other fields. In general, the low chemical crosslinking density of thermoset materials means poor mechanical properties. this study, we adjusted topological structure elastomers through formula design controlled hard segment content at same level. The tensile test results show that as elastomer decreases, fracture strength...

In order to explore the application of click chemistry in field elastomer materials, comparison between properties polyurethane and polytriazole elastomers has been carried out. Propargyl-terminated ethylene oxide-tetrahydrofuran copolymer (PTPET) prepared from (PET) by end modification. Using polyisocyanate N100 polyazide compounds as cross-linkers, PET PTPET have through urethane copper-catalyzed azide-alkyne huisgen [3 + 2] dipolar cycloaddition reactions, respectively. Mechanical...

Ethylene oxide–tetrahydrofuran copolyether (P(E-co-T)) crosslinked with isocyanate Desmodur (N100) is widely used as the binder system in solid energetic propellant. The effect of its cross-linking degree on physical properties important for evaluation propellant binders. In this work, an efficient method was presented simulating process, predicting microscopic behaviors and macroperformances cross-linked P(E-co-T)–N100 systems. During simulation network forming, initial mixture model...

Abstract Considering the high toxicity of toluene diisocyanate (TDI) and low reactivity isophorone (IPDI), a low‐toxicity curing agent, dimer acid (DDI), was used to cross‐link HTPB elastomers propellants. The unique long‐chain structure DDI not only ensures elastic modulus tensile strength elastomer, but also improves flexibility some extent. long flexible chains promote segment movement, which is very important for formation hydrogen bonds between segments. chemical cross‐linking network...

To improve mechanical properties of glycidyl azide polymer (GAP) elastomer, primary hydroxyl terminated GAP prepolymer (PH-GAP) has been synthesized by end-capping modification using carbamate reaction. FTIR, 13C-NMR, GPC results indicate that the functionality, molecular weight, and weight distribution PH-GAP are consistent with those original GAP. Mechanical tests elastomer much better than elastomer. Swelling discover apparent network chain in is less perfect structure. Network structure...

Abstract The influence of dimethyl hydantoin (DMH) on the mechanical properties GAP/RDX propellant was studied by molecular dynamics (MD) and dissipative particle (DPD) simulation. results showed that binding energies ( E ) between GAP different surfaces RDX were in order (010)>(001)>(100). Compared to GAP/RDX, grafted with DMH (GAP‐DMH) exhibits higher RDX, sequence turns (001)>(010)>(100). Radial distribution simulations demonstrated GAP‐DMH is more close increasing van der...

ABSTRACT The polytriazole polyether elastomers were prepared by the propargyl‐terminated ethylene oxide‐tetrahydrofuran [PTP(E‐ co ‐T)] prepolymer and multi‐azide group glycidyl ether with different curing parameter R . relationship between network structure, mechanical properties, crystallization behaviors of investigated swelling testing, tensile testing machine, differential scanning calorimetry (DSC), wide‐angle X‐ray diffraction (WAXD), in situ scattering at 60, 20, −40 °C,...

In order to reveal the relationship between 3,3-bis(azidomethyl) oxetane-tetrahydrofuran copolyether (P(BAMO-THF)) microstructure and its macro properties, segment sequence structure of a kind P(BAMO-THF) was characterized using quantitative 13C-NMR analysis. It found that is composed equimolar comonomers whose randomness factor (R) 1.09, belonging quasi-ideal random copolymer. Combining DSC polarizing optical microscopy, it verified thermal-effect 28 °C 41 attributes melting...

To improve the mechanical properties of polyurethane cross-linked poly (ethylene oxide-co-tetrahydrofuran) (P(E-co-T)) elastomers at room temperature, using and high-molecular-weight polyethylene glycol (PEG) as raw materials polyisocyanate N100 curing agent, a series blended polyether were prepared by changing elastomer-curing parameter R value (n(-NCO)/n(-OH)) P(E-co-T)/PEG ratio. Equilibrium swelling measurements showed that chemical cross-linkage tended to decrease with decreasing value,...

Abstract The thermal decomposition characteristics and fuel oxidation mechanism of ammonium dinitramide (ADN)‐based liquid propellant are great practical significance, but it is difficult to detect the whole intermediates products using traditional experimental methods. In this paper, ADN‐based at different temperatures (1500, 2000, 2500, 3000 K) was simulated reactive molecular dynamics method. effect temperature on distribution main were investigated. results showed that played a role in...

The relationship between temperature and the mechanical properties of an end cross-linked equal molar random copolyether elastomer 3,3-bis(azidomethyl)oxetane tetrahydrofuran (P(BAMO-r-THF)) was investigated. During this investigation, performances two P(BAMO-r-THF) elastomers with different thermal histories were compared at temperatures. as prepared 20 °C (denoted S0) exhibited semi-crystallization morphology. Wide angle X-ray diffraction analysis indicated that crystal grains within S0...

ABSTRACT Polyurethanes were synthesized based on an amorphous polyester polyol, and different chain extenders, comparing the universally accepted symmetric extender (1,4‐butanediol) with asymmetric (1,2‐propanediol) extender. The effect of incorporating a crystalline polyol polyhexamethylene adipate (PHMA) was investigated. resulting morphologies tensile properties are dramatically different. Based thermal infrared data obtained, sample exhibits phase‐separated morphology, which can change...

Propargyl terminal Polybutadiene (PTPB) was successfully prepared through hydroxyl polybutadiene (HTPB) end-capping modification. The FTIR and 13C NMR results indicated that the HTPB thoroughly replaced yielded target product, PTPB, with a theoretical propargyl content of 0.66 mmol g-1. In comparison HTPB, PTPB has lower viscosity. Using 1,6-diazide hexane as curing agent, polytriazole crosslinked (PTriPB) elastomers various functional molar ratios (R) were by CuAAC reaction, glass...

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