¹³C Spin−Lattice Relaxation Times and NOE Related Studies of Hydroxyl-Terminated Polybutadiene (HTPB)

Abstract

Hydroxyl-terminated polybutadiene, HTPB, carbon-13 spin-lattice(T 1) and nuclear Overhauser effect (NOE) relaxations data, obtained as a function of temperature (-50 to +70°C), in CDCl3, suggest that a log 2 distribution model is the most appropriate, in describing HTPB chain segmental motions. The local segmental motions are the major sources of relaxations, for the HTPB protonated carbons. The relaxation data show the chain segmental motions taking place in very short time intervals (on the order of tenth of a nanosecond). The activation energies of such conversions, from one conformer to another, are found to be on the order of kilojoules.

Synthesis of Propargyl‐Terminated Polybutadiene and Properties of Polytriazole Elastomers

“…By the structure of the HTPB, although it is polymerized from 1,3-butadiene monomer, the isomerization can occur during the polymerization process, mainly including 1,2 addition, and 1,4 addition, which results in 1,4 trans, 1,2 vinyl, and 1,4 cis structure in the main chain of HTPB. Among them, four types of carbon (A, E, F, D) in the 1,2 addition structure correspond to 142.85 ppm, 41.64 ppm, 38.44 ppm and 114.31 ppm respectively; only two types of carbon (G, B) in the trans 1,4 addition structure correspond to 32.94 ppm and 130.35 ppm respectively; two different types of carbon (H, C), corresponding to 27.45 ppm and 129.46 ppm, are also found in the cis-1,4 addition structure [29]. Because the hydroxyl groups of HTPB are modified, it is particularly important to find the carbon that is connected with hydroxyl terminated groups.…”

Oxidation of benzhydrol by tributylammonium chlorochromate: a kinetic and mechanistic study

“…In recent years, some new chromium(VI) based reagents like tetramethylammonium fluorochromate [1], N-methyl benzylammonium fluorochromate [2], benzyltrimethylammonium fluorochromate [3], tripropylammonium fluorochromate [4], benzyltriethylammonium chlorochromate [5], tetrapropylammonium bromochromate and tetrabutylammonium bromochromate [6] were proposed. Tributylammonium chlorochromate (TriBACC) is also one of such compounds used for the oxidation of alcohols.…”

Thermal stability and kinetic of decomposition of nitrated HTPB

“…Hydroxyl-terminated polybutadiene (HTPB) has long been one of the most commonly used polymers in composite solid propellants and plastic bonded explosives (PBXs) because of its unique, physicochemical properties as thermal dynamic, pyrolysis, elasticity, toughness and durability [1][2][3][4]. However, the use of this inert binder brings down the overall energy of the above systems.…”