Properties of hydroxyl‐terminated polybutadiene‐urethane systems

Abstract

synopsisThe properties of liquid hydroxyl-terminated polybutadiene (HTPB) stocks crosslinked with isocyanates of different functionalities were intensively investigated. The stocks were modified by inclusion of small proportions of various low molecular weight diols to increase the urethane concentration. The following studies were carried out:(1) the system functionality was varied at a low and relatively constant urethane concentration; (2) the system functionality was varied with the urethane concentration constant but at a higher level; (3) at a constant crosslink density, the urethane concentration was varied by adding low molecular weight diols; and (4) the structure of the diols used in the previous experiments was varied.A correlation between the per cent functional groups reacted, the average functionality of the system, and the mechanical properties of simple HTPB stocks was attained. Furthermore, a correlation was found between mechanical properties and urethane concentration at constant crosslink density. The properties of the stocks could be varied enormously by addition of low molecular weight diols in relatively small proportions by weight. The structure and concentrations of these diols caused significant variations in the elongation-at-break and tensile strength values.

Characterization of the network structure of hydroxyl terminated poly(butadiene) elastomers prepared by different reactive systems

“…Therefore, a lot of work has been devoted to the characterization of HTPB. [1][2][3][4][5] The most commonly used reactants for end linking of HTPB prepolymer are di-or polyfunctional isocyanates, and the resultant network has the polyurethane structure. 4 -7 The HTPB prepolymer ideally contains two hydroxyl end groups.…”

“…In the end-linking reactions, chain extension and branching can be controlled by adjusting the weight ratio of the two functional reactant to polyfunctional reactants. 4,5,7 Therefore, the primary objective of this study is to determine the thermodynamic solution properties of HTPB in two different solvents; second, to compare the effect of the type of reactive system on the endlinking of HTPB chains; and last, to characterize the network structure of HTPB elastomers by following the swelling, solubility and mechanical measurements.…”

Mechanical properties of HTPB-IPDI-based elastomers

“…3 The effect of crosslinking agents on the structure and properties of polyurethane elastomer composite poly-Polyurethane elastomers are widely used engimers has been studied for various mixtures of dineering materials and are well known for their cumyl peroxide and toluene diisocyanate dimer, 4 outstanding mechanical, thermal, and adhesive trimethylolpropane and toluene diisocyanate, 5,6 properties. Polyurethanes are also used as a liner and trimethylolpropane and 4,4-diphenylmethmaterial for HTPB-based composite solid propelane diisocyanate.…”

Synthesis of Propargyl‐Terminated Polybutadiene and Properties of Polytriazole Elastomers

“…Polyurethane (NHÀ COOÀ ) binder system formed by the reaction of hydroxyl-terminated (À OH) polymer with isocyanate (À NCO), due to its high wear resistance, chemical resistance, excellent mechanical properties and some additional application properties, is widely used in various types of rocket propellants. HTPB propellant has the best comprehensive performance and the widest application because of its low glass transition temperature, low viscosity, excellent mechanical properties, good processing behaviors, good electrical insulation and high oxidation stability [2]. But for the polyurethane system, the isocyanate curing agent reacts with not only hydroxyl, but also amino, water, urea and carbamate easily.…”