Polybutadiene, hydroxyl-terminated HTPB

Liquid rubbers In order to improve the flexibihty of short glass fiber-reinforced epoxy composites, Kaynak et al. [53] modified the epoxy resin matrix with hydroxyl-terminated polybutadiene (HTPB) liquid mbber. A silane coupling agent was also used to improve the interfacial adhesion between glass fibers and epoxy matrix. However, Humpidge et al. [54] reported some unique processing problems for the resulting pasty mixmres when short textile fibers were incorporated in a hquid mbber medium. 

Fig. 2.13 Homopolymeric R45HT (hydroxyl terminated polybutadiene, HTPB).

The high-polymeric binders in use today include polysulfides (PS), polybutadieneacrylic acid (PBAA), polybutadiene-acrylonitrile (PBAN), polyurethane (PU) and carboxyl- and hydroxyl-terminated polybutadiene (CTPB and HTPB). 

Problem 4.11 Following are the vapor phase osmometry data for a standard polystyrene of known molecular weight and an experimental sample of hydroxyl terminated polybutadiene (HTPB) in toluene solutions at 70°C. Calculate the molecular weight of HTPB. 

Hydroxyl-terminated polybutadiene (HTPB) can be produced by such reactions. Low-molecular-weight (3000-10,000) versions of such elastomers are used as binders and liquid rubbers, which can be shaped more easily than the conventional high-viscosity elastomers. The liquid rubbers can be vulcanized by reactions of their specific end groups. Hydroxyl-ended... 

The polymeric hydrocarbon acts also as a binder for each particle to bond to, forming a propellant grain. Ammonium perchlorate (AP) is a typical crystalline oxidizer and hydroxyl-terminated polybutadiene (HTPB) is a typical polymeric fuel. When AP and HTPB decompose thermally on the propellant surface, oxidizer and fuel gases are produced and diffuse each other, and then react to produce high temperature combustion gases. 

Some other specialised polyester polyols, like polycarbonate and polycaprolactone, possess superior hydrolytic resistance. Aliphatic polyhydrocarbon polyol such as hydroxyl terminated polybutadiene (HTPB), is advantageous in many respects. These substances are resistant to acidic or basic hydrolysis, possess good adhesion and can be used where low polarity and good electrical insulation are required. 

Suspension I was prepared to simulate a solid rocket fuel and contained 76,5 percent by volume of solids in a hydroxyl terminated polybutadiene (HTPB) matrix in which di-octyl-adipate, EX)A, was used as an antioxidant. The matrix was a Newtonian fluid with a shear... 

The preparation of hydroxyl-terminated polybutadiene (HTPB) by free radical methods is not well documented. As shown in Table 5, four commercial organizations in the United States suppUed these products in 1968. Two of these use ionic polymerization, and of the remaining two, Goodrich and Sinclair, Goodrich is believed to use a free radical method of preparation. The method of production of Sinclair s product is not known. 

Hydroxyl-terminated polybutadiene can be prepared from polymers having two living ends by addition of oxides, aldehydes, or ketones [279,282,285]. HTPB prepared by ionic methods is commercially available from Phillips Petroleum Company and General Tire and Rubber Company. The former supplies a secondary hydroxyl-terminated product and General Tire and Rubber Company produces both primary and secondary hydroxyl-terminated polybutadiene. 

New elastomeric networks based on saturated ethylene-propylene rubbers grafted with succinic anhydride groups (EPR-g-SA) crosslinked with a hydroxyl-terminated polybutadiene (HTPB) are hereafter described. Infrared techniques are employed to follow the kinetics of the monoesterification reaction and to assess its potential thermoreversibility, either on the macromolecular system (EPR-g-SA-I-HTPB), or on a model system, formed by EPR-g-SA and a low molecular weight diol, namely 1,9-nonandiol. 

Two separate series of experiments were carried out in order to study the reactivity of EPR-g-SA towards low Mw diols with or without the addition of a tertiary amine as catalyst, and the reactivity of EPR-g-SA towards a long-chain hydroxyl-terminated polybutadiene (HTPB). For both of them, the same experimental procedure was followed to ensure an intimate mixing of the reactants, they were all dissolved in a common solvent at room temperature and in a certain stoichiometric amount (in solution, the kinetics of esterification is very slow, thus the degree of reaction is negligible). Subsequently, the solvent is quickly removed by evaporation under vacuum at room temperature directly onto KBr disks to obtain a film which is used for IR analysis. 

The isocyanate-end capped polybutadiene (PBNCO) was prepared by a condensation reaction of diisocyanate with the hydroxyl terminal groups of rubber chains. In order to limit chain extension of HTPB through coupling reaction with TDI, a small excess of 5% with respect to the stoichiometric quantities of the latter was used. Larger excess are useless, as with an appropriate choice of the (reaction temperature, only the isocyanate group in para position will react [87]. The reaction was followed by DSC and IR spectroscopy. 

Nikje MMA, Mozaffari Z. Chemoselective epoxidation of hydroxyl-terminated polybutadiene (HTPB) using in-situ generated dimethyl dioxirane (DMD). Des Monomers Polym. 2007 10 67-77. 

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