Polymers as binders

Price, Propellants Plasticized with High Energy Compounds and Having High Energy Polymers as Binder , USP 3829336 (1974) CA 82,... 

Azide polymers such as GAP and BAMO are also used to formulate AP composite propellants in order to give improved specific impulses compared with those of the above-mentioned AP-HTPB propellants. Since azide polymers are energetic materials that burn by themselves, the use of azide polymers as binders of AP particles, with or without aluminum particles, increases the specific impulse compared to those of AP-HTPB propellants. As shown in Fig. 4.15, the maximum of 260 s is obtained at (AP) = 0.80 and is approximately 12 % higher than that of an AP-HTPB propellant because the maximum loading density of AP particles is obtained at about (AP) = 0.86 in the formulation of AP composite propellants. Since the molecular mass of the combustion products. Mg, remains relatively unchanged in the region above (AP) = 0.8, decreases rapidly as (AP) increases. 

The copolymer of vinyl ferrocene (VF) and butadiene has also been reported in the literature for use as a binder for composite propellants. It does not require any burn-rate (BR) accelerator because of the presence of iron (Fe) in vinyl ferrocene which is converted to finely divided Fe203 (a well-known BR accelerator) during combustion. A few groups of scientists have also studied fluorocarbon polymers as binders for composite propellants because of their excellent compatibility with oxidizers and fuels coupled with high density. Accordingly, Kel-F elastomer (a copolymer of vinylidene fluoride and chlorotrifluoroethylene, trade name of 3M, USA) and Viton-A (copolymer of hexafluoropropylene and vinylidene fluoride, trade name of Du Pont, USA) have also been reported for this purpose. The structures of Kel-F 800 [Structure (4.13)] and Viton-A [Structure (4.14)] are ... 

Marvola M. Nykanen P, Rautio S. Isonen N. Autere A-M. Enteric polymers as binders and coating materials in mulUpIc-unit site-specific drug delivery systems. Eur J Pharm Sci 1999 7 259-67-... 

On account of their higher electrical conductivity, silicate esters have clear advantages over organic polymers as binders. The resistivity of a one-pack silicate ester zinc dust paint is ca. 1 x 10 O cm, i.e., two to three orders of magnitude lower than that of commercially available purely organic systems with a comparable zinc content. 

Schuetz JE (1986) Methylcellulose Polymers as Binders for Extrusion of Ceramics. J Ceramic Bulletin vol 65 No 12 pp 1556-1559... 

The rough surface of ceramic filter media promotes adsorption of particles and bridging. Sintering of chamotte with a binder results in large blocks from which filter media of any desired shape can be obtained. Using synthetic polymers as binders, ceramic filter media that do not contain plugged pores are obtained. 

The idea of using polymers as binders for particulate bioceramics to prepare biocomposites with improved processing and retention characteristics and to overcome the problem of poor mechanical properties was reported. Poly(rac-lactide) (PDLLA) is a thermoplastic biodegradable, resorbable, and biocompatible aliphatic polyester, which in recent years received significant attention in the biomedical research field. It was also generally viewed as a polymer of the future because... 

Typical thermoplastic polymers as binders in HT-PEM bipolar plates are polyphenylensulfide (PPS), polyetheretherketone (PEEK), and derivatives of polyphenylsulfone (PSU). Looking at the plastics pyramid (Fig. 19.1), all of these polymers are in the upper right region of high temperature stability and semi-crystallinity. These polymers safely resist the acid and oxygen contact and provide heat deflection temperature far above the operating point of a high temperature PEM fuel cell. 

SILICON CARBIDE PRECERAMIC POLYMERS AS BINDERS FOR CERAMIC POWDERS... 

The procedures that we developed to evaluate preceramic polymers as binders are summarized in the following five steps. (1) pyrolyze a sample of bulk polymer to -1800 °C to obtain a stable ceramic char. As is shown in Figure 1 all of the polymers, if sufficient levels of carbon are present, afford stable chars by 1800 °C under an inert atmosphere. 

Yajima, S., Shishido, T., and Hamano, M. (1977) "SiC and S13N4 Sintered Bodies with New Borodiphenylsiloxanre Polymers as Binder" Nature (London), 266, 522-24. 

Silicon Carbide Preceramic Polymers as Binders for Ceramic Powders... 

Schurtz, J. R, Methylcellulose polymers as binders for extrusion of ceramics, in 39th Pacific Coast Regional Meeting (1986). 

In order to increase the stability, HPAs were incorporated in sols of alumina [11] and silica [12]. HPAs immobilized on supports like silica, although stable in the presence of water, could not be used as electrolytes in fuel cells in the powdered form. For this reason, composite membranes [13, 14] have been developed, using a polymer as binder for the formation of thermally and mechanically resistant membranes with low gas permeability and silicotungstic acid or phosphotungstic acid immobilized on silica as the inorganic proton conductor. 

The pristine PEDOT PSS dispersion in water has to be adjusted to meet the requirements of the specific deposition technique and to obtain uniform films. Important properties that determine the film quality are the viscosity, the surface tension, and the adhesion to the substrate. This can be done by using different grades of PEDOTrPSS, which differ in solids content, the ratio of PEDOT to PSS, the gel particle distribution, or by the addition of water soluble or dispersible additives (i.e. surfactants, stabilizers, and cross-linking agents or inert polymers as binders). Several ready-to-use formulations optimized for specific applications and deposition techniques are commercially available. For a discussion of common componenfs in formulations and their function refer to Chapter 10, Section 10.4. 

Generally coating compositions consist of quite a few different raw materials. Emulsion polymers as binder as well as pigments and extenders are the most crucial and basic constituents. They usually make up for the major part of a coating. However, they cannot be formulated into a paint that fulfils the required application properties. Additives have to be employed to adjust flow behaviour, ensure a proper dispersing of the pigments, improve film formation, control foam formation, prevent microbiological attack etc. (Bielemann, 2000). 

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