Binders characteristics

Tardos, G. I., Measurement of Powder and Binder Characteristics which Determine Agglomerate Growth during Granulation, Proc. of the 25th Israel Conf onMech. Eng., Haifa, Israel (1994)... 

The dimensional stability of the propellant grain is the result of the chemically crosslinked polymeric binder. Many of the mechanical properties of the final cured propellant will be dictated by binder characteristics. Another important consideration is the effect of filler, owing to its presence as well as its degree of interaction with the binder. 

Three tasks were pursued in the research and development phase of the Gulf Canada SA process SA binder characteristics, processing technology, and design technology. This chapter summarizes and reports the progress which has been made towards commercial application of the acquired technology. 

The real problem is, of course, the determination of and correlations between process data as input for the model and its solutions. Such expressions are different for each situation, i.e. they depend on feed material and binder characteristics, equipment design and operation, process variations, final product properties, and many more. Data that can serve as input for the model equations must be obtained experimentally. Since access to commercial, often restricted or large scale operations is not available or possible, typically the determination of data and their correlation is based on model experiments. In addition to the difference in size and operation between the laboratory model and the real system, the gathering of data is interrupting and critically changing the process. 

The binder characteristics may be affected by certain additives, particularly the organic additives. Certain organic additives may have the tendency to stiffen the binder at lower temperatures, which may consequently increase the potential for thermal cracking. However, it was found that that the stiffening effect is related to binder and additive type (Croteau and Tessier 2008). 

The built-up roof membrane consists of bitumen, reinforced with roofing felts, and aggregates which protect the bitumen from the UV radiation and oxidation. Bituminous materials have been used since 3500 BC. Because of their waterproofing, preservative, and binder characteristics, they were utilized by the ancients for the construction of houses and roads. " Bituminous materials were also used by ancient civilizations such as Egyptians for construction, mummification, waterproofing, preservatives, and binders. 

Oxidizers. The characteristics of the oxidizer affect the baUistic and mechanical properties of a composite propellant as well as the processibihty. Oxidizers are selected to provide the best combination of available oxygen, high density, low heat of formation, and maximum gas volume in reaction with binders. Increases in oxidizer content increase the density, the adiabatic flame temperature, and the specific impulse of a propellant up to a maximum. The most commonly used inorganic oxidizer in both composite and nitroceUulose-based rocket propellant is ammonium perchlorate. The primary combustion products of an ammonium perchlorate propellant and a polymeric binder containing C, H, and O are CO2, H2, O2, and HCl. Ammonium nitrate has been used in slow burning propellants, and where a smokeless exhaust is requited. Nitramines such as RDX and HMX have also been used where maximum energy is essential. 

Formulation Aids. Formulation aids, which include carriers, binders, fillers (qv), plasticizers (qv), and film-formers, are ingredients used in processing to impart a particular physical state or textural characteristic. Table 5 gives an overview of the formulation aids used in the food industry. 

Small, complex-shaped glass articles such as thread guides for the textile industry and television gun mounts for the electronics industry are made by the multiform process. The dry-milled powder is mixed with an inorganic binder and a fluid vehicle, and then atomi2ed by a spray dryer into small, dried agglomerates of glass powder and binder with good flow characteristics. They are subsequently pressed to the desired shape and fired. 

Mineral spirits, a type of petroleum distillate popular for use in solvent-based house paints, consist mainly of aUphatic hydrocarbons with a trace of aromatics. This type of solvent finds use in oil- and alkyd-based house paints because of its good solvency with typical house paint binders and its relatively slow evaporation rate which imparts good bmshabiUty, open-time, and leveling. Other properties include lower odor, relatively lower cost, as well as safety and health hazard characteristics comparable to most other organic solvents. 

Starch monophosphates are quite useful in foods because of their superior freeze—thaw stabiUty. As thickeners in frozen gravy and frozen cream pie preparations, they are preferred to other starches. A pregelatinized starch phosphate has been developed (131) which is dispersible in cold water, for use in instant dessert powders and icings and nonfood uses such as core binders for metal molds, in papermaking to improve fold strength and surface characteristics, as a textile size, in aluminum refining, and as a detergent builder. 

Vinylidene Chloride Copolymer Latex. Vinyhdene chloride polymers are often made in emulsion, but usuaUy are isolated, dried, and used as conventional resins. Stable latices have been prepared and can be used direcdy for coatings (171—176). The principal apphcations for these materials are as barrier coatings on paper products and, more recently, on plastic films. The heat-seal characteristics of VDC copolymer coatings are equaUy valuable in many apphcations. They are also used as binders for paints and nonwoven fabrics (177). The use of special VDC copolymer latices for barrier laminating adhesives is growing, and the use of vinyhdene chloride copolymers in flame-resistant carpet backing is weU known (178—181). VDC latices can also be used to coat poly(ethylene terephthalate) (PET) bottles to retain carbon dioxide (182). 

Asphalt (bitumen) also occurs in various oil sand (also called tar sand) deposits which occur widely scattered through the world (17) and the bitumen is available by means of various extraction technologies. A review of the properties and character of the bitumen (18) suggests that, when used as an asphaltic binder, the bitumen compares favorably with specification-grade petroleum asphalts and may have superior aging characteristics and produce more water-resistant paving mixtures than the typical petroleum asphalts. 

The thickness of the tape is controUed by the sHp characteristics, the height of the doctor blade, the casting rate, and the pressure head of the sHp reservoir behind the doctor blade. SHp viscosities in the range of 1 5 Pa-s (10—50 P) are used to cast tapes at 5—100 cm/s. To achieve the desired strength and flexibUity in the green tape, tape casting slurries contain more binder than those used in sHp casting, as weU as a plasticizer to ensure flexibUity. 

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