Fillers applications

Filler, "Application of the Detonation Head Model to the Mass Loading of Explosives , UnivUtahTechRept XLV1 (1955) Contract N7-onr-45107 4) Dunkle s Syllabus (1957-... 

Hemmings, R. T. Berry, E. E. 1986. Evaluations of Plastic Filler Applications for Leached Fly Ash. Electric Power Research Institute Report No. CS4765. 

The production process is able to produce all three crystal modifications of calcium carbonate and a wide variety of particle sizes and shapes, including plates and acicular forms [107]. However, only the calcite form with a rhombic shape and a low aspect ratio seems to have found much commercial application in polymers. For filler applications the particles have an ultimate particle size of 50-100 nanometers, a specific surface area of 15-25 m g and a low aspect ratio. 

Classification by particle size is helpful in classification since particle size will affect performance but, by itself, falls short as a criterion when selecting fillers for applications which require certain levels of conductivity (thermal or electric) or of chemical interaction, etc. In one publication, materials were divided into particulates, fibers, and colorants. These distinctions are not helpful for a material designer. For a classification to be useful in filler applications, it must include the most important properties of fillers which affect the resultant material. The eight most important are as follows ... 

In filler applications, the silicates group of greatest interest is in the subclass of tektosilicates. Four minerals (quartz, tridymite, cristobalite, and opal) belong to the silica group and three of them (quartz, cristobalite, and opal) are used as fillers or materials for their production. 

Applications General method also used in filler applications. The results give information on mobility of molecules in the presence of filler, changes in the structure of the matrix due to interaction with filler, the effect of fillers on matrix degradation, microphase separation, and other related phenomena. 

The laminates are not the main focus of this book and thus only a few examples from the current literature are given on filler applications in these products. 

Resin transfer moulding (RTM) is a low-pressure variation of transfer moulding where, instead of granules or preforms, a pre-mixed resin and catalyst (hardener) is injected into a closed mould containing dry glass, carbon or aramid fibre reinforcement. When the resin has cooled, the mould is opened and the composite part ejected. The resins used include polyester, vinylester, epoxies, phenolics and methyl methacrylate combined with pigments and fillers. Applications include small complex aircraft and automotive components as well as automotive body parts, baths and containers. 

Phenol-formaldehyde (PF) resins have been successfully used in FRP materials as inherently fire retardant resins, because they have low flame spread indexes and produce very Utde smoke or toxic fumes without the assistance of other fire retardant fillers. Applications include many fire-sensitive areas such as rocket... 

Portland cements extended with class F fly ash from coal burning power plants may be used for filler applications (Reeves, 1991) and for lightweight cement slurries. The fly ash content may reach up to 50 wt%. 

Today, most commercial products for filler applications appear to be based on maleic anhydride, rather than acrylic acid, and what comparative data are available suggest that the maleated forms are the more effective and can be used at lower levels. The acrylic acid forms have higher functionality levels than the maleated ones. 

The resins used include polyester, vinylester, epoxies, phenolics and methyl methacrylate combined with pigments and fillers. Applications include small complex aircraft and automotive components as well as automotive body parts, baths and containers. 

The conditions can be adjusted to give products with specific surface areas in the range 25-700 mVg". For filler applications, the range 25-250 mVg is the most favoured. The products are usually isolated by filtering and washing on filter presses. 

Low-cost carbon fibers are produced from an isotropic pitch with a low-softening point. The precursor is melt-spun, thermoset at relatively low temperature, and carbonized. The resulting fibers generally have low strength and modulus ( 35 - 70 GPa). They are suitable for insulation and filler applications. Their cost dropped to less than 20/kg in 1992. ... 

Powders are commonly used as fillers for rubber mixes. The most popular are carbon black, silica, kaolin, or more modem like graphene, fullerenes and carbon nanotubes. The nature of their surface is the main attribute of fillers, as surface energy and specific area determine the compatibility of filler with mbber matrix and the affinity to other c ingredients. One of the major problems is the tendency of fillers to agglomeration - formation of bigger secondary stmctures, associated with lower level of filler dispersion, what is reflected by the decrease of mechanical properties of mbber vulcanizates [1]. Surface modification of powder can improve interaction between mbber matrix and filler. Application of low-temperature plasma treatment for this purpose has been drown increasing attention recently [2, 3]. 

A two-part, microballoon filled epoxy potting compound for low-density mouldings, honeycomb inserts, edging and filler application. 

Traditional methods of additive analysis and the required instruments are often expensive and require the efforts of a skilled technician or chemist. In some cases a single instmment can not provide analyses for the wide variety of additives a particular organisation utilises. Additionally, laboratory techniques rarely provide results in a timely fashion. Determination of physical properties is not the least important if one thinks of pigments, talc and other fillers. Application of spectroscopic techniques to polymer production processes permits real-time measurement of those qualitative variables that form the polymer manufacturing specification, i.e. both chemical properties (composition, additive concentration) and physical properties (such as melt index, density). On-line analysis may intercept plant problems such as computer error, mechanical problems and human error with respect to additive incorporation in the resin production. Characterisation and quantitative determination of additives in technical polymers is an important but difficult issue in process and quality control. 

Calcium carbonate has a number of crystal modifications,but the calcite form is the one that is principally used for filler applications. Pure calcite is a relatively soft material (Moh hardness 3.0) with a specific gravity of 2.7. 

The charge of pigment dispersants is usually anionic but, in some applications, cationic dispersants are preferred. They are seldom needed in coating color pigments, but they are beneficial in pigment dispersions meant for filler applications or for specialty coating appHcations. Cationic dispersants are typically cationically charged polymeric compounds e.g. modified polyethylenimines, polyvinylamines. Usually they do not act as effectively as anionic dispersants. 

Mica can vary in color, but this is offset by better physical properties than talc in some filler applications. There are many forms of this widely distributed mineral. The naturally thin sheets of mica can be exploited by exfoliation to the nanothickness range. 

Wollastonite is a mineral that has enjoyed some success as an asbestos replacement as well as finding niche markets on its own. The shape is elongated so there is reinforcement as well as filler applications. A large use is in asbestos replacement applications. 

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