Pretreatment method, surface fillers

Methods of filler pretreatment if coupling agent is required, filler is usually pretreated before incorporation fluidized bed glass fiber impregnation in sheet forming surface modification of chalk and carbon fiber by acetylene gas plasma stearic and oleic acids phosphate coating for talc "... 

Methods of filler pretreatment drying especially for extrusion the surface of the injection molded part is affected by moisture... 

For cold-curing epoxides wide variations in adhesive material properties are possible, with different combinations of resin, hardener, filler, and the multitude of modifiers. Products which cure at ambient temperature cannot achieve the same performance as is obtained by curing at elevated temperature. For products cured at room temperature their TgS, at 40-50 °C initially, are relatively low and may be lowered even further by absorbed water, in liquid or vapour form. This may also be accompanied by a reduction in strength and modulus. Thus the use of materials with a slow and small water uptake is to be preferred, which implies a fairly highly cross-linked formulation. Such considerations do of course depend upon the performance and durability expectations in service. Whilst the environmental durability of joints can often be improved enormously by the surface pretreatment methods employed (see Chapters 3 and 4), the adhesive must be selected carefully to ensure long term durability in consideration of the modes and duration of loading, and the environmental conditions. Ideally the adhesive should be fairly tolerant of poor surface pretreatment procedures. 

In the pretreatment method, fillers are surface modified before mixing with a resin matrix. Pretreatment methods can be divided into two kinds dry processing and wet processing. 

The application of polymer affects choice of filler. For example, to prepare conductive materials, special fillers must be used to obtain the required properties. Also, the method of processing imposes certain constraints on the choice and treatment of the filler before its use. For example, polymers processed at high temperature require fillers which do not contain moisture. This affects both the choice of the filler and/or its pretreatment. The choice of additives used to improve the incorporation of the filler depends on the application and the properties required from a product but it is also determined by the processing method. For example, the viscosity of a melt is reduced by special lubricating agents whereas the viscosity of filler dispersions is controlled by the surface treatment of filler. In some cases, the order of addition is important or a special filler pretreatment is used to achieve the desired results. These methods are discussed in special section in the table. Some fillers simply caimot be used with some polymers. In other cases, special care must be taken to ensure polymer stability or filler may interact with some vital components of the formulation. This subject is discussed in special considerations of filler choice. 

Several filler surface pretreatment procedures are commercially used the neat silane (dry method I) or silane solution (slurry method II) are added uniformly onto the filler... 

The surface modification technique of inorganic fillers directly affects the filling modification. The common surface modification methods can be classified into three types inorganic filler pretreatment, blending, and masterbatch methods. 

In comparison with the physical methods, the effect of surface modification based on chemical interaction is more significant, as the latter provides stronger interaction between modifiers and nanoparticles. Besides, a fine adjustment of interfacial interaction in the composites with chemically pretreated nanoparticles can be completed by introducing modifiers containing reactive groups onto nanoparticles, which helps to construct chemical bonding between the fillers and the matrix. 

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