Physical properties of cured

Quahty control testing of siUcones utilizes a combination of physical and chemical measurements to ensure satisfactory product performance and processibihty. Eor example, in addition to the usual physical properties of cured elastomers, the plasticity of heat-cured mbber and the extmsion rate of TVR elastomers under standard conditions are important to the customer. Where the siUcone appHcation involves surface activity, a use test is frequently the only rehable indicator of performance. Eor example, the performance of an antifoaming agent can be tested by measuring the foam reduction when the sihcone emulsion is added to an agitated standard detergent solution. The product data sheets and technical bulletins from commercial siUcone producers can be consulted for more information. 

TABLE 2. Physical Properties of Cured Dental Compositions Containing Step 1 Hybrid Monomer 1... 

The temperature dependence of the dynamic mechanical properties of the cured resins is similar as in Fig. 5 33). This shows that the physical properties of cured resins are mostly characterized by the differences of Tg. 

Owing to this rapid cure, a compressive strength of 40 N/mm is possible within 2 h at temperatures down to 4°C (Shaw, 1993a). The properties of polyester binder depend primarily upon the chemical composition of the polyester resin component. Typical physical properties of cured polyester binders for concrete overlays are given in Table 9.3 (ACI, 1993). 

Table 93 Typical physical properties of cured polyester concrete...

Commercial Uses. Examination of a chart of the physical properties of cured unsaturated polyester resins in cast unrein orced form would... 

As is true for most rubbers, the physical properties of cured polysulfide polymers are poor unless reinforcing fillers are used. The semireinforcing blacks are best, and are the main fillers usually employed. Zinc sulfide, titanium dioxide, calcium carbo nate, and lithopone all are useful for reinforcing white or light stocks. In general, the same fillers are used in polysulfide rubbers aa in the other ssnathetic rubbers. 

The use of GRT instead of virgin elastomers, however, results in significant deterioration in the mechanical properties of these composites. It was reported (Hilyward et al., 1983 Phadke et al., 1984 Phadke and De, 1986) that the GRT has a detrimental effect on most of the physical properties of cured rubber, the extent of deterioration increasing with the amount and size of the GRT. There have been many investigations with the aim to improve the adhesion between the GRT and polymer matrix. 

The physical properties of cured polysiloxane materials are dramatically influenced by fillers (1,2). So-called non-reinforcing (extenders) and reinforcing fillers are typically used the most common reinforcing filler is silica. High surface area silica, called fumed silica, is formed by burning the product mixture obtained from the trichlorosilane (TCS) reaction of equation 8. Only a small amount of untreated... 

For example, the physical properties of cured adhesives can be evaluated by measuring stress-strain properties. This can be done with a testing machine as shown in Fig. 1. The machine records force applied to a specimen of defined shaped as a function of either separation of the jaws of the specimen holder or the elongation of the sample. 

Table 6 contains a compilation of the effect of various fillers on the physical properties of cured epoxy resin systems. 

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