Softening point determining

In the method of Martens a test rod is mounted upright in a support and the upper free end is put under a bending stress via a small weighted lever. The rod is slowly heated in an oven until a specified deflection is attained. The softening point determined in this way is called the Martens temperature. 

The dropping point corresponds to a solid fat content of about 5% (Papalois et al., 1996), and corresponds closely to the softening point determined by the method of Barnicoat (1944) (Timms, 1978 deMan etal., 1983 Papalois et al., 1996). Barnicoat s method was developed for application to milk fat fractions as an alternative to the tedious Wiley melting point technique (Mertens, 1973). In Barnicoat s method, the softening point is taken as the temperature at which a steel ball bearing, initially on the surface of a column of the fat, sinks halfway through the column. In the Wiley method, historically favored in the US, but now an AOCS surplus official method (Firestone, 1998), the melting point is taken as the temperature at which a disc of initially solid fat located at the interface between a layer of water and an (upper) layer of 95% ethanol, becomes spherical. The Barnicoat method is still used in the chocolate industry (Minifie, 1999). 

Softening Point Determine as directed for the Ring-and-Ball Method under Softening Point, Appendix IX. 

Clevenger Traps. .. 945 Apparatus for Drop Softening Point Determination. . . 947... 

FIGURE 39 Apparatus for Drop Softening Point Determination. 

In making a softening point determination of a refractory it seems desirable to grind the specimen so that the material will pass the 80-mesh sieve and to mold from it, by the use of dextrin or other organic glue, small tetrahedra, in. high and m. wide at the base. 

The softening point determined by thermomechanical methods may be as high as 500°C. A true ladder polymer can also be obtained by condensation of an aromatic tetracarboxylic acid or a dianhydride with an aromatic tetramine. An example is... 

The penetration index (I ) indicates the temperature susceptibility of the paving grade bitumens, for grades 20130 to 160/220. The penetration index is calculated from the values of penetration, at 25°C, and the softening point determined. 

Usually determined by ASTM D 36, softening point determines the temperature at which hard asphalts reach an arbitrary degree of softening. 

For a given bitumen specimen, the softening point determined in a water bath will be lower than that determined in a glycerin bath. Since the softening point determination is necessarily arbitrary, this difference matters only for softening points slightly above 80 C (176 F). 

Consistency (viscosity, penetration, and softening point) determines the temperature required for use or application and the final hardness and... 

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