Softening point INDEX

Tables 4 and 5 show properties of ground mica products. For all forms of ground mica the index of refraction is 1.58 wt %, Mohs hardness is 2.5, oil absorption (Brit. Stand. 3483) is 60.75%, water solubihty (Brit. Stand. 1765) is <0.3%, the phericity factor is 0.01, and the softening point in °C is 1538. For Microni2ed and wet ground micas the brightness (green filter), pH, and apparent density in kg/m are 75, 5.2, and 160—224, respectively for dry ground mica, 66—75, 6.2, and 192—561, respectively (1).

Vitreous sihca has many exceptional properties. Most are the expected result of vitreous sihca being an extremely pure and strongly bonded glass. Inert to most common chemical agents, it has a high softening point, low thermal expansion, exceUent thermal shock resistance, and an exceUent optical transmission over a wide spectmm. Compared to other technical glasses, vitreous sihca is one of the best thermal and electrical insulators and has one of the lowest indexes of refraction. 

This equation is based on the approximation that the penetration is 800 at the softening point, but the approximation fails appreciably when a complex flow is present (80,81). However, the penetration index has been, and continues to be, used for the general characteristics of asphalt for example asphalts with a P/less than —2 are considered to be the pitch type, from —2 to +2, the sol type, and above +2, the gel or blown type (2). Other empirical relations that have been used to express the rheological-temperature relation are fluidity factor a Furol viscosity P, at 135°C and penetration P, at 25°C, relation of (H—P)P/100 and penetration viscosity number PVN again relating the penetration at 25°C and kinematic viscosity at 135 °C (82,83). 

Figure II.5. Variation of Vicat softening point (5 kg load) with isotactic index and melt flow index.

Glass Type Thermal Coefficient of Expansion (0-300°C) xlO"7 Acm/cm/°C Strain Pont (=°C) Annealing Point (-°C) Softening Point ( °C) Working Point ( °C) Density (g/cm2) Refractive Index... 

Properties often used by epoxy resin manufacturers to specify particular grades of resin include the epoxy content, viscosity or softening point, and color. In addition, properties such as density, vapor pressure, flash point, refractive index, solubility characteristics, and hydroxyl content are often reported. The important properties of uncured epoxy formulations with regard to most adhesive applications are... 

Sample and Source Dropping Point (°C) Softening Point (°C) Polymorphic Form Hardness Index (g/min) SFC %) at 20° C (Tempered at 30° C) Air Content... 

Properties Softening point 1500C, temp limit in service 900C, linear coefficient of expansion per degree C = 0.0000008, d 2.18, refr index 1.458 (a similar glass, No. 7910, will transmit over 60% radiation at 254 millimicrons in a 2-mm section). 

NR, lSNR-5 EVAc, Exxon 218 (vinyl content = 18% melt-flow index = 1.7 g/10 min. Vicat softening point = 64°C) additives include zinc oxide, stearic acid, styrenated phenol, dibenzothiazyl disulfide, DCP and sulfur. 

Values for the physical properties of boric oxide are somewhat confused in the literature due to the tendency of this substance to react readily with water. Many physical properties of boric oxide are sensitive to water content, and the water content of samples used for measurements was not always carefully controlled. For example, at 0.28% water, the density of vitreous boric oxide is 1.853 gmL and the softening point 240-275°C. Reducing the water concentration to 20 p,g g reduced the density to 1.829 gmL and raised the softening point to 300-325°C. Other properties, such as thermal expansion, viscosity, and refractive index, are also significantly affected by moisture content. Water concentrations can be reduced to as low as 10p,gg by prolonged heating in vacuum. 

Copolymer composition Refractive index, Dd Softening point, °C Density p, kg/m ... 

The modification of bitumen with SBS copolymer powder was done using the mechanochemically devuicanized GRT (Zhu et al., 2009). The penetration index, softening point, 5°C ductility, aging behavior, and rheological properties of bitumens modified by 8,10, and 12 wt.% GRT/SBS mixtures were measured. In comparison with the bitumen modified by incorporation of 5.5 wt.% SBS alone, the majority of properties of the blends were improved, except their penetration. Rheological properties indicated that at high temperatures 10 wt.% GRT/SBS-modified bitumen was better than SBS-modifled bitumen. The SEM observation of the fractured surfaces showed that bitumens mixed with the GRT/SBS powder had a better interfacial adhesion with matrix than with SBS alone. 

The index numbers T % and T5 % of the distillation bitumen can be correlated with the softening point (Fig. 4-42 T5% = f(S.P. R B). The curves of T1 % and T5 % versus S.P. R B have very steep slopes for the distillation bitumens. The values for the blown bitumens are scattered, away from these curves. The values for the laboratory blown product (sample I) and for the bitumen BIO (sample 16) lie between the curves of the... 

Paving grade bitumens are characterised by their consistency at intermediate (determined by penetration test), consistency at elevated service temperatures (determined by softening point or viscosity test) and durability (determined by resistance to hardening test). Their brittleness at low service temperature (determined by the Fraass breaking test) and temperature dependence of consistency (determined by the penetration index) may also need to be determined to meet regional requirements for specific conditions such as extreme cold or wide ambient temperature variations. Flash point is also determined as well as, optionally, the density. 

By adding an elastomer to the bitumen, the penetration value decreases, the softening point increases and the penetration index increases. These changes indicate that the bitumen becomes harder and less susceptible to temperature variations. 

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. 

---