In the quality indicators of raw materials, some terms are often encountered, and an accurate understanding of its meaning helps to better grasp the performance of raw materials. Some commonly used terms are listed here.

(1) Density and relative density density refers to the mass contained in the unit volume of a substance, in short, the ratio of mass to volume, Its unit is million grams/meter 3(Mg/m3) or kg/meter 3(kg/m3) or gram/centimeter 3(g/cm3). The relative density, also known as the ratio of density, refers to the ratio of the density of a substance to the density of a reference substance under their respective specified conditions, or the mass of a certain volume of a substance at t1 temperature to that of an equal volume reference substance at t2. The ratio of mass at temperature. A common reference substance is distilled water, expressed in terms of Dt1/t2 or t1/t2, as a dimensionless quantity.

(2) Melting point and Freezing point (Melting point) A substance is liquid at its vapor pressure — The temperature at which the solid reaches equilibrium is called the melting point or freezing point. This is due to the regular arrangement of atoms or ions in the solid due to the rise in temperature, thermal motion becomes chaotic and activated, forming an irregular arrangement of liquid a phenomenon, the opposite process is solidification. The temperature at which a liquid becomes a solid is often called the freezing point or freezing point, which differs from the melting point in the release of heat rather than the absorption of heat. In fact, the melting point and freezing point of a substance are the same.

(3) Melting range refers to the temperature range from the beginning of melting to the full melting of the substance measured by capillary method.

(4) Crystal point refers to the phase change temperature of the liquid from liquid to solid during the cooling process.

(5) Pour point is one of the indicators of the properties of liquid petroleum products. Refers to the temperature at which the sample is cooled under standard conditions until it begins to stop flowing, that is, the lowest temperature at which the sample can still be poured when it is cooled.

(6) Boiling point The temperature at which the liquid boils when heated and turns into a gas. Or the temperature at which the liquid and its vapor are in equilibrium. In general, the lower the boiling point, the more volatile it is.

(7) Boiling range (Boiling range) in the standard state (1013.25 hPa, 0¡æ), in the product standard specified temperature range of the distillation volume.

(8) Sublimation: the phenomenon of sublimation that a solid (crystalline) substance directly transforms into a gaseous state without going through the liquid state. Such as ice, iodine, sulfur, naphthalene, camphor, mercury chloride, etc., can sublimate at different temperatures.

(9) Vaporizing velocity is the phenomenon of vaporization that occurs on the surface of a liquid. Evaporation velocity, also known as volatilization velocity, is generally judged by the boiling point of the solvent. The fundamental factor that determines the evaporation velocity is the vapor pressure of the solvent at this temperature, followed by the molecular weight of the solvent.

(10) Vapor pressure (Vapor pressure) Vapor pressure is the abbreviation of saturated vapor pressure. At a certain temperature, the liquid reaches equilibrium with its vapor, and the equilibrium pressure at this time changes only because of the nature and temperature of the liquid, which is called the saturated vapor pressure of the liquid at that temperature.

(11) Azeotrope A mixture of constant boiling point formed by two (or several) liquids is called an azeotrope, which refers to a mixed solution in equilibrium, where the composition of the gas phase and liquid phase is exactly the same. The corresponding temperature is called the azeotrope temperature or the azeotrope point.

(12) Refractive index The refractive index is a physical quantity indicating the ratio of the speed of light in two different (isotropic) media. The speed of light varies with the medium. When light enters another transparent medium with different density from one transparent medium, it changes in its direction due to the change of speed, so it is called refraction. The sine of the Angle of light incidence and the sine ratio of the Angle of refraction, or the speed ratio of the light through the vacuum and through the medium, is the refractive index. The generally expressed refractive index n is the value at which light enters any medium from air. Usually referred to the refractive index is the use of sodium yellow light (D line), measured in tC, so it is expressed by ntD, such as measured at 20 ¡ã C, it is n20D.

(13) Flashing point (Flashing point) Flashing point is also known as the flashing point, indicating one of the indicators of the properties of flammable liquids. It refers to the lowest temperature when the combustible liquid is heated to the vapor pressure on its liquid surface and the mixture of air comes into contact with the flame to flash. Flashover is usually a light blue spark that is extinguished with a flash and cannot continue to burn. Flashover is often the first sign of a fire. There are open-mouth cup method and closed-mouth cup method to determine the flash point, generally the former is used to determine the high flash point liquid, the latter is used to determine the low flash point liquid.

(14) Ignition point The ignition point, also known as the ignition point, is one of the indicators of the properties of flammable liquids. It refers to the lowest temperature at which the mixture of vapor and air on the surface of the flammable liquid is heated to contact with the flame and can continue to burn immediately. The ignition point of flammable liquid is 1 ~ 5¡æ higher than the flash point. The lower the flash point, the smaller the difference between the burning point and the flash point.

(15) Spontaneous ignition point The lowest temperature at which a flammable substance can ignite without coming into contact with an open flame. This is called the spontaneous ignition point. The lower the spontaneous ignition point, the greater the risk of ignition. The spontaneous ignition point of the same substance varies with pressure, concentration, heat dissipation and other conditions and test methods.

(16) Explosive limits Flammable gas, flammable liquid vapor or flammable solid dust at a certain temperature, pressure and air or oxygen mixed to reach a certain concentration range, when it meets the fire source will explode. This certain concentration range is called the explosion limit or the combustion limit. If the composition of the mixture is not within this certain range, no matter how large the energy supply, it will not catch fire. The vapor or dust mixed with the air and reached a certain concentration range, the lowest concentration that will burn or explode when encountering the fire source is called the lower explosive limit; The highest concentration is called the upper limit of explosion. The explosion limit is usually expressed as a percentage of the volume of the vapor in the mixture, i.e. % (vol); Dust is expressed in mg/m3 concentration. If the concentration is lower than the lower explosive limit, although the open flame will not explode or burn, because the proportion of air is large at this time, and the concentration of combustible vapor and dust is not high; If the concentration is higher than the upper limit of the explosion, although there will be a large number of combustible substances, but the lack of combustion-supporting oxygen, in the absence of air supplement, even in the case of open fire, will not explode for a while. Flammable solvents have a certain explosion range, the wider the explosion range, the greater the risk.

(17) Viscosity viscosity is the internal friction resistance generated by the fluid (liquid or gas) in the flow, and its size is determined by the type of substance, temperature, concentration and other factors. Generally is the abbreviation of dynamic viscosity, its unit is pa · Seconds (Pa· s) or millipa · Seconds (mPa· s). Viscosity is divided into dynamic viscosity, kinematic viscosity, relative viscosity, the three are different, can not be confused. Viscosity can also be coated. 4 or apply — 1 cup measurement, which is measured in seconds (s).

(18) Mooney viscosity, also known as rotational (Mooney) viscosity, is a value measured by the Mooney viscometer, which basically reflects the degree of polymerization and molecular weight of synthetic rubber. According to the GB 1232 standard, the rotational (Mooney) viscosity is expressed by the symbol Z100¡æ 1+4. Where Z— — Rotational viscosity value; 1— — The preheating time is 1min; 4— — The rotation time is 4min; 100¡æ— — The test temperature is 100¡æ, and it is customary to ML100¡æ 1+4 to indicate Mooney viscosity.

(19) Solubility (Solubility) At a certain temperature and pressure, the maximum amount of a substance dissolved in a given amount of solvent is called solubility. The solubility of a solid or liquid substance, generally expressed as the number of grams of a substance that can be dissolved in a 100g solvent. The solubility of gaseous solutes is often expressed in milliliters of dissolved gas per liter of solvent.

(20) Solubility parameter Solubility parameter is also called solubility parameter, is a measure of intermolecular force. The acting energy that holds molecules together is called cohesion energy. The cohesive energy per unit volume is called the cohesive energy density (CED), and the square root of CED (CED)1/2 is defined as the solubility parameter, codenamed δ Or SP.

(21) Surface tension and surface energy The attraction of molecules inside a liquid causes the molecules on the surface to be subjected to an inward force that causes the liquid to minimize its surface area to form a force parallel to the surface, called surface tension. Or the mutual pulling force between two adjacent parts of the liquid surface within a unit length, it is a manifestation of the molecular force. The unit of surface tension is N/m. The amount of surface tension is related to the properties, purity, and temperature of the liquid. Surface tension multiplied by the area of the surface is the surface energy. The greater the surface tension, the greater the surface area, and the greater the surface energy.

(22) Specific heat capacity The heat required to absorb when the temperature of a kilogram of material rises by 1K is called the specific heat capacity, and the unit is kJ/(kg· K). With constant pressure, the heat absorbed when the temperature increases by 1K is called the specific heat capacity at constant pressure.

(23) Thermal conductivity Used to be called the thermal conductivity or thermal conductivity, which reflects the ability of a substance to conduct heat. That is, inside the object perpendicular to the direction of thermal conductivity take two parallel planes 1cm apart, the area of 1cm2, if the temperature difference between the two planes is 1K, then the heat conduction from one plane to another plane in ls is specified as the thermal conductivity of the substance, its unit is W/(m· K).

(24) Water content The amount of water contained in a substance, but excluding crystalline water and associated water. It is usually expressed by the original mass of the sample and the percentage of the mass after the water loss of the sample.

(25) Water absorption is a measure of the degree of water absorption of substances. It refers to the percentage of mass gained by soaking a substance in water for a given time at a given temperature.

(26) Ash (Ash) Ash, also known as burning residue, refers to the residue of oxides and salts formed by its mineral components after evaporation and burning, expressed by percentage content.

(27) Needle penetration is the depth of vertical penetration of standard needle into asphalt specimen under certain load, time and temperature conditions, in 1/10mm. Unless otherwise specified, the combined weight of standard needle, needle connecting rod and additional weight is 100± 0.1g, the temperature is 25¡æ, the time is 5s. The greater the penetration of the needle, the softer, that is, the smaller the consistency; On the contrary, it means the harder, that is, the larger the consistency.

(28) Hardness (Hardness) Hardness is the resistance of the material to external forces such as stamping and scratching. According to different test methods, Shore hardness, Brinell hardness, Rockwell hardness, Mohs hardness, Barcol hardness, Vichers hardness and so on. The value of hardness is related to the type of hardness tester. In the commonly used hardness tester, Shore hardness tester has a simple structure and is suitable for production inspection. Shore hardness tester can be divided into type A, type C, type D, type A for the measurement of soft rubber, C and D for the measurement of semi-hard and hard rubber.

(29) Aniline point; A.P.) The aniline point is the lowest temperature at which an equal volume of petroleum alkanes and anilines dissolve each other, which is used to indicate the content of alkanes saturated hydrocarbons. The level of aniline point is related to the chemical composition, the higher the aniline point, the more alkane content; The lower the aniline point, the more aromatic hydrocarbon content.

(30) Volume resistivity, also known as volume resistance, volume resistivity, is an important indicator to characterize the electrical properties of dielectric or insulating materials. Indicates the resistance of 1cm3 dielectric to leakage current, the unit is Ω · m or Ω · cm. The greater the volume resistivity, the better the insulation.

(31) Oil absorption The amount of oil required when the absolute surface of the particles of a certain mass of skin (fill) material is completely soaked by oil.

(32) Acid value, also known as acid value, it represents an indicator of organic matter, is the number of milligrams of potassium hydroxide (KOH) required to neutralize the free acid in the non-volatile matter of 1g organic matter, that is, mgKOH/g.

(33) Hydroxyl value The number of milligrams of potassium hydroxide (KOH) equal to the hydroxyl group in a sample of 1g, expressed in mgKOH/g.

(34) Iodine value is an indicator of the degree of unsaturation of an organic substance. It is the mass percentage of iodine that can be absorbed by 1g of a sample. The higher the degree of unsaturation, the greater the iodine value.

(35) Epoxy value is the equivalent number of epoxy groups contained in 100g epoxy resin, that is, the larger the epoxy value, the smaller the molecular weight, the lower the viscosity.

(36) Epoxy equivalent (Epoxy equivalent) Epoxy equivalent represents each linkThe oxygen group corresponds to the molecular weight of the resin.

(37)HLB value (HLB value) HLB is a hydrophilic lipophilic equilibrium (Hydrophile— Lipophile— Balance), a measure of the relative strength of the polar and non-polar components of a surfactant molecule. The stronger the polar group, the larger the HLB value and the stronger the hydrophilicity; If the non-polar group is longer, its HLB value is smaller and its hydrophilicity is worse.

(38) Critical micelle concentration, also known as critical micelle concentration, referred to as CMC. The concentration range in which the properties of the emulsifier solution have a sudden change is called the critical micelle concentration of the emulsifier. When the critical micelle concentration is reached in the emulsion system, many emulsifier molecules gather to form micelles. The unit of CMC is mol/L.

(39) Degree Baum′ e) The value given by a Baume meter using a special indexing method in a glass tube float meter is called the Baume and the symbol is ° B′ e. Used indirectly to give the density of the liquid.

(40) Solid content, also known as non-volatile matter content, total solid content (TS), represents the ratio of the residual mass of the sample after heating at a certain temperature to the mass of the sample, expressed as a percentage.

(41) surfactants (Surface— active agent, also known as an interfacial active agent, is a substance that can significantly change the surface tension or two-phase interfacial tension of a liquid. Or a substance that strongly binds to the surface of another substance or aggregates on the surface of a solution, reducing the surface tension of a liquid or solid.

(42) Relative humitity A method of expressing humidity is the ratio of absolute humidity to absolute humidity at saturation under the same conditions (same temperature and pressure), that is, the ratio of the mass of water vapor actually contained in the air (or other gas) to the mass of saturated water vapor under the same conditions. Generally expressed as a percentage.

(43) Apparent density was once known as bulk density, loose density, pseudodensity, apparent density, indicating the mass of a substance per unit volume (including voids).

(44) Isomer compounds have the same molecular formula, but have different structures and properties of the phenomenon called isomerism. Compounds that can undergo isomerism are called isomers, or isomers for short.

(45) Relative molecular mass refers to the ratio of the average mass of the molecule or specific unit of a substance to the mass of the nuclide 10 6 C atom (1/12), symbolically Mr.

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