Polymer test equipment includes melt flow indexers, extrusiometers, and other specialized instruments for determining the processability and properties of plastics and elastomer materials. Polymers include rubber, elastomers, plastics, thermoplastics, thermoset resins, monomers, and oligomers. Polymer test equipment is used to test material properties such as adsorption, desorption, aeration, foamability, cloud point (CP), compressibility, heat deflection temperature (HDT), and Vicat softening point. Polymer testing equipment is also used in contaminant analysis and extrusiometry, and to test disintegration, dissolution, flammability, melt flow index (MFI), permeability, water absorption, wear or abrasion resistance, and wettability.
Selecting Polymer Testing Equipment
Selecting polymer test equipment requires an understanding of adsorption, desorption, chemisorption, and physiosorption. Adsorption is the physicochemical adhesion of a substance (liquid, gas, or dissolved-solids sorbate) onto the surface of a solid or liquid. Desorption is the release of the molecular layer of the adsorbed material on the surface of an absorbent. Chemisorption is the process in which sorbates are adsorbed and changed chemically by a reaction with the sorbent material. Physisorption is the process where molecules are bonded physically to the surface by Van der Vals and weak dipole forces. Polymer test equipment is also used to measure absorption, the accumulation of vapor or water onto the surface of a material.
Polymer test equipment is used to measure cloud point (CP) or cloud point temperature, and to perform contamination analysis. As temperature decreases in diesel fuels or oils, a wax separates out and forms floating cloudiness on the surface. The cloud point (CP) temperature can be thought of as the solubility limit of the sample in that particular solution. Compactability or compressibility is also an important material property, as it can be important in understanding the processing or end-use function of powders, foams, filter media, and other compressible or porous polymer materials. Finally, polymer test equipment may be used to perform contamination analysis, a determination of the amount of dirt, fiber, mold chips, wear particles, grinding debris, or other contaminants.
Some polymer test equipment is used to measure softening point, flammability, gelation, and melt flow index. Other polymer testing equipment is used to measure permeability and contact or wetting angles. Deflection, heat distortion temperature (HDT) or softening point (e.g., Vicat) instruments measure the temperature that reflects the point of softening to be expected when a material is used in an elevated-temperature application. Flammability is a measure of quickly a material will ignite and propagate combustion. Gelation refers to the amount of time a sample requires to form a gel. Melt flow index (MFI) testers are polymer test equipment for determining the melt flow rate of a sample material at a specific temperature (190° C).