AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |
Back to Blog
Sg temperature conversion2/28/2023 ![]() This case is mainly seen for polyethylenes. If the plastic has more molecular branching, the polymer chain cannot pack closely together thus, free volume will be more thereby decreasing the SG. Another factor that affects SG is the degree of branching. Thus, if plastic can crystallize, the chain׳s packing will be much more efficient, and higher densities can be achieved ( Gilbert, 2017). Generally, amorphous polymers consisting of only hydrocarbons are “lighter” atoms thus their SG lies 0.9–1.1, for example, polyethylene, polypropylene, polystyrene, etc., A polymer consisting of “larger” atoms like chlorine, fluorine, etc., has a larger specific gravity of more than 1.4, that includes polymer such as polyvinyl chloride, poly tetra fluoro ethylene (PTFE), etc., Also, higher the molecular chain packing, more will be the SG as free volume available will be less thus crystalline plastics, such as PTFE (2.2) and polyvinylidene chloride (1.7), have higher SG. SG/density of plastic generally depends on the molecular arrangement and the way in which they pack. SG being a dimensionless value, can be converted into density (g/cc) by multiplying it with the SG of water, 0.99756. Two basic strategies have been developed to measure the SG of plastic based on the form factor, Method A is used for rods, molded products and sheets, and Method B for pellets, flakes and powders. One of the most significant benefits that the selection of plastic material provides is that they are lightweight compared to their metal counterparts, which in turn reduces the overall price of the product. SG of plastic is less compared to other materials influence its price thus all plastic materials are sold on cost per weight basis. The testing method of SG for plastic systems is ASTM D792 and ISO 1183. ![]() ![]() Specific gravity = Density ( at 23 ° C ) / 0.99756 ( g / cm 3 ) ![]()
0 Comments
Read More
Leave a Reply. |