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A thermoplastic, or thermosoftening plastic, is any plastic polymer material that becomes pliable or moldable at a certain elevated temperature and solidifies upon cooling. [ 1 ] [ 2 ] Most thermoplastics have a high molecular weight .
The Gmelin rare earths handbook lists 1522 °C and 1550 °C as two melting points given in the literature, the most recent reference [Handbook on the chemistry and physics of rare earths, vol.12 (1989)] is given with 1529 °C.
The melting point of α-crystalline regions is given as 185 [15] [16] to 220 °C, [15] [17] the density as 0.936 to 0.946 g·cm −3. [18] [19] The β-modification is in comparison somewhat less ordered, as a result of which it forms faster [20] [21] and has a lower melting point of 170 to 200 °C.
Phthalates are contained in plastics at high percentages. For example, they can contribute up to 40% by weight to intravenous medical bags and up to 80% by weight in medical tubing. [ 49 ] Vinyl products are pervasive—including toys, [ 50 ] car interiors, shower curtains, and flooring—and initially release chemical gases into the air.
Replacing terephthalic acid (right) with isophthalic acid (center) creates a kink in the PET chain, interfering with crystallization and lowering the polymer's melting point. Another common modifier is isophthalic acid , replacing some of the 1,4-( para- ) linked terephthalate units.
However, some plastics are partially amorphous and partially crystalline in molecular structure, giving them both a melting point and one or more glass transitions (the temperature above which the extent of localized molecular flexibility is substantially increased).
The List of data references for chemical elements is divided into datasheets that give values for many properties of the elements, together with various references. Each datasheet is sequenced by atomic number .
If the s in a material exceeds the yield point, the strain caused in the material by the application of load does not disappear totally on the removal of load. The plastic deformation caused to the material is known as creep. At high temperatures, the strain due to creep is quite appreciable. [2] Density: Mass per unit volume (kg/m^3)