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Polymer chemistry is a sub-discipline of chemistry that focuses on the structures, chemical synthesis, and chemical and physical properties of polymers and macromolecules. The principles and methods used within polymer chemistry are also applicable through a wide range of other chemistry sub-disciplines like organic chemistry , analytical ...
For example, polycarbonates are highly resistant to impact, while polyamides are highly resistant to abrasion. Other properties exhibited by various grades of engineering plastics include heat resistance, mechanical strength, rigidity, chemical stability, self lubrication (specially used in manufacturing of gears and skids) and fire safety.
Demand for plastic resins in Europe during 2017 as a percentage of total plastic demand. [1] A comparison of standard plastics, engineering plastics, and high-performance plastics Commodity plastics or commodity polymers are plastics produced in high volumes for applications such as packaging, food containers, and household products, including ...
Mixing these together can give a material with inconsistent properties, which can be unappealing to industry. For example, mixing different colored plastics with different plastic colorants together can produce a discolored or brown material and for this reason plastic is usually sorted both by polymer type and color prior to recycling. [5]
LDPE has SPI resin ID code 4 Schematic of LDPE branching structure. Low-density polyethylene (LDPE) is a thermoplastic made from the monomer ethylene.It was the first grade of polyethylene, produced in 1933 by John C. Swallow and M.W Perrin who were working for Imperial Chemical Industries (ICI) using a high pressure process via free radical polymerization. [1]
The name high temperature plastics is in use due to their continuous service temperature (CST), which is always higher than 150 °C by definition (although this is not their only feature, as it can be seen above). The term "polymers" is often used instead of "plastics" because both terms are used as synonyms in the field of engineering.
The polymer chains associate by intermolecular forces, which weaken rapidly with increased temperature, yielding a viscous liquid. In this state, thermoplastics may be reshaped, and are typically used to produce parts by various polymer processing techniques such as injection molding, compression molding, calendering, and extrusion.
HDPE is known for its high strength-to-density ratio. [4] The density of HDPE ranges from 930 to 970 kg/m 3. [5] Although the density of HDPE is only marginally higher than that of low-density polyethylene, HDPE has little branching, giving it stronger intermolecular forces and tensile strength (38 MPa versus 21 MPa) than LDPE. [6]