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The polymers' structures result also in poor processing characteristics, in particular a high melting point and low solubility. The named properties are in particular based on a high percentage of aromatic carbons in the polymer backbone which produces a certain stiffness. [15] Approaches for an improvement of processability include the ...
A polymer (/ ˈ p ɒ l ɪ m ər / [4] [5]) is a substance or material that consists of very large molecules, or macromolecules, that are constituted by many repeating subunits derived from one or more species of monomers. [6]
They can be either thermoplastic or elastomeric materials, [citation needed] with melting points ranging from 40 to 180 °C. [ citation needed ] The mechanical properties and biocompatibility of PHA can also be changed by blending, modifying the surface or combining PHA with other polymers, enzymes and inorganic materials, making it ...
Polycaprolactone (PCL) is a synthetic, semi-crystalline, biodegradable polyester with a melting point of about 60 °C and a glass transition temperature of about −60 °C. [ 2 ] [ 3 ] The most common use of polycaprolactone is in the production of speciality polyurethanes .
Melting point 175 °C., and glass transition temperature 2 °C. Tensile strength 40 MPa , close to that of polypropylene. Sinks in water (while polypropylene floats), facilitating its anaerobic biodegradation in sediments.
Classes of step-growth polymers are: [6] [7] Polyester has high glass transition temperature T g and high melting point T m, good mechanical properties to about 175 °C, good resistance to solvent and chemicals. It can exist as fibers and films.
The melting point (or, rarely, liquefaction point) of a substance is the temperature at which it changes state from solid to liquid. At the melting point the solid and liquid phase exist in equilibrium. The melting point of a substance depends on pressure and is usually specified at a standard pressure such as 1 atmosphere or 100 kPa.
Polyester resins are synthetic resins formed by the reaction of dibasic organic acids and polyhydric alcohols. Maleic anhydride is a commonly used raw material with diacid functionality in unsaturated polyester resins. [1] Unsaturated polyester resins are used in sheet moulding compound, bulk moulding compound and the toner of laser printers.