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The generally poor processability of aromatic polymers (for example, a high melting point and a low solubility) also limits the available options for synthesis and may require strong electron-donating co-solvents like HFIP or TFA for analysis (e. g. 1 H NMR spectroscopy) which themselves can introduce further practical limitations.
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.
The direct spinning process avoids the stage of solid polymer pellets. The polymer melt is produced from the raw materials, and then from the polymer finisher directly pumped to the spinning mill. Direct spinning is mainly applied during production of polyester fibers and filaments and is dedicated to high production capacity (>100 ton/day).
For example, the melting point of silicon at ambient pressure (0.1 MPa) is 1415 °C, but at pressures in excess of 10 GPa it decreases to 1000 °C. [13] Melting points are often used to characterize organic and inorganic compounds and to ascertain their purity. The melting point of a pure substance is always higher and has a smaller range than ...
Polycyclohexylenedimethylene terephthalate (PCT) is a thermoplastic polyester formed from the polycondensation of terephthalic acid and cyclohexanedimethanol. [1] Its chemical structure is similar to that of polyethylene terephthalate (PET), with which it shares properties like dimensional stability and chemical resistance.
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.
This occurs when the internal energy of the solid increases, typically by the application of heat or pressure, which increases the substance's temperature to the melting point. At the melting point, the ordering of ions or molecules in the solid breaks down to a less ordered state, and the solid melts to become a liquid. Substances in the ...
The onset of thermal degradation dictates the maximum temperature at which a polymer can be used. It is an important limitation in how the polymer is manufactured and processed. For instance, polymers become less viscous at higher temperatures which makes injection moulding easier and faster, but thermal degradation places a ceiling temperature ...