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When melting points of the monomers are sufficiently low, a polyester can be formed via direct esterification while removing the reaction water via vacuum. Direct bulk polyesterification at high temperatures (150 – 290 °C) is well-suited and used on the industrial scale for the production of aliphatic, unsaturated, and aromatic–aliphatic ...
Additional energy is released upon melting a semicrystalline polymer. This energy can be measured with differential scanning calorimetry and compared with that released upon melting of the standard sample of the same material with known crystallization degree. [6] [20] X-ray diffraction
The cross-section is non-round, increasing surface area by an estimated 20% (over round fibers) in order to produce a wicking effect via capillary action. [ 1 ] [ 2 ] The Lycra Company makes extensive use of co-branding in their marketing of Coolmax and other clothing materials, partnering with their customers to increase awareness of their ...
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).
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.
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.
The degree of polymerization, or DP, is the number of monomeric units in a macromolecule or polymer or oligomer molecule. [1] [2] [3]For a homopolymer, there is only one type of monomeric unit and the number-average degree of polymerization is given by ¯ ¯ = ¯, where ¯ is the number-average molecular weight and is the molecular weight of the monomer unit.
By melting and solidifying at the phase-change temperature (PCT), a PCM is capable of storing and releasing large amounts of energy compared to sensible heat storage. Heat is absorbed or released when the material changes from solid to liquid and vice versa or when the internal structure of the material changes; PCMs are accordingly referred to ...