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Crystallization affects optical, mechanical, thermal and chemical properties of the polymer. The degree of crystallinity is estimated by different analytical methods and it typically ranges between 10 and 80%, with crystallized polymers often called "semi-crystalline". The properties of semi-crystalline polymers are determined not only by the ...
Polymers have both a melting temperature T m and a glass transition temperature T g. Above the T m, the polymer chains lose their molecular ordering and exhibit reptation, or mobility. Below the T m, but still above the T g, the polymer chains lose some of their long-range mobility and can form either crystalline or amorphous regions. In this ...
Because of the long chain and various conformation, it is hard for the polymers to be crystallized directly from solution. Few examples of polymer single crystals prepared in this way suffered from low quality and small size. [26] Topochemical polymerization provides a potential solution to yield high-quality polymer single crystals.
Some polymer solutions also have a lower critical solution temperature (LCST) or lower bound to a temperature range of partial miscibility. As shown in the diagram, for polymer solutions the LCST is higher than the UCST, so that there is a temperature interval of complete miscibility, with partial miscibility at both higher and lower temperatures.
The crystals are captured, stored, and sputter-coated with platinum at cryo-temperatures for imaging. The crystallization process appears to violate the second principle of thermodynamics. Whereas most processes that yield more orderly results are achieved by applying heat, crystals usually form at lower temperatures – especially by ...
In materials science, a thermosetting polymer, often called a thermoset, is a polymer that is obtained by irreversibly hardening ("curing") a soft solid or viscous liquid prepolymer . [1] Curing is induced by heat or suitable radiation and may be promoted by high pressure or mixing with a catalyst .
The temperature range offered by the PCM technology provides a new horizon for the building services and refrigeration engineers regarding medium and high temperature energy storage applications. The scope of this thermal energy application is wide-ranging of solar heating, hot water, heating rejection (i.e., cooling tower), and dry cooler ...
In polymer physics, spherulites (from Greek sphaira = ball and lithos = stone) are spherical semicrystalline regions inside non-branched linear polymers. Their formation is associated with crystallization of polymers from the melt and is controlled by several parameters such as the number of nucleation sites, structure of the polymer molecules, cooling rate, etc. Depending on those parameters ...