Static melting temperature, effect

Another example of static SIMS used in a more quantitative role is in the analysis of extmded polymer blends. The morphology of blended polymers processed by extrusion or molding can be affected by the melt temperature, and pressure, etc. The surface morphology can have an effect on the properties of the molded polymer. Adhesion, mechanical properties, and physical appearance are just a few properties affected by processing conditions. 

This effect of M can be explained as being due to the crystalline phase in the o semi-crystalline polymer. The presence of this crystalline phase reduces the molecular mobility. The crystalline structure is not something static, but it is perfected on annealing. The longer the reaction at a high temperature, the more perfect the crystalline phase, and the more the molecular mobility is restricted. After melting this starts all over again and the lower the M the faster is this crystallization process, o... 

At low pressures the solubility of C02 in PEG is low. The increase of the melting point of PEG with (static) pressure outweighs the diminishing effect of C02. In a medium pressure range the reducing effect of C02 dominates. At a further pressure increase, the amount of dissolved C02 in the liquid increases. At the same time pressure dependency of the gas solubility decreases (see fig. 2, slope of 0,05 line and 0,25 line). = higher pressures) again the liquefaction temperature... 

Due to the temperature dependent term TAS, the state (solid, liquid, gas) can be changed, e.g. by melting or evaporation. However, the pressure-dependent term p AV is more dominant, because the pressure can be increased to a much greater extent than the temperature. Table 9.4 summarizes the effects at static pressures of 5 000 bar, 50 000 bar or 500 000 bar, that can be achieved for a compound which shows a decrease in volume of AV = 20 cm3 mol-1. 

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