Effect of co-unit type in random propylene copolymers on the kinetics of mesophase formation and crystallization |
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Authors: | Daniela Mileva René Androsch |
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Affiliation: | (1) Center of Engineering Sciences, Martin-Luther-University Halle-Wittenberg, 06099 Halle/Saale, Germany; |
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Abstract: | Fast scanning chip calorimetry has been employed to study the effect of the type and concentration of co-units on the rate of mesophase formation and crystallization in random isotactic copolymers of propylene and 1-alkenes, including ethylene, 1-butene, 1-hexene, and 1-octene. The dependence of the rate of ordering on temperature of the propylene homopolymer shows two distinct maxima around 300 and 340–350 K which are related to mesophase formation and crystallization, respectively. Addition of 1-alkene co-units leads to a decrease of the maximum rate of both crystallization and mesophase formation. At comparable temperature and molar percentage of co-units in the propylene chain, ethylene, and 1-butene co-units cause less reduction of the maximum rate of ordering than 1-hexene or 1-octene co-units. The experimental observations are discussed in the context of possible incorporation of these chain defects into the ordered structures. |
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