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8246678 
Journal Article 
Влияние модификации изотактического полипропилена на его транспортные свойства 
Strusovskaya, NL; Matushkina, NN 
2020 
Voronezh State University 
20 
3 
335-342 
Russian 
Modification of industrial polymers can be used to create materials with a specific set of performance properties. In this study, the structure of 01030 grade isotactic polypropylene (PP) films was modified by treating them with liquid alkanes with an increasing number of carbon atoms (hexane, heptane, n-nonane), which led to an increase in the sorption and water permeability in the process of pervaporation. The experiments consisted of four tests for both PP swelling and pervaporation studies. Test 1 of the experiment showed that with an increase in the number of carbon atoms in the alkane molecule, the degree of PP swelling increases, and the pervaporation flux density decreases. Tests 3 and 4 involving the modification of PP films by alkanes revealed an increase in the mobility of segments of macromolecular chains and the distance between them. Upon the desorption of alkanes, the formed structure is apparently preserved. As a result of the complete removal of the previously dissolved substance (hexane and heptane) there remain «voids» through which water penetrates (test 3) and there is an increase in the equilibrium degree of PP swelling, while n-nonane is not completely removed, so water cannot penetrate into the PP. A similar behaviour is observed in the process of pervaporation of water in test 3. In case of test 4, which did not involve desorption of alkanes, water «pushes» the alkanes out of the polymer and following them penetrates into the film through the formed channels. With an increase of temperature in the studied interval, the alkane flux density increases (5 times for hexane). An increase in the density of the water flow after modification occurs for all the studied alkanes, however, it decreases upon the transition from hexane to n-nonane. Test 2 resulted in the modification of the film surface, whereas tests 3 and 4 led to volume modification. Thus, the modification of polymer films using hydrophobic substances leads to an increase in the sorption and permeability of hydrophilic substances (water). © 2020 Sorbtsionnye i Khromatograficheskie Protsessy. 
Alkanes; Modification; Permeability; Pervaporation; Polypropylene; Sorption