A study of blends of poly(n‐octadecyl methacrylate) with n‐dodecane and n‐octadecane

Abstract

DSC and X-ray diffraction analysis were used to study blends of poly(n-octadecyl methacrylate) with n-dodecane and n-octadecane crystallized from the melt to gain a better understanding of the interaction of comb-like polymethacrylates with paraffin waxes. In both sets of blends both components could crystallize in separate lattices. However, the polymer interfered with the crystallization of the n-paraffin, resulting in less crystalline paraffin than expected on the basis of blend composition. In the blends with n-dodecane, evidence was found for partial cocrystallization of the paraffin and the polymer side chains. No cocrystallization was observed in the blends with n-octadecane. ZUSAMMENFASSUNG:Mit Hilfe der Differential-Scanning-Calorirnetrie und RiSntgenbeugung wurde das Kristallisationsverhalten von Mischungen aus Poly(n-octadecylmethacry1at)en rnit n-Dodekan und n-Oktadekan bei der Kristallisation aus der Schmelze untersucht. Hierbei sollten bessere Erkenntnisse uber die Wechselwirkungen von kamm2hnlich strukturierten Polymethacrylaten rnit paraffinischen Kohlenwasserstoffen gewonnen werden. In beiden Mischungen war ein Auskristallisieren der beiden Komponenten in verschiedenen Gittern mtiglich. Es wurde jedoch gefunden, da8 das Polymere die Kristallisation der n-Paraffine beeinflufit rnit dem Ergebnis, da13 weniger Paraffin kristallisierte, als vom Paraffinanteil in der Mischung zu envarten war.In Mischungen rnit n-Dodekan wurden Anhaltspunkte fur eine teilweise Cokristallisation des Paraffins rnit den Seitenketten des Polymeren gefunden. In Mischungen rnit n-Oktadekan wurde keine Cokristallisation beobachtet.

Thermal Annealing of High cis-1,4-Polybutadiene/Octadecyl Acrylate Blends as a One-Step Process for Fabricating Shape Memory Polymers

“…As [ODA]/[B] decreases, the ODA melting temperature decreases. The melting point depression is consistent with other comb-like polyacrylate and polymethacrylate copolymers having crystallizable n -octadecyl side chains, while the presence of a single melting peak is consistent with blends of poly( n -octadecyl acrylate) with n -octadecanoic acid and n -aliphatic hydrocarbons − due to the combined effects from the entropic gain of mixing the chemically different units, decreasing ODA concentration, and the co-crystallization of ODA with the PB- x ODA that regulates the crystal growth and thereby the melting temperature and the enthalpy of melting. The enthalpy of melting (Δ H m ) in kJ/mol of ODA was calculated as Δ H m false( kJ / mol 0.25em ODA false) = Δ H m false( normalJ / normalg false) M ODA w ODA ( 1000 ⁢ J / k J ) where w ODA is w ODA = false[ ODA false] M ODA false[ ODA false] M ODA + false[ normalB false] M B and is plotted in Figure c.…”

Structural and thermal behavior of comb‐like polymer having n‐octadecyl side chains

“…16 This suggests that cocrystallization is produced because of the thermodynamically miscible parts of two components in the blend having similar crystallization rates. 17,18 The main chain of POMA strongly influences the crystallization behavior of n-octadecyl side chain.…”

“…In the solid‐state of POMA blended with n ‐dodecane and n ‐octadecane, side chains of the polymers were found to cocrystallize with n ‐hydrocarbon and to alter the solid‐state structure of low MW component 16. This suggests that cocrystallization is produced because of the thermodynamically miscible parts of two components in the blend having similar crystallization rates 17, 18.…”

“…5 The polymer was purified by repeated precipitation in acetone. The number-average molecular weight (M n ) of the sample was 6600, with a polydispersity index of 1.51. n-Octadecanoic acid (CH 3 (CH 2 ) 16 -COOH, C 18, Merck) and tetrahydrofuran (THF; Qualigens, India) were purified by standard methods.…”