Investigating compatibility between TPU and bitumen SARA fractions by means of Hansen solubility parameters and interfacial tension measurements. (28th June 2021)

• Record Type: Journal Article
• Authors: Gallu, Raïssa; Méchin, Françoise; Dalmas, Florent; Gérard, Jean-François; Perrin, Rémi; Loup, Frédéric
• Is Part Of: Construction & building materials. Volume 289(2021)
• Publication Date: 2021-06-28
• Subjects: Polymer-modified bitumen -- Thermoplastic polyurethane -- Hansen solubility parameters -- Interfacial tension; Building materials -- Periodicals; 624.18
• DOI: 10.1016/j.conbuildmat.2021.123151
• Languages: English
• ISSNs: 0950-0618

Abstract

Graphical abstract: Highlights: Soft segments of TPU are swollen by both aromatics and resins. Amorphous phase of hard domains of TPU is swollen only by resins. Higher amounts of resins lead to lower interfacial tension between TPU and bitumen. Rubbery modulus & flowing temperature of blends decrease when resin content increase. Resins increase compatibility between TPU and bitumen. Abstract: Hansen solubility parameters (HSP) and model oils were used to predict the affinity of each block of the TPU (thermoplastic polyurethanes) with the SARA fractions (Saturates, Aromatics, Resins, Asphaltenes) of bitumen, revealing the preferential compatibility of the bitumen with the soft block of the TPU. More specifically, aromatics are highly compatible with the soft block while resins are compatible with soft and hard blocks of the TPU. Companion SAXS analysis highlighted that the microstructure of TPU is however maintained with semicrystalline hard nanodomains dispersed in a soft matrix with its amorphous part being swollen by resins. Interfacial tension measured by drop deformation retraction method (DDR) highlighted the compatibilizing role of resins as a lower interfacial tension value was measured at high resin content. In turn, different mechanical properties of TPU-modified bitumens were obtained when changing their composition. With similar morphologies for the blends (i.e. continuous TPU phase swollen with the same ratio), a decrease in rubbery storage modulus and flowing temperature was observed as the amount of resins increases.