Chapter 3 Chemistry of polyurethane adhesives and sealants

Segura, Diana; Nurse, A. D.; McCourt, Andrea; Phelps, Renata; Segura, Ana

doi:10.1016/s1874-5695(02)80004-5

Cited by 45 publications

(31 citation statements)

References 9 publications

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“…Further reactions occur between the highly reactive amine and the isocyanate groups left in the cluster previously formed, with the development of a more compact microstructure, through the formation of urea linkages between smaller units which, as commented, still had reactive -NCO sites available (Carrera et al, 2009;Martín-Alfonso et al, 2008a, 2008bSegura et al, 2005).…”

Section: Bitumen Reactive Modification Through Urethane/urea Chemicalmentioning

confidence: 93%

Effect of transesterification degree and post-treatment on the in-service performance of NCO-functionalized vegetable oil bituminous products

Cuadri¹,

García‐Morales²,

Navarro³

et al. 2014

Chemical Engineering Science

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The bitumen modification through polyurethane prepolymers presents significant benefits for the manufacture of bituminous products for the paving industry. In this sense, this work explores the use, as bitumen modifier, of a novel reactive prepolymer synthesized by reaction of 4,4´,diphenylmethane diisocyanate (MDI) and a vegetable oil-based polyol, castor oil (CO), previously transesterified with pentaerythritol. On the one hand, thermal analysis on transesterified CO revealed a highly stable prepolymer, making it suitable to be used for bitumen modification in a wide range of processing temperatures, 90-180 ºC. On the other hand, the bitumen modification achieved for the polyurethane-modified strongly depends on the transesterification degree and posttreatment procedures involved. In this sense, Atomic Force Microscopy (AFM) proved that MDI-prepolymers, based on castor oil transesterified with 4 wt.% pentaerythritol, lead to modified samples with a more complex microstructure which enhances rheological properties and reduces thermal susceptibility. In any case, viscoelastic and flow tests showed that the addition of small quantities of this reactive prepolymer to bitumen leads to products with enhanced performance at high in-service temperatures.

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Section: Bitumen Reactive Modification Through Urethane/urea Chemicalmentioning

confidence: 93%

Effect of transesterification degree and post-treatment on the in-service performance of NCO-functionalized vegetable oil bituminous products

Cuadri¹,

García‐Morales²,

Navarro³

et al. 2014

Chemical Engineering Science

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“…-12 -Consequently, reactions 2 and 3 are expected to build up a more compact microstructure, through the formation of urea linkages between smaller units which, as commented, still had reactive -NCO sites available [25,26,33,34]. In addition, the Carreau's model fittings (see Table 4) reveal the development of a more complex microstructure for the "MDI-binder", as deduced from a higher value of viscosity (0) along with a lower value of the threshold shear rate c γ  (i.e.…”

Section: Rheological Behaviour At High In-service Temperaturesmentioning

confidence: 99%

Chemically modified bitumens with enhanced rheology and adhesion properties to siliceous aggregates

Cuadri¹,

Partal²,

Ahmad

et al. 2015

Construction and Building Materials

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Moisture damage is one of the major premature failures that worsens the performance and shortens service life of pavements. This research assesses the effect that two chemical modifiers (thiourea and an isocyanate-functionalized castor oil prepolymer) exerts on the bitumen rheology and on the resistance to potential moisture damage of asphalt mixtures based on siliceous aggregates. Both thiourea and the isocyanate-based prepolymer improve the viscous and viscoelastic behaviours of bitumen at high inservice temperatures, particularly the isocyanate-based reactive modifier. Likewise, the visual inspection of the degree of bitumen coating on loose mixtures exposed to water in a "rolling bottle" test, and further surface free energy measurements, showed that the bitumen modification by the isocyanate-based prepolymer seems to reduce moistureinduced damage on siliceous aggregates. Conversely, thiourea-based modification increases sensitivity of the bitumen-aggregate mixture to water. Different adhesion mechanisms, based on chemical or physical bonds with the aggregate surface, have been proposed for each modifier.

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“…A significant increase in the binder viscosity derived from the development of a complex microstructure is achieved (Segura et al, 2005;Martín-Alfonso et al, 2008). …”

Section: Prepolymers Characterizationmentioning

confidence: 99%

Isocyanate-functionalized castor oil as a novel bitumen modifier

Cuadri

García‐Morales

Navarro

et al. 2013

Chemical Engineering Science

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The use of biomaterials from renewable sources in the synthesis of polyurethanederived polymers is lately receiving great attention from social, environmental and economic standpoints. In this work, prepolymers having different -NCO/-OH ratio were synthesized, by reaction of 4,4´-diphenylmethane diisocyanate (MDI) with castor oil (CO), to be used as modifying agent of asphaltic bitumen. Reactions between MDI and CO, performed with -NCO/-OH molar ratios of 8:1 and 4:1, have led to suitable bitumen modifiers. Modification has been related to chemical reactions between -NCO groups, some bitumen compounds and air moisture (or added water), which gave rise to binders with enhanced resistance to permanent deformation. The results showed that a 2 wt.% of MDI-CO prepolymer leads to binders with higher viscosity than that corresponding to a 3 wt.% Styrene-Butadiene-Styrene (SBS) block copolymer, a polymer and concentration widely used in the paving industry. Furthermore, the resulting prepolymers are liquids that can be easily mixed with bitumen at 90 ºC, which significantly lowers the typical temperature used for commercial SBS-modified bitumen (about 180 ºC). This fact may represent energy savings, reduce bitumen oxidation and result in improvements of health and safety conditions during the product manufacture.However, if high processing temperatures are required, MDI-CO based modifiers have demonstrated much higher thermal stability than prepolymers derived from crude oil (e.g. based on polyethylene glycol). As a result, NCO-terminated prepolymers obtained from biomass-derived polyols (castor oil in this article) may become a promising alternative to the use of other petrochemicals in the paving industry.

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Chapter 3 Chemistry of polyurethane adhesives and sealants

Cited by 45 publications

References 9 publications

Effect of transesterification degree and post-treatment on the in-service performance of NCO-functionalized vegetable oil bituminous products

Effect of transesterification degree and post-treatment on the in-service performance of NCO-functionalized vegetable oil bituminous products

Chemically modified bitumens with enhanced rheology and adhesion properties to siliceous aggregates

Isocyanate-functionalized castor oil as a novel bitumen modifier

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