A Review of the Sustainable Approaches in the Production of Bio-based Polyurethanes and Their Applications in the Adhesive Field

Abstract

On account of the irreversible environmental damage caused by the utilization of non-renewable raw materials in industrial production, since the end of the twentieth century, the interest in replacing the traditionally applied petroleum-based starting compounds in the polyurethane production by more sustainable feedstocks has grown enormously. Such pursuit of Green Chemistry has been fostered by the implementation of a set of national and international initiatives and stricter regulations, especially in the field of adhesives. In this respect, the latest advances in the production of bio-based polyurethanes are collected in this review. Thus, after a brief introduction to this subject and main tendencies towards the production of more sustainable polyurethanes, the first section reviews the feasibility of manufacturing polyurethanes from a range of natural platforms, including lignocellulosic biomass and vegetable oils, whether modified or in their original form, along with some industrial wastes. Afterwards, the hitherto considered synthetic routes for the preparation of greener polyurethanes are assessed, encompassing waterborne, radiation-curable and non-isocyanate polyurethane techniques. Finally, the last section focuses on the research advancement on the synthesis, properties and different uses of bio-based polyurethanes specifically implemented in the field of adhesives.

Surface Properties of Poly(Hydroxyurethane)s Based on Five-Membered Bis-Cyclic Carbonate of Diglycidyl Ether of Bisphenol A

“…The obtained PHUs exhibited an initial degradation (at 5% weight loss) in the range of 239 °C to 283 °C and maximum decomposition rates in the range of 355 °C to 371 °C, values comparable to those observed previously by us [ 32 , 55 , 56 ]. The PHUs based on aliphatic diamines (NIPU1−NIPU3) exhibited the lowest temperatures of initial degradation (at 5% weight loss).…”

“…The values of total SFE determined with the Owens–Wendt approach are the highest for PHU-C10O3, equal to 57 mJ∙m −2 ; and the lowest value was calculated for PHU-CC6, equal to 47 mJ∙m −2 . The values of total SFE are much lower than those calculated by us in our previous works [ 25 , 31 , 55 ]. The results show that in the investigated coatings, mainly dispersive interactions occur.…”

“…In general, PHUs exhibit lower molar masses and slower kinetics [ 13 ], so their application is limited by their properties. However, some of the possible uses of PHUs have been already presented, e.g., coatings [ 53 , 54 ], adhesives and glues [ 11 , 16 , 20 , 25 , 26 , 30 , 31 , 54 , 55 ] and foams [ 19 ]. It should be highlighted that the number of works describing the potential applications of PHUs is constantly growing.…”

Enhanced aminolysis of cyclic carbonates by β-hydroxylamines for the production of fully biobased polyhydroxyurethanes

“…Polyurethanes (PUs), ranking 6 th among all polymers based on annual worldwide production, are commonplace in everyday life as foams, coatings, adhesives, elastomers, insulation, composites, and so forth. [1][2][3] They are present in a wide range of applications due to the numerous industrially available polyols, which allow to cover a large panel of properties. 4,5 However, their synthesis requires the use of isocyanates, known to be harmful for human health and for the environment.…”

One‐Pot Two‐Step Synthesis of Hydroxymethylated Unsaturated VHOSO and Its Application to the Synthesis of Biobased Polyurethanes

“…[ 6,7 ] There has been a continuous rise in the demand for bio‐PUs materials in the last 20 years, owing to their increasing use in end segment industries, with applications in foams, elastomers, thermoplastics, thermosets, adhesives, coatings, sealants, fibers, and so on. [ 8,9 ] Bio‐PUs are now the first used biobased polymer and the global production demand is expected to be more than 3 Mt by 2021. [ 10 ] To increase the renewable content, bio‐PUs are mainly obtained by reacting diisocyanates and polyols resulting from functionalization of vegetable oils extracted from various plants (rapeseed, soybean, palm, etc.).…”