Non-isocyanate Polyurethane Coating with High Hardness, Superior Flexibility, and Strong Substrate Adhesion

Abstract

Flexible hard coatings with strong adhesion are critical requirements for several foldable devices and marine applications; however, only a few such coatings have been reported. Herein, we report a non-isocyanate polyurethane (NIPU) coating prepared by the epoxy−oligosiloxane nanocluster−amine curing reaction and cyclic carbonate−amine polyaddition, where the former provides the coating with ceramic-like hardness and polymer-like flexibility while the latter polymerization results in NIPU with strong substrate adhesion. The coating is transparent (>92% transmittance), hard (5−7 H), and flexible (2 mm bending diameter). It has strong adhesion to various substrates including aluminum alloy, titanium, steel, glass, ceramic, epoxy, and polyethylene terephthalate (2−8 MPa), which can be attributed to the high density of polar groups in NIPU. Moreover, we can facilely endow the coating with anti-icing, self-cleaning, and anti-smudge capabilities by incorporating amine-terminated low-surface-tension polydimethylsiloxane (PDMS) to replace a part of the amine curing agent. Particularly, the mechanical properties of NIPU coatings are only slightly affected by the introduction of low-content PDMS since it intends to enrich on the surface. The novel coating has promising future for use in fields of foldable devices and marine applications.

Polyhydroxyurethanes from Biobased Monomers and CO2: A Bridge between Sustainable Chemistry and CO2 Utilization†

“…used DGC to form PHU linkages during the curing of nanosized epoxy‐oligosiloxane clusters with a diamine (DDCM, 4,4‐diaminodicyclohexylmethane) leading to hard flexible coatings with improved substrate adhesion. [ 212 ] Zhao et al . reported the preparation of hydrophobic and highly solvent resistant PHUs with a high renewable content by polyaddition of DGC with oligomeric diamines obtained from dimerized fatty acids.…”

Phosphate functionalized nonisocyanate polyurethanes with bio-origin, water solubility and biodegradability

“…28 In the past decade, there has been a surge in studies focusing on using bio-based resources, 29,30 such as vegetable oils, 31,32 algal oils, 33 lignin, 34 polyols, 35 and terpenes, 36 for the synthesis of NIPUs. The majority of studies on applications of biobased NIPUs have been centred around coatings and adhesives [37][38][39] and investigations into their mechanical properties. More recently, there has been a growing momentum in smart NIPUs with properties such as recyclability, [40][41][42] selfhealing, 43,44 and shape memory, 45,46 further expanding the potential applications and versatility of these promising polymeric materials.…”

Biobased, Biodegradable, and Water-Soluble Amine-Functionalized Non-Isocyanate Polyurethanes for Potential Home Care Application

“…8,28 However, the water solubility and dispersibility of NIPU are highly dependent on the structures of cyclic carbonate and amine monomers used for their synthesis and the hydrophilicity of functional groups present in the NIPU main chain or side chain. 27,29 Other than the functionalization of hydroxyl groups 30 on the NIPU side chain, a potential way to introduce hydrophilic functionalities in NIPUs would be by the use of polyamines as monomers. Indeed, a number of publications 19,28,31−48 reported the utilization of polyamine monomers for the synthesis of NIPUs.…”

“…Waterborne and water-soluble NIPUs are gaining further attention as alternatives to waterborne PUs used in consumer care products and biomedical applications. In general, NIPUs have 15–35 times higher water absorption capacity compared to conventional PUs owing to the hydrogen-bonding interaction between the primary/secondary hydroxyl groups on the polymer side chain and water. , However, the water solubility and dispersibility of NIPU are highly dependent on the structures of cyclic carbonate and amine monomers used for their synthesis and the hydrophilicity of functional groups present in the NIPU main chain or side chain. , Other than the functionalization of hydroxyl groups on the NIPU side chain, a potential way to introduce hydrophilic functionalities in NIPUs would be by the use of polyamines as monomers. Indeed, a number of publications ,,− reported the utilization of polyamine monomers for the synthesis of NIPUs.…”