Solvent-Free Preparation of Thermally Stable Poly(urethane-imide) Elastomers

Abstract

Polyurethanes (PUs) are widely used in many applications due to their versatile chemical and physical properties. To meet the increasing demands on PU with respect to intrinsic mechanical and thermal properties, they can be modified with thermally stable aromatic imide structures to form poly(urethane imide) (PUI). However, the preparation of PUI materials has been limited by the need for strong polar solvents, which hinder their industrial scale development. In this work, we prepared imide-containing isocyanate-terminated prepolymers via the reaction of polymeric aromatic or aliphatic isocyanates and pyromellitic dianhydride in completely solvent-free conditions. The subsequent PUI elastomers made from these prepolymers exhibited enhanced char formation and stiffness in comparison to the reference elastomers without imide structures, among which the aromatic PUI elastomer shows improved flame retardancy according to the initial cone calorimetry measurement. This work demonstrates the potential use of imide prepolymers in other PU applications where high thermal stability and flame retardancy are required. The solvent-free synthesis also paves a way for the large-scale production of PUI materials.

Self-assembly of hierarchical porous structure for stretchable superhydrophobic films by delicately controlling the surface energy

“…It should be noted that although some poly(amideimide-urethane) thermoplastic elastomers have been reported, which exhibit a large elongation at break, the rigidity (tensile strength) of poly(amide-imide-urethane) is much lower than that of the TPU-PAI substrate. 31,32 More importantly, the rigidity and flexibility of the PAI-TPU substrate is controllable by varying the ratio of TPU to PAI due to the high compatibility between PAI and TPU. For the superhydrophobic coating, a silane coupling agent named FAS-17 containing fluorinated alkyl chains was grafted on the surface of SiO 2 nanoparticles.…”

Novel Furfural-Derived Polyaldimines as Latent Hardeners for Polyurethane Adhesives

“…Polyurethanes (PU) represent a versatile class of polymers, widely utilized across various industries due to their remarkable properties and diverse applications. − Flexible and rigid foams , are the dominant sectors, followed by high-performance adhesives, , coatings, , sealants, , and elastomers . Furthermore, they are pivotal components in key industry sectors such as the automotive, construction, and textiles …”

“…1 − 3 Flexible and rigid foams 4 , 5 are the dominant sectors, followed by high-performance adhesives, 6 , 7 coatings, 8 , 9 sealants, 10 , 11 and elastomers. 12 Furthermore, they are pivotal components in key industry sectors such as the automotive, 13 construction, 14 and textiles. 15 …”

Synthesis and characterization of new nanocomposites based on poly(urethane-imide)s reinforced functionalized carbone nanotubes containing N-Trimellitimido-L-Valine as rigid segments

“…Poly(urethane-imide)s PUIMs are unique polymeric structures known for their interesting mechanical and thermal properties and also for their environmental friendly behaviors [5,8,9,10]. Incorporating symmetric aromatic imide rings with strong bonds into polyurethane backbone of PUIMs provide good balances between mechanical and thermal properties and flexibility of these materials [11,12].…”