High strength, recyclable and shape memory polyhydroxyurethanes with intrinsic fluorescent properties

Abstract

Polyhydroxyurethanes (PHUs), which are synthesized through the aminolysis of cyclic carbonates, avoid the use of toxic isocyanates compared with traditional polyurethanes (PUs) and have aroused great interest. The large number of hydroxyl groups in the network endows PHUs with unique features, such as recyclable properties and fluorescent properties. To establish the high performance and multifunctionality of PHUs, we designed a molecular structure to fabricate PHUs with mechanical robustness, shape memory properties, fluorescent properties, and recyclable properties. The yielded PHU crosslinked by the quaternary thiol and weak but dense hydrogen bonds (H‐bonds) shows unprecedented high mechanical properties with a tensile Young's modulus of 3.13 GPa, comparable to that of polyimide, a tensile strength of 59.2 MPa at room temperature and an excellent toughness of 27.9 MJ/m3 at 50°C, and good damping properties (tanδ ≥ 0.3, temperature range of 35.2°C). Interestingly, fluorescence caused by the aggregation of carbamate within PHUs allows it to be applied for damage self‐reporting to visualize tiny cracks or magnify fractures. Furthermore, both the thermosetting PHUs and recycled thermosetting PHUs presented excellent shape memory performance. This study provides certain inspiration for the design and development of highly rigid multifunctional polymers.

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

“…Sulfur‐based aliphatic bis‐5CCs EDTBC [ 156 ] and DODTBC [ 157 ] were prepared in studies targeting the synthesis of PHUs with triple shape memory properties by a thiol‐ene click reaction between 1,2‐ethanedithiol or 3,6‐dioxa‐1,8‐octanedithiol and vinyl ethyl carbonate ( VEC ). Other sulfur‐containing long‐chain bis‐5CCs ( EDTDMBC , MDTDMBC and DODTMBC ) were prepared by Wu, Chen et al .…”

“…Besides, PETMPBC was obtained by a thiol‐ene click reaction of VEC and pentaerythritol‐derived pentaerythritol tetrakis(3‐mercaptopropionate). [ 157 ] The use of PETMPBC in the preparation of PHUs led to attractive materials with fluorescence and shape memory properties and good recyclability. THPMTC , obtained from the reaction of tris(4‐hydroxyphenyl)methane and epichlorohydrin, was recently used by Torkelson et al .…”