Polyurethane/epoxy hybrid materials from CO2-sourced monomer were prepared via an environmentally-friendly and non-toxic route, which avioded the use of toxic isocyanate. A series of non-isocyanate polyurethane (NIPU)/epoxy hybrid materials, with different and controlled architectures, were synthesized from CO2, polypropylene glycol diglycidyl ether (PPGDGE), amines and diglycidyl ether of bisphenol-A (BADGE). Around 12 wt% CO2 was incorporated into PPGDGE to form a five-membered cyclic carbonate (5CC-PPGDGE). The complete conversion and selectivity of PPGDGE were obtained. The kinetics of 5CC-PPGDGE was investigated by reacting it with 1,2-ethylenediamine (EDA) at different temperatures. NH2-terminated pre-polymers were obtained by reacting 5CC-PPGDGE with various excessive amines. Finally, the hybrid materials were obtained by curing pre-polymers with BADGE. The results showed that a high content of amine with more functional groups led to better mechanical performances than diamine-based hybrid materials. This is the first time that architectures have been controlled by altering the amine ratio and functionality. And these hybrid materials exhibited satisfactory mechanical performances. The DETA-based and TETA-based materials with high amine ratio exhibited a tensile strength of 15.0 MPa and 12.5 MPa, accompanied with elongation at break of 151.3% and 170.9%, respectively. The gel content, glass transition temperature and thermodynamic stability went up first and then declined with the increase of amine ratio, which demonstrated the architectures of hybrid materials ranged from defective to cross-linked and linear structures.
Hydrogenolysis of glucose and cellobiose, used as the model feedstocks, over Ni–WO3/SBA-15 catalysts has been investigated to probe the influencing factors for the conversion of cellulose to ethylene glycol (EG). The conversion of glucose and cellobiose to EG showed different dependencies on reaction temperature; a lower reaction temperature was needed for the former. Additionally, the surface atomic ratio of W to Ni on the Ni–WO3/SBA-15 catalysts was the key factor for the product distribution. Both glucose and cellobiose had their own optimum W–Ni ratio for the production of EG, and the ratio of W to Ni for glucose was slightly lower than that of cellobiose. On the other hand, the Ni–WO3/SBA-15 catalysts were thoroughly characterized by N2 adsorption–desorption, X-ray diffraction (XRD), hydrogen-temperature programmed reduction (H2-TPR), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). The results indicated that the reducibility of Ni–WO3/SBA-15 catalysts with high Ni loading was more similar to that of pure NiO. More importantly, the change of surface atomic content of Ni and W of Ni–WO3 catalysts with various Ni loadings resulted from the surface W species of the catalysts being gradually covered by Ni species with the increase of Ni loading.
29 August 2018 in Applied Organometallic Chemistry