One-component polysulfide adhesive preparation by diisocyanate-terminated prepolymers and 1,4-butanedithiol (BSO) can provide convenient moisture curing and excellent mechanical properties, but the formation of polysulfide-urea (–NHCOS–) groups causes some reduction in solvent resistance limiting their further application in aircraft fuel tank sealing. Introducing silane side chains into polysulfide adhesive systems is a viable approach to improving the solvent resistance. In this work, a series of novel silane side chain-modified one-component polysulfide adhesives were synthesized by using chain extenders in different proportions of BSO and (3-(2-aminoethyl)aminopropyl)trimethoxysilane (AEAPTMS). The results showed that a moderate amount of silane side chains and restricting the formation of Si–O–Si crosslinked networks can effectively enhance the elongation, interfacial interaction and solvent resistance. The optimal overall performance was obtained when the mass ratio of BSO and AEAPTMS was 7 : 1 (Si-OCPS3). Conversely, the oil and water absorption content after 21 days of Si-OCPS3 were 2.21 ± 0.06% and 2.81 ± 0.31%, being 20.50% and 43.57% lower than before modification (Si-OCPS0), respectively. Moreover, Si-OCPS3 exhibited higher tensile strength of 17.34 ± 0.66 MPa (oil) and 15.67 ± 0.32 MPa (water) than Si-OCPS0. We believe our paradigm can provide a feasible approach for designing high-performance one-component polysulfide adhesives.
Families of bio-based hyperbranched epoxy (HBPEEs) were successfully prepared using renewable xylitol, bisphenol A and epichlorohydrin as feedstocks. The structure and physical performances of HBPEEs were characterized by FTIR, NMR, GPC and viscosity evaluation. Then, they were used as high efficient tougheners for diglycidyl of bisphenol A/diethylenetriamine (DGEBA/DETA) networks. The results indicated that the incorporation of HBPEEs into the DGEBA system can significantly enhance the mechanical properties and solvent resistance properties of the hybrid (HBPEEs/DGEBA). In particular, toughened hybrids with 15 wt% HBPEE-2 exhibited the outstanding impact strength than that of neat DGEBA (37.4 kJ/m 2 vs. 11.8 kJ/m 2 ) due to its excellent compatibility of with DGEBA. Simultaneously, the ductile fracture morphology of the modified hybrids was also confirmed by SEM. In addition, the activation energies of HBPEE-2/DGEBA hybrids calculated from the non-isothermal curing kinetics were lower than that of neat DGEBA. All of the results suggested that the bio-based HBPEEs could be used as efficient tougheners applied in epoxy resins industry.
危险品化学品经营许可证（带存储）