Toughness modification of cationic UV-cured cycloaliphatic epoxy resin by hydroxyl polymers with different structures

UV–thermal‐cured cycloaliphatic epoxy composites with enhanced mechanical properties via Ca2+‐modified nanocrystalline cellulose

“…Owing to the relatively rapid UV polymerization process, and therefore reactive monomers were quickly restricted in the initial crosslinked network, even if the UV-cured product had a post-thermal curing process, so the structure of the cross-linked network was defective. 18 NCC-Ca participated in the ring-opening polymerization of CAE through chain transfer reaction, counteracted the defects described above, further improved the crosslinked network of the UV-thermal-cured CAE composites and increased T g . On the other hand, due to the relatively complete crosslinked double networks of the NCC-Ca/ CAE composite, T g of the NCC-Ca/CAE composites is higher than that of the NCC/CAE composites.…”

“…8(a), the original CAE section shows flat and smooth morphology with some small structures. 18 However, NCC/CAE (Fig. 8(b)) and NCC-Ca/CAE (Fig.…”

“…Thus, various organic or inorganic modifiers, including thermoplastics, 9 rubber, 10,11 inorganic and organic fillers [12][13][14] and hyperbranched polymers, [15][16][17] have been employed to improve the toughness and other mechanical properties of epoxy resin. For example, Xia et al 18 designed a hydroxyl-terminated hyperbranched polyether compound to toughen epoxy resin. Benefiting from the activation mechanism of the terminal hydroxyl group and the flexible polyether molecular chain, the obtained epoxy resin showed excellent impact strength.…”

Enhancement of Epoxy Thermosets with Hyperbranched and Multiarm Star Polymers: A Review

“…More recently, Xia et al [ 80 ] studied the toughening effect of the hydroxyl-ended Boltorn ® H2004 and a poly(tetramethylene ether glycol) (both with molecular weight around 2000 g/mol) on a cycloaliphatic epoxy resin cured with UV-light. The photopolymerization kinetics were significantly faster with the HBP than with the linear polyether.…”

“…This results in the formation of hydroxyl groups which decreases the compatibility of epoxy and HBP leading to the formation of a two-phase microstructure [ 44 ]. In some cases, the flexible aliphatic structure of the HBP reduces the T g value despite the crosslinking density achieved [ 80 , 108 ].…”