Microstructural study of epoxy-based thermosets prepared by “classical” and cationic frontal polymerization

Abstract

Epoxides prepared by cationic frontal polymerization have a greater reduced void fraction than “classically” cured samples revealing free-volume consequences of waves.

Front velocity dependence on vinyl ether and initiator concentration in radical‐induced cationic frontal polymerization of epoxies

“…3,35 RICFP thus far has been studied as a method to frontally polymerize epoxide monomers. [44][45][46][47][48][49][50][51][52][53][54] There has been recent work showing RICFP of pure divinyl ethers and divinyl ether/epoxy/acrylate hybrid systems with nearinfrared sensitizers added to promote front initiation via near-infrared laser as well. 55 Use of vinyl ethers in small concentrations with pyrylium salts as a coinitiator system for photoinduced thermal FP has also been shown.…”

“…RICFP thus far has been studied as a method to frontally polymerize epoxide monomers 44–54 . There has been recent work showing RICFP of pure divinyl ethers and divinyl ether/epoxy/acrylate hybrid systems with near‐infrared sensitizers added to promote front initiation via near‐infrared laser as well 55 .…”

Photoinitiating systems and kinetics of frontal photopolymerization processes – the prospects for efficient preparation of composites and thick 3D structures

“…133 Photo-induced RICFP was also compared with "classically" thermally induced RICFP. 136 This investigation revealed that the phototriggered propagation is twice as fast as the thermally induced one with a comparable maximal reaction temperature and heat conductivity. Additionally, materials obtained with thermally-induced RICFP exhibit high microstructural heterogeneity, which confirmed the photo-induced process's predominance.…”

Frontal‐Photopolymerization of Fully Biobased Epoxy Composites

“…From the T max values, reported in Table 1, it is evident that the thermal fronts reached a very high temperature, up to 285°C, similar to the values previously reported for the RICFP of DGEBA with TPED and PAG (283°C). [51] To investigate the photo-crosslinking reaction of the DGEVA resin, FTIR transmission spectra were recorded before and after RICFP curing (Figure 3). The two intense peaks at 2930 and 2970 cm -1 can be attributed to the sp 3 C-H bond vibration of the aliphatic chain, [67] while the small ones at 3000 and 3060 cm -1 can be assigned to the methyl groups close to the epoxy rings.…”

“…[45][46][47] The first work on RICFP was reported by Mariani et al In this work, a thick sample of 3,4-epoxycyclohexylmethyl 3,4epoxycyclohexanecarboxylate (CE) resin was successfully cured with dibenzoyl peroxide and iodonium salt in the formulation. [48] Later, Crivello, [49] Bomze et al, [42] Klicovts et al, [50] and, Svajdlenkova et al [51] further investigated this subject. All of them, however, used petroleum-based epoxy-resins.…”