Radical induced cationic frontal polymerization in thin layers

Knaack, Patrick; Klikovits, Nicolas; Tran, Anh Dung; Bomze, Daniel; Liska, Robert

doi:10.1002/pola.29375

Cited by 32 publications

(64 citation statements)

References 19 publications

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“…They also showed that almost complete epoxy conversion can be achieved with a high concentration of thermal radical initiator without the need for a post curing [ 104 ]. Analogous to this study, Knaack et al [ 40 ] showed in the frontal curing of a BADGE formulation that the presence of a thermal radical initiator reduces the onset temperature of thermal curing from 190 to 110 °C. In addition, an increase in concentration of tetraphenyl ethanediol (TPED) (>1 mol %) only slightly decreases the thermal onset temperature of the curing [ 40 ].…”

Section: Chemistry Of Thermal Radical Initiatorssupporting

confidence: 67%

“…It was found that both diphenyliodonium and triarylsulfonium salts based on Al anion exhibited higher polymerization rates and monomer conversion than their corresponding SbF 6 - and (BC 6 F 5 ) 4 − anions [ 56 ]. Knaack et al [ 40 ] also tested an epoxy formulation consisting of BADGE, I-Al and TPED for its effect on frontal polymerization properties. It was found that a minimum of 0.015 mol % of I-Al with 1 mol % TPED is sufficient to achieve a self-sustaining front.…”

Section: Onium Salt Photoinitiators For Different Epoxy Monomersmentioning

confidence: 99%

“…The group also investigated the effect of variable mould depth on the frontal polymerization of BADGE using I-Al and I-Sb photoinitiators by measuring the minimum layer thickness of the cured polymer. The results showed a three times lower minimal layer thickness of the cured formulation containing I-Al compared to I-Sb at 1 mol % with increasing concentration of thermal radical initiator [ 40 ].…”

Section: Onium Salt Photoinitiators For Different Epoxy Monomersmentioning

confidence: 99%

“…The effect of various reactive diluents on the RICFP of a formulation of BADGE, iodonium salt photoinitiator and TPED was investigated by Knaack et al [ 40 ]. They found that (3-ethyloxetan-3-yl) methanol (EOM) gave the lowest minimal layer thickness on a PTFE mould ( Figure 17 ).…”

Section: Uv-induced Cationic Frontal Polymerization Of Different Ementioning

confidence: 99%

“…Subsequently, the carbon-centred radicals are oxidized to carbocations in the presence of the iodonium salt in a radical-induced cationic frontal polymerization (RICFP) mechanism [ 36 ]. In the last few years, the term RICFP has been used to define curing of epoxy and its composites specifically induced by UV light ( Scheme 2 ) [ 36 , 38 , 39 , 40 , 41 , 42 ].…”

Section: Introductionmentioning

confidence: 99%

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Review on UV-Induced Cationic Frontal Polymerization of Epoxy Monomers

et al. 2020

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Ultraviolet (UV)-induced cationic frontal polymerization has emerged as a novel technique that allows rapid curing of various epoxy monomers upon UV irradiation within a few seconds. In the presence of a diaryliodonium salt photoinitiator together with a thermal radical initiator, the cationic ring opening polymerization of an epoxide monomer is auto-accelerated in the form of a self-propagating front upon UV irradiation. This hot propagating front generates the required enthalpy to sustain curing reaction throughout the resin formulation without further need for UV irradiation. This unique reaction pathway makes the cationic frontal polymerization a promising route towards the efficient curing of epoxy-based thermosetting resins and related composite structures. This review represents a comprehensive overview of the mechanism and progress of UV-induced cationic frontal polymerization of epoxy monomers that have been reported so far in literature. At the same time, this review covers important aspects on the frontal polymerization of various epoxide monomers involving the chemistry of the initiators, the effect of appropriate sensitizers, diluents and fillers.

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Section: Chemistry Of Thermal Radical Initiatorssupporting

confidence: 67%

Section: Onium Salt Photoinitiators For Different Epoxy Monomersmentioning

confidence: 99%

Section: Onium Salt Photoinitiators For Different Epoxy Monomersmentioning

confidence: 99%

Section: Uv-induced Cationic Frontal Polymerization Of Different Ementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Review on UV-Induced Cationic Frontal Polymerization of Epoxy Monomers

et al. 2020

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Prospects in the application of a frontally curable epoxy resin for cured‐in‐place‐pipe rehabilitation

Malik,

Wolfahrt,

Domínguez Pardo

et al. 2023

J of Applied Polymer Sci

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Photocurable acrylates and vinyl esters are among the most commonly used resins in cured‐in‐place‐pipe (CIPP) rehabilitation technology, as they impart excellent thermomechanical properties in composite pipes. In the quest for achieving a higher energy efficiency of the photo‐curing process in CIPP, the frontal polymerization technique is a viable alternative that requires a lower irradiation dosage coupled with exceptionally high curing speeds and depths. Herein, for the first time, we report the application of frontal polymerization in the rehabilitation of underground pipes using a newly developed frontally curable epoxy‐based resin (Trelleborg Self‐Curing*). The neat resin is characterized for degree of cure, glass transition temperature, and mechanical properties via FTIR, DMA, and tensile tests, respectively. In a comprehensive way, the properties are benchmarked against commercially available acrylate (Trelleborg Light Cure*) and vinyl ester (Trelleborg Rapid Cure*) resins to evaluate their applicability for CIPP. The results show a higher glass transition temperature and final monomer conversion for the frontally cured resin, which cures significantly faster than the reference resins under the same irradiation conditions. In proof‐of‐concept trials, the newly developed resin successfully cures polymeric liners in a PVC host pipe with 100% water tightness and without losing its structural integrity. Results from ring stiffness tests for cured composite pipes additionally show that liners cured with Trelleborg Self‐Curing* resin pass the minimum required Young's modulus for non‐pressure drainage pipes as per ASTM F1216. Thus, frontally curable epoxy‐based resins are a promising and competitive alternative to acrylates and vinyl esters in CIPP.

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Synthesis and characterization of epoxy resin‐polydicyclopentadiene interpenetrating polymer networks by UV‐initiated simultaneously frontal polymerization

Yuan,

Huang,

Chen

et al. 2024

J of Applied Polymer Sci

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By combination of UV curing and frontal polymerization, interpenetrating polymer networks (IPNs) based on diglycidyl ether of bisphenol‐A (DGEBA) epoxy resin and polydicyclopentadiene (PDCPD) were prepared by UV‐induced simultaneously frontal polymerization in this paper. Compared with the net DGEBA cured polymer, the tensile strength, elongation at break and impact strength of the IPNs were simultaneously improved. The maximum tensile strength and elongation at break of the IPNs reached 100 MPa and 4.64%, respectively, and the maximum impact strength reached 7.34KJ/m2 with an improvement of 115.2% over that of the net DGEBA cured polymer. Thermogravimetric analysis (TGA) results revealed that the IPNs could enhance the thermal stability. Data of the differential scanning calorimetry (DSC) and TGA testing shows that the IPN shows a single glass transition temperature (Tg) which is between the Tg of DGEBA and DCPD, indicating homogeneous phase and highly cross‐linked IPN formed. Morphologies and molecular structure of the IPNs polymer were observed by scanning electron microscope (SEM) and characterized by Fourier transform infrared spectroscopy (FTIR), respectively, whose results also proved the formation of ideal IPNs structures.

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Radical induced cationic frontal polymerization in thin layers

Cited by 32 publications

References 19 publications

Review on UV-Induced Cationic Frontal Polymerization of Epoxy Monomers

Review on UV-Induced Cationic Frontal Polymerization of Epoxy Monomers

Prospects in the application of a frontally curable epoxy resin for cured‐in‐place‐pipe rehabilitation

Synthesis and characterization of epoxy resin‐polydicyclopentadiene interpenetrating polymer networks by UV‐initiated simultaneously frontal polymerization

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