The use of UV irradiation in polymerization

Decker, Christian

doi:10.1002/(sici)1097-0126(199802)45:2<133::aid-pi969>3.0.co;2-f

Cited by 382 publications

(298 citation statements)

References 7 publications

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“…Formation of a polymer and vitrification of an acrylate solution during polymerization significantly changes properties of a medium undergoing polymerization. As a result, it is doubtful whether the standard eq 2 for the rate of polymerization R can be applied: 3,28 where ω in is the rate of initiation of polymerization and [M] is the molar concentration of a monomer. 3,28 (Here and below we use k t for brevity instead of 2k t ).…”

Section: Chartmentioning

confidence: 99%

Direct and Sensitized Photolysis of Phosphine Oxide Polymerization Photoinitiators in the Presence and Absence of a Model Acrylate Monomer: A Time Resolved EPR, Cure Monitor, and PhotoDSC Study

et al. 2000

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The effect of triplet sensitizers on the photoinitiated polymerization (cure) of a model acrylate monomer, isobornyl acrylate (IBOA), has been investigated. Time-resolved electron paramagnetic resonance (TR EPR) spectroscopy was employed to investigate the initiation of polymerization. Cure monitoring and photodifferential scanning calorimetry (photoDSC) were employed to follow the course of the polymerization. Thioxanthen-9-one (TX) and 2-isopropylthioxanthen-9-one (ITX) were found to be effective sensitizers of the photopolymerization, which was initiated by radicals produced from (2,4,6-trimethylbenzoyl)diphenylphosphine oxide (TMDPO) and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (BAPO). TR EPR experiments demonstrated that the mechanism of sensitization involves T-T energy transfer from TX (or ITX) to TMDPO or BAPO followed by formation of radicals by R-cleavage of the photoinitiators. Direct photolysis of TMDPO and BAPO results in an absorptive chemically induced dynamic electron polarization (CIDEP) pattern due to the triplet mechanism (TM) of polarization of the substituted benzoyl and P-centered radicals produced by R-cleavage of the photoinitiators. TR EPR demonstrates that the same radicals were produced during direct and sensitized photolysis. However, a different CIDEP pattern is produced by photosensitization, namely an emissive/absorptive (E*/A) pattern. A TR EPR study of solutions containing phosphine oxide initiators and IBOA under direct and photosensitized conditions demonstrated that the polarized primary P-centered radicals add to the double bond of IBOA with the formation of polarized secondary radical adducts. Both primary and secondary radicals exhibit the same polarization pattern as the primary radical precursors, i.e., A in direct photolysis and E*/A in the presence of a sensitizer. The rate of polymerization of neat IBOA was followed by cure monitoring. In the presence of ITX the rate of cure increases significantly compared to direct photolysis of same. The heat evolved in the polymerization of IBOA photoinitiated (direct and sensitized) with TMDPO was monitored by photoDSC, and at early times was found to be higher in the sensitized photopolymerization. Time-intermittent UV irradiation allowed an estimation of the ratio of termination to propagation rate constants (k t /k p ) during dark periods of polymerization. The observed decrease of k t /k p with the progress of polymerization is discussed. The results suggest that photosensitization may provide a means of manipulating and controlling the parameters of photocuring of acrylates.

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Section: Chartmentioning

confidence: 99%

Direct and Sensitized Photolysis of Phosphine Oxide Polymerization Photoinitiators in the Presence and Absence of a Model Acrylate Monomer: A Time Resolved EPR, Cure Monitor, and PhotoDSC Study

et al. 2000

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“…Duen energia maila altua dela eta, lotura kimikoak apurtzeko eta ioiak eratzeko ahalmena dauka. Argi ultramorearen eraginpean, gainazal polimerikoek gune erreaktiboak sor ditzakete [5]. Gune horiek talde funtzional bihur daitezke gas baten presentzian edo erradiazio ultramoreaz induzitutako graft polimerizazioari hasiera eman diezaiokete.…”

Section: Erradiazio Ultramoreaunclassified

Poli(metilmetakrilatoa)ren gainazal eraldakea. Sentsore adimendunak

Azkune¹,

Larrakoetxea²,

Etxebarria³

et al. 2017

EKAIA

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Laburpena: Parametro biologikoak neurtzeko sentsore-plataforma adimendunak sortzea gainazalak eraldatzearen arrazoi nagusienetako bat da. Kontzentrazio baxuko disoluzioak neurtzeko, hautakortasun handia behar denerako edo sentikortasun itzela nahi den egoeretan neurketak egin ahal izateko, sentsore hauen garapena beharrezkoa da. Horrez gain, osasungintzan erabili ahal izateko, biobateragarritasuna ezinbesteko ezaugarria denez, polimerozko sentsoreen erabilpena hazi egingo dela aurresan daiteke. Esparru honetan, oso erabilia den poli(metilmetakrilatoa)ren historia, gaur egun gainazalaren modifikazioak egiteko teknika erabilienak eta horiek eragindako modifikazioa karakterizatzeko moduak azaltzen dira lan honetan. Gainera, poli(metilmetakrilatoa)n eginiko zenbait modifikazio eta emaitza erakusten dira eraldaketen parametroak optimizatu nahian. Hitz gakoak: Gainazalaren eraldaketa, poli(metilmetakrilatoa).Abstract: The need of measuring biological indicators is arousing new challenges for the polymer surface modification. Sensors capable of detecting substances in low concentration, when high selectivity is the key feature or when high sensitivity is needed, are the perfect solution. For using them in medical applications, the biocompatibility is a must-have feature and is then when smart polymer sensing platforms have their success. In this framework, the history of one of the most used polymer poly(methylmethacrylate), most common surface modification techniques and charac-EKAIA 31.indd 67 EKAIA 31.indd 67

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“…Free-radical polymerization has been initiated by a thermal initiator like ammonium persulfate [1] and azobisisobutyronitrile [2], or a method such as plasma [3], ultrasound [4], UV-irradiation [5], ionizing-irradiation [6], and redox initiation [7]. A monomer can also initiate free-radical polymerization by itself.…”

Section: Introductionmentioning

confidence: 99%

On the Thermal Self-Initiation Reaction of n-Butyl Acrylate in Free-Radical Polymerization

et al. 2018

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This experimental and theoretical study deals with the thermal spontaneous polymerization of n-butyl acrylate (n-BA). The polymerization was carried out in solution (n-heptane as the solvent) at 200 and 220 • C without adding any conventional initiators. It was studied with the five different n-BA/n-heptane volume ratios: 50/50, 70/30, 80/20, 90/10, and 100/0. Extensive experimental data presented here show significant monomer conversion at all temperatures and concentrations confirming the occurrence of the thermal self-initiation of the monomer. The order, frequency factor, and activation energy of the thermal self-initiation reaction of n-BA were estimated from n-BA conversion, using a macroscopic mechanistic model. The estimated reaction order agrees well with the order obtained via our quantum chemical calculations. Furthermore, the frequency factor and activation energy estimates agree well with the corresponding values that we already reported for bulk polymerization of n-BA.

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The use of UV irradiation in polymerization

Cited by 382 publications

References 7 publications

Direct and Sensitized Photolysis of Phosphine Oxide Polymerization Photoinitiators in the Presence and Absence of a Model Acrylate Monomer: A Time Resolved EPR, Cure Monitor, and PhotoDSC Study

Direct and Sensitized Photolysis of Phosphine Oxide Polymerization Photoinitiators in the Presence and Absence of a Model Acrylate Monomer: A Time Resolved EPR, Cure Monitor, and PhotoDSC Study

Poli(metilmetakrilatoa)ren gainazal eraldakea. Sentsore adimendunak

On the Thermal Self-Initiation Reaction of n-Butyl Acrylate in Free-Radical Polymerization

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