Method to analyse energy and intensity dependent photo-curing of acrylic esters in bulk PDF
Preview Method to analyse energy and intensity dependent photo-curing of acrylic esters in bulk
RSC Advances ce. PAPER View Article Online n ce View Journal | View Issue Li d e ort Method to analyse energy and intensity dependent p n U 0 photo-curing of acrylic esters in bulk† 3. M. cial Citethis:RSCAdv.,2015,5,67284 Amer M. Schmitt 40 m 2:05:onCo Theanalysisofthephoto-inducedpolymerizationofbulkmaterialsisaveryimportantaspectofscientific n 2/10/2023 1Attribution-N atlkihginnehdetltiinigscdhoautunsrstcaoreliuyassrlcerbeesashiseneaacdvrreceohatnosaenLbsdEetDoacpoitpnenlvcsicehidasnettoiirgoelaondtsge,.ywTthahhreeiecrmheibnhuyalt,tvhitpeheleebpeierneontneceerrhagsacysrtdiaoolnfynd/sdneibonvetteetiwlnnovsepeietmsynteidtgnheatept.eeiHndnei.dtnFieaoctnoert,rei,ntxthaflhemueenpmnelecoe,indnnogofmovfareeclrstUuaoncVrshd-, oaded ommons linikheibtihtoersq.uWanitthuimn tyhiiesldcoonftrtihbeutpiornimaardyorsaediacnadl fworamvealteionngtahnddetpheendreeancttipvritoyc’sedtouwrearisdsfirdsotluybdleesbcorinbdesdoinr wnlCo detail, which allows the analysis of the kinetics of the photo-curing and the solidification of oe July 2015. Dder a Creativ RAcecceepivteedd1251tshtJJuunlye22001155 UcmdaiVffuli-elbtvrirfieasuntnetscdymtsifiotoebndmraeelloalripenqstduiicnidaasl,narcaceolyrcnyseletiiacvdienreii,nnswgtedhrwesicethalwli-lii.skthnTpoohauwirsttnoancfoostvhomeellvmeRpenarrtomc.ciaaTenlhdieunUriVtepia-htvioosisrtosbs,-eaaptsureoepdly.mmToohenneriizatmoantruieoaldtnbipssbloeyilnuiandtnefluucinaeenndsdicteubssyRpoeatfhmctrtheraaneel ublished on 22 e is licensed un DwOwIw:.1r0sc.1.o0r3g9/a/cd5varan1c1e4s27f aFbosroerxbaemdppleh,ohtoignhseroynieeld.gs.cthanebkeinaectihcielevnegdtbhyolefstsheencehragientirceaancdtiolenssarientpenresseeinrrtaeddiaatniodn/.or demonstrated. ess Article. P This articl 1Fpro.elyemraIednrsic.tarSloop,odlmyumucletritpiziloaetinionnveisstaigvaetrioynfasmtoiliaarnamlyestehotdhelearedaicntgiotno aawsoncaruayyrllycatseoteesmpdeaooryfufobhtrlheemelpbotetrnnoipdealrsengoyasrltyaiasnnteheditbohiifnetsittoeehnneascniortdyamdfvpiuacorartuilhanetrdireosane.cffsTtiehvoceitftsyp.trhtCeoesowenlnaisgrtiedhddst- c Ac kinetics in solution can be found in the literature.1–10 But the ering applications such as 3D printing or UV-printing the en photo-polymerization is an efficient method for the fast properties of known/used initiators are far from perfect. p O production of cross-linked polymers from liquid resins/ Multiple problems in aspects of health and/or of efficiency monomers without solvents.11,12 Solvent-free (¼ bulk) photo- exist.30–37 polymerisation is used for the construction of materials and In the past, one process constant within the interplay coatings.Ourresearchfocusesonthephoto-polymerisationof between initiators, monomer and light source was the light multifunctional monomers, for example as used for printing source. For example, for printing applications like off-set or applications.13–17 exo printing a mercury mid-pressure lamp was the only Nowadays, “printing” is not only a coating procedure; it applicablelightsource(powerintherangeof200Wcm(cid:2)1,high ranges from coating text or images by UV-printing18 (off-set, intensityinUV-range).Suchcomplexsystemshavenotbeenor exo) or ink-jet printing to construction e.g. by photo-lithog- havehardlybeeninvestigatedbecauseanalysingthekineticsof raphy19 or 3D printing.20 This topic, including the multiple polymerization or solidication without a solvent is a chal- applications and advantages, was recently reviewed with the lenging problem, especially if practical orientations are focus on LED technology.21 Characterization of the kinetics of proposed.Nowadaysandinthefuturethelightsourceis,orwill photo-induced polymerization in bulk is also, from the scien- be,anadditionaladjustableparameter. ticaspects,aninterestingandmostimportanttopic.6,13,15,22–29 LEDtechnologycanbeconsideredasbeingwell-established Someaspectsthathavetobeanalysedaretheidenticationof in the visible range.21 In the UV-range LED’s are still in the the energy/intensity relations resulting in an effective radical process of development. Due to the multiple advantages of formation.Thisincludesthequantumyielddeterminationand LED21technology,curingunitsbasingonLEDsarepurchasable eventoday,forexample,ahighpowerLEDupto7Wcm(cid:2)1at 365nm(cid:3)6nm.38Thiswavelengthissmallerthantheonsetof Saarland University, Campus B 2 2, 66123 Saarbruecken, Germany. E-mail: mic. absorbance of a number of established initiators and some [email protected] resins.28 At the moment noLED’swith comparable intensities †Electronicsupplementaryinformation(ESI)available:Additionalequationsand exist in the main/strong absorption range of most initiators, visualizationsofallmeasurements.SeeDOI:10.1039/c5ra11427f 67284 | RSCAdv.,2015,5,67284–67298 Thisjournalis©TheRoyalSocietyofChemistry2015 View Article Online Paper RSCAdvances which is located below 365 nm. Hence, the initiators and the initiator monomer combinations cannot be characterized and new systems cannot be developed but “new photo-initiating systems and strategies”21 have to be developed. This lack can e. c beremovedbythetechniquesandprocedurespresentedwithin n e Lic thefollowingstudy. d RecentlyanUV-vissolidicationmonitoringsystem14andthe e ort combinationofRamanandtheUV-vismonitoringsystemwere p Un rstly introduced/discovered.16,17 The combination of the 0 3. Raman with the UV-vis system, Scheme 1, leads to the possi- M. cial bilitytoinvestigatetheefficiencyofinitiatorsindetail.Forthe Amer present study this system is further varied by a spectral and 2:05:40 onCom aabbssoolluutteeacnaldibsrpaetecdtralilgchatlisboruatrecde.3r9ecFeoirvearbfsoorluatelarcgaelibarmatoiuonntaonf 1N n 2/10/2023 Attribution- pevtoaxhprovilataaobrinnylesetdhislewteuierstn,heLedinrV.gFTythhaweneidmrtheaacenbcnouamtnslcydprdiapperatavs.besTlloehpletieendcrtoelpmenrasobdictisynedtaaotunitrodhenewtoopiflolvsaaasrllisyibnoitelhibateeyr ded omons intensitywithconstantenergybyusingltercombinationsand oam byfrequencyvariation. wnlCo The main objective of the presented study is a detailed oe 015. DCreativ adnoaselysainsdoefntehregynroevlealtieoxnpse,rliemadenintagltsoeetu.gp./kteinchetniciqlueen,gtinhcsluofdtinhge uly 2er a chainreactionanddifferentefficiencies.Thedemonstrationof Jd the complex but easily implementable procedure takes place ublished on 22 e is licensed un uifwnrsiaititgnhimagteotnharstr.ienegcTco,ho-Neimnoimrtriraiesstrthocrioa.t4ynl1,peea,vTIabIhielieannbzitloeiasp,ethwoceroen,nllon-dknoner,om4ow0annlBely,aPn,uds2ies-odhyatedonnrgoeunxtysho-ene2dr-- s Article. P This articl lpmioqelutyhimdyelpprirhzoaopttiiooo-pninhioetnfiaoctnohree,,mwDichMailcHlhyAu,isnissuatsauerdvaetrtesodatipinlreietpihaotilgeyhmtlyheeresffi.p42hcioTethnoet- s e cc third one, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, A n TPO-L, is also a highly reactive/efficient liquid photo-initiator. e Op DMHAandTPO-Lreactvialightabsorption,criticalactivation andthecleavageofafragilecarbonbond,NorrishtypeIiniti- ator. The model resin is a well-dened but multifunctional Scheme 1 UV-vis curing transmission (top) and Raman UV-vis inhibitorcontainingaprintableacrylicestermonomermixture, geometry (bottom). The fused silica windows and the prism are whichisapplicablee.g.asalacquerornishforoff-setprinting. markedbythinbrokenlines.Ifthegeometryisalternated(e.g.byusing To summarize, the contribution contains the development IRtransparentmaterial)theFT-Ramansystemcanalsobereplacedby of, and the demonstration for, wavelength and intensity aFT-ordisperseIRspectrometer(comparealsotoSection1withinthe ESI†). dependentexperimentalanalysisusingaRamanUV-vissetup. This includes a detailed analysis of the measured data, which meanstheRaman,theUV-visandthedimensionsofthecured solid. An important aspect is the identication of the signal acrylate double bonds or inhibition species) and band gap curing correlations of the UV-vis system, even in the “inu- effects(ifusingsemiconductorbasedinitiators13,16,17). enced” wavelength range. Recently, only the reection on the fusedsilicatoresininterfacewasanalysed,no.3inScheme1. 2. Experimental Additionally, a cascading effect of a 45(cid:4) incident angle of the 2.1 Materials Raman UV-vis setup is clearly proven for (semi-)transparent resins.Duetotheabsoluteandspectralcalibratedlightsource Theresinwasawell-dened2to3mixtureoftrimethylolpropane togetherwiththenoveldataanalysis,themeasurementsystem triacrylate,TMPTA,andbisphenolAdiglycidyletherdiacrylate, has the potential to enhance the analysis of photo-induced BAGdA, exactly (1-methylethylidene)bis[4,1-phenyleneoxy(2- polymerizations inbulk. Thisapplies notonlyforthe applica- hydroxy-3,1-propanediyl)]diacrylate received from Rahn AG, tion aspects but also for practical and theoretical studies con- Zu¨rich,Switzerland(hri¼1.148gml(cid:2)1).Thenumberofdouble cerningthekinetics,quantumyields(quantumyieldfortriplet, bondsn can becalculated by eqn (1), comparetoESI,† with DB quantumyieldofradicalformationorradicalreactivitytowards knownmassm . total Thisjournalis©TheRoyalSocietyofChemistry2015 RSCAdv.,2015,5,67284–67298 | 67285 View Article Online RSCAdvances Paper Table1 Investigatedinitiatorsandamountwithinthesample M Maximumof nINI/nC]C Weightcontent Brandname Name Formula [gmol(cid:2)1] absorbancec[nm] [mol%] [%] e. nc Genocure*BPa Benzophenone C13H10O 182.22 254 1.05 1.25 ce Irgacure*BPb d Li Genocure*DMHAa 2-Hydroxy-2- C10H12O2 164.20 247/277 0.95 1.02 orte Darocur*1173b methylpropiophenone p Genocure*TPO-La 2,4,6-Trimethylbenzoyl- C H O P 348.37 380 0.89 2.01 n 22 21 2 U Irgacure*TPO-Lb diphenylphosphineoxide 0 M. cial 3. aRahnAG(deliverer).bBASF.cManufacturerspecications. Amer 40 m 2:05:onCo 1N 0/2023 bution- n 2/1Attri ded omons oam wnlCo oe Dv 015. Creati uly 2er a Jd ublished on 22 e is licensed un s Article. P This articl Fig. 1 The calculated irradiated number of photons per nm for the ces differentfiltercombinations.Theilluminationswiththehighestimpact Fig.3 Visualisationoftherelationbetweenthemonomerconversion Ac oftheUG11filterarethemeasurementsperformedwiththeLVF-HL andthedetectedUV-vissignalvariations.Alldetermined“times”are en z370nm. markedwithinthefigure,comparealsotoFig.S5.† p O (cid:1) (cid:3) N 3(cid:5)0:4 2(cid:5)0:6 m n ¼ DB ¼ þ m ¼ total mol g(cid:2)1: (1) DB N M M total 153:23 A TMPTA BAGdA The three initiators investigated within this study, Table 1, werealsopurchasedfromRahnAG.Theinitiatorswereadded/ mixedpriortotherstmeasurementwiththemonomer. 2.2 UV-visandirradiation The transmission measurements of the compounds dissolved in isopropyl alcohol, iPA, were performed with a Carry50 Bio, Agilent, Waldbronn, Germany, Fig. S3.† For all other experi- mentsamodular,spectralandabsolutecalibratedbreoptical systemwasused.ThedetectionunitwasaMultiSpecDesktop/ USB system, tec5 AG, Oberursel, Germany equipped with a MCS FFT-CCD diode array detector, Carl Zeiss, Oberkochen, Germany. The back-thinned FFT-CCD Chip S7031-1006S, 1024 Fig.2 Relativeabsorptionoftheresincontaining2wt%TPO-L(d¼ (cid:5) 64 pixel, was fabricated by Hamamatsu Photonics K.K., 0.05mm),comparealsowithFig.S4.† Herrsching am Ammersee, Germany. For coupling a 74-UV collimatinglensandanopticalbre(corediameter0.4mm)UV- 67286 | RSCAdv.,2015,5,67284–67298 Thisjournalis©TheRoyalSocietyofChemistry2015 View Article Online Paper RSCAdvances Table2 Summaryoftherawdataofallmeasurements Median Ramant Ramant UV-vist UV-vist UV-vist Area Storageperiod i f i,1 i,2 1/2,2 Sample [nm] [10³.] [10³.] MN[%] [10³.] [10³.] [10³.] [mm2] [d] e. nc BPFLa 333.5 65.1 94.1 62.7 54.06 73.80 4.34 0.24 e c BP 317.5 100.0 0 0.00 d Li DMUHG1A1FLa 333.5 2.9 13.8 47.7 4.48 13.28 22.4 17.81 0.00 e ort DMHAUG11 317.5 7.2 18.8 54.5 7.99 7.99 10.2 12.72 5.99 p DMHA 317.5 9.3 15.4 53.7 8.28 8.28 9.6 14.39 0.09 n UG11 U DMHA 312.0 46.4 66.6 61.9 37.39 37.39 43.8 6.25 0.19 0 LVF M. cial 3. DDMMHHAALLVVFF++GG1111 331323..50 7400..96 7539..98 7527..81 6357..8600 6357..8600 7487..00 07..9772 01..9381 Amer DMHALVF 333.5 17.9 39.2 51.1 18.99 18.99 29.2 10.75 1.15 40 m DMHALVF 333.5 19.1 36.3 53.4 18.33 18.33 29.0 12.29 2.25 12:05:NonCo DDMMHHAALLVVFF 334698..00 26.4 49.8 15030..30 26.90 26.90 42.9 90.78 32..2055 0/2023 bution- TTTPPPOOO---LLLFFLLaa 333331337...555 001...783083 1221...428369 555131...389 002...897300 012...847390 28..64 121400...53862 11032...077016 n 2/1Attri TPO-LUUGG1111 317.5 1.40 8.48 48.6 2.71 5.21 9.6 21.1 2.98 ded omons TTPPOO--LLULVGF1+1UG11 331077..50 210..627 389..808 5620..81 221..6233 241..6203 288..43 280..89 15..6667 ownloae Com TTPPOO--LLLLVVFF++UUGG1111 331424..55 1107..60 2397..79 5546..88 1137..0518 1197..6650 27.9 1120..561 1143..9847 uly 2015. Der a Creativ TTTTPPPPOOOO----LLLLLLLLVVVVFFFF+++UUUGGG111111 333346604447....0050 2247663....2656 44514266....7209 65650835....5937 2239193....11960036 22919...119002 5112..20 18881....2446925 11204....98886464 ss Article. Published on 22 J This article is licensed und TTTTTTTTaPPPPPPPPOOOOOOOOOn--------lLLLLLLLLyLLLLLLLLwVVVVVVVVFFFFFFFFavelengths33333444<144660024255893345........555000000nmare11c4785672o.......n2065952sideredfor32112116677155th.......0520966eashlight155555550w75346750it........01601040houtal111te6767430r.......5620717(r9760600esultingin1118777432a.......3610717m6740606edianof34311111300901213........00642565bbnm).Thetot1111111a00245233l.......e8648788n743914ergyis1111a21554455r........o78797879u43941529nd115W cce m(cid:2)2. Themeasurementwithoutlterofthe TPO-Lcontainingsamplewas performed with200 ashesin-betweenthe Ramanmeasurements. n A bSecondsignalcannotbeidentiedwithoutanydoubt. e p O VIS XSR solarization-resistant QP400-2-SR-BX from Ocean OpticsGmbH,Ostldern,Germanywereused.Thebreoptical detector was connected with a PVC-housing containing a 0.15 mmpinholeoranabsorptiveneutraldensityND¼3(NE30A), ThorlabsInc.,Newton,NewJersey,USA. This unit can be connected with a Raman UV-vis16 (45(cid:4) geometry (a ¼ 90(cid:4))) or a UV-vis sample cell (90(cid:4) geometry det (a ¼180(cid:4)),transmission,aligned)formonitoringthephoto det induced polymerization of bulk acrylic esters, Scheme 1. For illumination, the cells were also connected via optical bre (corediameter0.4mm)toaPerkinElmeroptoelectronicsxenon ash light (LS-FX) FX 1160 (maximum output 0.5 J per ash, regular 370 mJ per ash, z25 W light output, 8 ms per ash, 66.6Hz).Thelightsourceismodiedinsuchawaythatalinear variable lter and a UG11 lter can be used simultaneously without alternation of the beam path. Both were purchased from Ocean Optics GmbH, Ostldern, Germany. The linear variablelter,LVF-HL,isanadjustablebandpasslterwiththe Fig.4 InitialtimesfortheRamanandtheUV-vissetup.Thecalculated workingrangeof300to750nm.Aspeciccorrectionfunction initialtimesinnumberofabsorbedphotonsarepresented,whichare A (l)existsforthedetector, proportionaltothenumberofflashes,comparealsotoFig.S6.† c Thisjournalis©TheRoyalSocietyofChemistry2015 RSCAdv.,2015,5,67284–67298 | 67287 View Article Online RSCAdvances Paper Table3 Exampleofmeasuredandcalculateddimensionsof/forthesolidsaftercuring Areameasured Areacalculated Theoreticalincident 2a[mm] 2b[mm] [mm2] [mm2] angle[(cid:4)] e. nc TPO-L307nm 2.65 4.02 8.45 8.37 41.2 e c TPO-L(+UG11)307nm 2.76 4.01 8.80 8.70 43.5 Li d TPO-L312nm 2.86 5.64 12.67 12.67 30.5 e ort TPO-L(+UG11)312nm 2.90 4.59 10.06 10.45 39.2 p DMHA312nm 1.97 4.06 6.25 6.28 29.0 n U TPO-L(+UG11)364.5nm 2.30 4.7 8.42 8.49 29.3 0 3. TPO-L(14.9d)364.5nm 2.7 5.88 14.44 12.47 27.3 M. cial Cyana 1.82 2.63 3.75 3.76 43.8 Amer Magentaa 1.88 2.75 4.05 4.06 43.1 40 m Yellowa 2.33 3.14 5.68 5.76 47.9 2:05:onCo Keya 1.29 1.89 2.00 1.92 43.0 0/2023 1bution-N aTheseexamplemeasurementsfornon-transparentresinsmaybefoundwithintheESI,Fig.S7. ded on 2/1mons Attri EðlÞ¼nðlÞphoton(cid:5)h(cid:5)l c¼nðlÞcounts(cid:5)AcðlÞ(cid:5)h(cid:5)l c; (2) Wfpuhlolmyto(cid:2)inl2lunumsuiminngbaetoerndnly(dlt)ehptheeoctctooinouninntaHnrzeuamm.b(cid:2)Te2hraenn(fdlu)tnchocuetniiotrnpraedirtisaaenrlrfcaeyisEo(fwl)tehilnle- oam whichwascomputedbyasophisticatedstatisticalprocedure,39 wnlCo Table S1.† This function can be used to calculate the average denedabove310nm.Below310nmeqn(3)isused, oe Dv 015. Creati uly 2er a Table4 Integralsofthecalculatedincidentirradiationnill,EillandrelativeabsorptionsoftheinitiatorsnINI,EINIandresinnR,ER Jd s Article. Published on 22 This article is licensed un BDDDSBaPPMMMmFULHHHGpa1AAAl1eFUULGGa1111 33333M[n31311em37377d.....]55555ian 22n[199933il0l33333900077p.....44499s(cid:2)1] 77333[EW77222ill.....88888m33000(cid:2)2] [n178344IN0737229I26900p.....10944s(cid:2)1] 23111[EW91455IN.....68266Im30644(cid:2)2] 77333[n111444r0e99555s9.....55000ps(cid:2)1] 22111[EW77222re.....s77999m11999(cid:2)2] 00000nnI.....iN33444llI36155 00000nI.....N00000I25488n(cid:2)illnres ces DMHALVF 312.0 210.2 7.58 94.9 3.45 68.4 2.49 0.45 0.13 Ac DMHALVF+G11 312.5 130.5 4.70 57.6 2.09 41.2 1.50 0.44 0.13 n DMHA 333.0 142.6 4.82 30.5 1.04 15.4 0.52 0.21 0.11 e LVF+G11 p O DMHALVF 333.5 223.6 7.55 47.2 1.60 23.7 0.80 0.21 0.11 DMHA 333.5 223.6 7.55 47.2 1.60 23.7 0.80 0.21 0.11 LVF DMHA 349.0 201.9 6.51 27.1 0.88 12.6 0.41 0.13 0.07 LVF DMHA 368.0 167.2 5.11 7.1 0.22 3.7 0.11 0.04 0.02 LVF TPO-L a 333.5 2337.9 77.83 1276.7 46.63 719.5 27.71 0.55 0.24 FL TPO-L a 333.5 2337.9 77.83 1276.7 46.63 719.5 27.71 0.55 0.24 FL TPO-L 317.5 930.4 32.80 660.4 23.95 345.0 12.99 0.71 0.34 UG11 TPO-L 317.5 930.4 32.80 660.4 23.95 345.0 12.99 0.71 0.34 UG11 TPO-L 317.5 930.4 32.80 660.4 23.95 345.0 12.99 0.71 0.34 UG11 TPO-L 307.0 87.3 3.20 81.8 3.00 42.7 1.58 0.94 0.45 LVF+UG11 TPO-L 312.5 130.4 4.69 113.7 4.10 40.4 1.47 0.87 0.56 LVF+UG11 TPO-L 344.5 102.5 3.35 38.0 1.25 7.6 0.25 0.37 0.30 LVF+UG11 TPO-L 344.0 100.4 3.28 37.2 1.22 7.5 0.25 0.37 0.30 LVF+UG11 TPO-L 364.0 62.5 1.93 19.1 0.59 1.7 0.05 0.31 0.28 LVF+UG11 TPO-L 364.5 60.6 1.87 18.5 0.57 1.6 0.05 0.31 0.28 LVF+UG11 TPO-L 307.0 158.1 5.81 148.3 5.45 78.5 2.91 0.94 0.44 LVF TPO-L 312.5 221.7 7.98 193.3 6.97 69.0 2.51 0.87 0.56 LVF TPO-L 345.5 202.4 6.60 73.9 2.42 14.5 0.48 0.36 0.29 LVF TPO-L 345.5 198.4 6.47 72.4 2.37 14.3 0.47 0.36 0.29 LVF TPO-L 368.0 167.2 5.11 50.7 1.55 3.7 0.11 0.30 0.28 LVF TPO-L 369.0 177.6 5.41 53.6 1.64 3.6 0.11 0.30 0.28 LVF TPO-L 403.0 177.0 4.94 22.9 0.65 0.0 0.00 0.13 0.13 LVF TPO-L 403.0 178.0 4.97 23.4 0.66 0.0 0.00 0.13 0.13 LVF TPO-L 424.0 196.0 5.20 1.5 0.04 0.0 0.00 0.01 0.01 LVF aOnlywavelengths<450nmareconsideredfortheashlightwithoutlter.Thetotalenergyisaround115Wm(cid:2)2.Themeasurementwithoutlter oftheTPO-Lcontainingsamplewasperformedwith200ashesbetweentheRamanmeasurements. 67288 | RSCAdv.,2015,5,67284–67298 Thisjournalis©TheRoyalSocietyofChemistry2015 View Article Online Paper RSCAdvances Ramanspectroscopy.Allsamplesweresufficientlytransparent toavoidheatingduetotheabsorptionofthe1064nmlaser(1 W) from the Multiram FT-Raman spectrometer (Bruker Optic, Eislingen,Germany).Foreveryvibrationalbanddetermination, ce. fourRamanspectra(6cm(cid:2)1resolution,averagespectrumof20 n Lice measurements, z1 min measuring time) of the samples were d recorded in back-reection, Scheme 1, vertically through the e ort cover during light-off phases (in general aer every 2.000 p Un ashes). UV-vis data were recorded/averaged during the illu- 3.0 mination with 10 (cid:5) 4 ashes. This recently introduced auto- M. cial maticRamanUV-vissystem16hastheuniqueabilitytomonitor Amer both the double bond content (deep curing by Raman) and 2:05:40 onCom sthoelidainaclaytsiiosno(fartehaecUuVri-nvigsbdyaUtaVw-vaiss).oBnelfyopreertfhoermpreedsefnotrswtuadvey-, 1N n 2/10/2023 Attribution- lliteenhnataedgtritafnhalglcrweat,oannvgneoeol.sen3ni-ngdintihwstShrucairhcnbhegemedtsherewe1is.taehBmcustitpuolffiinenccatiohtennitshttaseiiltnlufusudmsysetiidrntoawsntiigilolilcnaabbienstootserhrbnoeesswriitsnny, oaded ommons pFihgo.t5onsOnveforvriethweoinfititahteorsinacniddenthteirrreasdiniastidounrinngilloannedctyhceleaobfsiorrrabdeid- csiagnnabletoancaulryisnegd,cosrereelathtieons”ub(3s.e3c)t.ioAne“rAsnoalliydsiiscaotfiotnhethUeVs-tviilsl ownle Co athtieonillubmetiwnaeteionntshweiRthaimnaFnig.mSe9a.†suTrheemneunmtsb(eLVrFo-fHpLh)o.tCoonmsipsarreelaatlisvoettoo liquid monomer is removed by washing with ethanol and the 015. DCreativ thecalculatedilluminationarea,Table3. SsiMzeZo8f0t0hsetesroeloidm,iFcirgo.sSco1p,†ewcoauspdleetderwmitihneadDfSr-o2mMvimCaCgDescaomftehrae uly 2er a (cid:1) (cid:3) by the imaging soware NIS Elements D, 3.00 from Nikon s Article. Published on 22 J This article is licensed und istucnouontlffiiceltion.mcnsiTeiasvhnitedietoletynorfAuuabclnnðeelrcnieÞfdtsoide¼orut(nme0cAr.tl4mAicyo1ðc3i(innll1ml)ua0inbmminsletm2ihnvwÞ(eaazilttiqe3dh7du1o5.a0iu%lfnTnt(cid:2)th)tmuahetm1eo(cid:2)x7le6tdy11enie.nr7eo2tm6loe3ndcrntmopmioafimnsnthhh22;aoel(ril1geed0ah,e0nttoe%eicfsi)tt)hitto(hoe3inoesr) 2TPG.Vhm4(enbR̃)H,Da,amDtaau¨npssrdoealctdeaoswsrfien,rGgeeRFrat(mtnme)̃ada¼nnby.PymPuVlit(inp)̃,lepseudo-Voigtfunctio(n4s) s cce within an aligned (“transition”) nor within the Raman UV-vis PV(n)̃ ¼area(hg(n)̃ +(1(cid:2)h)l(n)̃), (5) Open A stheteuspu,bSscehcetimone “1C.aTlchuelastciaolninogfpthroeciendtuernesiwtyilalnbdeedneesrcgryiboefdthine g(cid:4)~n(cid:5)¼4pupffilffinffiffiffipðffiffiffiffiffi2ffiffiffiÞffiffi exp(cid:1)(cid:2)4lnð2Þ(cid:1)~n(cid:2)uvpeak (cid:3)(cid:3); (6) irradiatedlight”(3.6).ThelightusingtheND3lterorthe0.150 mmpinholediffersbyafactorof1/32to1/42.Thisvalueisin (cid:4) (cid:5) 1 0:5u tbhuetiroanngdeeaolfintghewditihffetrheendceestaiinledarecah,asraeceteTraibzaletio3nofofththeicsonbtrrie- l ~n ¼p(cid:7)(cid:4)~n(cid:2)vpeak(cid:5)2þð0:5uÞ2(cid:8)2; (7) opticalreceiver.39Anadditionalprovingoftheuniformillumi- toobtaintheareaofeachvibrationalband,especiallytheoneof nationis performed foran aligned setupand will bepart ofa thedoublebondsataround1635cm(cid:2)1.Theparametersu,v , furtherresearchreport. peak and0#h#1correspondtothefullwidthathalfmaximum,the peakposition(incm(cid:2)1)andtherelationbetweentheGaussian 2.3 RamanUV-viscuremonitoring shape, eqn (6), and the Lorentzian shape, eqn (7), which is individuallycalculatedforeveryband.Thespeciccurveshapes The sample cell of the Raman UV-vis system consists of PVC- oftherelativedoublebondarea(C]C toC]C )asa housing containing a fused silica isosceles right angle prism acrylic aromatic functionoftheirradiatedlight(“time”)fortheRamandatawere and two plugs for the collimator lens or the UV-vis detection; analysedbymodiedGompertzianfunctions(krateconstant,t Scheme1,bottomandFig.2inref.16.Theplugsarepositioned s shitime), atthecentreofthesmallerplanestoallowilluminationandUV- visdetectionina ¼90(cid:4)geometry(angleofincidence¼angle det f(t)¼b(cid:2)aexp((cid:2)exp((cid:2)k(t(cid:2)t))), (8) ofdetection¼45(cid:4)).Thelarger(top)planecanbecoveredwitha (cid:4) pffiffiffi(cid:5)s fusedsilicawindow(1mm),Scheme1,bottom.Atthecentreof t ¼kts(cid:2)ln 1:5þ0:5 5 ; (9) this plane, in-between the cover and the prism, the liquid i k samples were placed. The 0.05 mm thickness was ensured by (cid:4) pffiffiffi(cid:5) usingadistanceholder.Thicknessaccuracywascontrolled,as t ¼2kts(cid:2)ln 1:5(cid:2)0:5 5 (cid:2)t: (10) explainedwithin the discussion insection 3.5, byquantitative f k i Thisjournalis©TheRoyalSocietyofChemistry2015 RSCAdv.,2015,5,67284–67298 | 67289 View Article Online RSCAdvances Paper Table5 Summary ofthecalculatednumbersof absorbed photons,theRamanDnchain lengthand therelativeabsorption efficiencywith maximalinfluenceofthemonomerabsorbance,seealsoTablesS4andS5 Median Dn Dn n Raman n UV-vis n UV-vis Storageperiod RamanDn AE(min) i i,1 i,2 Sample [nm] Raman[1012p] UV-vis[1012p] [1012p] [1012p] [1012p] [d] chainlength [%] e. c n ce BP a 333.5 22.6 51.3 42.6 58.2 0.24 94 2.2 Li FL d BPUG11 317.5 0.00 3.7 orte DMHAFLa 333.5 21.8 36.8 5.1 7.8 23.2 0.00 117 5.0 p DMHA 317.5 11.3 4.3 8.2 9.0 9.0 5.99 261 8.1 n UG11 U DMHA 317.5 8.6 3.7 10.5 9.4 9.4 0.09 244 8.1 0 UG11 M. cial 3. DDMMHHAALLVVFF+UG11 331122..05 b9.3 56..95 1187..45 1146..82 1146..82 00..1998 198 1122..66 Amer DMHALVF+UG11 333.0 4.5 4.4 9.2 8.5 8.5 1.31 526 10.6 40 m DMHALVF 333.5 5.7 5.5 6.3 6.7 6.7 1.15 630 10.5 12:05:NonCo DDMMHHAALLVVFF 333439..50 55..82 77..22 65..78 65..59 65..59 23..2255 121671 170..25 0/2023 bution- TDTPPMOOH--LLAFLLVaaF 333633833...055 1151..87 18.5 57..83 67..95 162..95 1023...007051 211599 22233...188 n 2/1Attri TPO-LFULG11 317.5 47.5 51.3 6.3 12.8 12.8 12.76 60 33.9 ded omons TTPPOO--LLUUGG1111 331177..55 3323..16 4305..01 67..69 1122..84 2241..68 25..9687 9850 3333..99 ownloae Com TTPPOO--LLLLVVFF++UUGG1111 330172..05 290..93 7.4 1111..69 1142..53 2121..56 113..6867 215361 4546..82 uly 2015. Der a Creativ TTTTPPPPOOOO----LLLLLLLLVVVVFFFF++++UUUUGGGG11111111 333344664444....5005 18430....1057 1100..85 116711....9790 9788....4850 978...480 112144....89894644 265270205014 22229779....6897 s Article. Published on 22 J This article is licensed und TTTTTTTTTPPPPPPPPPOOOOOOOOO---------LLLLLLLLLLLLLLLLLLVVVVVVVVVFFFFFFFFF 333333444014466002725589334.........055500000 12186655140........97826342 11167677430........66301136 77635647........59291035 196455492........58431633 1196555451........58031661 111101524554........8877879763945291 234123529500087738470994 52214221098364829.........832211193 s cce aOnlywavelengths<450nmareconsideredfortheashlightwithoutlter.Thetotalenergyisaround115Wm(cid:2)2.Themeasurementwithoutlter n A oftheTPO-Lcontainingsamplewasperformedwith200ashesbetweentheRamanmeasurements.bOnlypartiallycured,comparetoESI. e p O Thisallowsfortheautomaticcomputationofthetimewhenthe second focus is on the calculation of the absolute number of reaction starts, t, (affected by inhibition and oxygen) and the absorbed photons (3.6) using the computed properties of the i timewhenthereactionisessentiallycompleted,t (thesystemis samples and the “light sources”. The detailed analysis is only f solidied). The term 1 (cid:2) a/b (from limit value consideration) possibleifgeometric andexperimentalinuencingfactorsare denotes the relative nal monomer content MN for Raman considered(3.4and3.5).Resin–initiator–lightsourcerelations measurements. Details concerning the Raman analysis like for these model samples were computed and summarized aspects of noise reduction may be found in the litera- within the last part (3.7 and 3.8). These sections also contain ture.13,15–17,28 Due to the used lters the UV-vis data cannot be different possibilities to visualize/analyse the results. All analytically tted,16 see the subsection “Analysis of the UV-vis experimental details concerning the reactivity of the initiators signaltocuringcorrelation”(3.3). maybefoundwithinTablesS2,S4andS5.† 3.1 Analysisofthesamplesandthe“lightsources” 3. Results and discussions UV-vis emission. The intensitiespassingthelinear variable This“Resultsanddiscussions”sectioncanbedividedinthree lter (z100 spectra), the UG11, the linear variable plus UG11 mainparts.Theanalysisofthesampleandthe“lightsources” lter (z100 spectra) and without a lter are collected in 180(cid:4) (3.1),togetherwiththeexperimentalcuringresults(3.2),arethe geometry(aligned,Scheme1,top),Fig.S2,†toallowthecalcu- requirements for the analysis of the novel experimental and lation of the irradiation to be possible. Before applying the analytical technique (3.3–3.6). The utilization of a FT-Raman sample onto the Raman UV-vis prism, Scheme 1, bottom, the unitisnotbeenmandatory.Thevibrationalbandanalysiswas total reected light I (l) was measured. Linear scaling (C) to tr performedtoverifytheUV-vissignalcuringcorrelations(3.3).A matchwiththealignedspectraandcomparingwiththexenon 67290 | RSCAdv.,2015,5,67284–67298 Thisjournalis©TheRoyalSocietyofChemistry2015 View Article Online Paper RSCAdvances e. c n e c Li d e ort p n U 0 3. M. cial Amer 40 m 2:05:onCo 1N 0/2023 bution- n 2/1Attri wnloaded oCommons tFhige.p7erfRoermlateivdeeexffipecriiemnecnietss,wEiffthnIlNiIn,ewairthvamriaabxliemfiallterersainndslcinoerarercvtaiorinabolef oe filterplusUG11. Dv 015. Creati uly 2er a tookplacetoverifythepositionsgivenbythedistributer,Table Jd ublished on 22 e is licensed un 01sTo..P8lFOu;ot-zrLioB1nsP.os1la)tunhwtdeioaaDsnbMmsthoHoernbAaiatabnonsrcoeaerddbisdafoilnatricroeg1neiMarsltlahsaboarsgnluoe1trripobtthneiola,onnFwia1g3t.0bzS0e33ln.o4†mw0F.n3oFm4ro0tr(hnA1emzsMe. s Article. P This articl Fttooorpre,d0(..t1hTiMrcaknnssoeitlsuisotni0o.nU05Va-vmmismasx)oimlwidueimrecaaptteioarfnrooreumxnpededr3im0to0enndtmest,ewrSmcahsinemmeoetnh1ie-, es optical absorption of the initiators and the resin and to c c A compute the absorbed light dose. Only one measurement per n Fig.6 Visualization oftherelations between theilluminationwave- e sample, resultinginsolidpolyacrylic estersofaround7.0mm p lengthandtheabsorbedphotonnumbertocompensatetheinhibition O andtocuretheresin(efficiency,eqn(15)),comparealsotoTable5and diameter, was performed so that no further analysis will be Fig.S10andS11.†Thestorageperiodislabelledwithinthefigure.The presented. Following these real time solidication measure- storage times have no simple correlation with the curing results, ments,TLO-L,whichalsohasthestrongestabsorbancewithin comparetotheLVF+UG11measurements. theinvestigatedwavelengthrange,Fig.S3,†resultsinthefastest photo-polymerisation of the used acrylic ester mixture. The wavelength dependent measurements rstly presented within lightspectrumwithoutalter,IXe,r(l),allowsthecalculationof thisstudycanbeusedtoanalysesomeoftheinuencingfactors theabsolutetransmissionT (l), ill (in addition to absorbance) like the quantum yield for triplet, I ðlÞC quantumyieldofradicalformationorradicalreactivitytowards TillðlÞ¼ ItXre;rðlÞ; (11) acrylatedoublebonds.Thespectralcorrectionprocedurerstly introducedin2011(ref.14)toremovetheeffectsofthediffer- whichwillbeusedtocompute theabsoluteirradiationIabs(l), ences in reection and refractive index with and without see subsection “Calculation of the intensity and energy of the sample, when measuring with the bre optical system, was irradiatedlight”(3.6),Fig.1. performedtodeterminetherelativeabsorptionoftheinitiators Thewidth(upperquartileminuslowerquartile)oftheirra- and oftheresin, Fig. 2andS4.† Therebythe relationbetween diationlightpassingthelinearvariablelteris,with11nm(cid:3)2 the transmitted intensity with, I(l), and without, I(l), sample nm,sosmallthattherefractiveindexinuences(Sellmeierian r wasanalyticallyanalysedbyeqn(12), equation)43canbeneglected.Inthisway,multiple“lightsour- ces”withsimilarandknownintensityandenergywererealized, IðlÞ ¼AðlÞ¼aþb(cid:5)lþc(cid:5)l2; (12) Fig.1. IrðlÞ UV-vis transmission and curing transmission. Determina- intherangeinwhichnoabsorbancetakesplace(>400/450nm). tion of the absorbance in non-absorbing solvents (pure iPA) ThisprocedureleadstotherelativeabsorptionA (l), b Thisjournalis©TheRoyalSocietyofChemistry2015 RSCAdv.,2015,5,67284–67298 | 67291 View Article Online RSCAdvances Paper A ðlÞ¼IrðlÞ(cid:2)IðlÞAðlÞ: (13) correlation between the initial times of the UV-vis ti,1 and ti,2 b IrðlÞ andtheRamanobservationsticanbeprovenbeyonddoubt.The sameisvalidforphoto-polymerisationefficiencyDn, nce. Dependencies from a number of not exactly controlled Dn¼nf(cid:2)ni, (15) e experimental parameters are likely, which can be reduced/ c d Li crosschecked by combining these results with the ones of the Fig.S5†and3.Forwavelengthrangessmallerthan350nmthe orte transmissionexperiments,Fig.S3.† efficiency Dn of the UV-vis data is smaller than the one of the p n Ramandataandforrangeslargerthan350nmviceversa.This U 0 3.2 ExperimentalresultsoftheRamanUV-viscuring implies that the penetration depth, which signicantly inu- 3. M. cial experiments ences the Raman measurement (deep curing), has a smaller Amer Wavelength dependent curing experiments were performed impactontheUV-vissetup.HencetheUV-vissignalvariationis, 40 m with irradiations passing the UG11 lter, the linear variable even for these (partially) transparent wavelength ranges, a n 2/10/2023 12:05:Attribution-NonCo aaconrllettlaeelaelrr’ycs(sat,deneiddedffqebwnfroyiertn(ht4hte)nevpoetooprsyriolt(ti7sceot)eren,dpasfut)r,roiaentmlhld,eirFetlrishiangced.erii1abaR.rteaEivdomavnreiai,rnanybwsRlseueaprbmeescleatatecnrvrtaeis,aorpnanwegdche(tt2dirhc.u.4hem)TU.whGTweeh1asr1eees stdr[heuisffaiotteal4rubem0tlneiaotpynlarossoichnobaefelstupthoeo¼enmseictqoerieounsnitiophtsolme,ursteteichnoeoentms(curupUebrasVsirone-alvcgubitstiio)liofi.ontanyB(tRu3ho.atif4nm)t,thlahaaenyene¼dprd.rt2aeTht0sweae0on0datiaffrseasepstreuhetchdneteysst wnloaded oCommons Fitniimgt.he3/e.aTnshhaeldtUfe,pVine-vniitdsiaedlnattitmaareweatei’rsaenwadenrtaehleyasneandlayalssemdeoxbnpyolameiqnenredc(8ow)nirtteehsniutnlMtitnhNge, csthiogennraerlsmiinss.cwToihrtrihesolaiusttetdhaenwymitdhoosttuhbiemtppthhooartttaont-hitnepdovuaicnreitdaotipfootnhlyimisnseurthibzesaetUciotVino-vnoi.sf 015. DoCreative nuseexdt sfuobrsseacmtiopnle(n3o.3m).eTnhcelatmureedioafnthoef tdhaetailelu.gm. winiathtiionnTlaigbhlet2is. SchTeomeem1p,hisaseizvee,nthaepp4l5ic(cid:4)a(baldeetfo¼r 9tr0a(cid:4)n)srpeareecnttiosnysUteVm-vsisbsuettuipts, July 2der a Tsuhbesepcrtoiocned“uCraelctuolactaiolcnuolaftethethientemnesditiyananidseenxeprlgayinoefdthienirtrhae- mhiagihnlyapdivgamnteangteedissythsteemfasc,tctahnatbneoann-atrlyasnesdp.arent systems, like ublished on 22 e is licensed un ddmwieoaomrtsketosdnrseltithagrcrahtottieu”vegt(hh3ai.n6tei)tt.lhieaTecthtoTreorP.nOraT-Lwhtreaadsnaiasntfacietlripe,aartevotsarreibpnlbleteeepndhsztooianpttoheT-ieannqbioutlieneaent2o,crhcwilisenhagtirhc,l4hey4 ssiyagssntAheadmeldsivat(anpiorodinastasthiliolbeynl,Ue,tVhdi-esovicwschnoeaqrntruogeilep1aimtnedearneshftwr)haitacthhtsiavatnehbieetnhtdtseeeorRxlir,adewmishoacilcnuahttiieoocqannuuiwspoeimftshetthh4n0eet s Article. P This articl r3e.3sultAsnianlyasilsowofytiheledUaVn-dviissstihgenasllotwoecsutriinnigticaotorrreblaytifoanr. (pm2e0ur0flto0irpmleaadnshaceteas)op.foAirndetdasli-t(teiiovmneerayll(y0t,.h5itsnhmede).UteAVcl-tlvoiorsfdtshoyeswstneemmtouall3tliopwmlessd)tahotaef es points specically vary during the measurement whereas c Ac Recently it was demonstrated that the light within strong specic vibrational bands measured e.g. by disperse infrared pen absorbing ranges of a sample that is reected at the prism to (810cm(cid:2)1)23,24orRamanspectroscopy(1635cm(cid:2)1)consistonly O resin interface can be automatically analysed, resulting in the of a few evaluable data points.‡ Further, the UV-vis setup, areasolidicationanalysisofthesystem,Scheme1.16Duetothe Scheme 1, is not restricted to transmission experiments. Both linear variable lter and the tested initiators such unaffected 45(cid:4) (a ¼90(cid:4))and90(cid:4) (a ¼180(cid:4))weremeasuredandana- det det rangesdonotexistinthisstudy.Nevertheless,theCCDdetector lysed.The“always”presentlightsourcecanbeusedforcuring monitored up to two irregular deviations for reected light, and monitoring. Last but not least the fused silica is much Fig.3.Thenumberofmeasurementswastoosmall,soallofthe easier to handle/clean than materials that are transparent for presentedhypotheseswithinthissubsectionhavetobeveried IR-radiation. By varying the construction a similar UV-vis byfutureexperimentalandtheoreticalstudies.Onlyamanual receiver can also be connected with any real-time IR spec- determinationoftwoinitialtimest ,t andthe“halfeffect” i,1 i,2 trometry,seealsotheESI.† timet waspossible.Thelastoneisusedtocalculatethenal 1/2,2 timerespectivetothenalabsorbedphotonnumbernf,2, 3.4 Analysisgeometryeffectsofthesetup n ¼n +2(n (cid:2)n ). (14) Geometry effects: position. Analysis of the data, Table 2, f,2 i,2 1/2,2 i,2 conrms that the Raman and UV-vis positions are within the Ingeneral,therstirregulardeviationti,1/ni,1ismeasuredat area of maximal intensity. The measurement of the DMHA thestartoforbeforetheRamanobservation.Thismeansitcan containing system with an irradiation median of 312.5 nm be correlated well with the initial time for the Raman resultsinanareaof0.97mm2.Themeasurablesignalchanges measurements, Fig. 3, S5† and 4. Both UV-vis signals were both for the UV-vis and the Raman setup. This fact clearly clearly recognisable for measurements with a high number of underlinesthegoodmatchbetweentheUV-visandtheRaman absorbedphotons(TPO-LUG11,DMHAFL)andinthecasesof measuring position. This is also the position of maximal strongresinabsorbance(TPO-L<312.5nm),Table2.Thenthe rst effect is less wide and intense than the second UV-vis ‡DetailsconcerningtheUV-vis,RamanandIRmaybefoundwithintheESI†and signal, Fig. 3 and S5.† But at the moment no one-to-one withinliterature,Fig.4inref.16. 67292 | RSCAdv.,2015,5,67284–67298 Thisjournalis©TheRoyalSocietyofChemistry2015 View Article Online Paper RSCAdvances intensity, which will be less inuenced by reection effects, Nevertheless the area ofthe cured solid,Fig. S8† andTable 2, comparedwiththeinuenceoftheincidenceangle,seebelow. can be used to predict the effectivity of the initiator for low- Geometryeffects:volume.Forquantumyieldcalculationthe intensity illumination in combination with the cascading numberofdoublebondshavetobeknown.Hencethedetection effect, if the total number of ashes for the experiment is ce. volumehastobespecied.Duetotheillumination(Scheme1, similar,TableS2.†Frompracticalaspectsthislowerintensityin n Lice bottom) the volume is considered as a 45(cid:4) prism (height 0.05 combinationwiththeeffectsofthe(semi-)transparencyleadsto d mm)wherebythediameterofthebasearearangesfromz0.15 thepossibilitytoidentifyhighlyreactivesystems.Thesesystems e ort mm (laser) to 0.20 mm (collected by the pinhole). For the leadtoaneffectivereactionwithlowphotonux(power).Hence p n U calculations,Fig.4,theminimaldiameterischosen.Thenthe the overall curing process of industrial applications may be 0 3. amountofsample/doublebondswithinthecuringvolumecan optimisedbythevariationoftheexposuretime. M. cial easily be calculated from the data by eqn (1). Note that for Amer quantumyieldcalculationtheuncertaintyintheareaiswithout 2:05:40 onCom adnoyubilmepbaocntds(pahroetcoanlcunluamtebdebryimsuinltipHlyzinmg(cid:2)w2i)t.hTthheeccoonnvseurmsioend 3T.h5e fFuirntehecrorarnecatliyosnisooffththeeladyaertathwicitkhnoeustscaonrdrercetsiionnalgeidngto a n 2/10/2023 1Attribution-N i(en1vce(cid:2)GirdyeMeopnmNocse)ei,ttaiTronyangbelleiffenoe2tfci.tmtsNh:eeoitcinerarcntaihddbaeietantacdiloeesntoeawrntmhigtelhiend.4eod5Iun(cid:4)bbllyetehaedebqsonintdo(de8aa)c.nloncealtlesinpettitfchoaerl pcc(uoorsennipsnaiigdrcaetUitrniGeogd1n.1r.eF)Hsosutrealtnturcttnheead,attieentlayhrt,ehlitiechsruecrbiuaunsstgeew,dotafhRsteahmelnaDaiysneMhrseHtedhtAuilcacpktoenanrel,tlsao6siwndhsianaycsgsotrnaoetsrbieonerl ded omons cured solid with the well-dened aspect ratio of 2(cid:2)0.5. Within of the accuracy of the layer thickness by comparing the oam the rst presentation of the Raman UV-vis system16 a second computed intensities of the maximum of the double bond wnlCo curingareawasdescribed,whichwasmonitoredforhigh-yield vibrational band I at 1635 cm(cid:2)1 before the rst irradiation. oe 015. DCreativ tinraitnisaptoarrsen(otrreasihnus.gTehnisumsebceorndofcuarisnhgesa)rebayitsesatffinegctesduffibycitehnet TwhheesreebinytfeonrsitthieesraerseinmsocroenotrailnesinsgraTnPdOom-Llythdeisatrviebruagteedvianlutiemies July 2der a lSicghhetmtoeta1l.-rTeheecdteedtaialtedthaencaolyvseirswoifntdhoewaraeiarsinwtietrhfiancet,hniso.st1udiny hfoIir¼th0e.0s3ec8o(cid:3)nd0.m00e4asfourretmheentrsctymcleeahsIuir¼em0.e0n3t6c(cid:3)ycl0e.0(t0<26(td>)1a2n.d5 ss Article. Published on 22 This article is licensed un ewtFlehqoiaetnrdhcvsi(uin1str6uoes)da,etlmhsizoeial-titfdiraoacsnntigstapnhtaiahrteecanoarntcetasstlisiyynccseaðatvqeldeimiÞinnn¼scgiifid22enneabffon:eustceeatcnnoocgnfelsdethtcqehuieirisrinrdcagiadmlaicareuetnleaasdietoexlndii(sg1tbho6sytf). dUtUwmh)nGGh.oeai11dCclt11ehwoarnomaclstltmooeitede/rurserrenueairtttsisffihnpcuneagcorfnienaetdmhdnnbieffsdeteneratatrethsobesssensuuoaoclimftnresbtsiehtiieodignedafntlDtRhihpaMaamhectmaoHcotntahuuAotnernnicrtntsiohengnnsitticithe,enkanxbencpisytseieictsensroysqilgrminrgivrseheea(cnt1sDrtliii8tyInao)utan¼iwsgoieinnot0dh.fg..0FFttt1hhhoo2eeerr, e cc hIi(cid:4) (cid:5) n A nf ¼ I nf;0(cid:2)ni þni; (18) Ope TheareaAellcanalsobecalculatedwiththedeterminedaxis aandb, leads to a higher accuracy of the measured curing behaviour, seethesection“Intensityandenergyrelationsoftheinitiators” A ¼pab, (17) (3.7). ell to prove the geometric form of the cured solid, Table 3. The results conrm that the rst curing area is elliptical. If the 3.6 Calculationoftheintensityandenergyoftheirradiated systemissufficientlytransparentacascadingeffect,suchasthe light light(multi-)reectedattheresintofusedsilicainterfaces,no.2 The absolute and spectral calibration of the bre optical inScheme1,isclearlyrecognizablebythetheoreticalincident detectorledtoacorrectionfunctionA (l),eqn(2),whichisvalid c angle(cid:6)45(cid:4).Fornon-transparentsystems(CMYB;highlylled if the whole detection area is illuminated by a uniformly resins),respectiveforwavelengthswithintheopticalabsorption distributed light source39 and correlates the count number of of the monomer/polymer, for example experiment TPO-L (+ the detection unit with the photon number per array. Within UG11)307nm,theeffectdoesnotexist.Byanalysingthedata, thecitedpublicationthespecicenergyiscalculatedbytrapeze even a distinction between the absorption effectivity of the formula, DMHAandtheTPO-Lrelativetotheoneoftheresinispossible. P Hence the measured areas are strongly inuenced by the Value¼0.5 (value(li)+value(li(cid:2)1))(cid:5)(li(cid:2)li(cid:2)1). (19) reectionsontheresintofusedsilicainterface,no.2inScheme 1.Thegeometryofthesolidismostlikelyalsoinuencedbythe Here the number of photons is calculated by trapeze formula.Thegeneraltechniquetotransfer/calculatenecessary widthofthebeamrelativetothesectionsofthelinearvariable lter.Concerningtheareaanalysis,alsotheeffectsofthevari- spectra was described within the cited publication in detail.39 First of all the spectra of the illumination xenon light source ance in layer thickness cannot be separated, see the section “Fine correction of the layer thickness and resin aging” (3.5). passingaND3-lter(alignedgeometry)andapinhole(0.15mm) are recorded. Note that the effective beam width (diameter of Thisjournalis©TheRoyalSocietyofChemistry2015 RSCAdv.,2015,5,67284–67298 | 67293
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