Termická analýza 01 Diferenciální Skenovací kalorimetrie (DSC) Přednášející: Doc. Jiří Sopoušek Brno, prosinec 2011 Obsah Heat flux DSC a Power compensation DSC Teorie Kalibrace Měření lat. Tepel a Cp * Diskuse ICTAC: DSC is the generic term for the following two measurement methods. •Heat Flux DSCs H A technique in which the temperature of the sample unit, formed by a sample and reference material, is varied in a specified program, and the temperature difference between the sample and the reference material is measured as a function of temperature. Power Compensation DSC A technique in which difference of thermal energy that is applied to the sample and the reference material per unit of time is measured as a function of the temperature to equalize their temperature, while temperature of the sample unit, formed by the sample and reference material, is varied in a specified program. Základní typy DSC: heat-flux a power compensation power-comp. Furnace Temp&rature sensors Heat-flux Furnace Resistance ihermcmeEer Heating wire Cooling block Rozdíly: cena, přesnost, periferie, výměna s hfDSC (heat-flux) Rcf wane* «11 Sample cell Heat sink Heat rasis^noe Temperature sensor I Icaicj Heater drive ? Twnpwature sensor =)- er Amplifier Microcomputer : ►I Te*npe*aftjne coniifoi[ AT recording (Heat flow recording) 5 Heating and cooling system Výměnné držáky hfDSC TG-DSC sensor getter materia\ getter support radiation shield TCUTft HPipto currltr TG ÍJTpl* (.Jrriar Kelímky (ampule), lisovací kelímky AI. Reakce s kelímkem, čištění kelímků, Na DSC signál má vliv: kontakt se dnem kelímku (lks vzorku), velikost vzorku, rychlost ohřevu,.. Kelímky Pan Type 7i Aluminum 7i Copper 7i Gold 7i Graphite 7i Al Hermetic 7i Al Alodined Hermetic 7i Gold Hermetic 7iHigh Volume (lOf^L) 7i Al Solid Fat Index (SFI) 7i Platinum Upper Temp Limit 7i600°C 7i725°C (in N2) 7i7250C 7\125°C ^600°C ^600°C 7i725°C 7i250°C ^600°C ^725°C (in N2) (3 atm.) (3 atm.) (6 atm.) (safety lid) (no cover) (no cover) Použití kelímků Materiál Ano Ne Pozn. Slinutý AI203 Kovy B« Oxidy Levné, ne pro Ti Pt Anorganika, org.látky Kovy Drahé AI Organika Kovy Levné do 600stC Cu PÍ+AI203 Kovy Měření Cp Fe Au Biolog, materiál Kovy Spec. alikace, jinak nevhodné grafit Au,Ag Pro nereaktivní kovy m Kelímky DSC - korundové kelímky Víčka mj. chrání před radiačními ztrátami tepla! Měřící a referenční kelímek po měření vzorku AlNiZn (ANZ3) 11 {Hiq 286 -AHf in kJ/mol for JS O2 UsO 535 BeO BIO 2to MbC^s) 2m/n U(s) * Oj(g) 4S = 184±10J/K ŮS= 16±5J/K iH-=49fikJ NaQ 41J NaOs 261 MaOs* 130 NfcCV 256 St ab ilii ta KíO 361 KCte 142 KíOí* 142 CaO 635 ScA 623 TijQj 490 TíOj 472 TijOj 507 TiOÉ 543 W 456 VO 431 V/J/ 4C6 VOř" 357 VsOs* 31Ů CfzOj37e CfOj 293 CfOj* 196 MnO 365 Mn^Oj 346 319 MnOs* 270 FeassO 264 FesOa 290 Fe20)*274 CoO 239 COjO* 226 RttíO 330 RbíOj 176 SrO 604 Srd 326 VíCb 627 ZrOs 547 NbO 410-NbOa 399 WoOi ^94 MoCb24B T0O3 216 TcOg 160 RjOj 150 RuO, 46 HhO 92 RhaOa* 119 RhOi 96 C&Q 318 CS2O3 188 BaO 581 Hf02 556 TaaOs 408 WOi 295 Wí03 2S4 WQj* 261 RbOj 213 ReOj 205 ReaOřMTB OsCrf 147 OsOi 97 frOi 111 Fr Ra CfeOa 5S9 CeCh 594 PrOfe 475 MdíOfj 602 Pm ThOí 613 Pa tA 541 602 UA* 447 UO3' 408 NpOj 514 PuOj 527 BäOj 426 CT in (WiO^ -10 ÍHíOi) 15 O . Ne AliOj 550 PiOj m PA ei PjOi' 300 SOi 151 locii) ei Ar CtoO 171 CuO 156 GfeO GajOí 363 GeO 212 GeOi 363 GeQs*290 AfcO* 19a asíOí ias ScO* 112 SůíOí 82 Br Kr PdO 96 PdO* lis ftgiO 30 C4Q 258 SnO 295 SnOi 290 TeQi iei 1 Ke PtO; 45 HgO Si T1;Q 166 TIíOí 129 PDO 217 PfoO*179 POQť 137 PO At Rn EuOT 59: EifcCj 5G4 tyíOí 621 LiteOa 625 AiUdOj 585 Cm Bk er Fm MO kv k Povlaky kelímku Y203.....pro slitiny kovů , a Ti slitiny BN....A1 slitiny Špatná volba kelínků Plyny Čištění plynů: trapy, vymrazovaní N2, atd. plyn Použití Pozn. Synt. Vzduch Oxidy, kinetika Oxidace Argon Kovy slitiny Inert Dusík Kovy, organika Vznik nitridů Helium Speciální Drahé Redukční Kinetika Pozor na směsi N2-H2 termočlánky Thermal Conductivity at 300 SC (W/mK) Air Ar 0.018 CO 0-025 C02 0.0 J 7 H 0.182 He 0.J5I N2 0.026 Nc 0.049 O, 0.027 pcDSC (kompensacni DSC) Sampte sample cell Reference cell } ShakJ Common !'2at2- drive t ni'Fsrenlial healer driv* Temperature program! Temperatur contra! wonpenEal cn eortrel j re-nperature- recording AmphliGr Ci PerwiltaJ input recording (Heal flw weeding) ■ft Figure 2 (a) J&asic construction of heaE-rtux DSC (with copyright permission from Seiko Instruments Inc.). (b) Basic construction of po^tr compensation DSC (with copyright permission from Seiko Instruments Inc) Praktická realizace Velmi podobné hfDSC >/dt=konst. dT Stacionární stav P < f Záznam DSC (b) ffme / min Differential Scanning Calorimetry (DSC) 10 'C/mln Blank {reference) —VAWA Figure 1 Basic principle of DTA and DSC: (a) change in temperature of reference 7r and sample 7s with increasing furnace temperature 7P; (b) typical signal output converted to differential temperature AT with passage of time 20 Teorie DSC Sample S Kelímek sample CS Tepelný odpor mezi CS a P Tepelný odpor mezi CS a S dTp/dt= např. OK/min Reference R Kelímek ref. CR Tepelný odpor mezi CR a P Tepelný odpor mezi CR a R Figure 1 Mraw + [Ccsín - CcR(r>]} drP/dr = K+(T)dAqs/út Odečet (b)-(a): (b) Cs(T)dTj>/dt = /^(DdA^/dr (c) where dA^/df ^ dA^s/d/ - dAWdr Podobně pro prázdný CR a CS se standardem: CRM(T)ůTP/dt = ^(Dd^M/dř (d) dA^w/df = dAÍRM/dř -dAí0/dr. Podělením ( c) / {d) se zbavíme K(|)(T): hf DSC Cp měření time D (sample) Cp (sample) x mass of sample D (sapphire) Cp (sapphire) x mass of sapphire PET 0.5 1.0 Reference, normally sapphire Empty pans 1.6 2.0 Time (min) 2.5 3,0 3,298 figu re 1.1 Heat ca pac ity of PET obta i ned u si ng fast scann i ng tec h n i q ues showing the three traces req u i red for subtraction. The height of the sample compared to the empty pan is divided by the scan rate and the mass of sample to obtain a value for Cp. This is referenced against a known standard such as sapphire for accuracy. If small heating steps of, for example, 1°C are used the area under the curve can be used to calculate C9, This calculation is employed as an option in stepwise heating methods. Exo - Endo (zmena entalpie AH) TT n rl ntVi ^r*m Solid-solid transition J-iAV/lllVl M.M.M. 1-illVtV/ 1>11 VI J.H Crystallisation Melting Vaporisation * L Sublimation Adsorption L Desorption Desolvation (drying) Decomposition Solid-solid reaction * Solid-liquid reaction Solid-eas reaction Curing Polymerisation Catalytic reactions Exo -Endo u 32 Kalibrace Pro konstantní rychlost ohřevu, plyn, držák, termočlánek, kelímky, víčka, ....atd. Teplota (známe body F transformací, Ttr=Tm+AT(T) čisté kovy) Entalpie (plocha peaku, čisté kovy) Ä#{T> •Rychlost tepelného toku (korundový Kalibrace na teplotu Table 1,1 Commonly used standards and reference material Standard Indium Tin Lead Zinc K2SO4 K2Cr207 Substance Cyclopentane Cyclopentane Cyclohexane Cyclohexane ji-Heptane n- Octan e rt"Decane ff-Dodecane rt-Octadecane Melting point TO 156-6 231.9 327.5 419.5 585.0 670.5 Transition Crystal Crystal Crystal Melt Melt Melt Melt MeJt Melt Heat of fusion (J/g] 28.42 108.26 Transition temperature (°0 -151.16 -135,06 -87,06 6.54 -90.56 -56.76 -29.66 -9.65 28.24 Kovy Anorg. Soli Organika Magn. Látky. FT (eutektika, peritektika) Čisté kovy Material Tm (^C) Hf (J/g) Mercury -38.8344 11.469 Gallium 29.7646 79.88 Indium 156.5985 28.62 Tin 231.298 7.170 Bismuth 271.40 53.83 Lead 327.462 23.00 Zinc 419.527 108.6 Aluminium 660.323 398.1 + Ag, Au, Ni Další čisté kovy a eutektika Table 2 -Fixed Point Temperatures for Calibration [69Bar, 90PreŤ 9óBed] Substance Ref. In 156.5985 90Pre Sn 231,928 90Pre Bi 271.402 96Bed Cd 321.069 96Bed Pb 327,462 96Bed Zn 419.527 90Pre Sb 630,628 96Bed AI 660323 90Fre Ag - 28,t % Cu* 779.63 96Bcá Ag 96L7S 90Pre Au 1064.18 90Pre Cu 1084,62 90Pre Ni 1455 69Bar Co 1494 69Bar Pd 1554,8 96Bed *Eutetic composition. In this document, the % symbol will refer to percentage by mass. DSC /(mW/mg) T exo Baseline s prázdnými kelímky 200 400 Vacuum /% 100 80 60 40 20 600 800 Temperature řC 1000 1200 Kalibrace hfDSC na citlivost Známy standard(In): 55 45 §^40 cl 35 % 30 | 25 Š. 20 | 15 10 5Q, Indium check after calibration Peak = 158.024°C - Area = 327.064 mJ AH = 28,391 0/g Onset = 156.523°C ■t S...citlivost na uvolněné latentní teplo Výpočet pro vzorek: 154 156 158 160 162 164 Temperature (°C) 166 168 Figure 1.4 Indium run as a check after a calibration procedure has been completed showing the onset calculation for meJting point, and area calculation for heat of fusion. This particular curve would benefit from a higher data point collection rate to remove the stepping effect of the data and improve overall accuracy. =S. (ploch a peaku) 40 Citlivostní závislost Sensitivity |iV/mW 1.2 Q_2 "I—1—1—1—1—1—1—1—1—1—1—1—1—1—1—1—1—1—1—1—1—1—1—1—1—1—1—1—1— 0 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 TfC hfDSC měřeni vzorku DSC /(|jV/mg) Slitina SnZnSb závislost hfDSC signálu na čase. Teplotní závislost DSC /(|jV/mg) t exo 1.5 1.0 0.5 0.0 -0.5 Onset: 162.6 °C Čistý cín Onset: 228.3 °C 150 Temperature řC Vacuum /% h 100 [ 80 h 60 [40 [20 0 Slitina SnZnSb závislost hfDSC signálu na teplotě. 1.2.3 cyklus (run). Reprodukovatelnost při ohřevu, podchlazení při chlazení. (lOKmin, 70mlAr6Nmin). Tepelné efekty při vzniku spojů mezi Cu substráty DSC /(mW/mg) t exo 4 Spoje: Cu / pájecí materiál / Cu 10Kymin,70ml AtßN/min Value: 120.5 °C, 0.04838 mW/mg nanosilver Onset: 215.7 °C SAC pájka (217stC) Onset: 228.0 °C Sn bulk (231 stC) 150 200 Temperature ľC Závislost DSC na rychlosti ohřevu (k) 89,94 80 ~ 70 60 50 40 30 20 10 0 -5.971 Cl Z3 O E 03 Indium at 20,50 and 100aC/min Shown on a temperalure axis i 47.9a 60 30 100 120 140 Temperature f*G) 160 180 1953 figure 1.3 The effect of increasing scan rate on indium. Part (a) (upper curve) is shown with the x-axis in time; part (b) (lower curve) is shown with the x-axis in temperature. The same energy flows faster in a 45 DSC /(MV/mg) t exo 1.0 0.5 0.0 -0.5 ■1.0 Závislost na rychlosti ohřevu [3,3] [1.3] [1.3] 20 40 60 SnSOZn (v argonu) [1.4] [1.5] DSC /(ijV/mg) T exo 1.0 80 Time /min 0.5 0.0 -0.5 -1.0 Temp./°C Vacuum 1% Y 100 h so \ h 60 [1.6] uo 200 150 Onset: 195.5 °C Vacuum!% 100 46 Závislost na hmotnosti vzorku Práškové vzorky vykazují větši kontaminaci. Nej vhodnější je jeden kousek s rovnou hranou (dobrý tepelný kontakt). Figure 23. Effect of sample mass on DTA signal for pureAg* The reference mass was held constant. Heating rate is 10 Kfmin. Závislost na pořadí ohřevu 1. Run... vy tvoření tepelně vodivých spojů (a) i—1—r 940 960 T (X) (b) n—1—l—'—l—■—I—* 780 800 820 S4Q T CC) Figure 2 A. DTA signal for melting of (a) pure Ag (211.6 mg; 10 K/min) and (b) Ag-Cu eutectic (231J mg; 15 Klmin) comparing first melt (red) and second melt (blue), Note the offset of the baselines, the more rounded onsets and the lack of linearity of the down-slopes for the first melt compared to the second. _ 48 T exo .1 0.3 70ml Ar/min 200 220 Temperature /°C 240 Fázové transformace 1. řádu Kalibrace na In AI kelrnky (I scr/sni) Onset: 153.6 °C Onset: 152 0 °C Onset: 152.1 °C 10K/min 70ml Ai6N/min Area: "2534 ľVs/mg Area: -25.23 fiVs/mg Area: -25.19 (jVs/mg 80 100 120 Temperature ľ C 140 160 180 200 Ffcnit2 Typical trace plotted against time for a first-order j&iase transition, signal starts to deviate from the baseline; ^t extrapolated onset; tu inflection point where the slope of the trace is maximum; tp, peak maximum hfDSC-Indium STA409 FT 2. radu -e-cooling Figure 3 Heat capacity (a) and idealized trace ft) in classical DTA and saied DSC for a second-order phase transition Ideální a pcDSC Figure 4 Principle of drawing baseline lo separate a thermal event. Thermal behavi (left) and corresponding ideal traces in power-compensated DSC (right) Glass transition (skelný přechod) Tg Skelný přechod je reverzibilní přeměna, kdy amorfní látka (často polymer) viskózního nebo „gumovitého" charakteru řechází do stavu tuhého a relativně křehkého. B I ry] Liquid (2) Rubbery ^© State/ Glassy State ^ Crystalline State j Temperature Tg Teplota skelného přechodu Tg je teplota, která reprezentuje oblast kdy dochází k skelnému přechodu 53 24 PLA below T„ PLA above T. Physical property Response on heating through Tg Specific Volume Increases Modulus Decreases 1/E, Coefficient of Increases CTE thermal expansion Specific Heat Increases Cp Enthalpy Increases H& Entropy Increases S Tg závisí na: Heat ine Rate Heatine & Cooline Aeine is Molecular Weight Plasticizer Filler Temperature Crystalline Content Copolymers Side Chains Polymer Backbone Hydrogen Bonding Vyhodnocení Tg z DSC signálu Tc = Temperature of First Deviation (°C) Tf = Extrapolated Onset Temperature (°C) —---_To v Tf Tm = Midpoint Temperature (&C) Ts = Inflection Temperature (°C) 4-V rn ■A \ T Te = Extrapolated Endset Temperature (°C) Tr = Temperature of Return-to-Baseline (°C) l/2li' \ 1 T / \ \ ' V , L 1 y \ : : \ ■—..............-----------------v S* I TEMPERATURE (°C) Glass Transition Temperature tor Selected Polymers i Organic Polymer T„CC) Polyacenanhthalene 264 Polyvinylpyrrolidone 175 Poly-n-vinyI benzyl alcohol 160 Po1y-/>vinyl benzyl alcohol 140 Poly methacry loni tri le 120 Poly aery lie acid 106 Polyvinyl formal 1 TerillOp 1(15 Polystyrene 1 100 Polyacrylonitrile IctSty Qfr Polyvinyl chloride S7 Polyvinyl alcohol S5 Polyvinyl acetat 82 Polyvinyl proprional 72 Pory thy tene terephthalate 69 Polyvinyl isoburyTal 56 Polycaprolactam (nylon 6) 50 Polyhexann ethylen e adiparcide (nylon 6,6) 50 Polyvinyl butyral 49 Polyctilorolritlnorerhylene 45 Hthyj cellulose 43 Organic Polymer T0(°C) Polyhexamethylene sebacamide (nylon 6.10) 46 Polyvinyl aceŕaŕe 29 Po lyperfl uoropropy 1 ene 11 Poly m ethyl aery late 9 Polyvinyl i dene chloride -17 Polyvinyl fluoride -20 Poly- l-butene -25 Polyvinyl i dene fluoride -39 Poly-l-hexene -50 Polychloroprene -30 Po 1 y vi ny 1 - i j-butyl ether -52 Polytetram ethyl ene sebacate -57 Poly butyl ene oxide -60 Polypropylene oxide -60 Poly-1 -octene -65 Polyethylene ad i pate -70 Polyisobutylene ^^^^^^^ -70 Natural rubber plltY„r Polyisoprene Gumy 1 ~72 -73 Poly dimethyl siloxane -85 Poly dimethyl siloxane -123 Závislost Tg na rychlosti změny teploty Q- 03 LU CD E a. .pomalé chladnutí, b. . .rychlé chladnutí Liquid Temperature m Určování fázových diagramů pomocí DSC Jednoduché binary u. Sv 1 y ] 0 Composition Figure 1 Schematic phase diagram for a binary system with a eutectic phase transi tion + y, and the corresponding DSC curves for compositions A, Br C and D respectively a ^10 -20 -30 10 a e ,5 -10 - -■20 -30 L-1 T~n—r micelle solution micelle solution + liquid crystal ^ mleefie sokition : ice \ f -W- liquid crystal liquid crystal ice crystal liquid crystal +■ crysiat i j_i_I_i—i—i—L -lJL £0 40 60 SO Weight percent of DeTAB Figure 2 DSC heating curves for DeTAB-water mixtures with various compositions a, b> c, d, and e, and the phase diagram of (he DeTAB -water binary system* 60 FD viceslozkovvch soustav y DSC /(mW/mg) T exo Peak: 839.3 °C Peak: 859.9 °C Peak: 857.7 °C Peak: °C Sample vie D5 Onset: 825 Onset: 827. Onset: 828. Value: 812.0 °C, 3.144 mW/mg Value: 637.0 °C, 2.315 rnW/rng 500 600 700 800 Temperature FC Area: -227.2 J/g Area: -229.9 J/g Area: -231.7 J/g 900 Vacuum /% 100 SO 60 40 20 1000 S/ftina 9.26at%Ag-14,81 %Ba-81,48%Ge DSC měření Al-Ni-Zn 1000 DSe/íirMrhig) Texo 10 Slitina AI Ni Zn ANZ3 57.0 7.0 36.0 \^CLLrrr% YÉLe 72D0^87C9nWrg pouze tato část neovlivněna vypařováním Zn 230 300 400 333 Ten^paräueŕC 600 7O0 100 80 80 40 20 O Vyhodnocení DSC křivek pro vzorek ANZ3 62 Stanovení čistoty (D -C O "C1 LU 95% 99% O TJ LLI Eutectic point t 375 380 385 77K 380 390 400 410 t/k Figure 1 DSC curves of NIST SRM1514 (pheitacetines doped with nominal 0*0, 0.7 2.0 and 5.0mol % of /?-aminobenTOic acid) DSC /(mW/mg) Temperature TC Výměna plynu DSC/{mW/mg} 0.20 -0.20 -0.40 -0.19 4.11 ■□,25 11» 1W 1H4 1344 13» U» 1«D 15« TYrWi TomperatureTC 200 180 160 140 120 100 SO 60 200 400 600 SOO 10DO 1200 1400 1600 1800 2000 65 ermni krystalizace -0.4 - -03 - -0.6 Figure 1 Thermogram of isothermal crysiailizaiion of polyvinyl idsne fluoride) Model: Avrami Adsorbce a desorbce H2 ve slitinach t E ! LU n- E ■— i UJ i Hydrogen ation. (exothermic) y y Dehydrogenation ' (endothermic) " /\/ Heating V - 4- r Hydrogenation Cooling 1 (c) Dehydrogenation Heating Low^ Temperature- High Figure 1 Schematic traces of DTA or DSC of a hydrogen-absorbing alloy under hydrogen atmosphere Diskuze (Netzsch STA 409 CD/3/403/5/G) 409 1 ...Furnace (0.1 -20 K min1, 25-1450QC) 2...QMS range 1-512 amu resolution 0,5amu IE = 25 -100 eV 3...Turbomolecular Pump 4...TA System Controller (TASC) 5..Vacuum Controller, (cca 9-106 mbar) 6...QMS Controller 7.Purification Column (oxygen) (Argon 99,999) Mass Flow Controller (MFC) Reálné látky metastabilní stav - skelný monoklinic 200 v o 55 100 ľ Za lAtm a nízkého tlaku 100 200 7VK 300 100 200 77K 300 Figur« 2 Heat capacity and entropy of cyclohexanol 69 27.07--■-■-■----■- 155.0 155.5 156.0 156.5 157.0 157.5 158,0 156.5 159.0 Temperature (&C) Figure 1*5 ! nd ium heated at 5° C/m i n jhowi ng an a I most triangu lar mel ting prof 11 e ty pica I of si ngl e crystal mett at lower scan rates. The slope of the leading edge ot the melt of a pure material such as indium gives a value for the thermal resistance constant Rq.