q=2π/d BNL-NSLS NSLS d = α β b β c Long d Spacing small Bragg angle 2L wide Bragg angle Though this be madness yet there is method in t X rays

Transcription

1 Crysallizaio of fas uder shear: X-ray diffracio ad NMR daa Crysallie srucure of fas Log d Spacig small ragg agle 2L 3L Giafraco Mazzai Dalhousie Uiversiy, Halifax, Caada Shor d Spacig wide ragg agle a Modified from Gari & Sao: Crysallizaio a c Processes i Fas ad Lipid Sysems, 2 d ed. a β b β c b c a 2 dimesioal powder scaerig NL-NSLS NSLS Sychroro q=2π/d λ d = 2siθ X rays 2θ X χ Though his be madess ye here is mehod i

2 Experimeal seup: Couee cell roohave X eamlie Huch 5 ºC (3 mi) 7 ~ 22 ºC a 3 ºC/mi Palm Oil Mil fa Mil fa TGs Sychroro X-Rays 2D Deecor 2θ u wro γ = s r r r o i ImageJ plugi for es of housads of 2D DXray X-ray daa Phase characerizaio D d c q Pea posiio q = 2π/d c FWHM =2π/D2 Iegraed Iesiy~ Crysallie mass

3 Phase rasiios I esiy II, a.u. 7 V β 4 Iesiy, Time, mi Time Diffracio paers from palm oil Pea Posiio 2L Log β d 2L Spacig small ragg agle 2L Q, Å- 7 C & 44 s q =.34 Å -,.3 mi q =.48 Å -, 3.9 mi Orieaio of crysals Diffracio paers from palm oil Pea Posiio Iegraed Iesiy Oi Orieaio i χ iesiy Relaive S =.79 S = zimual agle χ esiy Relaive ie L 9 Deg 55 Deg β 2L zimual agle χ

4 Orieaio disribuio 75 χ-fw WHM, Deg 8 Relaive ie siy Deg 55 Deg zimual agle χ Effec of shear o groups of paricles uhal zim 6 Palm oil Mil fa Mil fa TG Cocoa buer 3 4 Shear rae, s - a b c Iegraed Iesiy Iegraed iesiy of phase palm oil egraed C,% Ies siy SF rom I fr 3 2 β oβ Example: Palm oil, 9 s -, 7 ºC Time, mi esiy, a.u u. egraed I I 3. 7 C 22 C Time, mi

5 Iegraed iesiy of phase β palm oil Ose ime reducio - β palm oil. esiy, a.u egraed I I C 22 C Time, mi Time, mi Ose C 22 C Shear rae, s - = l( γ γ ) = oβ ' GENERL OSERVTION FOR LL FTS STUDIED! m Why does i happe? No acceleraio of : o effec o liquid? Shear forces are o eough o alig molecules Forces o he surface of he crysals are o eough o iduce he realigme, bu hey may ifluece surface diffusioi We believe i is due mosly o chages i physical disribuioib i of ucleaio Some composiioal chages may iervee as well: relaed o pea posiio. ii Pea posiio ad composiio Pea posiio q = 2π/d c d c

6 Pea posiio variaio palm oil Pea posiio variaio mil fa 7 C 22 C.54 MF MFT.484 Pea posi io, Å Icre easig sh hear Icrea asig sh ear Pea pos siio, Icre easig sh hear Icrea asig sh ear Time, mi Time, mi Two crysallizaio composiioal rules from d-spacig chages HMF MMF LMF % size % size % size Palm oil med/shor 46 med/log 43 med/log Mil fa 2 log med 7 med/shor The loger molecules of a give fracio will ed o crysallize firs, followed by he shorer oes of ha fracio. The proporio p of molecules of he HMF mixed wih MMFLMF icreases wih emperaure or shear. Kieics of Phase growh 3a 2 β 3b

7 Differeial form of vrami equaio Differeial form of vrami equaio l = mou of maerial ye o be rasformed mou of maerial ye o be rasformed Maximum amou of available maerial o rasform Growh mode expoe Time scalig cosa Time scalig cosa Model of Model of 3b 3a simulaeous simulaeous ODE ODE β 2 3b ODE ODE 2 3a ' l ) ( l β > = l l = ' >oβ 2 >oβ ' l ) ( = 3b β = ) ( ) ( ' ' oβ > Daa vs. model Daa vs. model 3 Example: Palm oil, 9 s -, 7 ºC 3 β 2 C,% Time, mi Mil fa, a sep closer o equilibrium Mil fa, a sep closer o equilibrium 2 p q p q β )5 oβ ' FC (%) Diffusio Model 5 SF ODE Model 7 5 C C, 8 s Time (mi)

8 Rheo-NMR We Developed reliable NMR measuremes uder flowig codiios Two mehods: Complemeig he XRD fidigs USE OF NMR UNDER SHER Direc Mehod Idirec Mehod - Direc Mehod Temperaure calculaed durig i siu crysallizaio Shear affeced rae of crysallizaio Highes shear rae = lower Viscous heaig Excelle correlaio wih isrume Temperaure measured (saic) Used direc for correced liquid sigal Compued raio of acual vs correced Pu io parabolic bli equaio for emperaure

9 Resuls Resuls Saic Resembled previous research depede o Temperaure Icreased Temp = prologed Trasiios 7.5 C remaied aroud 5% Form II o V, o form IV 72 s - lower Viscous heaig Form II o IV Resuls Resuls 2 C grew o 5% afer rasiio Lower a 72 s - Form V prese a 72 s - Gree curve = hree phase rasiio 22.5 C ll rasiio: form II o IV o V more variable s shear rae icreased, decreased Form IV prese i 2 highes shear rae = lower due o melig emperaure

10 Resuls summary Whe form V prese (lower emp ad shear rae) Max aroud 5% No depede o emperaure Ouside melig rage Coclusios Solid phase rasiio ose acceleraio is caused by crysallies segregaio, evideced by a preferred crysallie orieaio (Mazzai e al. CGD 23 ad CGD 24a, Mazzai e al. Physical Review E, 25) ) Pea posiio displaceme follows composiioal chages explaied by mass rasfer cosideraios (Mazzai e al. CGD 24b, Mazzai e al. Physical Review E, 25, Mazzai e. l CGD 27, Mazzai e al. CGD 29) Phase rasiio ca be modeled as a series-parallel ieic mechaism, wih lile effec of shear o he growh raes. (Mazzai e al. Physical Review E, 25) Near equilibrium a sep-growh diffusio corolled regime aes over (Mazzai e al. Eur J Phys E, 26) Correlaio bewee NMR Solid Fracio ad XRD daa is possible uder shear (Mazzai e al. CGD 28, Mudge, om & Mazzai, JOCS 29)