Polymer Crystallization in Droplets and Confined Layers Using Multilayered Films
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POLYMER CRYSTALLIZATION IN DROPLETS AND CONFINED LAYERS USING MULTILAYERED FILMS by Deepak Langhe Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy Dissertation Advisers: Prof. Eric Baer and Prof. Anne Hiltner Department of Chemical Engineering CASE WESTERN RESERVE UNIVERSITY January, 2012 CASE WESTERN RESERVE UNIVERSITY SCHOOL OF GRADUATE STUDIES We hereby approve the thesis/dissertation of _______Deepak Langhe______________________________ candidate for the Ph.D. degree *. (signed) __Prof. Eric Baer_______________________ (chair of the committee) Prof. James Anderson___________________ Prof. David Schiraldi____________________ Prof. LaShanda Korley___________________ (date) ____September 20, 2011_____________ *We also certify that written approval has been obtained for any proprietary material contained therein. Copyright © 2011 by Deepak Langhe All rights reserved Dedicated to my grandparents and parents TABLE OF CONTENTS LIST OF TABLES………………………………………………………………… ii LIST OF FIGURES……………………………………………………………….. iii ACKNOWLEDGEMENTS……………………………………………………….. xiv ABSTRACT………………………………………………………………………… xvi CHAPTER PART I 1. STRUCTURE AND CRYSTALLIZATION KINETICS OF HOMOGENEOUSLY NUCLEATED POLYPROPYLENE DROPLETS AT HIGH UNDERCOOLINGS………………………….. 2 2. TRANSFORMATION OF ISOTACTIC POLYPROPYLENE 32 DROPLETS FROM THE MESOPHASE INTO THE Α-PHASE…….. 3. FRACTIONATED CRYSTALLIZATION OF α- AND β- 65 NUCLEATED POLYPROPYLENE DROPLETS……………………... 4. EFFECT OF ADDITIVES, CATALYST RESIDUES AND CONFINING SUBSTRATES ON THE FRACTIONATED CRYSTALLIZATION OF POLYPROPYLENE DROPLETS………... 105 PART II 5. MELT CRYSTALLIZATION OF SYNDIOTACTIC POLYPROPYLENE IN NANOLAYER CONFINEMENT IMPACTING STRUCTURE…………………………………………….. 142 6. PHYSICAL AGING OF POLYSTYRENE IN NANOLAYER 178 CONFINEMENT…………………………………………………………. BIBLIOGRAPHY………………………………………………………………… 204 i LIST OF TABLES CHAPTER 1 1.1 Crystallization half times for smectic PP droplets 21 1.2 Growth rate and chain diffusion coefficients obtained from smectic 22 bundle size and crystallization half times. CHAPTER 2 2.1 Melting Enthalpies of Annealed Smectic Polypropylene Particles 50 CHAPTER 3 3.1 Effect of MD on crystallization enthalpies of PP particles 87 3.2 Effect of QQ on crystallization enthalpies of PP particles 88 CHAPTER 4 4.1 Different additives present in ZN-PP and PS 126 4.2 Grades of PP synthesized using different catalysts 127 4.3 Crystallization enthalpies of cPP droplets produced from 200 nm 128 layers 4.4 Crystallization enthalpies of ZN-PP droplets produced from ZN- 129 PP/PC multilayered films CHAPTER 5 5.1 Details of multilayered sPP/PC films 163 CHAPTER 6 6.1 Details of PS/PC multilayered films 192 6.2 Tg of PS layers obtained after cooling PS at 60 °C/min 193 6.3 Aging rates of PS obtained after aging the films at 80 °C 194 ii LIST OF FIGURES CHAPTER 1 1.1 (a) AFM phase image of the cross-section of coextruded PP/PS film 23 with 12 nm PP layers; (b) AFM image of the PP particles obtained from 12 nm layers obtained after dissolving PS matrix; (c) PP particle volume distribution image (a). 1.2 a) High resolution AFM phase image of a PP particle from 12 nm 24 layers revealing granular morphology; (b) Cooling thermograms of PP particles produced from breakup of 12 nm layers and bulk PP, obtained at 10 °C/min. Thermograms were obtained after heating the samples to 230 °C for 3 min. 1.3 (a) WAXS pattern of smectic PP particles in PS matrix, PS control 25 and PP particles obtained after subtracting PS contribution; (b) SAXS pattern of smectic PP droplets obtained after subtraction of PP/PS melt contribution 1.4 Hierarchical structure of the granular PP droplets (~500 nm) 26 containing grains (~ 20 nm) which constituted fringed micellar smectic bundles (~ 6 - 8 nm). The smectic bundles constituted right and left handed PP helices. Cross section of the smectic bundle is shown here at molecular scale. 1.5 Evolution of the smectic bundles by homogeneous nucleation and 27 growth process. Homogeneous nuclei are formed with a few PP chains (l>>w), and lateral growth resulted into 6-8 nm smectic chain bundles. 1.6 Heating thermogram of PP droplets obtained after subtraction of PS 28 contribution. The beginning of the transformation of smectic phase into a-phase at 56 °C was considered as melting temperature. 1.7 Crystallization half times for PP droplets crystallized isothermally 29 iii and was extrapolated to 500 years to get the equilibrium melting of 71.5 °C. Slope of the curve, S, represents the temperature dependence of both nucleation and growth rates. 1.8 Cooling thermograms of PP droplets obtained at 5 °C/min after 30 isothermal crystallization at 54.5 °C for fixed times as labeled. 1.9 Crystallinity fraction (Xt) of PP droplets versus time plots for droplets 31 crystallized isothermally at temperatures as labeled. The lines are added as guides. CHAPTER 2 2.1 AFM image of PP/PS multilayered film with 12 nm PP layers. A few 51 PP layers are indicated by arrows. 2.2 (a) AFM image of PP particles from 12 nm layers obtained after 52 dissolving PS matrix (b) PP particle volume distribution obtained from image (a). 2.3 The cooling and subsequent heating thermogram of the PP droplets 53 produced from 12 nm PP layers from PP/PS film. 2.4 The melting thermograms of PP particles annealed at various 54 temperatures for 30 minutes. 2.5 (a) WAXS patterns of the PP particles annealed at various 55 temperatures for 30 minutes, in the presence of the PS matrix (b) WAXS patterns of the PP particles obtained after subtraction of the PS contribution. 2.6 SAXS patterns of annealed smectic PP droplets after subtracting 56 PP/PS melt contribution 2.7 Long spacing calculated from SAXS patterns of annealed droplets, 57 obtained from Figure 2.6. 2.8 AFM images of PP particle morphology annealed at various 58 temperatures and quenched at 100°C/min: (a) Without annealing; (b) iv Annealed at 120°C for 30 min; grain size distribution obtained from AFM images of PP particle morphologies from (a) and (b). 2.9 (a) Hierarchical structure of the mesophase droplets constituting 59 smectic bundles of PP; (b) Hierarchical structure of the transformed smectic phase into an ordered alpha phase. The increased chain order was observed due to translational and rotational motion. 2.10 (a) The DSC cooling thermograms obtained at 10 °C/min after 60 annealing the PP particles at 140 and 160 °C for 2 hrs; (b) Subsequent heating thermogram of the PP particles annealed in (a), obtained at 40 °C min-1. 2.11 (a) The WAXS patterns of the PP particles annealed at various 61 temperatures for 2 hrs in the presence of PS matrix; (b) The WAXS patterns of the PP particles obtained after subtraction of the PS contribution. 2.12 SAXS pattern of the smectic PP droplets annealed for 2 hrs and cooled 62 to RT at 10 °C min-1, obtained after subtracting PP/PS melt contribution 2.13 AFM images of PP particle morphology annealed at various 63 temperatures and cooled at 10°C/min: (a) Annealed at 140°C for 120 min ; (b) Annealed at 160°C for 120 min. Corresponding Grain Size distribution obtained from AFM images of PP particles (c) Annealed at 140°C for 120 min ; (d) Annealed at 160°C for 120 min 2.14 (a) Hierarchical structure of annealed PP droplets with alpha phase 64 crystals and merged grain boundaries. Grain boundaries diffusion led to the formation of bigger grains; (b) Hierarchical structure of the transformed smectic phase into lamellar alpha morphology. Melting and recrystallization resulted into lamellae formation. v CHAPTER 3 3.1 AFM phase images of the cross-sections from coextruded PP/PS film 89 with 12 nm PP layers with (a) 0.0% QQ, (b) 0.3% QQ; AFM images of PP particles from 12 nm layers with (c) 0.0% QQ, (d) 0.3% QQ; particle size distribution from 12 nm layers with (e) 0.0% QQ, (f) 0.3% QQ; and PP particle volume distribution from 12 nm layers with (g) 0.0% QQ, (h) 0.3% QQ. 3.2 AFM images of PP particles from 12 nm layers with 0.5% MD (a) 90 crystallized by cooling at 10°C/min after thermal breakup at 230°C (b) crystallized at 137°C for 24hrs before cooling at 10°C/min to room temperature; particle size distribution from 12 nm layers with 0.5% MD obtained crystallizing PP particles by (c) cooling at 10°C/min after thermal breakup at 230°C (d) crystallization at 137°C for 24hrs; and corresponding PP particle volume distributions obtained under the same crystallization conditions as described above are shown in (e) and (f). 3.3 (a) Cooling thermograms of PP droplets from breakup of 12 nm layers 91 containing MD; and (b) heating thermograms of the PP particles from breakup of 12 nm layers containing MD. The PS contribution was subtracted. 3.4 AFM images of PP particles obtained from 12 nm layers with (a) 92 0.0% MD; (b) 0.5% MD; and (c) 2.0% MD. 3.5 (a) WAXD patterns of the PP particles from PP nanolayers after 93 subtraction of the PS contribution; (b) SAXS patterns of the PP particles from PP nanolayers obtained after subtracting the PS contribution; and (c) effect of MD concentration on the long spacing. 3.6 Schematic phase diagram for the binary system in the low MD 94 concentration region and schematics of the grain morphology. 3.7 Cooling thermograms of droplets with 0.5% MD after crystallizing 95 isothermally for 24 hrs at 137 °C and cooled from 230 °C at 10 °C vi min-1. The PS contribution was subtracted. 3.8 (a) AFM images of PP particles with 0.5% MD obtained after 96 isothermal crystallization at 137 °C for 24 hrs; and (b) effect of MD concentration and isothermal crystallization on long spacing of MD- nucleated particles.