A reactive melt modification of polyethylene terephthalate

More documents

Recommendations

Info

CHAPTER 2 PURPOSE AND SCOPE This thesis focuses on understanding the structural modification of PET and its effect on the polymer rheological properties through a reactive melt processing approach using low MW multifunctional epoxides, for improving processability, particularly in extrusion foaming. Reactive processing, in this case, involves undesirable degradation reactions and desirable chain extension and branching reactions resulting in changes in MW and MWD of PET. As sketched in Figure 2.1, extrusion foaming of PET to low densities is challenged by its low melt viscosity, melt strength, and melt elasticity. Researchers have correlated improvements in these and other rheological/processing properties with bubble stability and resistance to bubble coalescence during foaming. This thesis attempts to 18
19 understand the effect of evolving branched polymeric structures, caused by reactions in a controlled environment, on the rheological properties of interest and their relation with foamability of the modified resin in extruders. The experimental work involves first the selection of the PET resins and the epoxy modifiers combined with their full characterization. Specifically, for PET, parameters that were studied were (i) initial MW, MWD, (ii) end group content, and (iii) thermal stability. For epoxy modifiers, parameters that were studied were (i) structure, (ii) functionality, (iii) thermal stability, and (iv) concentration. Melt modification was monitored and analyzed by carrying it out in three types of batch reactors: (1) intensive batch mixer, (2) dynamic mechanical analyzer (rheometry), (3) high temperature sodium chloride crystal cell for FT-IR, prior to proceeding with the reaction in continuous extruders. During melt processing, PET may undergo undesirable thermal degradation. Thus, the role of such degradation reactions on the desirable chainlextension branching reactions was also evaluated. In order to understand the evolving and resultant macromolecular structures) and their particular rheological/processing properties, a combination of online, inline, and offline characterization methods were used. They include carboxyl content determination, insoluble content determination, and rheological analysis of the reaction products. The changes in the properties, which were monitored during melt modification, were analyzed to obtain the reaction kinetics information. The developed kinetic data in association with the resultant reaction product properties were used to define the requirements for and extending the reaction in an
Page 1 and 2: Copyright Warning & Restrictions Th
Page 3 and 4: ABSTRACT REACTIVE MELT MODIFICATION
Page 5 and 6: REACTIVE MELT MODIFICATION OF POLYE
Page 7 and 8: BIOGRAPHICAL SKETCH Author: Rahul R
Page 9 and 10: Copyright © 2003 by Rahul Ramesh D
Page 11 and 12: ACKNOWLEDGEMENTS I always considere
Page 13 and 14: TABLE OF CONTENTS Chapter Page 1 IN
Page 15 and 16: TABLE OF CONTENTS (Continued) Chapt
Page 17 and 18: LIST OF FIGURES Figure Page 1.1 Mac
Page 19 and 20: LIST OF FIGURES (Continued) Figure
Page 21 and 22: LIST OF FIGURES (Continued) Figure
Page 23 and 24: Striation Thickness Time Diffusion
Page 25 and 26: tertiary amine terephthalic acid th
Page 27 and 28: CHAPTER 1 INTRODUCTION After its in
Page 29 and 30: 3 of 0.5-1.00 mm Hg (Sorenson 2001)
Page 31 and 32: where rib is the solution viscosity
Page 33 and 34: 7 are not suitable for most of the
Page 35 and 36: 9 In the case of sheet applications
Page 37 and 38: 11 operation (Dealy and Wissbrun, 1
Page 39 and 40: 13 During the cell growth phase of
Page 41 and 42: 15 suitability of extruders as cont
Page 43: 17 conditions and additive concentr
Page 47 and 48: CHAPTER 3 LITERATURE REVIEW This ch
Page 49 and 50: 23 absence of modifiers is accompan
Page 51 and 52: 25 The primary objective while modi
Page 53 and 54: 27 Polypropylene resins with high m
Page 55 and 56: 29 initially the reaction with hydr
Page 57 and 58: 31 A diglycidyl ether, often in the
Page 59 and 60: 33 Characterizing the products of t
Page 61 and 62: 35 5. Ease of mixing in the polymer
Page 63 and 64: 37 Figure 3.4 Epoxy or 0xirane ring
Page 65 and 66: 39 carbocation stability overrides
Page 67 and 68: 41 Figure 3.9 Anhydride — epoxy r
Page 69 and 70: 43 Figure 3.12 Base catalyzed hydro
Page 71 and 72: 45 activity to enhance the PET-epox
Page 73 and 74: 47 4.1.2 Chain EDtenders The struct
Page 75 and 76: TGDDM was used in the batch mixer s
Page 77 and 78: 51 4.2 Processing and Characterizat
Page 79 and 80: 53 specimens as a function of freVu
Page 81 and 82: 55 to the parallel plates). An addi
Page 83 and 84: 57 background spectrum. It took app
Page 85 and 86: CHAPTER 5 RESULTS AND DISCUSSION Th
Page 87 and 88: 61 molecular weight of MPET as also
Page 89 and 90: 63 rate expressions analogous to th
Page 91 and 92: Figure 5.5 Possible reactions betwe
Page 93 and 94: 67 taking place by the convective;
Page 95 and 96:
69 5.1.4 Comparison of Epoxides Fig
Page 97 and 98:
71 5.1.5 Reactions of TGIC with HPE
Page 99 and 100:
73 Figure 5.11 shows the vanation o
Page 101 and 102:
75 Figure 5.13 shows the effect of
Page 103 and 104:
77 to time. In a general sense, the
Page 105 and 106:
79 5.1.7 Study on Role of Catalysts
Page 107 and 108:
81 groups adjacent to the tertiary
Page 109 and 110:
83 overall less activity towards TG
Page 111 and 112:
85 5.2.1 Typical Batch MiDing Runs
Page 113 and 114:
87 It appears that the higher proce
Page 115 and 116:
89 injection (Dealy and Wissbrun, 1
Page 117 and 118:
91 rheological power scaling law fo
Page 119 and 120:
93 In the calculations, the freVuen
Page 121 and 122:
95 whereas H(?.) of the unmodified
Page 123 and 124:
97 However, the disintegration of t
Page 125 and 126:
99 the Section 4.1.3. As evident fr
Page 127 and 128:
101 changes in dynamic moduli and m
Page 129 and 130:
103 In the case of 270 °C, the mod
Page 131 and 132:
105 accessibility of unreacted grou
Page 133 and 134:
107 believed to be charactenzed by
Page 135 and 136:
109 increase in the melt elasticity
Page 137 and 138:
111 In general, for crosslinked sys
Page 139 and 140:
113 crosslinked gels in swelling eV
Page 141 and 142:
115 formation of epoxy/PET reaction
Page 143 and 144:
117 A seVuential reactive extrusion
Page 145 and 146:
CHAPTER 6 CONCLUSIONS AND RECOMMEND
Page 147 and 148:
121 of PET by the selected tnepoxid
Page 149 and 150:
REFERENCES S. Abe and M. Yamaguchi,
Page 151 and 152:
125 L. M. Dossin and W. W. Graessle
Page 153 and 154:
127 P. Huang, Z. Zhong, S. Zheng, W
Page 155 and 156:
129 J. Meissner and J. Hostettler,
Page 157 and 158:
131 T. Shiwaku, K. Hijikata, K. Fur
Page 159 and 160:
133 M. Xanthos and S. K. Dey, "Foam
show all

A reactive melt modification of polyethylene terephthalate

Create successful ePaper yourself

Delete template?

Save as template?