A reactive melt modification of polyethylene terephthalate

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10 1.2.2 Limitations of PET Rheologically, PET, a linear polycondensation polymer, is usually considered as unsuitable for extrusion blow molding because it is nearly Newtonian above its melt temperature (Dealy and Wissbrun, 1990). Use of a multifunctional monomer such as 1,4- cyclohexane dimethanol instead of ethylene glycol or tetraerythritol, or trimellitic anhydride which produce long chain branching and broadens the MWD can render PET the desirable processing and rheological properties for extrusion blow molding (Edelmen et a1., 1979 and 1980). It is obvious that this option of varying the monomer functionality during commercial synthesis in compliance with different end use application(s) may be expensive from the point of view of bulk manufacturers. In order to understand the significance of the limitations of PET due to its properties, it is necessary at this point to define the process requirements, particularly for extrusion blow molding and extrusion foaming. By contrast to the injection blow molding of PET, described earlier, the extrusion blow molding process would be faster on a time scale and more economical because of the fewer number of steps involved and time savings over cooling the parison. In the generalized extrusion blow molding process, shown in Figure 1.6, a tube or parison of melt is extruded from a die (Rodriguez, 1996). The mold halves then close around the parison to pinch it off at one end and if a bottle is to be made, to form a threaded neck at the other. Then the parison is inflated to conform to the shape of the mold. The extrusion can be intermittent, halting while the parison is pinched, inflated and cooled, or it can be continuous, by the use of two or more moving molds. In addition to parison swell and sag, 'shark skin' or 'melt fracture' is a parameter of concern in extrusion blow molding
11 operation (Dealy and Wissbrun, 1990). Shark skin is a distortion of the extrudate that can affect the surface finish of an extrusion blow molded container. Extrusion distortion is most severe in the case of polymers with narrow MWD (Dealy and Wissbrun, 1990). There are certain rheological requirements for polymers used in the extrusion blow molding process, which are normally absent from linear PET resins in the melt state. "Die" or extnidate swell, a prime requirement, greatly varies from polymer to polymer, strongly affected by the degree of branching and the molecular weight distribution (Rosato and Rosato, 1989). Extnidate swell is used as a parameter for designing a die for blow molding operations. It is also useful in determining the stability of parison/preform of a polymer (Dealy and Wissbrun, 1990). For linear polymers such as PET, broadening of MWD generally results in higher extradite swell. Extrudate swell is highly sensitive to the small amounts of high molecular weight material, which could be in the form of long chain branching (Rosato and Rosato, 1989). Raising the high molecular weight fraction increases the ultimate swell but decreases the rate of approach to the steady state value (Koopmans, 1988). Koopmans also found that highly branched
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: 9 In the case of sheet applications
Page 39 and 40: 13 During the cell growth phase of
Page 41 and 42: 15 suitability of extruders as cont
Page 43 and 44: 17 conditions and additive concentr
Page 45 and 46: 19 understand the effect of evolvin
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
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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
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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
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105 accessibility of unreacted grou
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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
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113 crosslinked gels in swelling eV
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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
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A reactive melt modification of polyethylene terephthalate

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