Polyethylene terephthalate fundamentals

Figure 10.7 DSC curves of polyethylene terephthalate)-poly(acrylonitrile-butaliene-styrene) (PET-ABS) blends (a) conventional DSC first and second heating curves with heating and cooling rate of lOKmin-1 and (b) temperature modulated DSC (TMDSC) first heating curves with /3=2Kmin 1, p = 60s and 5= 1K. Tg, glass transition temperature. (Reproduced with permission from T. Hatakeyama and F.X. Quinn, Thermal Analysis Fundamentals and Applications to Polymer Science, 2nd ed., John Wiley Sons Ltd, Chichester. 1999 John Wiley Sons Ltd.)...

This chapter covers fundamental and applied research on polyester/clay nanocomposites (Section 31.2), which includes polyethylene terephthalate (PET), blends of PET and poly(ethylene 2,6-naphthalene dicarboxy-late) (PEN), and unsaturated polyester resins. Section 31.3 deals with polyethylene (PE) and polypropylene (PP)-montmorillonite (MMT) nanocomposites, including blends of low density polyethylene (LDPE), linear low density polyethylene (LLDPE), and high density polyethylene (HDPE). Section 31.4 analyzes the fire-retardant properties of nanocomposites made of high impact polystyrene (HIPS), layered clays, and nonhalogenated additives. Section 31.5 discusses the conductive properties of blends of PET/PMMA (poly (methyl methacrylate)) and PET/HDPE combined with several types of carbon... 

It is not clear from the discussions whether or not the states involved are the same at the surface or in the bulk. From a mathematical viewpoint, there is little difference in the formulation of the charging and subsequent distribution of the transferred charge. Practically speaking, there is little difference. However, from a more fundamental viewpoint, the existence of surface and bulk states is of interest although the experimental determination is difficult. Von Seggern has recently published a series of papers demonstrating the existence of traps at the surface of Teflon FEP, which are shallower than the bulk traps, whereas in polyethylene he shows the reverse to be true. There are apparently no surface traps associated with Mylar polyethylene terephthalate. 

Numerous attesnpts have been made to predict the effectiveness of potential nxacleating agents with particular attention having been paid to the crystallisation of isotactic polypropylene, isotactic polystyrene (6), polyethylene (2 9) ard poly(ethylene terephthalate) (10,11). However, little can be concluded about the fundamental mechanism of heterogeneous nucleation, or the propeirties of effective nucleating agents. 

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