Polymer polycarbonate + poly ethylene

It is well known from diffusion theory that different types of polymers have different diffusion behaviours. For example, the polyester type polymers like poly(ethylene terephthalate) (PET), poly(ethylene naphthalate) (PEN) and polycarbonate (PC) as well as rigid poly(vinyl chloride) (PVC), which have a high glass transition temperature, are low diffusive polymers. The migration of potential contaminants in these polymers will result in low migration values. In contrast, polyolefins like high density polyethylene (HDPE), polypropylene (PP) or low density polyethylene (LDPE), which... 

Moderately stable polymers, like poly (ethylene terephthalate) and polycarbonate. 

Polycarbonate + Poly(ethylene terephthalate) PC + PET, Polycarbonate + Liquid crystall polymer PC + LCP, Polycarbonate -I- Poly(butylene terephthalate) PC -t- PBT, Poly(ethylene terephthalate) + Polystyrene PET - - PS, Poly(butylene terephthalate) - - Polystyrene PBT + PS Polymer Blends IV... 

Polycarbonate + poly(ethylene terephthalate), PC + PET polycarbonate -i- liquid crystal polymer, PC +... 

Table 3.3-32 Polycarbonate + poly(ethylene terephthalate), PC + PET polycarbonate + liquid crystall polymer, PC + LCP polycarbonate + poly(butylene terephthalate), PC + PBT poly(ethylene terephthalate) + polystyrene, PET + PS poly(butylene terephthalate) + polystyrene, PBT + PS...

Althongh nanocomposite matrix materials may be metals and ceramics, the most common matrices are polymers. For these polymer nanocomposites, a large number of thermoplastic, thermosetting, and elastomeric matrices are used, including epoxy resins, polynrethanes, polypropylene, polycarbonate, poly(ethylene terephthalate), silicone resins, poly(methyl methacrylate), polyamides (nylons), poly(vinylidene chloride), ethylene vinyl alcohol, butyl rubber, and natural rubber. 

For the thermal fluctuations of density, a situation is more complicate. For instance, the experimental temperature dependences of the density fluctuations in polycarbonate, poly(ethylene terephthalate), and poly(methyl methacrylate) (54), have two breaks—at Tg and at T < Tg. It was found that the fluctuations begin to increase at temperatures T close to Tg, that is, quasi-independent, liquidlike motion of the chain segments appear in these polymers and grow in number with increasing temperature. Their scale exceeded three units. As T > Tg, these movements acquired a cooperative nature, although independent segmental movements partly remained. It implies a common nature of and a-relaxation that will be discussed below. 

In 1954 the surface fluorination of polyethylene sheets by using a soHd CO2 cooled heat sink was patented (44). Later patents covered the fluorination of PVC (45) and polyethylene bottles (46). Studies of surface fluorination of polymer films have been reported (47). The fluorination of polyethylene powder was described (48) as a fiery intense reaction, which was finally controlled by dilution with an inert gas at reduced pressures. Direct fluorination of polymers was achieved in 1970 (8,49). More recently, surface fluorinations of poly(vinyl fluoride), polycarbonates, polystyrene, and poly(methyl methacrylate), and the surface fluorination of containers have been described (50,51). Partially fluorinated poly(ethylene terephthalate) and polyamides such as nylon have excellent soil release properties as well as high wettabiUty (52,53). The most advanced direct fluorination technology in the area of single-compound synthesis and synthesis of high performance fluids is currently practiced by 3M Co. of St. Paul, Minnesota, and by Exfluor Research Corp. of Austin, Texas. 

Other Polymers. Besides polycarbonates, poly(methyl methacrylate)s, cycfic polyolefins, and uv-curable cross-linked polymers, a host of other polymers have been examined for their suitabiUty as substrate materials for optical data storage, preferably compact disks, in the last years. These polymers have not gained commercial importance polystyrene (PS), poly(vinyl chloride) (PVC), cellulose acetobutyrate (CAB), bis(diallylpolycarbonate) (BDPC), poly(ethylene terephthalate) (PET), styrene—acrylonitrile copolymers (SAN), poly(vinyl acetate) (PVAC), and for substrates with high resistance to heat softening, polysulfones (PSU) and polyimides (PI). 

Fig. 15. Oxygen permeability versus 1/specific free volume at 25 °C (30). 1. Polybutadiene 2. polyethylene (density 0.922) 3. polycarbonate 4. polystyrene 5. styrene-acrylonitrile 6. poly(ethylene terephthalate) 7. acrylonitrile barrier polymer 8. poly(methyl methacrylate) 9. poly(vinyl chloride) 10. acrylonitrile barrier polymer 11. vinyUdene chloride copolymer 12. polymethacrylonitrile and 13. polyacrylonitrile. See Table 1 for unit conversions.

When dipoles are directly attached to the chain their movement will obviously depend on the ability of chain segments to move. Thus the dipole polarisation effect will be much less below the glass transition temperature, than above it Figure 6.4). For this reason unplasticised PVC, poly(ethylene terephthalate) and the bis-phenol A polycarbonates are better high-frequency insulators at room temperature, which is below the glass temperature of each of these polymers, than would be expected in polymers of similar polarity but with the polar groups in the side chains. 

It has already been shown (e.g. Chapters 20 and 21) that the insertion of a p-phenylene into the main chain of a linear polymer increased the chain stiffness and raised the heat distortion temperature. In many instances it also improved the resistance to thermal degradation. One of the first polymers to exploit this concept commercially was poly(ethylene terephthalate) but it was developed more with the polycarbonates, polysulphone, poly(phenylene sulphides) and aromatic polyketones. 

Birley, A.W. and Chen, X.Y., A preliminary study of blends of bisphenol A polycarbonate and poly (ethylene terephtalate), Brit. Polym. J., 17, 297, 1985. 

The photoablation process consists of the absorption of a short-wavelength laser pulse to break covalent bonds in polymer molecules and eject decomposed polymer fragments. Channels of various geometries and dimensions can be obtained using an appropriate mask. Many commercially available polymers can be photoablated, including polycarbonate, poly(methyl methacrylate) (PMMA), polystyrene, nitrocellulose, poly(ethylene terphtalate) (PET), and poly(tetrafluoroethylene) (Teflon). ... 

---