Polyethylene theory

Mitsoulis. E Wagner, R and Heng, F. L. (1988) Numerical Simulation of Wire-Coating Low-Density Polyethylene Theory and Experiments. Polym. Eng. Sci., 28, 291-310. 

FIG. 23-23 Batch and continuous polymerizations, (a) Polyethylene in a tiihiilar flow reactor, up to 2 km long hy 6,4 cm ID, (h) Batch process for polystyrene, (c) Batch-continuous process for polystyrene, (d) Suspension (head) process for polyvinylchloride, (e) Emulsion process for polyvinylchloride, (Ray and Laurence, in Lapidus and Amundson, eds, Chemical Reactor Theory Review, Frentice-Hall, 1977. )... 

Vinyl chloride (1835) formed by reacting acetylene with hydrochloric acid, was polymerized a.v polyvinyl chloride (PVC) in 1912, The theory of polymerization by Staudinger in the 1920s- led to the advances that followed. The acrylate were polymerized as polymethylmethacrylate to come into production in 1927. Polystyrene was developed. similarly and concurrently. Polyethylene came into production in 1939 for use in radar and now is ubiquitous. 

To illustrate the application of corresponding-states theory to polymer solution calculations, we consider two cases of sol-vent/polymer vapor-liquid equilibria. The first case we consider is that of the chloroform/polystyrene solution. The second is that of benzene/polyethylene oxide. 

To illustrate the use of the gas sorption mode , we show in Figure 7 results of the supercritical ethylene sorption in low-density polyethylene (12,16). As seen in Figure 7, the theory is capable of fitting the ethylene sorption data. In this instance, the data at three temperatures can be fit within experimental precision using interaction parameters (p o) of 3235 atm, 3178 atm, or 3101 atm at 126°C, 140 0, and 155 C, respectively. 

There Is a large body of experimental literature relating to polymer fractionation In liquid-liquid equilibria. In addition, numerous authors have analyzed polymer fractionation using Flory-Huggins theory. We have considered use of the corresponding states theory to model polymer fractionation for the ethylene/ polyethylene system at reactor conditions (18). Results of the... 

Industrial Engineering Chemistry Research 37, No.7, July 1998, p.2582-91 POLYETHYLENE PYROLYSIS THEORY AND EXPERIMENTS FOR MOLECULAR WEIGHT DISTRIBUTION KINETICS Sezgi N A Cha W S Smith J M McCoy B J California,University... 

In the classical Lauritzen-Hoffman theory for the mechanism of polymer crystal growth [106], it is assumed that the observed lamellar thickness corresponds to those crystallites that happen to have the largest growth velocity. However, this picture is hard to reconcile with the experimental observation that the thickness of polyethylene single crystals can be modulated by varying the temperature at which they are grown [117,118]. In fact, simulations by Doye et al. [119,120] suggest that the observed lamellar thickness does... 

Mean-field lattice theory proved to be capable of predicting the phase behaviour of the ternary block copolymer polyethylene-b-poly(propylene oxide)-b-poly(ethylene oxide), PE-b-PPO-b-PEO in the selective solvent water [164], The ethylene block is known to be highly hydrophobic, and its hydrophobicity does not depend strongly on temperature. The difference in hydrophobicity between PPO and PEO, on the other hand, is moderate... 

Molecular orbitals, in organic semiconductors, 22 211 Molecular orbital theory, 16 737 Molecular orientation, in linear low density polyethylene, 20 188-189 Molecular oxygen, 17 746. See also Oxygen (0)... 

Perchlorotoluene, 6 327 Perchlorylation, 12 183 Perchloryl fluoride, 18 279 Percolation leaching, 16 153 Percolation processes of filled polymers, 11 303 for wood, 26 358-359 Percolation theory, 20 345 23 63 Percolation transition, 10 16 Percutaneous transluminal coronary angioplasty (PTCA), 3 712 -per- designation, 7 609t PE resins, applications of, 20 206t. See also Polyethylene (PE)... 

A theory for this acid effect has been developed essentially from the wool and cellulose work (3,4). Recently, in a brief communication, we reported analogous acid enhancement effects in the radiation grafting of monomers such as styrene in methanol to nonpolar synthetic backbone polymers like polypropylene and polyethylene (5). In the present work, detailed studies of this acid enhancement effect are discussed for the radiation grafting of styrene in various solvents to polyethylene. The results are fundamentally important since most of the experiments reported here have been performed in solvents such as the low molecular weight alcohols which, unlike cellulose and wool systems, do not swell polyethylene. 

In the case of polyethylene, the volatile component was cyclohexane and here, too, good agreement was obtained between the measured exit concentration and the predicted values using Pe = 40 in the solution of Eq. (38) (see Fig. 16). Tliese data also suggest that mass transfer is occurring by molecular diffusion through a wiped film since the exit concentration varies with N in accordance with the theory. It is somewhat disconcerting, however, that the value of B used in the theoretical expression was not reported, and the question naturally arises as to whether realistic values were used to obtain the fit with the data. 

---