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Polyethylene solution

Stable aggregates have been shown to present a problem in the characterization of polyvinyl chloride (1,2) and it has been suggested that residues of crystalline structures may persist in polyethylene solutions at temperatures below the polymer s crystalline melting point (3-5). [Pg.273]

Three processes are used commercially to make linear polyethylene-solution, slurry, and gas phase. All are called low-pressure processes (< 50 atm) to distinguish them from the free radical or high-pressure process that makes highly branched polyethylene. In the solution mode a hydrocarbon solvent at 125-170°C dissolves the polymer as it forms. The reaction usually slows as the solution becomes viscous because it becomes difficult to stir ethylene into the liquid phase. In contrast, The slurry process uses a poor solvent and low temperature (60-110°C) to prevent dissolving or even swelling of the polymer. Each catalyst particle creates a polymer particle several thousand times larger than itself. There is no viscosity limitation in the slurry method the diluent serves to transfer heat and to keep the catalyst in contact with ethylene and other reactants. Finally, the gas-phase process is much like the slurry method in that polymer particles are formed at similar temperatures. A bed of catalyst/polymer is fluidized by circulating ethylene, which also serves as a coolant. [Pg.59]

Kuwahara, N. Saeki, S. Chiba, T. Kaneko, M., "Upper and Lower Critical Solution Temperatures in Polyethylene Solutions," Polymer, 15, 777 (1974). [Pg.174]

Pan, and Radosz, M., Modeling of SEE in naphthalene, normal-alkane and polyethylene solutions. Fluid Phase Equilibria, 155, 57, 1999. [Pg.743]

In other words, when a homogeneous polyethylene solution was cooled at a constant rate, the point of beginning crystallization was reached. This point was indicated by the first visual turbidity. At all concentrations, homopolymer A had a point of beginning crystallization about 10°C higher than that of copolymer B. This finding seemed reasonable since the crystallization temperature depends on the comonomer content and on the degree of short-chain branching of the polyethylene. From the curve we concluded that the temperature at which styrene diffused into LDPE A was about 10°C above that for diffusion into LDPE B at a comparable rate of diffusion. [Pg.234]

KI2 Kiran, E., Xiong, Y., and Zhunag, W., Modeling polyethylene solutions in near and supercritical fluids using the Sanchez-Lacombe model,/. Supercrit Fluids, 6, 193, 1993. [Pg.230]

The gelation behaviour of polyethylene solutions is the result of a combination of L-L-demixing from a bad solvent, followed by L-S demixing (i.e. crystallisation) or by L-S-demixing from a good solvent. TTie first method is used for the... [Pg.120]

Cellulose nitrate In diethyl phthalate (23%) Polyethylene (solution chlorinated) Cl content = 56.6 w/w, amorphous, in bis(2-ethylhexyl)phthalate 298 8.84 165.5 166 ar,s from creep and dynamic mechanical measurements. [Pg.473]

Kiran, E., Xiong, Y. and Zhuang, W. (1993) Modeling Polyethylene Solutions in Near and Supercritical Fluids Using the Sanchez-Lacombe Model, The Journal of Supercritical Fluids 6, 193-203. [Pg.225]

Figure 6.10 uses polyethylene as the model material. The orthorhombic cell structure and the a- and 6-axes are illustrated. The c-axis runs parallel to the chains. The dimension is the thickness of the crystal. The predominant fold plane in polyethylene solution-grown crystals is along the (110) plane. Chain folding is also supported by NMR studies (see Section 6.7) (49-51). [Pg.258]

Wang H (2006) SANS study of the early stages of crystallization in polyethylene solutions. Polymer 47(14) 4897 900... [Pg.142]

MA1 Matsuo, M., Miyoshi, S., Aztrrrra, M., Bin, Y., Agari, Y., Sato, Y., arrd Korrdo, A., Phase separation of several kirtds of polyethylene solution rrrtder the gelation/ crystalhzation process, Macro io/ecM/e5, 38,6688, 2005. [Pg.4]

KUW Kuwahara, N., Saeki, S., Chiba, E., and Kaneko, M., Upper and lower critical solution temperatures in polyethylene solutions. Polymer, 15, 111, 1974. [Pg.700]


See other pages where Polyethylene solution is mentioned: [Pg.223]    [Pg.273]    [Pg.65]    [Pg.212]    [Pg.237]    [Pg.180]    [Pg.731]    [Pg.601]    [Pg.416]    [Pg.724]    [Pg.59]    [Pg.233]    [Pg.101]    [Pg.457]    [Pg.122]    [Pg.169]    [Pg.93]    [Pg.283]    [Pg.740]    [Pg.212]    [Pg.50]    [Pg.753]    [Pg.166]    [Pg.166]    [Pg.260]    [Pg.623]    [Pg.186]    [Pg.163]   


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