Ethylene-poly system

Figure 18 Coexistence curves of tert-butyl acetate/PS and water/poly(ethylene glycol) systems (Yang et al, 2006cb).

The problem of complex formation of the copolymers stabilized by hydrogen bonds has been studied very insufficiently. UntU recently, there have been available various data both on the complex formation in the maleic acid/styrene-poly(ethylene glycol) system and the matrix polymerization of acrylic acid with acrylamide of styrene copolymers in the presence of N-vinylpyrrolidone >. 

Kinzl, M. et al., SAFT modeling of inert-gas effects on the cloud-point pressures in ethylene copolymerization systems poly(ethylene-co-vinyl acetate)- -vinyl acetate-i-ethylene and poly(ethylene-co-hexene-l)-thexene-l-tethylene with carbon dioxide, nitrogen or -butane, Ind. Eng. Ghent. Res., 39, 541-546, 2000. 

Poly(A,A-dimethylacryIamide-co-acrylic acid)gel-poly(ethylene glycol) system... 

In general, most of the random copolymers form crystals composed of the major comonomer units of more crystallizable comonomer units alone, as incorporation of the minor component units into the crystalline phase need a large amount of excess free energy. So the cocrystallization of polymers is a rare phenomenon and a very few examples, such as poly(vinylidene fluoridej/vinylidene fluoride-tetrafluoro-ethylene copolymers system [58] and high-density polyethylene/linear low-density polyethylene [59], have been reported. Hence, the occurrence of cocrystallization found for the P(3HB-CO-3HV) copolymer is one of the rare examples. 

Fakirov, S. and Fakirova, C., Direct determination of the orientation of short glass fibers in an injection-molded poly(ethylene terephthalate) system, Polym. Composites, 6, 41 (1985). 

The relationship is, however, only strictly valid in those systems where either molecular diffusion or migration of electronic energy is possible. The former has been shown to occur in the triplet-state quenching of the poly(ethylene)-cyclooctadiene system at 80°C (26), and where energy transfer was equally efficient in either solution or the solid due to ready diffusion of small molecules through the polymer matrix at temperatures above the glass-transition temperature. 

BEY Beyer, C. and Oellrich, L.R., Cosolvent studies with the system ethylene/ poly(ethylene-co-aciyhc acid) Effects of solvent, density, polarity, hydrogen bonding, and copolymer composition, Helv. Chim. Acta, 85,659, 2002. 

The separation of methanol from ethylene glycol is an important industrial process in the synthesis of poly(ethylene terephthalate). The methanol/ethylene glycol system has been extensively studied using various analytical methods and pervaporation experiments as well. The methanol selectivity reaches up to 250 at low methanol concentrations, however, the total flux decreases in this region. 

Hossain, M.K., Hinata, S., Lopez-Quin-tela. A., and Kunieda, H. (2003) Phase behavior of poly(oj ethylene) poly(oxypropylene) poly(oj ethylene) block copolymer in water and water-C12E05 systems./. Dispersion Sci. Technol, 24,441 22. 

For the application of supercritical carbon dioxide as a medium for the production of polyolefins, it is important to have rehable thermodynamic data for the systems involved. Knowledge of the phase behavior of the reaction mixture is crucial to properly choose process variables such as temperature and pressure in order to achieve maximum process efficiency. For this reason, the ethylene-poly (ethylene-co-propylene) (PEP)-C02 system has been taken as a representative model system [3]. The effect of molecular weight as well as the influence of CO2 on the phase behavior has been studied experimentally by cloud-point measurements. In addition, the Statistical Associating Fluid Theory (SAFT) has been applied to predict the experimental results. 

ZAF Zafarani-Moatlar, M.T. and Hamzehzadeh, Sh., Measurement and correlation of densities, ultrasonic velocities, and compressibilities for binary aqueous poly(ethylene glycol), disodium succinate, or sodium forrrrate and ternary aqueous poly(ethylene glycol) systems contairring disoditrm succinate or sodium forrrrate at T = (298.15, 308.15, and 318.15) K, J. Chem. Eng. Data, 50,603, 2005. 

Taepaiboon P, Junkasem J, Dangtungee R, Amornsakchai T and Supaphol P (2006) In situ micro-fibrillar-reinforced composites of isotactic polypropylene/recycled poly(ethylene terephthalate) system and effect of compatibilizer, J Appl Polym Sci 102 1173-1181. 

Polymer brushes at the air-water interface were formed from poly(ethyl ethylene)-poly(styrene sulfonate), PEE-PSS, diblock copolymers [71]. In this system, PEE is the hydrophobic part with liquid properties at room temperature, whereas PSS is the water-soluble polyelectrolyte. Experiments at different salt concentrations show a transition from the osmotically swollen to the salted brush, in which about 90% of the counter-ions remain immobile. 

The solubility characteristics of poly(ethylene glycol) systems in water has led to the employment of this polymer in alternative drug delivery systems. For example, Schluter... 

CHA Chalykh, A.E., Dement eva, O.V., and Gerasimov, V.K., Phase diagrams of poly(methyl methaciylate)-poly(ethylene glyeol) system (Russ.), Vysokomol. Soedin., Ser. A, 40, 815, 1998. 

Figures 2.19 and 2.20 show experimental cloud-point curves and PC-SAFT modeling of the ethylene + poly(E-co-EA) and ethane + poly(E-co-BA) systems, respectively [85], at a polymer concentration of 5 wt.%. The model correctly predicts the change in the location of the cloud point with changing comonomer concentration in the polymer. Especially interesting is the ethylene + poly(E-co-EA) system, in that the curve of cloud-point pressure as a function of the EA concentration in the polymer shows a minimum. This behavior is correctly described by the model.

The applicabihty of the SP treatment for practical purposes thus appears to be well supported by the present analysis of the system ethylene/poly(ethylene). Its value is greater than that, however. The system cyclohexane/poly(styrene) has recently been analyzed with the SP treatment. Here we have a complex phase behavior to deal with, upper as well as lower critical miscibility, and misdbihty improving or declining with increasing pressure, depending on the polymer molar mass. Again the SP approach allowed all data to be covered in a nearly quantitative fashion with a single interaction function [54, 98]. 

As we have indicated above the presence of these block and graft copolymers at the interface between two polymer melts has a substantial influence on the interfacial tension between the two melt phases (see Section 5.7). This effect has been investigated by various researchers [26, 44 to 47]. Typical results are shown in Table 6.1 for the polyethylene-poly(ethylene terephthalate) system [47]. This indicates that block copolymers where the two segments dissolve in different melt phases cause substantial reductions in interfacial tension. This also is the case when the block/graft copolymer are added they are chemically react with the molecules of one of the phases as in the case of the maleated polyethylene and maleated ethylene copolymers with polyamides or polyesters in blends with polyolefins. 

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