Cloud‐Point Pressure Curves of Ethene/Poly[ethylene‐co‐((meth)acrylic acid)] Mixtures

Abstract

Ethene‐methacrylic acid (MAA) and ethene‐acrylic acid (AA) copolymers of narrow polydispersity and high chemical homogeneity have been synthesized at acid unit copolymer contents up to 9 mol‐% within a continuously operated stirred tank reactor at overall monomer conversions of about 2%. Cloud‐point pressures (CPPs) of mixtures of 3 wt.‐% copolymer in ethene (E) have been measured in an optical high‐pressure cell at pressures and temperatures up to 3 000 bar and 260 °C, respectively. The CPP weakly increases with acid copolymer content up to about 3.5 mol‐%. Toward higher acid contents, the CPP is strongly enhanced, in particular at the lower edge of the experimental temperature range at around 200 °C. This increase in CPP is more pronounced for the AA than for the MAA systems. The data suggest that hydrogen‐bonding interactions are operative in the pressurized E/poly(E‐co‐(M)AA) mixtures at temperatures of 260 °C and perhaps even above. E‐AA and E‐MAA copolymers with acid contents of about 5.6 mol‐% have also been completely methyl‐esterified to yield the associated methyl esters. The CPPs of the resulting E‐methyl acrylate and E‐methyl methacrylate copolymers in mixtures with E are significantly below the CPPs of the corresponding E/poly(E‐co‐(M)AA) systems.

Phase equilibria in polydisperse and associating copolymer solutions: Poly(ethene-co-(meth)acrylic acid)–monomer mixtures

“…[14,22,23]. The experimental part thus can be very brief, as details about the CPP measurements are given in Ref.…”

“…The experimental part thus can be very brief, as details about the CPP measurements are given in Ref. [14]. The poly(E-co-(M)AA) samples were synthesized under steadystate conditions in a continuously operated stirred tank reactor (CSTR) of about 50 mL internal volume at 2000 bar and at temperatures up to 550 K. Di-tert-butylperoxide was used as the initiator.…”

“…The model expressions were derived by applying the perturbation theory of Barker and Henderson [13] to chain molecules. PC-SAFT has already been successfully applied to phase equilibrium studies for solutions of several homopolymers and to ethylene copolymer systems without hydrogen-bonded interactions [12,14].…”

“…The CPP data that serve for fitting the PC-SAFT parameters and for demonstrating the applicability of this type of modeling have been determined in experiments where copolymer materials from steady-state copolymerization in an almost perfect continuously operated stirred tank reactor were used [14]. These copolymers are of high chemical homogeneity, i.e., the chemical compositions of individual copolymer molecules are very close to each other.…”

Modification of Sako-Wu-Prausnitz equation of state for fluid phase equilibria in polyethylene-ethylene systems at high pressures

“…High density polyethylene (HDPE)-ethylene systems were investigated by (de Loos 1981, Rousseaux et al, 1985, Nieszporek, 1991. Low density polyethylene (LDPE)-ethylene systems were investigated by (Swelheim et al, 1965, Steiner and Horle, 1972, Cheng and Bonner, 1977, Rätzsch et al, 1980, Spahl and Luft, 1981, 1986, Wohlfarth et al, 1981, Kobyakov et al, 1987, Nieszporek, 1991 Brazilian Journal of Chemical Engineering Heukelbach and Luft, 1993., de Loos et al, 1995, Muller, 1996, Horst et al, 1998, Dietzsch, 1999, Beyer et al, 2002, Buback and Latz, 2003, Trumpi et al, 2003Becker et al, 2004, Davis et al, 2004. Systems of ethylene and different linear copolymers of polyethylene have also been examined (Heukelbach and Luft, 1993, Gregg et al, 1993, Chan et al, 2000.…”