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Copolymer Content (copolymer + content)

Distribution by Scientific Domains
Polymers and Materials Science100%

Selected Abstracts

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

MACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 4 2003
Michael Buback
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. Cloud-point pressure vs temperature curves for several E/poly(E- co -methacrylic acid) systems. The subscripts denote copolymer content in mol-%. A cloud-point pressure curve for E/polyethylene (PE) is included for comparison. [source]

Nanostructured thermosets from self-assembled amphiphilic block copolymer/epoxy resin mixtures: effect of copolymer content on nanostructures

POLYMER INTERNATIONAL, Issue 4 2010
Miren Blanco
Abstract Nanostructure formation in thermosets can allow the design of materials with interesting properties. The aim of this work was to obtain a nanostructured epoxy system by self-assembly of an amphiphilic diblock copolymer in an unreacted epoxy/amine mixture followed by curing of the matrix. The copolymer employed was polystyrene- block -poly(methyl methacrylate) (PS- b -PMMA). The thermoset system, formed by a diglycidyl ether of bisphenol A-type epoxy resin and diaminodiphenylmethane hardener, was chosen to ensure the miscibility of most of the PMMA block until matrix gelation. Transparent materials with microphase-separated domains were obtained for copolymer contents lower than 40 wt%. In systems containing 20 and 30 wt% block copolymer, the PS block formed spherical micelles or worm-like structures before curing, which were stabilized through curing by the more compatible PMMA block phase. Nanostructured thermoset systems were successfully synthesized for self-assembled amphiphilic block copolymer,epoxy/amine mixtures for copolymer contents lower than 40 wt%. Copyright © 2009 Society of Chemical Industry [source]

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

MACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 4 2003
Michael Buback
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. Cloud-point pressure vs temperature curves for several E/poly(E- co -methacrylic acid) systems. The subscripts denote copolymer content in mol-%. A cloud-point pressure curve for E/polyethylene (PE) is included for comparison. [source]