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Aqueous polymer dispersions based on carboxylated polymers.

Record Type:	Language materials, manuscript : Monograph/item
Title/Author:	Aqueous polymer dispersions based on carboxylated polymers./
Author:	McHugh, Nicholas.
Description:	1 online resource (181 pages)
Notes:	Source: Dissertations Abstracts International, Volume: 79-11, Section: C.
Contained By:	Dissertations Abstracts International79-11C.
Subject:	Polymer chemistry. -
Online resource:	click for full text (PQDT)
ISBN:	9780355918397

Aqueous polymer dispersions based on carboxylated polymers.
McHugh, Nicholas.

Aqueous polymer dispersions based on carboxylated polymers. - 1 online resource (181 pages)

Source: Dissertations Abstracts International, Volume: 79-11, Section: C.

Thesis (Ph.D.)--The University of Manchester (United Kingdom), 2000.

Includes bibliographical references

A new route was investigated for forming polymer dispersions from carboxylated polymers. A series of acrylate based monomers were copolymerised with acrylic acid (AA) by a free radical polymerisation. After selective precipitation, the prepared copolymers were dissolved in an organic solvent. The acrylic acid groups were then neutralised using an aqueous solution of base. The polymer solution was emulsified in water. In a last step, the organic solvent was removed from the dispersion by distillation. The influence of various parameters, including the acrylic acid concentration of the polymer, on its emulsification behaviour was investigated. Copolymer blends were prepared using a mixture of a hydrophobic copolymer with a more hydrophilic ionisable copolymer and dispersing the ionised copolymer blend in water and removing the organic solvent as discussed. Techniques employed to characterise the prepared copolymers included gel permeation chromatography (GPC) and both 13C and 1H nuclear magnetic resonance (NMR). Dynamic light scattering (DLS), rheology, minimum film forming temperature (MFFT) and surface tension were used to investigate the properties of the polymer dispersions. Dispersions with low AA (<10% w/w) were found to have a broad particle size distribution, with at least two essentially separate populations of particle sizes. The particles of smaller size were attributed to molecular clusters. The larger particles were attributed to aggregated micellar type structures, formed by chain inter association between hydrophobic chain segments. At higher AA concentrations (10-20% w/w) solution polymer was evident. The structure of the dispersed particles, was considered to be composed of an interior of hydrophobic chain segments, with the ionic groups situated towards the particle surface, thus providing colloidal stability through electric double layers. It was shown from rheological studies that the particles behaved more like hard spheres at low AA concentrations (20% w/w). By blending chains with different hydrophobicity, it was possible to achieve aqueous dispersions with polymer solids content of greater than 40 % w/w, compared to less than 35 % w/w for non-blended systems. Experiments were carried out to investigate the effect of shear rate and solution conditions on the dispersion process. These factors were found to be particularly important for systems of low acrylic acid content (<7 % w/w).

Electronic reproduction.
Ann Arbor, Mich. :
ProQuest,
2024

Mode of access: World Wide Web

ISBN: 9780355918397Subjects--Topical Terms:

1182163
Polymer chemistry.
Subjects--Index Terms:

CopolymersIndex Terms--Genre/Form:

554714
Electronic books.

Aqueous polymer dispersions based on carboxylated polymers.
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520 $a A new route was investigated for forming polymer dispersions from carboxylated polymers. A series of acrylate based monomers were copolymerised with acrylic acid (AA) by a free radical polymerisation. After selective precipitation, the prepared copolymers were dissolved in an organic solvent. The acrylic acid groups were then neutralised using an aqueous solution of base. The polymer solution was emulsified in water. In a last step, the organic solvent was removed from the dispersion by distillation. The influence of various parameters, including the acrylic acid concentration of the polymer, on its emulsification behaviour was investigated. Copolymer blends were prepared using a mixture of a hydrophobic copolymer with a more hydrophilic ionisable copolymer and dispersing the ionised copolymer blend in water and removing the organic solvent as discussed. Techniques employed to characterise the prepared copolymers included gel permeation chromatography (GPC) and both 13C and 1H nuclear magnetic resonance (NMR). Dynamic light scattering (DLS), rheology, minimum film forming temperature (MFFT) and surface tension were used to investigate the properties of the polymer dispersions. Dispersions with low AA (<10% w/w) were found to have a broad particle size distribution, with at least two essentially separate populations of particle sizes. The particles of smaller size were attributed to molecular clusters. The larger particles were attributed to aggregated micellar type structures, formed by chain inter association between hydrophobic chain segments. At higher AA concentrations (10-20% w/w) solution polymer was evident. The structure of the dispersed particles, was considered to be composed of an interior of hydrophobic chain segments, with the ionic groups situated towards the particle surface, thus providing colloidal stability through electric double layers. It was shown from rheological studies that the particles behaved more like hard spheres at low AA concentrations (20% w/w). By blending chains with different hydrophobicity, it was possible to achieve aqueous dispersions with polymer solids content of greater than 40 % w/w, compared to less than 35 % w/w for non-blended systems. Experiments were carried out to investigate the effect of shear rate and solution conditions on the dispersion process. These factors were found to be particularly important for systems of low acrylic acid content (<7 % w/w).
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