Rheology of waterborne coatings

Hester, Roger D.; Squire, D. R.

doi:10.1007/bf02696097

Cited by 61 publications

(22 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…39 In addition, amphiphilic polymers are known to increase the viscosity of aqueous solutions; they are, therefore, referred to as associative thickeners. 40,41 This behavior can be explained by the transient network theory. 42 Water-soluble polymers with ''sticky'' hydrophobic end-groups associate in water to form physically stabilized networks in which the cross-links are weak enough to constantly break and re-combine.…”

Section: Viscosity Of Macromonomer Solutionsmentioning

confidence: 96%

Design of hydrogels for delayed antibody release utilizing hydrophobic association and Diels–Alder chemistry in tandem

et al. 2016

View full text Add to dashboard Cite

Biodegradable hydrogels were prepared from furan-and maleimide-functionalized eight-armed poly-(ethylene glycol) with an average molecular mass of 40 000 Da (8armPEG40k-furan and 8armPEG40k-maleimide) using the Diels-Alder (DA) reaction as a cross-linking mechanism. Hydrophobic 6-aminohexanoic acid (C 6 ) and 12-aminododecanoic acid (C 12 ) spacers were introduced between the polymer backbone and the functional end-groups; the influence on the gel properties was studied. Modification with C 6 and C 12 spacers induced hydrophobic interactions between the macromonomers leading to association and increased viscosity of the polymer solutions; both effects were influenced by the spacer length. In combination with DA cross-linking, hydrophobic derivatives of 8armPEG40k-furan and 8armPEG40k-maleimide led to hydrogels with improved properties. Upon introduction of C 12 spacers, gelation of 8armPEG40k hydrogels occurred twice as fast. Interestingly, no effect was observed when only one of the two components had been modified. Our experiments suggest that the association of macromonomers by hydrophobic interactions facilitates chemical cross-linking via DA chemistry. This hypothesis is supported by calculations of the network mesh size and the Young's modulus of compression, which showed an increased cross-linking density of hydrophobically modified hydrogels. As a consequence of the increased cross-linking density, the degradation stability of C 12 -modified hydrogels increased by a factor of 4.Moreover, hydrophobic modification improved the hydrolytic resistance of maleimides; this also contributes to gel stability. The in vitro release of bevacizumab, which served as a model antibody, could be delayed for almost 60 days using modification with C 12 . Similar trends were observed for C 6 -modified 8armPEG40k hydrogels; however, the effects were considerably weaker. In summary, utilizing hydrophobic association and chemical cross-linking in tandem is a promising approach to create biodegradable hydrogels for delayed antibody release.

show abstract

Section: Viscosity Of Macromonomer Solutionsmentioning

confidence: 96%

Design of hydrogels for delayed antibody release utilizing hydrophobic association and Diels–Alder chemistry in tandem

et al. 2016

View full text Add to dashboard Cite

show abstract

“…Nearly all show evidence of a surrounding pulsar wind nebulae (PWNe). Most notably, early Chandra observations of the Crab pulsar (Weisskopf et al 2000) revealed a complex emission structure, involving co-aligned toroidal arcs, axial jets, and wisps, similar to that seen from the optical Crab nebula (Hester 1998). Subsequent Chandra observations of the Vela pulsar resulted in the discovery of strikingly similar features, including the tori, jets, and wisps (Helfand et al 2001).…”

Section: Introductionmentioning

confidence: 91%

Correlation between the X-ray Spectra of Young Pulsars and their Wind Nebulae

Gotthelf

2003

Symp. - Int. Astron. Union

View full text Add to dashboard Cite

Abstract. A significant correlation is discovered between the X-ray spectra of young pulsars (PSRs) and that of their associated wind nebulae (PWNe). For a sample of nine bright Crab-like pulsar systems observed with the Chandra X-ray observatory, we report a linear relationship between the photon indices for the PWNe and those of the phase-averaged pulsar emission, wherer p w N = 0.72±0.13xrp s R+0.86±0.20. Furthermore, we find that the spectral slopes of younger, more energetic, pulsars tend to be steeper. These results confirm a consistent pulsar emission mechanism and provide important new observational constraints on the current theory of shock acceleration models for pulsar wind emission.

show abstract

“…However, to achieve the equivalent properties of solvent-borne paints, the addition of rheology modifiers and coalescing aids is required. 2 A common coalescing aid used in latex paints is 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate (TMPD-MIB), which softens latex particles, allowing them to fuse together to form a continuous film free from distinct physical boundaries. 3 Despite the prevalence of TMPD-MIB in latex paints, exposure of painters and building occupants to TMPD-MIB and associated health effects, if any, are still not well understood.…”

Section: Introductionmentioning

confidence: 99%

Fate of a coalescing aid after latex paint application

2009

View full text Add to dashboard Cite

Water-based coatings require coalescing aids to achieve properties equivalent to solvent-borne paints. A common coalescing aid in latex paints is 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate (TMPD-MIB). The relatively large quantity of TMPD-MIB used in latex paints has raised concerns regarding its emissions to both indoor and outdoor atmospheres. In this study, a one-dimensional dual (paint and material) layer diffusion model was developed to estimate emissions of TMPD-MIB from two latex paints applied to gypsum board. The paints contained different pigment volume concentrations (PVC) and different amounts of TMPD-MIB. Different modeling approaches were used depending on the PVC of the paint. The proposed model for paint drying and TMPD-MIB emissions was tested with data from previous chamber experiments. Experimental data were first used for purposes of parameter estimation, and the model was then compared against an independent experimental dataset. The diffusion coefficient of the paint layer was adjusted as a function of the water content remaining in the wet paint film. The effective diffusion coefficient of TMPD-MIB in the paint layer was found to be dependent on the PVC and water content of the paint. Nomenclature j A Rate of mass transfer per unit area (mg m À2 h À1 ) c A Concentration of TMPD-MIB in paint film or gypsum board (g m À3 ) z Space coordinate measured normal to the section (m) D AL1 Diffusion coefficient for TMPD-MIB in paint film (m 2 h À1 ) D AL2 Diffusion coefficient for TMPD-MIB in gypsum board (m 2 h À1 ) R A Kinetic retardation factor for transport in paint film or gypsum board c L1 Concentration of TMPD-MIB in layer 1 (paint) (mg m À3 ) c L2Concentration of TMPD-MIB in layer 2 (material) (mg m À3 ) D eff1Effective diffusion coefficient of TMPD-MIB in layer 1 (m 2 h À1 ) D eff2Effective diffusion coefficient of TMPD-MIB in layer 2 (m 2 h À1 ) R 1 Kinetic retardation factor for transport of TMPD-MIB in layer 1 R 2 Kinetic retardation factor for transport of TMPD-MIB in layer 2 k a TMPD-MIB mass transfer coefficient (m h À1 ) k c Water mass transfer coefficient (m h À1 ) aMaterial thickness (m) bLocation of the paint-air boundary (m) M T Initial mass of TMPD-MIB applied to gypsum board (mg) f T Fraction of TMPD-MIB present in the paint Dz 1 Distance between nodes in layer 1 (m) A Area over which the paint is applied (m 2 ) 291 DdVariation of the paint thickness (m) C w Saturation vapor density of the water (kg m À3 ) qDensity of water (kg m À3 ) RH Relative humidity (%) t evap Time for water to completely evaporate from the film (h)

show abstract

Rheology of waterborne coatings

Cited by 61 publications

References 1 publication

Design of hydrogels for delayed antibody release utilizing hydrophobic association and Diels–Alder chemistry in tandem

Design of hydrogels for delayed antibody release utilizing hydrophobic association and Diels–Alder chemistry in tandem

Correlation between the X-ray Spectra of Young Pulsars and their Wind Nebulae

Fate of a coalescing aid after latex paint application

Contact Info

Product

Resources

About