Effect of ionic monomer concentration on latex and film properties for surfactant-free high solids content polymer dispersions

Bilgin, Sevilay; Asúa, José M.

doi:10.1016/j.eurpolymj.2017.06.029

Cited by 28 publications

(31 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A typical acrylic formulation, 50/50 MMA/BA was used, and two different functional monomers were chosen to give the ionic character to the latexes. NaSS ( Figure 1 a) was used as the anionic functional monomer, which was incorporated onto MMA/BA polymer particles following the synthesis procedures reported by Bilgin et al [ 37 ]. DMAEMA was selected as cationic monomer ( Figure 1 b) due to its pH dependency, which might help to control the amine protonated state.…”

Section: Methodsmentioning

confidence: 99%

“…Conductivity of water was followed until a value around 2 µS/cm was achieved, which corresponds to the deionized water conductivity. The main characteristic of NaSS specie is its relatively low pKa (around 1) [ 37 ], while pKa of poly(DMAEMA) is around 7.5 [ 44 ]. This means that when the pH is below 7.5 all the ionic species are in their cationic and anionic state favoring the formation of the ionic network between oppositely charged polymer particles, whereas when the pH is higher than 7.5, the DMAEMA molecules are in their molecular form avoiding the interaction between the oppositely charged ionic groups ( Figure 2 ).…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Ionic Inter-Particle Complexation Effect on the Performance of Waterborne Coatings

2021

Self Cite

View full text Add to dashboard Cite

The performance of waterborne (meth)acrylic coatings is critically affected by the film formation process, in which the individual polymer particles must join to form a continuous film. Consequently, the waterborne polymers present lower performance than their solvent-borne counter-polymers. To decrease this effect, in this work, ionic complexation between oppositely charged polymer particles was introduced and its effect on the performance of waterborne polymer films was studied. The (meth)acrylic particles were charged by the addition of a small amount of ionic monomers, such as sodium styrene sulfonate and 2-(dimethylamino)ethyl methacrylate. Density functional theory calculations showed that the interaction between the selected main charges of the respective functional monomers (sulfonate–amine) is favored against the interactions with their counter ions (sulfonate–Na and amine–H). To induce ionic complexation, the oppositely charged latexes were blended, either based on the same number of charges or the same number of particles. The performance of the ionic complexed coatings was determined by means of tensile tests and water uptake measurements. The ionic complexed films were compared with reference films obtained at pH at which the cationic charges were in neutral form. The mechanical resistance was raised slightly by ionic bonding between particles, producing much more flexible films, whereas the water penetration within the polymeric films was considerably hindered. By exploring the process of polymer chains interdiffusion using Fluorescence Resonance Energy Transfer (FRET) analysis, it was found that the ionic complexation was established between the particles, which reduced significantly the interdiffusion process of polymer chains. The presented ionic complexes of sulfonate–amine functionalized particles open a promising approach for reinforcing waterborne coatings.

show abstract

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Ionic Inter-Particle Complexation Effect on the Performance of Waterborne Coatings

2021

Self Cite

View full text Add to dashboard Cite

show abstract

“…[31][32][33] In films containing surfactants, water uptake does not reach a plateau and water reservoirs continuously swell. 34 Although the use of PISA solves the problem of surfactant mobility and aggregation through self-stabilized particles, the amount of hydrophilic species used in previous work (> 5 wt.%) is still too high to ensure good water barrier properties. Recent studies have been able to reduce this figure to below 3 wt.% while keeping particles stable using poly(acrylic acid) (PAA), 30,35 poly(methacrylic acid) (PMAA), 36,23 or poly(sodium 4-styrenesulfonate) (PSSNa).…”

Section: Theymentioning

confidence: 99%

Enhanced Water Barrier Properties of Surfactant-Free Polymer Films Obtained by MacroRAFT-Mediated Emulsion Polymerization

Martín-Fabiani

Haye

Schulz

et al. 2018

ACS Appl. Mater. Interfaces

View full text Add to dashboard Cite

The presence of low-molar-mass surfactants in latex films results in detrimental effects on their water permeability, gloss, and adhesion. For applications such as coatings, there is a need to develop formulations that do not contain surfactants and have better water barrier properties. Having previously reported the synthesis of surfactant-free latex particles in water using low amounts (<2 wt %) of chains synthesized by controlled radical polymerization (Lesage de la Haye et al. Macromolecules 2017, 50, 9315-9328), here we study the water barrier properties of films made from these particles and their application in anticorrosion coatings. When films cast from aqueous dispersions of acrylate copolymer particles stabilized with poly(sodium 4-styrenesulfonate) (PSSNa) were immersed in water for 3 days, they sorbed only 4 wt % water. This uptake is only slightly higher than the value predicted for the pure copolymer, indicating that the negative effects of any particle boundaries and hydrophilic-stabilizing molecules are minimal. This sorption of liquid water is 5 times lower than what is found in films cast from particles stabilized with the same proportion of poly(methacrylic acid) (PMAA), which is more hydrophilic than PSSNa. In water vapor with 90% relative humidity, the PSSNa-based film had an equilibrium sorption of only 4 wt %. A small increase in the PMAA content has a strong and negative impact on the barrier properties. Nuclear magnetic resonance relaxometry on polymer films after immersion in water shows that water clusters have the smallest size in the films containing PSSNa. Furthermore, these films retain their optical clarity during immersion in liquid water for up to 90 min, whereas all other compositions quickly develop opacity ("water whitening") as a result of light scattering from sorbed water. This implies a remarkably complete coalescence and a very small density of defects, which yields properties matching those of some solvent-borne films. The latex stabilized with PSSNa is implemented as the binder in a paint formulation for application as an anticorrosive barrier coating on steel substrates and evaluated in accelerated weathering and corrosion tests. Our results demonstrate the potential of self-stabilized latex particles for the development of different applications, such as waterborne protective coatings and pressure-sensitive adhesives.

show abstract

“…The design of surfactant-free latexes, performing as well as their surfactant-containing analogues, has therefore been a target for both academia and industry for more than twenty years. [5][6][7][8][9][10][11] In the specific field of emulsion polymerization in water, different strategies have been employed, most of them relying on the use of hydrophilic (macro)molecules able to participate in one of the key steps (initiation, propagation, termination) of the free radical polymerization process. The resulting species are trapped at the surface of the particles ensuring the stability via their hydrophilic moiety.…”

Section: Introductionmentioning

confidence: 99%

Hydrophilic MacroRAFT-Mediated Emulsion Polymerization: Synthesis of Latexes for Cross-Linked and Surfactant-Free Films

et al. 2017

View full text Add to dashboard Cite

A major drawback of conventional emulsion polymers arises from the presence of migrating low molecular weight surfactants that contribute to poor water barrier properties and low adhesion to substrates. In this paper, we demonstrate how living polymer chains obtained by reversible addition-fragmentation chain transfer (RAFT) can be used as an efficient stabilizer in emulsion polymerization, leading to the production of surfactant-free latexes, which then form crosslinked films with beneficial properties. Hydrophilic poly(methacrylic acid) (PMAA) chains obtained by RAFT performed in water are used to mediate emulsion polymerization and produce film-forming latex particles from mixtures of methyl methacrylate, n-butyl acrylate and styrene. Stable dispersions of particles with sizes between 100 and 200 nm are obtained, with very low amounts of coagulum (< 0.5 wt.%). The particles are stabilized by the PMAA segment of amphiphilic block copolymers formed during the polymerization. Remarkably, low amounts of PMAA chains (from 1.5 wt.% down to 0.75 wt.%) are enough to ensure particle stabilization. Only traces of residual PMAA macroRAFT agents are detected in the final latexes, showing that most of them are successfully chain extended and anchored on the particle surface. The Tg of the final material is adjusted by the composition of the hydrophobic monomer mixture so that film formation occurs at room temperature. Conventional crosslinking strategies using additional hydrophobic comonomers, such as 1,3-butanediol diacrylate (BuDA), diacetone acrylamide (DAAm), and (2acetoacetoxy)ethyl methacrylate, are successfully applied to these formulations as attested by gel fractions of 100%. When particles are internally crosslinked with BuDA, chain interdiffusion between particles is restricted, and a weak and brittle film is formed. In contrast, when DAAm undergoes crosslinking during film formation, full coalescence is achieved along with the creation of a crosslinked network. The resulting film has a higher Young's modulus and tensile strength as a result of crosslinking. This synthetic strategy advantageously yields a surfactant-free latex that can be formed into a film at room temperature with mechanical properties that can be tuned via the crosslinking density.

show abstract

Effect of ionic monomer concentration on latex and film properties for surfactant-free high solids content polymer dispersions

Cited by 28 publications

References 39 publications

Ionic Inter-Particle Complexation Effect on the Performance of Waterborne Coatings

Ionic Inter-Particle Complexation Effect on the Performance of Waterborne Coatings

Enhanced Water Barrier Properties of Surfactant-Free Polymer Films Obtained by MacroRAFT-Mediated Emulsion Polymerization

Hydrophilic MacroRAFT-Mediated Emulsion Polymerization: Synthesis of Latexes for Cross-Linked and Surfactant-Free Films

Contact Info

Product

Resources

About