Understanding particle formation in surfactant-free waterborne coatings prepared by emulsification of pre-formed polymers

González‐Álvarez, María José; Paternoga, Jan; Breul, Katharina; Cho, Hyungjun; Roshandel, Mahtab Z.; Soleimani, Mohsen; Winnik, Mitchell A.

doi:10.1039/c7py00387k

Cited by 14 publications

(25 citation statements)

References 30 publications

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“…Polymer latex derived from emulsion polymerization is widely used in many industries such as binders, textile finishing, paper coating, architectural and pharmaceutical industries, because it can largely reduce the volatile organic compound (VOC) emission [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 ]. In particular, technical/smart textiles can be facilely developed by casting functional polymer latex into conventional textiles [ 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 ].…”

Section: Introductionmentioning

confidence: 99%

Porous Film Coating Enabled by Polyvinyl Pyrrolidone (PVP) for Enhanced Air Permeability of Fabrics: The Effect of PVP Molecule Weight and Dosage

Jiang

Shen

et al. 2020

Polymers

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This study developed a versatile and facile method for creating pores and tuning the porous structure in the polymer latex films by selectively etching the added functional polyvinyl pyrrolidone (PVP) molecules. The pore formed in the latex films had a similar morphology to that of PVP aggregation before etching. This observation promotes us to regulate the pore morphology that determines the film’s property, such as air permeability through varying the PVP molecule weight and dosage. To this end, the effects of PVP molecule weight and dosage on the pore formation were systematically studied. The results showed that the average pore size of porous film decreased from >10 μm to sub-micron (about 0.4 μm) as the molecular weight or the dosage of PVP increased. This was ascribed to the strong adsorption affinity of PVP molecule onto the latex particle surface, which further hindered the diffusion and self-assembly of PVP molecule. In addition, this interaction became much stronger when the higher molecule weight of PVP or the higher dosage of PVP was employed, leading to the decreased size of PVP aggregation, as well as the formed pores in the latex films. Furthermore, the addition of PVP had little effect on the color of coated fabric based on the results of CIE L*a*b* measurement. The proposed facile method can be used to improve the air permeability of coated fabrics.

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Section: Introductionmentioning

confidence: 99%

Porous Film Coating Enabled by Polyvinyl Pyrrolidone (PVP) for Enhanced Air Permeability of Fabrics: The Effect of PVP Molecule Weight and Dosage

Jiang

Shen

et al. 2020

Polymers

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“…Phenanthrylmethyl methacrylate (PhenMA, Toronto Research Chemicals Inc.), 4-(dimethylamino)benzophenone (Nben, Aldrich), and 4-(dimethylamino)-2-methacryloxy-5-methylbenzophenone (NbenMA, Eastern Sources Inc.) were used as received. Phen-HCl and Nben-NH 3 Cl were synthesized as reported previously . We labeled the hmPIC with Phen as the donor dye or Nben as the acceptor dye as described in a previous report .…”

Section: Methodsmentioning

confidence: 99%

Film Formation of Waterborne 2K Polyurethanes: Effect of Polyols Containing Different Carboxylic Acid Content

et al. 2021

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While the interaction of NCO with carboxylic acids has been documented, a comprehensive knowledge of its effect on the film formation in a two-component waterborne polyurethane (2K-WPU) system is lacking. In this work, we synthesized a series of carboxylfunctional acrylic polyols (M n ≈ 5000 g/mol, Đ ≈ 2.7, T g ≈ 15 °C) of uniform diameter (120 nm) with varying amounts of methacrylic acid introduced into the latex. For 2K-WPU dispersions with a molar NCO/ OH ratio of 1.3:1, we monitored particle size by dynamic light scattering and NCO consumption by FTIR. In the dispersion, we found that the particle size remained nearly constant, and the NCO was almost completely consumed after 2 days. Incorporating COOH in the polyol latex accelerated the consumption of NCO. We synthesized polyol samples labeled with donor and acceptor dyes for fluorescence resonance energy transfer (FRET) studies of polymer diffusion and molecular mixing. In films formed from the polyol latex in the absence of hmPIC, the COOH content of the polyols had no significant effect on the rate or extent of polymer diffusion. In contrast, in films formed from the 2K-WPU dispersions with a stoichiometric NCO/OH ratio (1.3:1), the extent of ET rapidly increased to the maximum value, showing that the full extent of molecular mixing of the two components can be accomplished in films. Thus, the hmPIC acts as a reactive plasticizer. In parallel experiments in which the hmPIC was labeled with the donor dye, we found evidence for partial mixing of the PIC and polyol in the dispersed state. We also showed that the rate of mixing of the hmPIC and the polyol in the films cast from these dispersions was accelerated by −COOH groups in the polyol.

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“…4-(Dimethylamino)benzophenone (Nben, Aldrich) and 4-dimethylamino-2-methacryloxy-5-methylbenzophenone (NbenMA, Eastern Sources Inc.) were used as received. 9-Aminomethylphenanthrene (Phen, donor dye) hydrochloride was synthesized as reported previously . 4′-Dimethylamino-2-aminoethyl-5-methylbenzophenone hydrochloride (Nben-NH 3 Cl, acceptor dye) was obtained by etherification of 4′-dimethylamino-2-hydroxyl-5-methylbenzophenone as described in the Supporting Information (SI).…”

Section: Methodsmentioning

confidence: 99%

“…Donor fluorescence decay curves were measured at room temperature on the newly formed films and on films subjected to various annealing protocols. Individual donor (Phen-) fluorescence intensity decay profiles [ I D ( t )] were fitted to a stretched exponential function (eq S1) with the unquenched donor lifetime set to τ D = 44 ns as described in ref . The fitted curve was then integrated to calculate the area under the decay curve.…”

Section: Methodsmentioning

confidence: 99%

Monitoring Polymer Diffusion in a Waterborne 2K Polyurethane Formulation Based on an Acrylic Polyol Latex

et al. 2020

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We report experiments based upon fluorescence resonance energy transfer (FRET) measurements designed to examine mixing at the molecular level of the components of a waterborne 2K polyurethane (WB2KPU) formulation. The system consists of an acrylic polyol latex (M n = 4200 g/mol, D̵ = 2, T g ≈ 15 °C) with a uniform hydrodynamic diameter (d h ) ≈ 120 nm plus a water-dispersible polyisocyanate (hmPIC, Basonat HW1000 from BASF). We prepared components labeled with phenanthrene (Phen) as the donor dye or with a dimethylaminobenzophenone (Nben) as the acceptor dye. Dynamic light scattering was used to monitor the size and size distribution of the components in the dispersed phase in solution. This signal was dominated by the polyol nanoparticles, which were much larger than the tiny droplets formed by the hmPIC in water. Experiments were carried out at a mole ratio of NCO/polyol-OH of 1.3. We found that the particle size and narrow size distribution remained unchanged up to 22 h after mixing the polyol with the PIC. FRET experiments were carried out on samples in the dispersed state as well as on films formed from these dispersions. Films formed from a 1:1 mixture of (polyol-Phen + polyol-Nben) showed relatively little energy transfer (Φ ET = 0.19) even after several hours aging at ambient temperature, indicating that little polymer diffusion occurred in these low-molecular-weight latex films. In contrast, films formed from mixtures of (polyol-Phen + polyol-Nben + hmPIC) showed more extensive energy transfer (ET) (Φ ET = 0.51), indicating essentially complete mixing at the molecular level of the polymer molecules in the presence of hmPIC. The key conclusion is that hmPIC is a reactive plasticizer that promotes diffusion in this system on a much faster scale than the cross-linking reaction. This result is confirmed by experiments that examined mixtures of (hmPIC-Phen + polyol-Nben), which also showed essentially molecular scale mixing between these two different components. In this later system, aging at room temperature led to a small decrease in Φ ET over time that was more prominent for films aged at high humidity (75%) than at lower humidity (45%). This result suggests that hydrolysis of NCO groups in the film, leading to polyurea formation, promotes local phase separation accompanied by a net increase in the average separation of Phen and Nben groups in the film.

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Understanding particle formation in surfactant-free waterborne coatings prepared by emulsification of pre-formed polymers

Abstract: Concern for the environment has been driving major changes in the coatings industry.

Cited by 14 publications

References 30 publications

Porous Film Coating Enabled by Polyvinyl Pyrrolidone (PVP) for Enhanced Air Permeability of Fabrics: The Effect of PVP Molecule Weight and Dosage

Porous Film Coating Enabled by Polyvinyl Pyrrolidone (PVP) for Enhanced Air Permeability of Fabrics: The Effect of PVP Molecule Weight and Dosage

Film Formation of Waterborne 2K Polyurethanes: Effect of Polyols Containing Different Carboxylic Acid Content

Monitoring Polymer Diffusion in a Waterborne 2K Polyurethane Formulation Based on an Acrylic Polyol Latex

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