Crosslinking versus interdiffusion in two pot one pack acetoacetoxy-amine based binder system

A two-pot-one-pack waterborne crosslinking system is studied by following the crosslinking and interdiffusion between the polymer particles functionalized with acetoacetoxy on one hand and with polyethyleneimine on the other. FTIR spectroscopy and rheological measurements are used to follow the evolution of crosslinking, while pyrene excimer fluorescence is used to analyse the interdiffusion of polymer chains between neighbouring particles during film formation. Both crosslinking and interdiffusion proceed slowly at room temperature. However, crosslinking is complete after 24 h at 60 °C, while interdiffusion does not proceed further at this temperature. TEM images confirm the presence of a honeycomb structure in the final film, produced by the crosslinked moieties between polymer particles that can act as a barrier for interdiffusion of polymer chains between particles. Nevertheless, strong films are produced even in the absence of significant interdiffusion, due to the crosslinks between particles.We acknowledge the financial support provided by the Industrial Liaison Program of POLYMAT

Challenges to incorporate high contents of bio-based isobornyl methacrylate (IBOMA) into waterborne coatings

Emulsion polymerization of (meth)acrylic bio-based monomers is a promising method to obtain waterborne coatings with reduced carbon footprint. However, the high hydrophobicity of some bio-based monomers can hinder the straightforward incorporation of such monomers in waterborne dispersions. In this work, we explore the copolymerization of bio-based isobornyl methacrylate (IBOMA) with 2-octyl acrylate (2-OA) to produce latexes with >70 % bio-content suitable for coating applications. First, the homopolymerization of IBOMA is studied to gather more information on the emulsion polymerization of the monomer producing high Tg polymer with different surfactants. It is found that the batch emulsion homopolymerization of IBOMA is challenging due to coagulation during the polymerization, likely as a result of mass transport limitations due to the high hy-drophobicity of IBOMA. Interestingly, stable dispersions are achieved when 5 % of the IBOMA is substituted by methyl methacrylate. The stability of the IBOMA/2-OA copolymer system is found to be dependent on both the IBOMA concentration in the copolymer and the solids content of the latex. Thus, we provide a stability map for IBOMA/2-OA copolymers with different compositions and solids contents showing the areas where stable and not-stable dispersions are obtained.Financial support from Eusko Jaurlaritza (GV-IT-999-16), MICINN (PDC2021-121416-I00) and MINECO (CTQ2017-87841-R) is gratefully acknowledged

Taking Advantage of Phosphate Functionalized Waterborne Acrylic Binders to Get Rid of Inhibitors in Direct-to-Metal Paints

In this paper, two phosphate functionalized acrylic binders are formulated to yield direct-to-metal paints without using corrosion inhibitors. The difference between both binders is the addition of polystearylacrylate crystalline nanodomains in one of them, and an amorphous methyl methacylate-co-butyl acrylate copolymer in the other. The water sensitivity, mechanical stability, adhesion, and the performance of the paints against corrosion (high humidity resistance, accelerated weathering, and salt-spray tests) are assessed and compared with a DTM paint formulated from a commercial binder. The performance of both phosphate functionalized paints formulated without corrosion inhibitors in high humidity and weathering tests is superior to the commercial DTM paint formulated without corrosion inhibitors and similar to the DTM paint formulated with them. Furthermore, the paint based on the amorphous copolymer binder provides significantly good performance in the salt spray test (even superior to that of the DTM paint formulated with corrosion inhibitors).This research was funded by the Basque Government (IT-999-16) and the Spanish Government (MINECO CTQ-2017-87841-R and MICINN PDC2021-121416-I00)

Incorporation of a Coumarate Based Corrosion Inhibitor in Waterborne Polymeric Binders for Corrosion Protection Applications

The incorporation of organic corrosion inhibitors into waterborne coatings is optimized in this work. Herein, p-coumaric acid (4-hydroxycinnamic acid) is modified by a butyl radical and its effectiveness as an anticorrosive free inhibitor in solution is confirmed by potentiodynamic polarization (PP). The molecule is then successfully incorporated into waterborne polymeric binders by employing different polymerization techniques in dispersed media. Whenever possible, the inhibitor is also blended into the bare latexes to compare the effect of the incorporating method. The anticorrosion performance of the obtained coatings is tested and compared by electrochemical analysis. Promising results are obtained for the coatings produced by semibatch emulsion polymerization even at the low concentration of 1.5 mg of inhibitor g(-1) latex. The intact control coating without inhibitor shows an impedance of up to 10(6) omega and a phase angle of 72 degrees after 1 h of immersion in the corrosive medium, meanwhile the coating with inhibitor shows higher values, 10(6.7) omega and 80 degrees. Active corrosion inhibition is observed in the coating with inhibitor in which a defect has been done, as the impedances drop to 10(3.9) omega after 24 h of immersion in the saline solution while in the control scratched coating it drops to 10(3.6) omega.The authors would like to thank for the financial support received from the Basque Government (IT-999-16), and the Spanish Government (MINECO CTQ -2017-87841-R and MICINN PDC2021-121416-I00)

Polymer Colloids: Current Challenges, Emerging Applications, and New Developments

Polymer colloids are complex materials that have the potential to be used in a vast array of applications. One of the main reasons for their continued growth in commercial use is the water-based emulsion polymerization process through which they are generally synthesized. This technique is not only highly efficient from an industrial point of view but also extremely versatile and permits the large-scale production of colloidal particles with controllable properties. In this perspective, we seek to highlight the central challenges in the synthesis and use of polymer colloids, with respect to both existing and emerging applications. We first address the challenges in the current production and application of polymer colloids, with a particular focus on the transition toward sustainable feedstocks and reduced environmental impact in their primary commercial applications. Later, we highlight the features that allow novel polymer colloids to be designed and applied in emerging application areas. Finally, we present recent approaches that have used the unique colloidal nature in unconventional processing techniques.The authors would like to thank the financial support received from the Basque Government (IT-1525-22), from the Spanish Government (MINECO PID2021-123146OB-I00, MICINN PDC2021-121416-I00, and PID-117628RJ-I00)). This work was partially funded by the Michelin North America, Inc. and currently funded by the National Science Foundation (NSF) GOALI grant in partnership with Michelin (CMMI – 1762712). In addition, the Basque Government also financially supported this work (ELKARTEK/bmG22/ref: KK-2022/00008). The Basque Health Department (projects 2022333035, 2022333039, and 2022333031) and the University of the Basque Country (projects COLLAB22/05 and GIU21/033) are also acknowledged for their financial support

Design of Waterborne Asymmetric Block Copolymers as Thermoresponsive Materials

AB diblock waterborne copolymers made of styrene (St) and 2-ethylhexyl acrylate (2EHA) were synthesized by means of two-step reversible addition fragmentation chain transfer (RAFT) (mini)emulsion polymerization. Monofunctional asymmetric RAFT agent was used to initiate the polymerization. The hard polystyrene “A” block was synthesized via miniemulsion polymerization followed by 2EHA pre-emulsion feeding to form the soft “B” block. Polymerization kinetics and the evolution of the molecular weight distribution were followed during synthesis of both initial and final block copolymers. DSC measurements of the block copolymers revealed the existence of two glass transition temperatures (Tgs) and thus the occurrence of two-phase systems. Microscopic techniques (atomic force microscopy (AFM) and transmission electron microscopy (TEM)) were used to study the phase separation within the particles in the latex form, after film formation at room temperature cast directly from the latex and after different post-treatments well above the Tg of the hard-polystyrene domains, when complete particle coalescence had occurred. The morphological differences observed after different annealing temperatures were correlated with the mechanical properties analyzed by DMTA measurements. Finally, the differences found in the mechanical properties of the block copolymers annealed at different temperatures were correlated to their heat seal application results.The European Union’s Horizon 2020 research and innovation programme is acknowledged for providing the financial support through the project TRACKWAY-ITN 642514 under the Marie Sklodowska-Curie grant agreement