Versatile Monomer Platform for Plant Oil-Based Latex Coatings

Abstract

Today coatings made from renewable biobased resources are still being over performed by coatings made from petroleum-based sources in the way they act mechanically, thus leaving them less useful from the industrial standpoint. Such properties of films/coatings as toughness or rigidness are accessible for control through regulating their cross-link density. As the curing process continues, the double bonds that do not get polymerized are capable of reforming to link the alkyl groups of monomers together, thus varying the cross-link density of the material. Use of plant-oil-based monomers in this case can be advantageous because the amount of unsaturation of the fatty acid chains in those monomers is generally much higher than that of their petro-based counterparts and can be regulated. Using the developed in our group one-step method of plant oil direct transesterification, a library of acrylic monomers has been recently synthesized [1-4]. Using emulsion and miniemulsion polymerization latexes from new monomers based on plant oils (soybean, linseed, canola, sunflower, high oleic soybean, olive, hydrogenated soybean oil) (POBMs) with remarkably different amount of unsaturation (compositions of fatty acids in oil triglycerides) have been developed. Presence of plant oil-based fragments impacts thermomechanical properties of latex films by decreasing glass transition temperature (thus, providing plasticizing effect) of latex copolymers. The thermomechanical properties of resulting latex nanoparticles depend considerably on the amount of incorporate oil-derived fragments. Biobased ingredient makes latex copolymers more flexible, improves material film forming properties, provides some flexibility and toughness, as compared to the normally rigid polystyrene and poly(methyl methacrylate). In addition, plant oil-based fragments enhance hydrophobicity of the resulting latex films and can be considered as additives to reduce water sensitivity of the polymer. At this point, stable latexes containing up to 70 wt% of biobased content can be synthesized using the miniemulsion process of copolymerization of POBMs with different vinyl counterparts. Their unsaturation amount can be utilized as a criterion in studying the resulting latex properties, including the effect of variation in monomer feed unsaturation on the crosslink density of latex films and, consequently, on polymer thermal and mechanical properties. It is observed that in oxidatively cured latex films, the crosslink density depends linearly on reaction feed unsaturation. Based on that, the latex network thermomechanical properties can be adjusted by simply combining various plant oil-based monomers at certain ratios ("given" unsaturations) in the reaction feed.

Synergistic Effects of Cardanol- and High Oleic Soybean Oil Vinyl Monomers in Miniemulsion Polymers

“…This indicates that fatty acid double bonds are available for post-polymerization reactions, particularly for cross-linking of latex films and polymer network formation. These findings are in good agreement with our previous results [15][16][17] . Glass transition temperature (T g ) is one of the most important thermophysical properties of amorphous polymers, which gives an indication of their suitability for specific applications.…”

“…Successful syntheses of CBM and HOSBM have been reported in our recent publications along with both monomers' feasibility in free radical (co)polymerization, including emulsion and miniemulsion processes [15][16][17][18][19][20] . For the previously reported plant oil-based monomers, the rate of polymerization depends noticeably on their chemical structure and is higher for the monomers derived from lower quantities of unsaturated plant oil.…”

“…The incorporation of plant oil-based monomers in copolymerization with conventional petroleum-based counterparts provides several benefits to the final copolymers such as plasticizing properties, the elimination of coalescence aids in latex applications, reducing minimum film formation temperature and film-forming properties. The ability of fatty acid fragments to undergo autoxidation (due to presence of allylic double bonds in resulting macromolecules) after latex application and yield the crosslinked polymer networks can balance the mechanical properties of final latex products, which can be beneficial as well 13,17,20 .…”

“…Recently, we reported on emulsion polymers with biobased content of up to 60 % wt. synthesized in miniemulsion from new vinyl monomers derived from a variety of plant oils using transesterification reaction [15][16][17] .…”

Incorporation of Cellulose Nanocrystals into a Cottonseed Oil-Based Network Polymer: Effect on Mechanical Properties

“…58,59 In addition to improving or altering the mechanical properties of polymers, it has been demonstrated that CNCs also improve the biodegradability of the polymers into which they are incorporated. 60−62 Although there are reports on CNCs incorporated during polymerizations of some other plant oils, such as with SBO (epoxidized and mixed with polylactide, 40 high oleic, 63 acrylated, 64 and modified via thiol− ene click chemistry 45 ), foamed polyurethanes from castor oil, 50 or sunflower oil, 65 a CNC-incorporated cotton oil-based polymers with evidence of good CNCs dispersity has not been reported widely in the literature.…”