Versatile Platform for Controlling Properties of Plant Oil-Based Latex Polymer Networks

A series of latexes from acrylic monomers (made from olive, soybean, linseed, and hydrogenated soybean oils), significantly different in terms of fatty acid unsaturation, were synthesized using miniemulsion copolymerization with styrene. The number-average molecular weight and the glass transition temperature of the resulting copolymers with high levels of biobased content (up to approximately 60 wt %) depend essentially on the amount of unsaturation (the number of double bonds in triglyceride fatty acid fragments of plant oil-based monomers) in the reaction feed. When plant oil-based latex films are oxidatively cured, the linear dependence of the cross-link density on reaction feed unsaturation is observed. Dynamic mechanical and pendulum hardness measurements indicate that the properties of the resulting plant oil-based polymer network are mainly determined by cross-link density. On the basis of the linear dependence of the cross-link density on monomer feed unsaturation, it can be concluded that the latex network formation and thermomechanical properties can be adjusted by simply combining various plant oil-based monomers at certain ratios (“given” unsaturations) in the reaction feed. Assuming a broad variety of plant/vegetable oils available for new monomers synthesis, this can be considered as a promising platform for controlling properties of plant oil-based latex polymer networks

Synthesis and Free Radical Copolymerization of a Vinyl Monomer from Soybean Oil

A one-step method that converts soybean oil into (acryloylamino)­ethyl soyate, a new vinyl monomer of free radical polymerization, was developed. The synthesized monomer combines a vinyl double bond (acryloyl functional group) and nonconjugated (isolated) double bonds of fatty acids. The double bond of the acryloyl group is reactive in a free radical chain polymerization that yields linear macromolecules containing isolated double bonds in side chains. Monomer reactivity ratios (<i>r</i>₁, <i>r</i>₂) in copolymerization of the new soybean oil-based acrylic monomer (SBA) with styrene, methyl methacrylate, and vinyl acetate, as well as the <i>Q</i>–<i>e</i> parameters of the SBA, were determined. The obtained results indicate that copolymerization can be described with the classical Mayo–Lewis equation. In terms of polymerizability, the SBA can be classified as an acrylic monomer. The double bonds of the fatty acid chains remain mainly unaffected during the free radical polymerization. The remaining unsaturated fragments in the side chains make the resulting macromolecules capable of further oxidative cross-linking and the development of cross-linked polymer coatings

Solvent-Responsive Self-Assembly of Amphiphilic Invertible Polymers Determined with SANS

Amphiphilic invertible polymers (AIPs) are a new class of macromolecules that self-assemble into micellar structures and rapidly change structure in response to changes in solvent polarity. Using small-angle neutron scattering (SANS) data, we obtained a quantitative description of the invertible micellar assemblies (IMAs). The detailed composition and size of the assemblies (including the effect of temperature) were measured in aqueous and toluene polymer solutions. The results show that the invertible macromolecules self-assemble into cylindrical core–shell micellar structures. The composition of the IMAs in aqueous and toluene solutions was used to reveal the inversion mechanism by changing the polarity of the medium. Our experiments demonstrate that AIP unimers self-assemble into IMAs in aqueous solution, predominantly through interactions between the hydrophobic moieties of macromolecules. The hydrophobic effect (or solvophobic interaction) is the major driving force for self-assembly. When the polarity of the environment is changed from polar to nonpolar, poly­(ethylene glycol) (PEG) and aliphatic dicarboxylic acid fragments of AIP macromolecules tend to replace each other in the core and the shell of the IMAs. However, neither the interior nor the exterior of the IMAs consists of fragments of a single component of the macromolecule. In aqueous solution, with the temperature increasing from 15 to 35 °C, the IMAs’ mixed core from aliphatic dicarboxylic acid and PEG moieties and PEG-based shell change the structure. As a result of the progressive dehydration of the macromolecules, the hydration level (water content) in the micellar core decreases at 25 °C, followed by dehydrated PEG fragments entering the interior of the IMAs when the temperature increases to 35 °C

Soy-Based Surface Active Copolymers As a Safer Replacement for Low Molecular Weight Surfactants

Environmentally friendly soybean-based polymeric surfactants (SBPS) were synthesized using cationic polymerization of a vinyl ether monomer derived from soybean and tri­(ethylene glycol) ethyl vinyl ether. The ability of SBPS to form micelles that solubilize hydrophobic molecules has been shown. Micellar “capacity” (size of micellar interior) increased with increasing polymeric surfactant concentration and temperature. The obtained results provide evidence for potential use of SBPS as a safer replacement for low molecular weight surfactants in the solubilization of poorly soluble ingredients in cosmetics. The macromolecules developed can be used as both a surface active agent and an additive that enhances the surface activity of low molecular weight surfactants (for example, anionic sodium lauryl sulfate) in personal-care products

Free Radical Polymerization Behavior of the Vinyl Monomers from Plant Oil Triglycerides

A one-step method of plant oil direct transesterification was used to synthesize new vinyl monomers from sunflower (SFM), linseed (LSM), soybean (SBM), and olive (OVM) oils. The degree of unsaturation in plant oil fatty acids was used as a criterion to compare the free radical polymerization behavior of new monomers. The number-average molecular weight of plant oil-based homopolymers synthesized in toluene in the presence of AIBN at 75 °C varies at 11 000–25 000 and decreases as follows: poly­(OVM) > poly­(SFM) > poly­(SBM) > poly­(LSM), corresponding to increasing degree of unsaturation in the monomers. Rate of polymerization depends noticeably on the degree of unsaturation in monomers. Due to the allylic termination, chain propagation coexists with effective chain transfer during polymerization. The obtained values of <i>C</i>_M (ratio of chain transfer and propagation rate constants) depends on monomer structure as follows: <i>C</i>_M(LSM) > <i>C</i>_M(SBM) > <i>C</i>_M(SFM) > <i>C</i>_M(OVM). ¹H NMR spectroscopy shows that the fraction of the reacting allylic atoms does not vary significantly for the synthesized monomers (7–12%) and is determined entirely by plant oil degree of unsaturation. The glass transition temperature of homopolymers [<i>T</i>_g = 4.2 °C for poly­(SFM), <i>T</i>_g = −6 °C for poly­(SBM)] from new monomers indicates that varying biobased fragments in copolymers might considerably change the intermolecular interactions of macromolecules and their physicochemical properties