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A new approach to the formation of cross-linked colloidosomes was developed on the basis of Pickering emulsions that were stabilized exclusively by peroxidized colloidal particles. Free radical polymerization and a soft template technique were used to convert droplets of a Pickering emulsion into colloidosomes. The peroxidized latex particles were synthesized in the emulsion polymerization process using amphiphilic polyperoxide copolymers poly(2-tert-butylperoxy-2-methyl-5-hexen-3-ine-co-maleic acid) (PM-1-MAc) or poly[N-(tert-butylperoxymethyl)acrylamide]-co-maleic acid (PM-2-MAc), which were applied as both initiators and surfactants (inisurfs). The polymerization in the presence of the inisurfs results in latexes with a controllable amount of peroxide and carboxyl groups at the particle surface. Peroxidized polystyrene latex particles with a covalently grafted layer of inisurf PM-1-MAc or PM-2-MAc were used as Pickering stabilizers to form Pickering emulsions. A mixture of styrene and/or butyl acrylate with divinylbenzene and hexadecane was applied as a template for the synthesis of colloidosomes. Peroxidized latex particles located at the interface are involved in the radical reactions of colloidosomes formation. As a result, covalently cross-linked colloidosomes were obtained. It was demonstrated that the structure of the synthesized (using peroxidized latex particles) colloidosomes depends on the amount of functional groups and pH during the synthesis. Therefore, the size and morphology of colloidosomes can be controlled by latex particle surface properties. [ABSTRACT FROM AUTHOR]

This study demonstrated that polymerization behavior of plant oil-based acrylic monomers (POBMs) synthesized in one-step transesterification reaction from naturally rich in oleic acid olive, canola, and high-oleic soybean oils is associated with a varying mass fraction of polyunsaturated fatty acid fragments (linoleic (C18:2) and linolenic (C18:3) acid esters) in plant oil. Using miniemulsion polymerization, a range of stable copolymer latexes was synthesized from 60 wt.% of each POBM and styrene to determine the impact of POBM chemical composition (polyunsaturation) on thermal and mechanical properties of the resulted polymeric materials. The unique composition of each plant oil serves as an experimental tool to determine the effect of polyunsaturated fatty acid fragments on POBM polymerization behavior and thermomechanical properties of crosslinked films made from POBM-based latexes. The obtained results show that increasing polyunsaturation in the copolymers results in an enhanced crosslink density of the latex polymer network which essentially impacts the mechanical properties of the films (both Young's modulus and toughness). Maximum toughness was observed for crosslinked latex films made from 50 wt.% of each POBM in the monomer feed. [ABSTRACT FROM AUTHOR]

In recent years, polymer chemistry has experienced an intensive development of a new field regarding the synthesis of aliphatic and aromatic biobased monomers obtained from renewable plant sources. A one-step process for the synthesis of new vinyl monomers by the reaction of direct transesterification of plant oil triglycerides with N-(hydroxyethyl)acrylamide has been recently invented to yield plant oil-based monomers (POBMs). The features of the POBM chemical structure, containing both a polar (hydrophilic) fragment capable of electrostatic interactions, and hydrophobic acyl fatty acid moieties (C15-C17) capable of van der Waals interactions, ensures the participation of the POBMs fragments of polymers in intermolecular interactions before and during polymerization. The use of the POBMs with different unsaturations in copolymerization reactions with conventional vinyl monomers allows for obtaining copolymers with enhanced hydrophobicity, provides a mechanism of internal plasticization and control of crosslinking degree. Synthesized latexes and latex polymers are promising candidates for the formation of hydrophobic polymer coatings with controlled physical and mechanical properties through the targeted control of the content of different POBM units with different degrees of unsaturation in the latex polymers. [ABSTRACT FROM AUTHOR]

• Monomers from plant oils copolymerized with water soluble counterparts in emulsion. • Resulted latex particle formation occurs by both micellar and homogeneous mechanism. • Emulsion copolymerization loci change when hydrophobicity of feed increases. • Aqueous solubility of POBM counterpart determines particle formation mechanism. • POBM presence is kinetically irrelevant if reactivity of counterpart radicals is high. Highly hydrophobic vinyl monomers from soybean (SBM) and olive (OVM) oil with different amounts of unsaturation were copolymerized in emulsion with significantly more soluble in water comonomers, methyl methacrylate (MMA), vinyl acetate (VA), and methyl acrylate (MA). Our intention was to demonstrate that higher aqueous solubility of the comonomer impacts the mechanism of the emulsion process by balancing latex particle homogeneous and heterogeneous (micellar) nucleation. Using an experimental method based on water insoluble dye Blue 70, it is shown that particle nucleation indeed depends to a great extent on aqueous solubility of the comonomer, along with the plant oil-based monomer (POBM) content in the feed. Upon addition of POBM into the monomer mixture with MMA (aq.solubility 1.5 wt%), the latex polymer particles originating from micellar nucleation essentially increased. In copolymerization of POBM with MA (aqueous solubility 4.9 wt%), this effect is even more pronounced. Those findings clearly indicate that copolymerization loci change when monomer feed hydrophobicity increases, and the magnitude of this effect is dependent on the comonomer aqueous solubility. Experimentally determined changes in reaction order with respect to emulsifier and initiator upon addition of POBM confirm that kinetics of emulsion copolymerization is impacted by comonomer aqueous solubility. The latter finding can be indicative of changing latex particle nucleation mode when monomer feed hydrophobicity changes. Overall, the portion of latex particles originating through micellar nucleation is higher in the copolymerization of more unsaturated SBM (with both MMA and MA) in comparison to OVM. No impact of POBM content on the reaction kinetics was observed in copolymerization with VA (aq. solubility 2.5 wt%). Here, high reactivity of growing PVA radicals in chain transfer reactions makes the presence of POBM in monomer feed kinetically irrelevant. [ABSTRACT FROM AUTHOR]

Abstract: A new copolymer of N-[(tert-butylperoxy)methyl]acrylamide (tBPMAAm), containing a primary–tertiary peroxide group and maleic anhydride (MA), was synthesized and employed as a reactive surfactant (inisurf) for the emulsion polymerization of styrene to yield surface-functionalized (peroxidized) reactive latex particles. The copolymerization characteristics were analyzed to determine the monomer reactivity ratios and to provide a way to control the copolymer composition. The ability of tBPMAAm–MA to act as a reactive surfactant during emulsion polymerization was confirmed by the synthesis of monodisperse polystyrene latexes of varying particle size. In addition, peroxide groups were localized on the surface of the particles in a controllable amount (depending on the copolymer concentration), thus, providing the opportunity for further modification of the surface of the particles. This novel copolymer is expected to be a promising and efficient material in the synthesis of functional polymer nanoparticles with well-defined core–shell morphologies. [Copyright &y& Elsevier]