Unravelling the Influence of Surface Modification on the Ultimate Performance of Carbon Fiber/Epoxy Composites

Article asserts that the overall performance of polymer composites depends on not only the intrinsic properties of the polymer matrix and inorganic filler but also the quality of interfacial adhesion. The authors report carbon fiber (CF)/epoxy composites with improved interfacial adhesion by covalent bonding between CFs and the epoxy matrix, which leads to the improved ultimate mechanical properties and enhanced thermal aging performance

The Effect of Fatty Acid Unsaturation on Properties and Performance of Monomers and Latex Polymers from Plant Oils

The interest in renewable natural resources, including plant oils, has become increasingly appealing due to the oil abundance, availability, and wide range of applications for polymers and polymeric materials thereof. In this dissertation, a library of plant oil-based acrylic monomers (POBMs) with a broad range of unsaturation was synthesized using a one-step transesterification. It is demonstrated that the unsaturation degree of plant oil remains preserved during the synthesis and determines the structure and properties of POBMs. The life cycle assessment (LCA) was conducted in this study to evaluate the environmental impact of soybean oil-based acrylic monomer (SBM) production. LCA was applied to provide guidance for SBM synthesis optimization, including the type of catalyst, the ratio between reactants, renewable sources (soybean oil/biodiesel), and solvent recycling. The performed LCA shows the positive effect of the inclusion of the solvent recycling step in the SBM synthesis. This study shows that POBMs behave as conventional vinyl monomers in free radical polymerization and copolymerization. The monomer unsaturation impacts polymerization rate and molecular weight of resulted polymers decreasing as follows: poly(OVM) > poly(SFM) > poly(SBM) > poly(LSM), due allylic termination presented during polymerization. A series of stable POBM-based latexes with high solid content (40-45 %) and monomer conversion (95-97 %) were synthesized using miniemulsion process. The incorporation of POBMs fragments provides the plasticizing effect on the resulting latex polymers, as seen by a noticeable decrease in their glass transition temperature (Tg). The crosslink density of POBM-based latex films follows the linear dependence vs. monomer feed unsaturation, providing a tool for controlling latex mechanical properties, including hardness, toughness, Young's modulus, etc. Besides, the presence of highly hydrophobic POBM fragments enhances water resistivity of latex coatings and films. Following the "greener" vector of research, a variety of stable latexes from high oleic soybean oil-based monomer (HOSBM) and cardanol, eugenol, and guaiacol derivatives were synthesized in miniemulsion. Resulting polymeric materials advantageously combine flexibility provided by HOSBM fragments with strength facilitated by aromatic biobased units

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

International audienc

Biobased Latexes from Natural Oil Derivatives

International audienceVinyl monomers from eugenol (EBM) and guaiacol (GBM) were copolymerized in miniemulsion process with high oleic soybean oil-based (HOSBM) counterpart to yield latexes with higher biobased content. Fully renewable monomer feed yields a broad range of new emulsion polymers with the number-average molecular weight varying at 25,000-650,000 g/mol. Increasing GBM/EBM content in the reactive feed leads to increasing latex molecular weight due to the decreasing unsaturation degree (lower content of HOSBM). Monomer feed unsaturation effect found to be more pronounced for latexes from EBM and HOSBM, since GBM shows higher reactivity in free radical polymerization if compared to GBM. Presence of oil-derived unsaturated fragments in emulsion polymers provides an opportunity to crosslink latexes in a controlled way and adjust the resulting polymer networks mechanical properties. Biobased latexes from 25-90 wt.% of GBM/EBM and 10-75 wt.% of HOSBM were synthesized, characterized and tested in terms of thermomechanical properties of latex crosslinked films and coatings. It is demonstrated that characteristics of latex films and coatings are determined by nature and ratio of aliphatic oil residues of HOSBM and aromatic fragments of EBM/GBM in the macromolecular backbone. Incorporation of rigid fragments of GBM/EBM enhances Young's modulus of the films, whereas the soft plant oil-based units contribute to flexibility of films and coatings. All crosslinked latex films exhibited decent properties and performance in terms of hardness, impact resistance, as well as adhesion to the steel substrate. By combination of aliphatic fatty acid fragments of HOSBM with aromatic GBM/EBM structure, durable latexes can be synthesized with ability to balance thermomechanical properties of the latex polymer networks in a broad range

Synergistic Effect of Cardanol- and High Oleic Soybean Oil Vinyl Monomers In Miniemulsion Polymers

Along with characterization of vinyl monomers from high oleic soybean oil (HOSBM) and cardanol (CBM) in free radical (co)polymerization, a series of stable latexes based on various ratios of these fully renewable plant-based monomer mixtures have been synthesized using a miniemulsion process. The combination of aliphatic fatty acid fragments of HOSBM with aromatic CBM structure led to the formation of durable latexes from fully renewable feeds as well as the ability of the resulting cross-linked latex films to balance thermomechanical properties. Biobased latexes were synthesized from 10 to 75 wt % of CBM and 25–90 wt % of HOSBM in the feed, characterized, and tested in films and coatings performances. The synergistic effects of both the constituents in the films and coatings were observed. The incorporation of cardanol-based fragments enhances the Young’s modulus of the films, whereas the plant oil-based units contribute to softer and more flexible films. Even small (10 wt %) fractions of CBM can provide noticeable strength to the soft latex polymer material based entirely on HOSBM. All cross-linked latex films in this study exhibit decent properties and performance in terms of pendulum and pencil hardness, water and solvent resistance, as well as adhesion to the steel substrate. To the best of our knowledge, latexes from fully renewable plant-based monomer mixtures have not been reported before in literature

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

Non-Conventional Features of Plant Oil-Based Acrylic Monomers in Emulsion Polymerization

International audienceIn 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

Non-Conventional Features of Plant Oil-Based Acrylic Monomers in Emulsion Polymerization

International audienc