The Prospering of Macromolecular Materials Based on Plant Oils within the Blooming Field of Polymers from Renewable Resources

Abstract

This paper provides an overview of the recent progress in research and development dealing with polymers derived from plant oils. It highlights the widening interest in novel approaches to the synthesis, characterization, and properties of these materials from renewable resources and emphasizes their growing impact on sustainable macromolecular science and technology. The monomers used include unmodified triglycerides, their fatty acids or the corresponding esters, and chemically modified triglycerides and fatty acid esters. Comonomers include styrene, divinylbenzene, acrylics, furan derivatives, epoxides, etc. The synthetic pathways adopted for the preparation of these materials are very varied, going from traditional free radical and cationic polymerizations to polycondensation reactions, as well as metatheses and Diels–Alder syntheses. In addition to this general appraisal, the specific topic of the use of tung oil as a source of original polymers, copolymers, and (nano)composites is discussed in greater detail in terms of mechanisms, structures, properties, and possible applications.

Monomers and Macromolecular Materials from Renewable Resources: State of the Art and Perspectives

“…For decades, vegetable oils were preferred for polymer synthesis among other bioresources due to their abundance and democratic geographical distribution, low price, easiness of chemical modification of the triglyceride structures, and potential biodegradability of the final materials. A book fully devoted to the production of polymers from vegetable oils was published a few of years ago [ 90 ], however, as it is a hot topic in the field of polymers from renewable resources, an update seems convenient and is available for the interested reader [ 91 ]. In fact, mostly in the past two decades, the development of novel polyesters, polyurethanes, polyamides, polycarbonates, UV-curable coatings, among many other materials based on vegetable oils, has been described [ 90 , 91 , 92 ].…”

“…A book fully devoted to the production of polymers from vegetable oils was published a few of years ago [ 90 ], however, as it is a hot topic in the field of polymers from renewable resources, an update seems convenient and is available for the interested reader [ 91 ]. In fact, mostly in the past two decades, the development of novel polyesters, polyurethanes, polyamides, polycarbonates, UV-curable coatings, among many other materials based on vegetable oils, has been described [ 90 , 91 , 92 ]. The strategy may involve, on the one hand, the preparation of highly branched and crosslinked materials, as a result of exploiting the polyfunctional nature of crude triglycerides, and on the other, the breakdown of triglycerides into the corresponding fatty acids prior to the synthesis of linear materials.…”

“…The direct polymerization of polyfunctional vegetable oils into thermosets is a possibility that avoids preliminary synthetic steps and therefore represents a more sustainable approach towards polymeric materials [ 93 ]. The 1,2-disubstituted C=C unsaturation of common fatty acids often react slowly in the presence of free radical and cationic initiators, and this strategy demands an association with a more reactive comonomer such as styrene and divinylbenzene, or a preliminary step for converting triglycerides into more reactive monomers, such as epoxidation or thiol-ene reactions [ 90 , 91 ]. The epoxidation of vegetable oils corresponds to a routine industrial process employed, for example, for the synthesis of plasticizers for several commodity polymers, but it is also a useful platform for the design of novel macromolecular materials.…”

“…The use of pristine and chemically modified triglycerides as monomers that possess their multifunctional nature preserved is an important strategy for the preparation of original cross-linked materials with lower Tg, with respect to other commercial resins based on the fossil platform. However, hydrolysis and transesterification reactions are more frequently conducted for the isolation of fatty acids (or of their corresponding fatty esters) and further preparation of linear, hyperbranched, and cross-linked materials [ 91 ]. In fact, the concept of producing linear polymers from plant oils started in the 1950s and has witnessed an impressive evolution in the past few years.…”

“…In industrial processing, vegetable oils are converted to glycerol plus fatty acids, methyl esters, and fatty alcohols, and subsequent chemical modification steps are often conducted to obtain the specific chemicals of interest [ 91 ]. Taking the biodiesel industry into account, the search for novel high value-added products based on glycerol is a topic that deserves attention, mostly because its industrial surplus has induced an unneglectable market saturation.…”