Sustainable Synthetic Approaches for the Preparation of Plant Oil‐Based Thermosets

Abstract

a more sustainable future. Due to an ever-increasing population on our planet and industrial developments, a major focus is on energy and fuel supply, as well as chemical and polymer production. In search for alternatives to the finite fossil feedstocks, the renewability and structural diversity of biomass makes it an excellent candidate [1][2][3][4][5][6]. Especially in polymer science, the use of renewable resources has been intensively investigated and discussed in several reviews over the last years [7][8][9][10][11]. Amongst biomass, vegetable oils constitute a platform of aliphatic hydrocarbons, particularly studied as polymer precursors due to their good availability, low price, inherent biodegradability and potential for chemical modifications [12][13][14][15][16]. Vegetable oils are composed of triglycerides, which consist of three fatty acid chains esterified with glycerol. Fatty acids vary in their chain length, as well as degree and location of their unsaturations. The fatty acid structures of the plant oils discussed in this review are shown in Scheme 1 and the composition of these oils displayed in Table 1. The fatty acid composition of the triglycerides, depending on the plant origin, influences their properties significantly [14]. Well-defined fatty acids can be recovered after hydrolysis of triglycerides and further separation and purification [17]. The latter can be transformed into difunctional monomers for the synthesis of a broad range of thermoplastic polymers [18]. However, this additional step decreases the sustainability of the synthesis. Thus, the direct polymerization of poly-functional vegetable oils into thermoset polymers represents a "greener" approach towards polymeric materials.Thermosets are cross-linked polymeric materials known for their good thermomechanical properties and chemical resistance. The production of these polymers represents ~20% of the total annual polymer production [19]. Thermosets can be synthesized in different chemical ways and the production of biobased thermosets has been recently Abstract The good availability and high degree of functionalization possibilities of plant oils entitles them to be one of the most intensively studied renewable resources, especially in polymer science. However, in line with the principles of green chemistry, the use of renewable resources should be accompanied with catalytic procedures, comparably less or non-toxic chemicals, as well as reduction of waste and energy consumption to achieve an overall sustainable process. In this review, these aspects are addressed using the example of plant oil-based thermoset materials, which bear the advantage, in terms of sustainability, of not requiring a separation or purification step prior to polymerization. The direct homopolymerization of plant oils, as well as copolymerization, exclusively with other renewable resources, are highlighted. The sustainability of the synthesis of a broad range of thermosets including epoxy resins, polyurethane networks, polybenzoxazines and unsaturated poly...

Epoxidized soybean oil cured with tannic acid for fully bio-based epoxy resin

“…In the EP eld in particular, exploring sustainable epoxy thermosets, including both EP and curing agents from renewable resources, has been an area of ever-increasing concern in recent years. [9][10][11][12] Different biomass resources, through years of research, such as plant oils, [13][14][15][16] isosorbide, 17,18 itaconic acid, 19,20 lignin derivatives, 21 vanillin, 22 and sugar, [23][24][25] have been used to design and prepare bio-based epoxy thermosets.…”

Development and Characterization of Palm Flower Carbon Reinforced DOPO‐Urea Diamine Based Cardanol Benzoxazine‐Epoxy Hybrid Composites

“…The corrosion usually takes place through the redox reaction of iron and oxygen in the presence of water or moisture in the air. Rust may consists of any one of these form or combined form of hydrated iron (III) oxides (Fe 2 O 3 ÁnH 2 O), iron(III) oxidehydroxide (FeO(OH), and Fe(OH) 3 . The occurrence of process of corrosion involved in the steel may be explained according to Eqs.…”

Metathesis Curing of Allylated Lignin and Different Plant Oils for the Preparation of Thermosetting Polymer Films with Tunable Mechanical Properties

“…Thus, the products and side products of the cross-metathesis differ in their chain length. Linoleic acid and α-linoleic acid, the main building block of linseed oil's triglyceride (6), can lead to the formation of a triglyceride dimer (7) and hex-3-ene (8) in a side reaction (Scheme 2). Other side reactions that form short chain products are possible.…”

“…, , 1700177 Scheme 2. Self-metathesis of linseed oil (representative triglyceride from linoleic and alpha-linolenic acid, 6) as possible side reaction to form the dimer (7) and hex-3-ene (8).…”