Renewable Aromatic-Aliphatic Copolyesters Derived from Rapeseed

4-Vinyl Guaiacol: A Key Intermediate for Biobased Polymers

In order to contribute to the shift from petro-based chemistry to biobased chemistry, necessary to minimize the environmental impacts of the chemical industry, 2-methoxy-4-vinylphenol (4-vinyl guaiacol, 4VG) was used to synthesize a platform of biobased monomers. Thus, nine biobased monomers were successfully prepared. The synthesis procedures were investigated through the green metrics calculations in order to quantify the sustainability of our approaches. Their radical homopolymerization in toluene solution initiated by 2,2'-azobis(2-methylpropionitrile) (AIBN) was studied and the effect of residual 4VG as a radical inhibitor on the kinetics of polymerization was also explored. The new homopolymers were characterized by proton nuclear magnetic resonance (1H-NMR) spectroscopy, size exclusion chromatography and thermal analyses (dynamical scanning calorimetry DSC, thermal gravimetric analysis TGA). By varying the length of the alkyl ester or ether group of the 4VG derivatives, homopolymers with Tg ranging from 117 °C down to 5 °C were obtained. These new biobased monomers could be implemented in radical copolymerization as substitutes to petro-based monomers to decrease the carbon footprint of the resulting copolymers for various applications.

Valorization of Ferulic Acid from Agro-Industrial by-Products for Application in Agriculture

The use of bioplastic mulch in agriculture has increased dramatically in the last years throughout the world. Nowadays, biodegradable materials for mulching films strive to constitute a reliable and more sustainable alternative to classical materials such as polyethylene (PE). The main challenge is to improve their durability in the soil to meet the required service length for crop farming by using benign and sustainable antioxidant systems. Here, we report the design and fabrication of biodegradable materials based on polybutylene (succinate adipate) (PBSA) for mulching applications, incorporating a fully biobased polymeric antioxidant deriving from ferulic acid, which can be extracted from an industrial by-product. Poly-dihydro (ethylene ferulate) (PHEF) from ferulic acid was synthesized by a two-step polymerization process. It is characterized by improved thermal stability in comparison with ferulic acid monomer and therefore suitable for common industrial processing conditions. Different blends of PBSA and PHEF obtained by melt mixing or by reactive extrusion were prepared and analyzed to understand the effect of the presence of PHEF. The results demonstrate that PHEF, when processed by reactive extrusion, presents a remarkable antioxidant effect, even in comparison with commercial additives, preserving a high level of the mechanical properties of the PBSA matrix without affecting the biodegradable character of the blend.

Polyesters with bio-based ferulic acid units: crosslinking paves the way to property consolidation

A bio-based ferulic acid monomer is inserted in random terpolyesters with high molar mass and offers the possibility of crosslinking after processing. Both ferulate monomer and solvent-free polycondensation make the new materials more sustainable.

Cinnamic acid derivatives as promising building blocks for advanced polymers: synthesis, properties and applications

A global overview of the use of cinnamic acid derivatives in polymer science is given in this review paper.

Selective Fragmentation of Biorefinery Corncob Lignin into p-Hydroxycinnamic Esters with a Supported Zinc Molybdate Catalyst

Lignin is the largest renewable resource of bioaromatics, and the catalytic fragmentation of lignin into phenolic monomers is increasingly recognized as an important starting point for lignin valorization. Herein, we report that ZnMoO₄ supported on MCM-41 can catalyze the fragmentation of biorefinery technical lignin, enzymatic mild acidolysis lignin, and native lignin derived from corncob to yield lignin oily products that contain 15-37.8 wt % phenolic monomers, in which the high selectivities towards methyl coumarate (1) and methyl ferulate (2) were obtained (up to 78 %). The effects of some key parameters such as the influence of the solvent, reaction temperature, time, H₂ pressure, and catalyst dosage were examined in view of activity and selectivity. The loss of Zn from the catalyst is discussed as the primary cause of deactivation, and the catalytic activity and selectivity can be well preserved in at least six runs by thermal calcination. The high selectivity to 1 and 2 leads to their easy separation and purification from lignin oily product to provide sustainable monomers for the preparation of functional polyether esters and polyesters.

Bright Side of Lignin Depolymerization: Toward New Platform Chemicals

Lignin, a major component of lignocellulose, is the largest source of aromatic building blocks on the planet and harbors great potential to serve as starting material for the production of biobased products. Despite the initial challenges associated with the robust and irregular structure of lignin, the valorization of this intriguing aromatic biopolymer has come a long way: recently, many creative strategies emerged that deliver defined products via catalytic or biocatalytic depolymerization in good yields. The purpose of this review is to provide insight into these novel approaches and the potential application of such emerging new structures for the synthesis of biobased polymers or pharmacologically active molecules. Existing strategies for functionalization or defunctionalization of lignin-based compounds are also summarized. Following the whole value chain from raw lignocellulose through depolymerization to application whenever possible, specific lignin-based compounds emerge that could be in the future considered as potential lignin-derived platform chemicals.

Ferulic Acid-Based Polymers with Glycol Functionality as a Versatile Platform for Topical Applications

Ferulic acid-based polymers with aliphatic linkages have been previously synthesized via solution polymerization methods, yet they feature relatively slow ferulic acid release rates (∼11 months to 100% completion). To achieve a more rapid release rate as required in skin care formulations, ferulic acid-based polymers with ethylene glycol linkers were prepared to increase hydrophilicity and, in turn, increase ferulic acid release rates. The polymers were characterized using nuclear magnetic resonance and Fourier transform infrared spectroscopies to confirm chemical composition. The molecular weights, thermal properties (e.g., glass transition temperature), and contact angles were also obtained and the polymers compared. Polymer glass transition temperature was observed to decrease with increasing linker molecule length, whereas increasing oxygen content decreased polymer contact angle. The polymers' chemical structures and physical properties were shown to influence ferulic acid release rates and antioxidant activity. In all polymers, ferulic acid release was achieved with no bioactive decomposition. These polymers demonstrate the ability to strategically release ferulic acid at rates and concentrations relevant for topical applications such as skin care products.

Base catalyzed sustainable synthesis of phenyl esters from carboxylic acids using diphenyl carbonate

Phenyl esters were obtained in moderate to high yields by reaction of aliphatic and aromatic carboxylic acids with one equivalent of diphenyl carbonate in the presence of catalytic amounts of tertiary amine bases, under neat conditions at elevated temperatures (>100 °C).

Facile and Highly Efficient Strategy for Synthesis of Functional Polyesters via Tetramethyl Guanidine Promoted Polyesterification at Room Temperature

A facile and highly efficient strategy for the synthesis of functional polyesters from 10-undecenoic acid, which is abundantly available and derived from ricin oil, has been successfully achieved using 1,1,3,3-tetramethyl guanidine (TMG) as a promoter at room temperature. The experimental results indicate that high molecular weight polyesters have been obtained and a variety of functional groups, such as alkenyl, alkynyl, nitro, epoxy, hydroxyl, and bromoisobutyrate, can be incorporated as pendant groups. The structures of the obtained polymers were demonstrated by ¹H and ¹³C NMR spectroscopy and their thermal properties were studied by DSC and TGA.

Renewable polyesters derived from 10-undecenoic acid and vanillic acid with versatile properties

A series of renewable polyesters were synthesized derived from 10-undecenoic acid and vanillic acid. An outstanding feature is that the incorporation of vanillic acid segments into the polyester backbone results in improved mechanical properties.