The substitution of fossil-based monomers in the thermosetting formulations is a fundamental issue to face the environmental concerns related to the use of traditional resins. This study relies on the preparation of styrene-free thermosetting resins starting from vegetable oils with different compositions and unsaturation degrees, namely soybean, hempseed, and linseed oils. Using terpenic comonomers such as limonene and myrcene allows one to prepare thermosets avoiding the traditional fossil-based diluents such as styrene, thus obtaining an outstanding gain in terms of both environmental and safety concerns. The materials obtained reveal tunable physical properties upon the proper choice of the monomers, with glass transition temperature ranging from 40 to 80 °C and Young's modulus ranging from 200 to 1800 MPa [1]. The evaluation of the bio-based content of the prepared materials gives a quick idea of the effect obtained in the substitution of styrene with terpenes. Moreover, a product's bio-based content is defined as the "amount of bio-based carbon in the material or product as a percent of the weight (mass) of the total organic carbon in the product" [2]. The starting oil (i.e., soybean oil as a benchmark) is obtained from renewable materials and contains ~77% carbon. After epoxidation and acrylation the total carbon content goes down to ~64% and the bio-based carbon to ~50%. A typical resin preparation mixture is based on 80% by weight of AESO and 20% by weight of comonomer. Therefore, comparing the resin obtained with AESO and limonene (100% bio-based) and the one obtained with AESO and styrene (0% bio-based), the calculation of the biobased content according to Pan et al. [3] gives bio-based C content of 83.7 % and 57.0 % for AESO-Limonene and AESO-Styrene respectively. The possibility of preparing composite materials starting from the resins prepared in this way and natural fibers has also been explored due to the potential applications of bio-based composites in several industrial sectors. Moreover, the use of Waste Cooking Oil (WCO) instead of extracted oils has been explored revealing comparable performances of the materials obtained, thus disclosing the possibility to upgrading a waste for this purpose. A further step forward in this topic aims at the substitution of acrylic acid.
Tapping into renewable sources for the preparation of styrene-free thermosetting materials with tunable properties
Federica Zaccheria;Nicoletta Ravasio;Adriano Vignali;Benedetta Palucci;Fabio Bertini
2023
Abstract
The substitution of fossil-based monomers in the thermosetting formulations is a fundamental issue to face the environmental concerns related to the use of traditional resins. This study relies on the preparation of styrene-free thermosetting resins starting from vegetable oils with different compositions and unsaturation degrees, namely soybean, hempseed, and linseed oils. Using terpenic comonomers such as limonene and myrcene allows one to prepare thermosets avoiding the traditional fossil-based diluents such as styrene, thus obtaining an outstanding gain in terms of both environmental and safety concerns. The materials obtained reveal tunable physical properties upon the proper choice of the monomers, with glass transition temperature ranging from 40 to 80 °C and Young's modulus ranging from 200 to 1800 MPa [1]. The evaluation of the bio-based content of the prepared materials gives a quick idea of the effect obtained in the substitution of styrene with terpenes. Moreover, a product's bio-based content is defined as the "amount of bio-based carbon in the material or product as a percent of the weight (mass) of the total organic carbon in the product" [2]. The starting oil (i.e., soybean oil as a benchmark) is obtained from renewable materials and contains ~77% carbon. After epoxidation and acrylation the total carbon content goes down to ~64% and the bio-based carbon to ~50%. A typical resin preparation mixture is based on 80% by weight of AESO and 20% by weight of comonomer. Therefore, comparing the resin obtained with AESO and limonene (100% bio-based) and the one obtained with AESO and styrene (0% bio-based), the calculation of the biobased content according to Pan et al. [3] gives bio-based C content of 83.7 % and 57.0 % for AESO-Limonene and AESO-Styrene respectively. The possibility of preparing composite materials starting from the resins prepared in this way and natural fibers has also been explored due to the potential applications of bio-based composites in several industrial sectors. Moreover, the use of Waste Cooking Oil (WCO) instead of extracted oils has been explored revealing comparable performances of the materials obtained, thus disclosing the possibility to upgrading a waste for this purpose. A further step forward in this topic aims at the substitution of acrylic acid.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
