The use of renewable resources for plastic production is an imperious need for the reduction of the carbon footprint and the transition towards a circular economy. With that goal in mind, fully biobased epoxy resins have been designed and prepared by combining epoxidized linseed oil, lignin, and a biobased diamine derived from fatty acid dimers. The aromatic structures in lignin provide hardness and strength to an otherwise flexible and breakable epoxy resin. The curing of the system was investigated by infrared spectroscopy and differential scanning calorimetry (DSC). The influence of the different components on the thermo-mechanical properties of the epoxy resins was analyzed by DSC, thermal gravimetric analysis (TGA), and tensile tests. As the content of lignin in the resin increases, so does the glass transition, the Young's modulus, and the onset of thermal degradation. This correlation is non-linear, and the higher the percentage of lignin, the more pronounced the effect. All the components of the epoxy resin being commodity chemicals, the present system provides a realistic opportunity for the preparation of fully biorenewable resins at an industrial scale.
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http://dx.doi.org/10.3390/molecules25051158 | DOI Listing |
Polymers (Basel)
January 2025
Department of Mechanical and Aerospace Engineering, Politecnico di Torino, 10129 Turin, Italy.
This paper experimentally investigates the impact response of composite laminates made with conventional and bio-based epoxy resin. Drop tower impact tests were conducted at varying energy levels, including repeated low-energy impacts, to evaluate perforation resistance. The laminates' residual strength and damage tolerance were assessed using the Damage Index (DI) and by analysing the resonance frequency variations through the Impulse Excitation Technique (IET).
View Article and Find Full Text PDFMaterials (Basel)
January 2025
Center for Advanced Technologies, Adam Mickiewicz University in Poznań, Uniwersytetu Poznańskiego 10, 61-614 Poznań, Poland.
Recycling end-of-life wind turbines poses a significant challenge due to the increasing number of turbines going out of use. After many years of operation, turbines lose their functional properties, generating a substantial amount of composite waste that requires efficient and environmentally friendly processing methods. Wind turbine blades, in particular, are a problematic component in the recycling process due to their complex material composition.
View Article and Find Full Text PDFMaterials (Basel)
January 2025
CITAB-Centre for the Research and Technology of Agro-Environmental and Biological Sciences, School of Science and Technology, University of Trás-os-Montes and Alto Douro, 5000-801 Vila Real, Portugal.
Epoxy resins are extensively employed as adhesives and matrices in fibre-reinforced composites. As polymers, they possess a viscoelastic nature and are prone to creep and stress relaxation even at room temperature. This phenomenon is also responsible for time-dependent failure or creep fracture due to cumulative strain.
View Article and Find Full Text PDFClin Oral Investig
January 2025
Department of Restorative Dentistry - Endodontics, Faculdade de Odontologia de Piracicaba, Universidade Estadual de Campinas, Piracicaba, SP, Brazil.
Objectives: To investigate volumetric changes, in vivo biocompatibility, and systemic migration from eight commercial endodontic sealer materials in paste/paste, powder/liquid, and pre-mixed forms.
Materials And Methods: The sealers AH Plus Bioceramic, AH Plus Jet, BioRoot RCS, MTApex, Bio-C Sealer, Bio-C Sealer Ion+, EndoSequence BC Sealer and NeoSEALER Flo were studied. After characterisation by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), Raman spectroscopy and X-ray diffractometry (XRD), tubes were implanted in Wistar rats' alveolar bone and subcutaneous tissues.
Mol Cell Endocrinol
January 2025
Programa de Pós-graduação em Medicina (Endocrinologia), Faculdade de Medicina, Universidade Federal do Rio de Janeiro, Rio de Janeiro-RJ, Brazil; Centro de Pesquisa em Medicina de Precisão, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro-RJ, Brazil; Programa de Pós-graduação em Ciências Biológicas (Fisiologia), Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro-RJ, Brazil.
The large-scale industrial production characteristic of the last century led to an increase in man-made compounds and mobilization of natural compounds, many of which can accumulate in the environment and organisms due to their bioaccumulation and biomagnification properties. The endocrine system is especially vulnerable to these compounds that are known as endocrine disruptor chemicals (EDCs). Thyroid hormones (THs) are essential for normal development and growth, besides being the main regulators of basal metabolic rate.
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