Photosensitive acrylates containing bio-based epoxy-acrylate soybean oil for 3D printing application

Stereolithography is a 3D-printing process that is rapidly shifting from being an expensive and limited technology to an affordable, precise, and fast method of mass production. However, most of the current resins are petroleum-based, which makes them toxic, non-degradable and with poor biocompatibility. In this study, a standard petroleum-based resin containing urethane acrylate and acrylic monomers was combined with epoxy-acrylate soybean oil (EASO), aiming to reduce its impact on the environment. Ratios varying from 10 to 50 wt% of EASO were incorporated into the commercial resin while maintaining the viscosity low, between 0.27 and 1.06 Pa s. The printed samples showed good quality and complete integration between the layers. The addition of 50 wt% of EASO increased the samples elongation at break by 108% (from 2.3% to 4.8%) and decreased the contact angle by 26.4% (from 72 to 53°). Moreover, the mixture showed good thermal and swelling stability and tensile strength in the range of other commercial cured systems. The addition of EASO may significantly contribute to the exploitation of greener materials, which well matches today's circular economy concept

Preparation and characterization of 3D-Printed biobased composites containing micro- or nanocrystalline cellulose

Stereolithography (SLA), one of the seven different 3D printing technologies, uses photosensitive resins to create high-resolution parts. Although SLA offers many advantages for medical applications, the lack of biocompatible and biobased resins limits its utilization. Thus, the development of new materials is essential. This work aims at designing, developing, and fully characterizing a bio-resin system (made of poly(ethylene glycol) diacrylate (PEGDA) and acrylated epoxidized soybean oil (AESO)), filled with micro- or nanocellulose crystals (MCC and CNC), suitable for 3D printing. The unfilled resin system containing 80 wt.% AESO was identified as the best resin mixture, having a biobased content of 68.8%, while ensuring viscosity values suitable for the 3D printing process (>1.5 Pa s). The printed samples showed a 93% swelling decrease in water, as well as increased tensile strength (4.4 ± 0.2 MPa) and elongation at break (25% ± 2.3%). Furthermore, the incorporation of MCC and CNC remarkably increased the tensile strength and Young’s modulus of the cured network, thus indicating a strong reinforcing effect exerted by the fillers. Lastly, the presence of the fillers did not affect the UV-light penetration, and the printed parts showed a high quality, thus proving their potential for precise applications

Gold Derivatives Development as Prospective Anticancer Drugs for Breast Cancer Treatment

Commonly used anticancer drugs are cisplatin and other platinum‐based drugs. However, the use of these drugs in chemotherapy causes numerous side effects and the onset of frequent drug resistance phenomena. This review summarizes the most recent results on the gold derivatives used for their significant inhibitory effects on the in vitro proliferation of breast cancer cell models and for the consequences deriving from morphological changes in the same cells. In particular, the study discusses the antitumor activity of gold nanoparticles, gold (I) and (III) compounds, gold complexes and carbene‐based gold complexes, compared with cisplatin. The results of screening studies of cytotoxicity and antitumor activity for the gold derivatives show that the death of cancer cells can occur intrinsically by apoptosis. Recent research has shown that gold (III) compounds with square planar geometries, such as that of cisplatin, can intercalate the DNA and provide novel anticancer agents. The gold derivatives described can make an important contribution to expanding the knowledge of medicinal bioorganometallic chemistry and broadening the range of anticancer agents available, offering improved characteristics, such as increased activity and/or selectivity, and paving the way for further discoveries and applications

Antibacterial Effect of Stainless Steel Surfaces Treated with a Nanotechnological Coating Approved for Food Contact

Stainless steel, widely present in the food industry, is frequently exposed to bacterial colonization with possible consequences on consumers’ health. 288 stainless steel disks with different roughness (0.25, 0.5 and 1 μm) were challenged with four Gram-negative (Escherichia coli ATCC 25922, Salmonella typhimurium ATCC 1402, Yersinia enterocolitica ATCC 9610 and Pseudomonas aeruginosa ATCC 27588) and four Gram-positive bacteria (Staphylococcus aureus ATCC 6538, Enterococcus faecalis ATCC 29212, Bacillus cereus ATCC 14579 and Listeria monocytogenes NCTT 10888) and underwent three different sanitizing treatments (UVC, alcohol 70% v/v and Gold lotion). Moreover, the same procedure was carried out onto the same surfaces after a nanotechnological surface coating (nanoXHAM® D). A significant bactericidal effect was exerted by all of the sanitizing treatments against all bacterial strains regardless of roughness and surface coating. The nanoXHAM® D coating itself induced an overall bactericidal effect as well as in synergy with all sanitizing treatments regardless of roughness. Stainless steel surface roughness is poorly correlated with bacterial adhesion and only sanitizing treatments can exert significant bactericidal effects. Most of sanitizing treatments are toxic and corrosive causing the onset of crevices that are able to facilitate bacterial nesting and growth. This nanotechnological coating can reduce surface adhesion with consequent reduction of bacterial adhesion, nesting, and growth

Phosphorus-Silica Sol-Gel Hybrid Coatings for Flame Retardant Cotton Fabrics

This work investigates the use of organic-inorganic sol-gel coatings based on silica and phosphorous compounds for providing cotton fabrics with fl ame retardant features. To this aim, diethylphosphatoethyltriethoxysilane precursor was employed for the synthesis of several sols in combination with different chemical additives. Sols were reacted with azo-based compounds and repeatedly applied onto the cellulosic substrate in a multilayer assembly, aiming at assessing the eff ect of the concurrent presence of Si, P and N on the overall fi re behaviour of the fabric. In order to evaluate the flame retardancy of treated cellulosic fabrics, flammability tests were carried out. The obtained results showed that the phosphorus-silica coating is able to promote the formation of a stable char that acts as insulator barrier. Finally, an additive P-N effect of the ceramic oxide coating in terms of increased residue and decreased heat release rate and total burning time was observed in cone calorimetry tests

Surface Modification of Polyester/Viscose Fabric with Silica Hydrosol and Amino-Functionalized Polydimethylsiloxane for the Preparation of a Fluorine-Free Superhydrophobic and Breathable Textile

This work attempted to fabricate superhydrophobic fabric via a simple immersion technique. Textile fabrics were coated with silica nanoparticles prepared from tetraethoxysilane (TEOS) to obtain sufficient roughness with hydrophobic surface chemistry. Then, the coated fabrics were treated with polydimethylsiloxane (PDMS) and aminopropyltriethoxysilane (APTES) to reduce the surface energy. The effects of the PDMS concentration on the surface morphology and superhydrophobicity of as-prepared fabric were investigated. The morphology and the composition of superhydrophobic fabric were characterized by scanning electron microscopy (SEM), energy dispersive X-ray (EDS), and Fourier transform infrared (FTIR) spectroscopy. The results revealed the formation of spherical silica nanoparticles with an average particle size of 250 nm throughout the fabric surface. The possible interactions between silica nanoparticles and APTES, as well as the fabrics, were elucidated. Investigating the hydrophobicity of fabrics via water contact angle (WCA) measurement showed that the treated fabric exhibits excellent water repellency with a water contact angle as high as 151° and a very low water sliding angle. It was also found that the treated fabric maintained most of its hydrophobicity against repeated washing, as the WCA of superhydrophobic fabrics decreased to 141° after 25 repeated washing cycles. The comfort properties of the obtained superhydrophobic fabrics in terms of air permeability and bending length did not reveal any significant changes

Preparation and characterization of a fully biobased resin system for 3d‑printing, suitable for replacing fossil‑based acrylates

The exploitation of plant-based monomers for additive manufacturing is a very promising approach to reduce the usage of petroleum-based plastics. In vat photopolymerization, acrylate epoxidized soybean oil (AESO) stands out as a versatile photocurable resin that can be modified and combined with other materials for multiple applications. In this work, different ratios of AESO were combined with isobornyl methacrylate (IBOMA), to develop a resin that exhibits similar mechanical properties to standard fossil-based resins. The photopolymerization reaction and conversion rate was monitored using FT-IR analysis, which showed conversions above 80%. Furthermore, curing tests revealed that the biobased resin needed less energy to cure when compared to commercial resins. The parts fabricated using the biobased resin also demonstrated enhanced tensile strength, tunable elongation at break and swelling resistance, which were comparable to standard fossil-based resins. This work demonstrates the potential of the proposed systems as a valuable alternative to traditional resins, paving the way for the development of high-performance materials for stereolithographic applications