Development of a redox polymer based on poly(2-hydroxyethyl methacrylate)for disposable amperometric sensors

Membranes based on poly(2-hydroxyethyl methacrylate), chemically modified with ferrocene functionalities, are proposed as novel coatings for the development of disposable amperometric sensors. They are mass-produced on an inert support through an UV photo-induced polymerization, forming self-standing films that can be transferred on an electrode surface. Thanks to the characteristic of the functionalized methacrylate matrix to rapidly and reversibly swell by incorporation of large amounts of water, the ferrocene moieties are in intimate contact with the electrolytic solution. They can activate effective electrocatalytic processes that can be exploited in the field of amperometric sensing. The performance of the methacrylate coating with respect to the determination of hydroquinone benchmark analyte has been tested both in a static solution and in a flux cell

Fine Tuning of the Mechanical Properties of Bio-Based PHB/Nanofibrillated Cellulose Biocomposites to Prevent Implant Failure Due to the Bone/Implant Stress Shielding Effect

A significant mechanical properties mismatch between natural bone and the material forming the orthopedic implant device can lead to its failure due to the inhomogeneous loads distribution, resulting in less dense and more fragile bone tissue (known as the stress shielding effect). The addition of nanofibrillated cellulose (NFC) to biocompatible and bioresorbable poly(3-hydroxybutyrate) (PHB) is proposed in order to tailor the PHB mechanical properties to different bone types. Specifically, the proposed approach offers an effective strategy to develop a supporting material, suitable for bone tissue regeneration, where stiffness, mechanical strength, hardness, and impact resistance can be tuned. The desired homogeneous blend formation and fine-tuning of PHB mechanical properties have been achieved thanks to the specific design and synthesis of a PHB/PEG diblock copolymer that is able to compatibilize the two compounds. Moreover, the typical high hydrophobicity of PHB is significantly reduced when NFC is added in presence of the developed diblock copolymer, thus creating a potential cue for supporting bone tissue growth. Hence, the presented outcomes contribute to the medical community development by translating the research results into clinical practice for designing bio-based materials for prosthetic devices

Further Step in the Transition from Conventional Plasticizers to Versatile Bioplasticizers Obtained by the Valorization of Levulinic Acid and Glycerol

Valorization of glycerol and levulinicacid by a solvent-freeand mild-condition reaction to obtain a high-efficiency bioplasticizersuitable for different polymers.In the last two decades,the use of phthalates has beenrestrictedworldwide due to their well-known toxicity. Nonetheless, phthalatesare still widely used for their versatility, high plasticization effect,low cost, and lack of valuable alternatives. This study presents thefully bio-based and versatile glycerol trilevulinate plasticizer (GT)that was obtained by the valorization of glycerol and levulinic acid.The mild-conditions and solvent-free esterification used to synthesizeGT was optimized by investigating the product by Fourier transforminfrared and NMR spectroscopy. An increasing content of GT, from 10to 40 parts by weight per hundred parts of resin (phr), was testedwith poly(vinyl chloride), poly(3-hydroxybutyrate), poly(3-hydroxybutyrate-co-3-hydroxyvalerate), poly(lactic acid), and poly(caprolactone),which typically present complicatedprocessability and/or mechanical properties. GT produced a significantplasticization effect on both amorphous and semicrystalline polymers,reducing their glass-transition temperature and stiffness, as observedby differential scanning calorimetry measurements and tensile tests.Remarkably, GT also decreased both the melting temperature and crystallinitydegree of semicrystalline polymers. Furthermore, GT underwent enzyme-mediatedhydrolysis to its initial constituents, envisioning a promising prospectivefor environmental safety and upcycling. Furthermore, 50% inhibitoryconcentration (IC50) tests, using mouse embryo fibroblasts,proved that GT is an unharmful alternative plasticizer, which makesit potentially applicable in the biomedical field

Levulinic acid-based bioplasticizers: a facile approach to enhance the thermal and mechanical properties of polyhydroxyalkanoates

PHB has been engineered by incorporating different levulinic acid-based bioplasticizers, which enhance flexibility and thermal processability of the neat biopolymer, while retaining excellent biocompatibility and biodegradability

Poly(hydroxyalkanoate)s-Based Hydrophobic Coatings for the Protection of Stone in Cultural Heritage

Reversibility is a mandatory requirement for materials used in heritage conservation, including hydrophobic protectives. Nevertheless, current protectives for stone are not actually reversible as they remain on the surfaces for a long time after their hydrophobicity is lost and can hardly be removed. Ineffective and aged coatings may jeopardise the stone re-treatability and further conservation interventions. This paper aims at investigating the performance of PHAs-based coatings for stone protection, their main potential being the ‘reversibility by biodegradation’ once water repellency ended. The biopolymer coatings were applied to three different kinds of stone, representative of lithotypes used in historic architecture: sandstone, limestone and marble. Spray, poultice and dip-coating were tested as coating techniques. The effectiveness and compatibility of the protectives were evaluated in terms of capillary water absorption, static and dynamic contact angles, water vapour diffusion, colour alteration and surface morphology. The stones’ wettability after application of two commercial protectives was investigated too, for comparison. Finally, samples were subjected to artificial ageing to investigate their solar light stability. Promising results in terms of efficacy and compatibility were obtained, although the PHAs-based formulations developed here still need improvement for increased durability and on-site applicability

Erratum: Andreotti, S.; Franzoni, E.; Fabbri, P. Poly(hydroxyalkanoate)s-Based Hydrophobic Coatings for the Protection of Stone in Cultural Heritage. Materials 2018, 11, 165

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