Cellulose nanocrystal-based poly(butylene adipate-co-terephthalate) nanocomposites covered with antimicrobial silver thin films

In this study, we reported the preparation and prospective application of the nanocomposites of poly(butylene adipate-co-terephthalate) (PBAT) reinforced with cellulose nanocrystals (CNCs). CNCs were isolated from bleached sugarcane bagasse by acid hydrolysis and functionalized with adipic acid. Nanocomposites were prepared with different concentration of CNCs (0.8, 1.5, and 2.3 wt% CNC) by solution-casting method and then were covered with silver thin film by magnetron sputtering. The results showed that the surface modification increased the degree of crystallinity of nanocrystals from 51% to 56%, decreasing their length and diameter. Moreover, AFM-IR spectroscopy revealed that the modified CNCs were covered by adipic acid molecules, improving the dispersion of nanocrystals in PBAT. Well-dispersed modified CNCs acted as heterogeneous nuclei for crystallization of PBAT, and increased the storage modulus of the polymer by more than 200%. These improvements in thermal and mechanical properties of CNC-based PBAT associated with the decrease of 56% in the Escherichia coli biofilm formation on nanocomposites (antibacterial properties) qualify the CNC/PBAT nanocomposites covered with silver thin films to be used as food packaging. POLYM. ENG. SCI., 59:E356-E365, 2019. (c) 2019 Society of Plastics Engineers59s22E356E365CNPQ - Conselho Nacional de Desenvolvimento Científico e TecnológicoNÃO CONSTANÃO CONSTA2016/09588-9CAPES - Coordenação de Aperfeiçoamento de Pessoal e Nível SuperiorFAPESP – Fundação de Amparo à Pesquisa Do Estado De São Paul

A combined computational and experimental study on the polymerization of ϵ-caprolactone

This paper reports the study on the synthesis of poly(ϵ-caprolactone) - PCL by ring-opening polymerization (ROP) of ϵ-caprolactone (CL) monomer with focus on mathematic developing of the growth mechanisms of polymer chain. Kinetics and mathematical modeling of ROP of CL was carried out to replicate the different experimental conditions. The computational results of conversion and molecular weight of the polymer were found to be comparable with the experimental results of nuclear magnetic resonance (NMR) spectroscopy and showed that the polymerization is highly dependent on the moisture (ROH). Moreover, parametric studies have shown how the concentrations of octanoic acid and catalyst affect the conversion and molecular weight of the polymer. The study here presented provides further understanding of synthesis of PCL, reporting mathematical models of PCL synthesis which can be used for predicting the characteristic of this biocompatible and biodegradable polymer. © 2018 American Chemical Society57401338713395FAPESP – Fundação de Amparo à Pesquisa Do Estado De São Paulo2016/09588-9; 2016/19847-

Porous nanocellulose gels and foams : Breakthrough status in the development of scaffolds for tissue engineering

| openaire: EC/H2020/788489/EU//BioELCellWe report on the latest scientific advances related to the use of porous foams and gels prepared with cellulose nanofibrils (CNF) and nanocrystals (CNC) as well as bacterial nanocellulose (BNC) – collectively nanocelluloses – as biomedical materials for application in tissue regeneration. Interest in such applications stems from the lightweight and strong structures that can be efficiently produced from these nanocelluloses. Dried nanocellulose foams and gels, including xerogels, cryogels, and aerogels have been synthesized effortlessly using green, scalable, and cost-effective techniques. Methods to control structural features (e.g., porosity, morphology, and mechanical performance) and biological interactions (e.g., biocompatibility and biodegradability) are discussed in light of specific tissues of interest. The state-of-the-art in the field of nanocellulose-based scaffolds for tissue engineering is presented, covering physicochemical and biological properties relevant to these porous systems that promise groundbreaking advances. Specifically, these materials show excellent performance for in vitro cell culturing and in vivo implantation. We report on recent efforts related to BNC scaffolds used in animal and human implants, which furthermore support the viability of CNF- and CNC-based scaffolds in next-generation biomedical materials.Peer reviewe

Environmentally friendly polymer composites basedon PBAT reinforced with natural fibers fromthe amazon forest

Biodegradable composites based on poly(butyleneadipate-co-terephthalate) (PBAT) and three differentnaturalfibers (Croton lanjouwensis—Fiber C,Malvas-trum tomentosum—Fiber M, andTrema micrantha—Fiber T) from the Amazon forest have been reported forthefirst time. Naturalfibers were extracted throughmechanical processing and the composites were pre-pared by melt mixing procedure. All composites showedgreater modulus of elasticity than neat polymer and thisimprovement varies according to the type offiber usedas reinforcement. Addition of Fiber C increased 48% themodulus of elasticity of the polymer, while the additionof the Fibers M and T increased 70 and 72% the modu-lus of elasticity of the PBAT, respectively. The resultsreported in the present work support the idea that theabove-mentioned naturalfibers can be used asfillermaterial to obtain environmentally friendly polymer com-posites with improved properties.POLYM. COMPOS.,40:3351–3360, 2019. © 2019 Society of Plastics Engineers408335133602016/09588-9; 2016/08295-1NÃO TEMNÃO TEMFAPESP – Fundação de Amparo à Pesquisa Do Estado De São PauloFAPESP – Fundação de Amparo à Pesquisa Do Estado De São PauloCAPES - Coordenação de Aperfeiçoamento de Pessoal e Nível SuperiorCNPQ - Conselho Nacional de Desenvolvimento Científico e Tecnológic