Cork biomass biocomposites: lightweight and sustainable materials

Chapter 17. Cork biomass biocomposites: lightweight and sustainable materials.The authors would like to thank to the financial support from the Portuguese Foundation for Science and Technology (FCT) for the fellowship grant of Emanuel M. Fernandes (SFRH/BPD/96197/2013), “Fundo Social Europeu”- FSE and “Programa Diferencial de Potencial Humano POPH”.info:eu-repo/semantics/publishedVersio

Polyethylene composites with lignocellulosic material

The aim of this chapter is to describe in detail the advances in polyethylene reinforced with lignocellulosic material. Indeed, the successful employment of natural based materials to reinforce/improve the properties of polyolefins has been growing in a wide range of applications. Firstly, basic concepts and terminology adopted in the lignocellulosic composite materials are reviewed. The objective is to bring the readerâ s attention to important issues that must to be taken into account when working in this subject as well as by providing the most appropriate references for those with interest to delve into the topic. In the context of polyethylene lignocellulosic composites, ongoing research is then summarised mainly focussing on (i) the main aspects related to the selection of the commonly used lignocellulosic materials and the potential of its main chemical constituents, (ii) the principal methods used for the improvement of interfacial adhesion and (iii) the main adopted processing routes and the composite properties. Finally, applications, new challenges and opportunities of these polyethylene-lignocellulosic composites are also discussed.(undefined)info:eu-repo/semantics/publishedVersio

Hybrid cork-polymer composites containing sisal fibre : morphology, effect of the fibre treatment on the mechanical properties and tensile failure prediction

In this study, we investigated the use of short sisal fibre with and without polyethylene-graft-maleic anhydride (PE-g-MA) as a strategy to reinforce cork–polymer composite (CPC) materials. The use of alkali treatment of sisal to improve fibre–matrix adhesion was evaluated. High density polyethylene (HDPE) was used as matrix and the composites were produced in a two-step process using twin-screw extruder followed by compression moulding. FTIR, TGA and XRD were used to confirm the sisal fibre modification. Additionally, morphology, density, diameter and tensile properties of the fibres were evaluated before processing. The hybrid composites containing cork powder (40 wt.%) and randomly distributed sisal fibres were evaluated in terms of morphology and mechanical properties. The use of a 10 wt.% sisal fibre in the presence of a 2 wt.% coupling agent based on maleic anhydride, has shown to improve the tensile and flexural properties of the composites. The higher mechanical properties were achieved by using alkali treated sisal fibres and PE-g-MA. In the presence of the coupling agent the composite morphology revealed good interfacial adhesion between the natural components and the polypropylene matrix, being in accordance with the mechanical results. Weibull cumulative distribution was successfully used to accurately predict the tensile strength failure of the hybrid CPC materials.We gratefully acknowledge to Amorim Revestimentos S.A. for the supply of cork and to Pallmann GmbH for the polymer in the grinding form. To QREN FCOMP-01-0202-FEDER-003107 financing support on the project "NovelComp". EMF acknowledge to Portuguese Foundation for Science and Technology (FCT) Grant (SFRH/BD/71561/2010)

Rotação de culturas. XXIII. Efeitos das culturas de inverno sobre o rendimento de grãos e sobre algumas características agronômicas de plantas de soja, num período de nove anos.

bitstream/item/133654/1/ID12354-1988-1989sojaresultados-p88-99.pdfTrabalho apresentado na XVII Reunião de Pesquisa de Soja da Região Sul, Porto Alegre, 1989

Novel cork-polymer composites reinforced with short natural coconut fibres : effect of fibre loading and coupling agent addition

Composites from high density polyethylene filled with cork powder and coconut short fibres, in two different ratios, were prepared in a twin-screw extruder followed by compression moulding process. The main motivation of this work was to improve the mechanical performance without compromising the use of high weight percentage of natural component used in the preparation of cork-based composites. The morphology of the hybrid composites were more homogeneous in the presence of the coupling agent (CA) displaying enhanced fibre–matrix adhesion. Moreover, the use of CA based on maleic anhydride promotes a mechanical reinforcement effect on the tensile properties, including the elongation at break. The addition of coconut fibre resulted on an increase of 27% in elastic modulus and 47% in the tensile strength when compared with the unreinforced cork-based (50–50) wt.% composite. This work clearly shows that the addition of 10 wt.% of short-coconut fibres, randomly distributed, can be effectively used as reinforcing strategy of cork-based composite materials, preferably in the presence of 2 wt.% of CA.The work was performed within the project of Corticeira Amorim S.G.P.S. on the development of new products based in/with cork. We gratefully acknowledge to Amorim Revestimentos S.A. for the supply of cork and to Amorim Isolamentos S.A. for the coconut fibres and to Pallmann GmbH for the grinding polymer. E.M.F. and V.M.C. acknowledges to Portuguese Foundation for Science and Technology (FCT) grants (SFRH/BD/71561/2010) and (SFRH/BPD/64790/2009) respectively

Natural fibres as reinforcement strategy on cork-polymer composites

Cork powder, the most important sub-product of cork processing, combined with thermoplastic matrixes like, high density polyethylene (HDPE), offer a new class of cork-polymer composite (CPC) materials with high added-value. Therefore, reinforcing strategies must be considered to increase the mechanical performance, especially when high content of cork powder is added to the formulation. Coconut fibres have several advantages, such as, low density, renewable source, low cost and biodegradability. The use of these fibres on the reinforcement of CPC materials will not only contribute to improve the mechanical performance but also for increasing the amount of natural component present on the final composition. The main goal of this work was to prepare HDPE/cork (50-50 wt.%) composites reinforced with discontinuous coconut fibres (5 and 10 wt.%) with and without the addition of coupling agent (2 wt.%) by extrusion. The developed reinforced cork based composites were characterized regarding its morphology and mechanical performance. Optical micrographs have shown a homogeneous distribution of the fibres. The coupling agent effect on CPC performance was also investigated. The tensile strength and tensile modulus of the reinforced composites were significantly improved with the addition of coupling agent. The use of 10 wt.% of coconut fibres in the presence of coupling agent promote an increase on maximum tensile strength of around 41 % comparing with the HDPE/cork (50-50 wt.%) composites. Scanning electron microscopy (SEM) micrographs of the tensile fractured specimens confirmed that the use of coupling agent promoted the interfacial adhesion between the fibres and the thermoplastic matrix. Since, like cork powder, coconut fibres have good thermal and acoustic properties, we consider that the novel reinforced CPC herein described have high potential to be used in building and construction systems and other structural 3D applications.Corticeira Amorim S.G.P.S. (Portugal)Fundação para a Ciência e a Tecnologia (FCT)Project ”NovelComp”QREN FCOMP-01-0202 FEDER-00310

Experimental determination of the non-extensive entropic parameter qq

We show how to extract the $q$ parameter from experimental data, considering an inhomogeneous magnetic system composed by many Maxwell-Boltzmann homogeneous parts, which after integration over the whole system recover the Tsallis non-extensivity. Analyzing the cluster distribution of La$_{0.7}$Sr$_{0.3}$MnO$_{3}$ manganite, obtained through scanning tunnelling spectroscopy, we measure the $q$ parameter and predict the bulk magnetization with good accuracy. The connection between the Griffiths phase and non-extensivity is also considered. We conclude that the entropic parameter embodies information about the dynamics, the key role to describe complex systems.Comment: Submitted to Phys. Rev. Let

Isolation of adipose stem cells (ASCs) subpopulations with distinct differentiation potential

[Excerpt] ASCs are becoming the elected cells for TE applications because ASCs have been easily isolated and have shown good differentiation potential. The aim of this work was to isolate the ASCs using immunomagnetic beads coated with different antibodies (Ab) markers and to test the differentiation potential of the different subpopulations isolated. [...]Marie Curie Actions Alea Jacta Est, Project HIPPOCRATES, NoE EXPERTISSUESinfo:eu-repo/semantics/publishedVersio

Molecularly imprinted intelligent scaffolds for tissue engineering applications

The development of molecularly imprinted polymers (MIPs) using biocompatible production methods enables the possibility to further exploit this technology for biomedical applications. Tissue engineering (TE) approaches use the knowledge of the wound healing process to design scaffolds capable of modulating cell behavior and promote tissue regeneration. Biomacromolecules bear great interest for TE, together with the established recognition of the extracellular matrix, as an important source of signals to cells, both promoting cellâ cell and cellâ matrix interactions during the healing process. This review focuses on exploring the potential of protein molecular imprinting to create bioactive scaffolds with molecular recognition for TE applications based on the most recent approaches in the field of molecular imprinting of macromolecules. Considerations regarding essential components of molecular imprinting technology will be addressed for TE purposes. Molecular imprinting of biocompatible hydrogels, namely based on natural polymers, is also reviewed here. Hydrogel scaffolds with molecular memory show great promise for regenerative therapies. The first molecular imprinting studies analyzing cell adhesion report promising results with potential applications for cell culture systems, or biomaterials for implantation with the capability for cell recruitment by selectively adsorbing desired molecules.The authors wish to thank Dr. Julia Vela-Ramirez, Ms. Heidi Culver, and Mr. John Clegg for important discussions and suggestions. This work was supported in part by the University of Texas-Portugal Collaborative Research Program, and the Grant UTAP-ICDT/CTM-BIO/0023/2014. M.E.W. is supported by a National Science Foundation Graduate Research Fellowship

Studies of P(L/D)LA 96/4 non-woven scaffolds and fibres; properties, wettability and cell spreading before and after intrusive treatment methods

Poly(L/D)lactide 96/4 fibres with diameters of 50 and 80 microm were produced. The smaller diameter fibres were carded and needle punched to form a non-woven mat. Fibres and non-woven mats were hydrolysed for a period of 20 weeks. Fibres and pressed non-woven discs were treated with low-temperature oxygen plasma and alkaline KOH hydrolysis and ethanol washing was used as a reference treatment. The non-wovens lost 50% of their tear strength after 8 weeks in vitro while the fibres still retained 65% tensile strength after 20 weeks. Hydrolysation time in KOH, treatment time and power settings of the oxygen plasma were all directly proportional to the mechanical properties of the fibres. Increasing time (and power) resulted in lower tensile properties. Rapid wetting of the scaffolds was achieved by oxygen plasma, KOH hydrolysation and ethanol washing. Cell culturing using fibroblast cell line was carried out for the treated and non-treated non-woven scaffolds. In terms of adhesion and the spreading of the cells into the scaffold, best results after 3-day culturing were obtained for the oxygen plasma treated scaffolds