Special Issue Editor
* Correspondence: email@example.com
Departamento de Ingeniería Química, Facultad de Química, Universidad de Sevilla, 41012, Sevilla, Spain
Interests: Biopolymers; Processing of biopolymer-based materials; Rheological and microstructural characterization of materials; Valorization of food by-products; Nanomaterials; Electrospinning; Tissue Engineering.
* Correspondence: firstname.lastname@example.org
Departamento de Ingeniería Química, Facultad de Química, Universidad de Sevilla, 41012, Sevilla, Spain
Interests: Processing of biopolymer-based materials. Development of emulsions, bioplastics and biomaterials. Valorization of food by-products. Rheological and physicochemical characterization of micro and nanostructured, multicomponent systems and their applications.
Special Issue Information
Aim and Scope: The importance of materials has been, is and will be very important for life. Recently, the technology of materials is being focused on polymers and composite materials, since with them it is possible to obtain a material with optimal properties for the required application. Specifically, the convergence of materials science with materials engineering leads to the combination of the production and characterization of materials for different specific applications. Nowadays, polymer-based materials have been proposed for different applications like foods (formation and stabilization of foods, supply dietary fibers or micro- and nanoencapsulation), packaging (structural and mechanical properties or edible films), cosmetic and pharmaceutical industry (low cost, sustainability and naturalness, even in regenerative medicine as biomaterials. Aiming to explore these concepts, this Special Issue will focus on the current trends for polymer-based materials and their possible applications, as well as the study of traditional and emerging processing techniques. In addition, different characterization techniques will be evaluated and described. Submissions can cover the following topics (but are not limited to them):
– Natural-based polymers;
– Polysaccharides and proteins in materials science;
– Synthetic polymers in materials science;
– Processing of biopolymers;
We kindly invite you to submit a manuscript(s) for this Special Issue. Full papers, communications, and reviews are all welcome.
Subtopics: Natural polymers: Polysaccharides and proteins; Modified natural polymers: Cellulose acetate; Synthetic polymers: PLA; Composite materials (combination of natural and synthetic polymers).
Keywords: Bio-based polymers; biodegradable polymers; physicochemical characterization; mechanical characterization; microstructural characterization; nanotechnology; biomaterials.
Deadline for manuscript submissions:
30 May 2020
Deadline extended: 30 September 2020
Manuscript Submission Information
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1) Chitin, Chitosan, and Submicron-Sized Chitosan Particles Prepared from Scylla serrata Shells
1 Department of Chemistry, Faculty of Science, Universiti Brunei Darussalam, Jalan Tungku Link, Gadong BE1410, Brunei Darussalam; firstname.lastname@example.org
2 Centre for Advanced Material and Energy Sciences, Universiti Brunei Darussalam, Jalan Tungku Link, Gadong BE1410, Brunei Darussalam; email@example.com
3 Department of Chemical Engineering, Faculty of Engineering, Universitas Indonesia, Kampus Baru UI, 16424 Depok, Indonesia; firstname.lastname@example.org
(1) Characterization of Taquara-Lixa (Merostachys Skvortzovil Sendulsky) fibers with and without alkali treatment for their possible use in polymer composites#
Camilo Borges Neto1,, Thais Sydenstricker Flores-Sahagun2, Kestur Gundappa Satyanarayana3*, Alan Sulato Andrade4 and Irineu Mazzaro5
1- Department of Transport, Federal University of Paraná (UFPR), Curitiba, P.O Box 19049, Zip: 81.531-990, Paraná, Brazil; Tel/Fax:+55 (41) 3361-3388;E-mail: email@example.com; firstname.lastname@example.org.
2- Department of Mechanical Engineering, Federal University of Paraná (UFPR), Curitiba, P.O Box 19011, Zip: 81.531-990, Paraná, Brazil; Tel: 55 (41) 3361-3430; E-mail: email@example.com.
3-Honorary Professor, Poornaprajna Institute of Scientific Research (PPISR), Sy. No. 167, Poornaprajnapura, Bidalur Post, Devanahalli, Bengaluru- 562110 (Karnataka, India). * Corresponding Author: Tel: + 91 (80) 2760 7242 / 2764 7701; Fax: +91(80)-27647444; E-mail: firstname.lastname@example.org; email@example.com.
4- Department of Engineering and Forest Technology, Federal University of Paraná (UFPR), Curitiba, P.O Box 19049, Zip: 81.531-990, Paraná, Brazil; Tel:+55(41)3360-4291; E-mail: firstname.lastname@example.org.
5- Department of Physics, Federal University of Paraná (UFPR), Curitiba, P.O Box 19049, Zip: 81.531-990, Paraná, Brazil; Tel: +55 (41) 3361-3663; E-mail: mazzaro@física.ufpr.br.
Efforts to find new resources to replace the synthetic fibers such as glass and carbon fibers in the development of polymeric and cementiceous matrices based composites have been made to take care of growing environmental concerns. Bamboo is one such lignocellulosic material, which is abundantlygrown in most developing countries and is sustainable and strong. Of the various varieties of bamboo grown in Brazil, Taquara-lixa stands out due to its large availability and low cost besides its physical and mechanical characteristics. However, not many studies have been reported on its use in the development of composites probably due to very little reports on various properties of this fiber. Accordingly, this paper presents extraction of fibers from the stem of taquara-lixa bamboo, their characterization in respect of chemical composition, pH, crystallinity index and thermal stability. Further, effect of alkali treatment of fibers on the chemical composition, thermal stability and crystallinity index has also been presented. While the alkali treatment has reduced the moisture and lignin contents as well as solubility in cold and hot water, holocellulose content increased slightly. There was no change in the values pH, crystallinity index and thermal stability of the fibers with the alkali treatment.
#- Part of this was presented in the 13th Annual Congress of Brazilian Polymers – Natal, RN – 18 – 22 October, 2015 and included in the Proceedings.
(2) Influence of chemical treatments on the properties of açaí and curauá fibers
Larissa R. Gehlen1, # Thais H. S. Flores-Sahagun2,#, Suelen G. de Souzac, Elisane Koller3, Claudio E. Nunes Junior3, Ana Paula T. Pezzin3 and Kestur Gundappa Satyanarayana4,*
1- Post-graduation Program in Engineering and Materials Science/PIPE, Federal University of Parana, P.O. Box. 19011, Curitiba, CEP: 81531-980 (Brazil). E-mail: email@example.com; firstname.lastname@example.org.
2– Department of Mechanical Engineering, Federal University of Parana, P.O. Box. 19011, Curitiba, CEP: 81531-980 (Brazil), Tel: +55(41) 3361 3308; E-mail: email@example.com.
3- Department of Chemical Engineering, University of the Region of Joinville, Paulo Malschitzk Road, 10 – North Industrial Area, Joinville – SC, 89219-710, Brazil, Tel: +55 (47)3461-9066/34619180; E-mail: firstname.lastname@example.org; email@example.com; firstname.lastname@example.org; email@example.com.
4- Honorary Professor, Poornaprajna Institute of Scientific Research (PPISR), Sy. no. 167, Poornaprajnapura, Bidalur Post, Devanahalli, Bangalore 562 110 (Karnataka-India). E-mail: firstname.lastname@example.org; email@example.com. * Corresponding Author.
Continuing the studies on the Brazilian lignocellulosic fibers by the authors to increase their applications, this paper presents chemical and thermal properties of açai and curauá fibers, which are some of the unique fibers of the country. While there is very limited published report on the effect of chemical treatments of açaí fibers, no report is available of sodium borohydride (sodium tetrahydroborate) treatment of both these fibers. This paper presents effect of alkaline treatments with and without sodium borohydride on these two fibers for possible use in polymer based composites. Chemical composition studies of both the fibers revealed these chemical treatments increased cellulose and decreased hemicelluloses contents of both the fibers; while spectroscopic studies using Fourier transform infrared showed that wide hydroxyl bands are not affected by the chemical treatments, while other bands showed slight variations in their trough parts compared to those of fibers without any treatment. Both the fibers exhibited improved thermal stability after the alkaline treatment. These results clearly underlined that the chemical treatments were effective in for improvement of their thermal properties, while the effectiveness of these treatments on fibers surfaces can be seen when they are used in a polymer matrix and removal of components.
(3) PVA composites: natural fibers as additive and reinforcement
Aline Caldonazo1, Heloise Sasso Teixeira2, Elaine Cristina Lengowski3, Eraldo Antonio Bonfatti Júnior4 and Kestur Gundappa Satyanarayana5.
- Postgraduate Program in Pharmaceutical Sciences (PPGCF), Federal University of Paraná (UFPR), Av. Pref. Lothário Meissner, 632, Jardim Botânico, Curitiba, PR 80210-170, Brazil; E-mail: firstname.lastname@example.org.
- Graduate Program in Engineering and Materials Science (PIPE), Federal University of Paraná (UFPR), Cel. Francisco H. dos Santos, 100 Av., 632, Jardim das Américas, Curitiba, PR 81.530-000, Brazil. E-mail: email@example.com.
- Faculty of Forestry Engineering, Federal University of Mato Grosso (UFMT), Fernando Corrêa da Costa St, 2367 – Boa Esperança, Cuiabá, MT 78068-600, Brazil. E-mail: firstname.lastname@example.org; email@example.com
- Department of Forest Engineering and Technology (DETF), Federal University of Paraná (UFPR), Av. Pref. Lothário Meissner, 632, Jardim Botânico, Curitiba, PR 80210-170, Brazil. E-mail: firstname.lastname@example.org.
- Honorary Professor, Poornaprajna Institute of Scientific Research (PPISR), Sy. no. 167, Poornaprajnapura, Bidalur Post, Devanahalli, Bangalore 562 110 (Karnataka-India). E-mail: email@example.com;firstname.lastname@example.org * Corresponding Author.
Polyvinyl alcohol (PVA) is a biodegradable, biocompatible synthetic polymer that has demonstrated good performance in several areas of application as packing, agriculture but mainly in biomedicine field. The natural fibers, or lignocellulosic fibers, play an increasingly important role in polymer composites, since they are not only “biofriendly” polymers, easy to obtain and abundantly found in nature, but also add great improvement in the physical-chemical properties of synthetic polymers, at a relatively low cost. Such fibers are found in several types of plants and can be obtained by different methods (chemical, physical or biological), which can provide some different properties needed in each case of application. This article overviews the most recent advanced studies in the development of PVA composites reinforced with natural fibers, as well as the improve properties, processing methods, characterizations tests and the applications of these composites in the industry field.
(4) Nanocellulose based composites as advanced materials
Sisira, M. K.1, Anju, P. 1, Prasad, V. S. 1 and Satyanarayana, K.G. 2,*.
- Materials Science and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvannathapuram 695019 (Kerala- India). E-mail: email@example.com, firstname.lastname@example.org; email@example.com
2- Honorary Professor, Poornaprajna Institute of Scientific Research (PPISR), Sy. no. 167, Poornaprajnapura, Bidalur Post, Devanahalli, Bangalore 562 110 (Karnataka-India). E-mail: firstname.lastname@example.org;email@example.com * Corresponding Author.
Nanocellulose is emerging as an advanced reinforcement material for composites with higher mechanical properties at lower fiber loading, retaining its transparent nature with better processability and ecofriendly characteristics compared to natural fiber based systems. Various cellulose resources including plant fibers such as sisal, banana, coir, jute, areca fibers, rice husk etc. and wood pulp have been used for the synthesis of nanocellulose by chemical as well as mechanical processing including steam explosion to make these nanofibers in bulk with cost effective processes. In-situ crosslinking strategies have been tried in composites with biopolymer matrices such as poly(lactic acid), poly(glycolic acid), poly(butylene succinate) etc. for forming interpenetrating network structures in nanocomposites for better properties. The possibility for functionalization and self-assembly in nanocellulose opened up a novel area of composites with self-aligned fiber incorporated composites showing applications in stimuli responsive materials and devices especially in biomedical applications having better biocompatibility. These composites with improved gas barrier properties and ecofriendly nature is the best bet for packaging and advanced material applications. This review paper covers all the above and presents some perspectives for the future.
(5) Decellularized natural tissues as versatile biopolymer based scaffolds for tissue engineering applications
Mohammad Amin Shamekhi1, Hamid Mahdavi 2
1Department of Polymer Engineering, Islamic Azad University, Sarvestan Branch, Iran
2Novel Drug Delivery Systems and Biomaterial Department, Science Faculty, Iran Polymer and Petrochemical Institute, Tehran, Iran
Abstract: Decellularized natural tissues have attracted considerable attention due to the resemblances to the extracellular matrix (ECM). Such biopolymer-based scaffolds constitute a structural platform for cell proliferation, differentiation, and maturation. Decellularization and corresponding recellularization approaches showed to have considerable effect on the scaffold physical, mechanical and biochemical properties. The decellularization procedure may change the structure of the ECM and correspondingly affect the scaffold properties. On the other hand stem cell niche induct differentiation behavior and so different decellularized ECMs may have different induction performance. In this review, different decellularization protocols are studied and the effect of the decellularization on the remained biopolymer composition is discussed. Characterization of the compositional change in the physical, mechanical and biochemical properties are also discussed comprehensively.
Keywords: decellularized extracellular matrix, decellularization and recellularization processes, compositional change, characterization
(6) Alginic Acid: A Potential Biopolymer From Brown Algae
Kalyani Sreekumar and B Bindhu*
Department of Physics, Noorul Islam Centre for Higher Education, Kumaracoil, Thuckalay, India-629180
*corresponding author: firstname.lastname@example.org
Abstract: The ascending rates of environmental issues are compelling various industries to rely upon biopolymers rather than synthetic plastics. These biopolymers have the capability to become a green solution for environmental attributes in the time to come. However, relatively deficient mechanical and barrier behavior limit the use of these biopolymers. This can be hurdled with the incorporation of suitable other polymers or materials to the matrices of the concerned biopolymer. Alginic acid is a biopolymer that is being widely researched owing to their various physiochemical properties. This paper focuses on a comprehensive discussion on alginic acid from its properties to composites/blends and various applications.
Keywords: biopolymer; alginic acid; polymer composites
(7) Arabinoxylan and arabinoxylan gel effects on blood serum lipids and glucose levels of Wistar rats
aFigueroa-Pizano María Dolores, aCampa-Mada Alma Consuelo, bCanett-Romero Rafael, aPaz-Samaniego Rita, aCarvajal-Millan Elizabeth
a Research Center for Food and Development, CIAD, A.C. Carretera Gustavo Enrique Astiazarán Rosas No. 46, Hermosillo, Sonora 83304, MexicobUniversity of Sonora, Rosales y Blvd. Luis D. Colosio, Hermosillo, Sonora 83000, Mexico
Abstract: Several studies have described the health benefits of arabinoxylan (AX) as probiotics; however, others authors have related them with an anti-nutrient effect as AX increases the viscosity of the alimentary bolus. In this work, the impact of AX and AX-Gel on blood serum lipids and glucose levels of Wistar rats was investigated. AX was extracted from maize bran, presented a Fourier Transform Infra-Red spectrum typical for this polysaccharide and a molecular weight of 250 kDa. AX solution at 5% (w/v) formed covalent gels induced by a laccase. Twelve male Wistar rats (4 per treatment) were feed with a standard diet supplemented with 5% lyophilized AX or AX-Gel in a single meal. Blood glucose levels were determined, collecting a drop of blood from the tail vein of rats at 0, 6, and 14 h after food consumption. Plasma total cholesterol, triglycerides, HDL-cholesterol, and VLDL-cholesterol, were also determined at 14 h. Postprandial blood glucose of the treatment groups was maintained at the same level as the control group. The plasma lipid profile levels also remained similar to the control group. The obtained results revealed that consumption of AX and AX-Gel at moderated levels does not interfere with the absorption of these nutrients.
Keywords: arabinoxylan; gels; blood glucose; plasma lipids; viscosity.
(8) Graphene Nanoparticle Reinforced Poly Lactic Acid (PLA) And Epoxy Resin Based Hybrid Nano Composites For Structural Applications
N. Vijaya Kumar1, N.R. Banapurmath2, Ashok M. Sajjan3 and Arun Y. Patil4
1,2,4Centre for Material Science, BVB College of Engineering and Technology, KLE Technological University, Hubballi
1,2,4School of Mechanical Engineering, BVB College of Engineering and Technology, KLE Technological University, Hubballi
Corresponding Author: email@example.com
Abstract: Biopolymers are considered to be eco-friendly alternative materials to petrochemical polymers due to their biodegradability property. In recent years biopolymer based composites are gaining prominence for different engineering applications as they offer reductions in weight, cost and carbon dioxide emissions and are recyclable. Polylactic Acid (PLA) is one of the most promising biopolymers used nowadays as it has many applications in food, packaging, medical and pharmaceutical industries. In view of this biopolymer composites were developed using both epoxy resin and PLA combinations. Quantity of PLA in epoxy resin was varied from 10 to 40 wt % of the total polymer resin in steps of 10%. Further 20% PLA reinforced epoxy resin was optimized in terms of improved mechanical and microstructural properties. In the next case this 20% PLA reinforced epoxy resin was used for preparing bio-nano composites reinforced with different nano-fillers such as Graphene, Multiwalled Carbon Nanotubes (MWCNTs). Nano filler concentration was varied from 0.1 to 0.4% of weight of the biopolymer composites developed. The developed biopolymer with 0.2 wt% of graphene and MWCNTs showed increased tensile strength. Hence 0.2% reinforced Graphene biopolymer can be used as an alternative material for structural applications.
Key words: Nano-composites, Biopolymer, PLA, Nano-fillers, Graphene, MWCNTs, dispersion.
(9) Thermal Characterization Of Benzoxazine Resin Composites Reinforced With 5% Macadamia Nut Biomass
Cirlene Fourquet Bandeira, Ariana Carmem Antunes da Costa, Sérgio Roberto Montoro, Michelle Leali Costa, Edson Cocchieri Botelho
Abstract: Benzoxazine resins have been gaining space in the consumer market in recent decades due to their properties that surpass those traditional epoxy and phenolic resins. However, due to its relatively high curing temperature (~190oC), few reinforcements from biomass have been used in the formulation of its composites. The macadamia nutshell is very promising, as its degradation temperature is above the curing temperature of this resin. Therefore, this work aims to produce and characterize composites using benzoxazine resin reinforced with macadamia biomass, in nature and hydrothermally treated in the proportion of 5% v/v. The thermal characterizations were performed in TGA, DSC and DMA and showed, in general, that the reinforcement does not considerably affect the thermal properties of the resin.
Keywords: XU 35610, hydrothermal treatment, recycling, thermal analysis, green materials.
(10) Development of electrospun photo-crosslinkable soy protein-based scaffolds
Matthäus Davi Popov Pereira da Cunha, Ana Agustina Aldana, Gustavo Abel Abraham.
Instituto de Investigaciones en Ciencia y Tecnología de Materiales (INTEMA), UNMdP-CONICET, Mar del Plata, Argentina
Abstract: The mimicking of the extracellular matrix (ECM) is essential for developing biomaterials that could modulate cell adhesion, proliferation, and differentiation. Among the techniques for reproducing the ECM’s morphology, electrospinning has been intensively employed to obtain nanofibrous structures. Soy protein isolate (SPI), which is composed primarily of β-conglycinin, glycinin, and lipophilic proteins, has been studied for different biomedical applications, such as wound dressing, tissue engineering, and drug delivery systems. However, the high-water solubility of electrospun proteins limits their use. In this work, we synthesized successfully soy protein isolate methacrylate (SPIMA) (54.8% modification), which could be covalent crosslinked. Then, we optimized the electrospinning processing and obtained SPIMA-based mats with homogeneous fibrous structure. The electrospun mats were then crosslinked using an UV-lamp (λ=360nm) during different times (0, 2.5, 5, and 10 minutes). The crosslinked samples showed a swollen-like structure, induced by the crosslinking process; however, the aimed fibrous structure remained. FTIR spectra did not show any alterations by the crosslinking procedure. Our results demonstrated that modified soy protein isolate is promising for producing fibrous biopolymer-based scaffolds, which have potential application in tissue engineering.
Keywords: electrospinning, soy protein isolate, photo-crosslinking.
(11) Natural Polymers As Modulators for Biomineralization: Present Status and Clinical Applications
Eman Mazyed a and Farid A. Badria b*
aDepartment of Pharmaceutical technology, Faculty of Pharmacy, Kafrelsheikh University, Kafrelsheikh 35516, Egypt
bDepartment of Pharmacognosy, Faculty of Pharmacy, Mansoura University, Mansoura 35516 Egypt
Corresponding Author: Farid A. Badria, Ph.D
*Tel.: +20 1001762927; e-mail: firstname.lastname@example.org
Abstract: The biomineralization process is the formation of mineral-like inorganic substances by some organisms inside or outside their bodies. There are various types of biominerals that are different in terms of their morphology, composition, structure, and role, depending on the organisms. It involves not only basic researches that focus mainly on the mechanisms and processes of biomineral development, but also applied researches including medical, environmental, agricultural, dental, and materials sciences. Furthermore, many strategies have been investigated in the literature for the formation of bioactive bone-like materials such as using bioactive glasses. Fundamental aspects of biomineralization are also important in order to propose new techniques to improve calcification onto the biomaterial surface or to develop bioactive tridimensional templates that could be used in regenerative medicine. The challenge of developing new biomaterials or using natural polymers is not only to understand their mechanism of action in nature but also to properly coordinate the complex interplay between chemistry, physics, biology, and engineering. Not only pure polymers on their own are considered but also their different mixtures, with the possibility to involve some chemical steps for further functionalization and tailoring of the final material properties. Nevertheless, the current challenges are the low-cost manufacturing and the scale-up of surface modification (eg, micro- and nanopatterned) in order to mimic nature’s selection of materials and to use them in a different environment to offer novel solutions in the biomedicine and tissue engineering. Natural polymers are materials that present widely in nature or are extracted from animals or plants. Natural polymers are important to our daily life because our human forms are based on them. Some examples of these polymers are proteins and nucleic acid that occur in the human body, starch, natural rubber, and honey. Starch is a natural polymer that consists of hundreds of glucose molecules. Similarly, natural rubber is a polymer obtained from the rubber tree latex. Honey is another naturally occurring polymer that is obtained from bees and used significantly in everyday life. With the great progress in sciences and technology, the synthesis of nanoparticles (NPs) has accelerated, with the emergence of the latest methods using various natural products in order to attain eco-friendly (green) synthesis of NPs. Natural polymers such as chitosan, hyaluronic acid, heparin, alginate, gelatin and fibrin are safe and biodegradable making them interesting biomaterials in pharmaceutical formulations for a wide range of clinical applications. Chitosan is a polysaccharide derived from chitin. Hydrogels and nanocomposite hydrogels based on chitosan have been broadly used for different biomedical applications. Hyaluronic acid is a hydrophilic polysaccharide with moisturizing and anti-wrinkle characteristics. Self-assembled hyaluronic acid-based nanoparticles have been widely studied for their pharmaceutical and biomedical applications because they are biocompatible and have excellent receptor-binding properties. Hence, heparin-based nanoparticles have biocompatible properties; this makes them useful for various applications like cancer treatment, imaging, and antibacterial activity. Alginate is a naturally-derived copolymer that is used for the fabrication of various hydrogels and nanocomposite hydrogels. Gelatin is widely used for preparing hydrogels and nanocomposite hydrogels with improved thermal and mechanical properties by the addition of nanoparticles to a gelatin-based hydrogel. Fibrin has been investigated as an excellent delivery system to achieve controlled drug release. These natural polymers owing to their biocompatibility and excellent characteristics could be promising materials for more efficient drug delivery, regenerative medicine, and tissue engineering. The present review will focus on various fabrication techniques and clinical applications of many natural polymers as pro and anti-biomineralization.
Keywords: biominerlization; natural polymers; polysaccharides; polypeptides, hydrogels. nanoparticles, regenerative medicine; drug delivery systems.
(12) Review on Extraction, Chemical Treatments and Applications of Natural Fiber Composites
Sathish S 1*, Prabhu L 2, Gokulkumar S 3, Karthi N 4,
1 Assistant Professor, KPR Institute of Engineering and Technology, Arasur, Coimbatore-641407; email@example.com
2 Assistant Professor, KPR Institute of Engineering and Technology, Arasur, Coimbatore-641407; firstname.lastname@example.org
3 Assistant Professor, KPR Institute of Engineering and Technology, Arasur, Coimbatore-641407; email@example.com
4 Assistant Professor, KPR Institute of Engineering and Technology, Arasur, Coimbatore-641407; firstname.lastname@example.org
* Correspondence: email@example.com;
Abstract: Sustainable and ecofriendly products are gaining more attraction currently because of their low weight, abundantly available and their recyclability in various engineering industries. The natural fibers reinforced composites properties could be enhanced by proper chemical treatments. This review proposes a detailed assessment of the different types of extraction methods, chemical treatments and applications of natural fibers. We recapitulate key findings from the literature and the treatment effects of the natural fibers properties are being highlighted.
Keywords: Natural Fibers, Extraction Methods, Chemical Treatments, Synthetic Fibers
(13) Facile synthesis and Synergistic effect of calcium sulfate fillers on the adhesive properties of bisphenol A (DGEBA) epoxy resin
College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, P.R. China
Abstract: The synergist effect of calcium sulfate fillers on the adhesive properties of epoxy resin with calcium sulfate fillers was evaluated. It is learned that the porosity of modified calcium sulfate fillers resulted in the achievement of a high tensile modulus. The addition of calcium sulfate fillers significantly increased the tensile modulus at lower wt % and achieved high crystalline CaSO4 composite. The scanning electron microscopy (SEM) shows an even distribution of concentrated CaSO4. Clusters formed at higher CaSO4 ratios, produced large expansion, low crystallinity, and increased elongation. Further, it was observed that even distribution and dispersion of fillers enhanced transformation, greatly improved and enriched the bonding performance of epoxy resin in the interfacial area. Enhancing the mechanical properties of epoxy resin via CaSO4 fillers have broadened applications prospect in environmental fields. This suggests and encourages the widespread use of CaSO4 fillers in environmental engineering in terms of adhesive properties.
Keywords: Calcium sulfate fillers; tensile modulus; scanning electron microscopy; elongation.
(14) Biomass Use Of Açaí Shell In Nature And Treated Via Alkaline Solution As Reinforcements In High Impact Polystyrene Composites
Rafael Aparecido de Morais Nogueira, Maria Cristina Carrupt Ferreira Borges, Deisi Vieira, Jorge Luiz Rosa, Cirlene Fourquet Bandeira, Sérgio Roberto Montoro*
Abstract: The growing need for the use of clean technologies strengthens research focused on materials obtained from renewable sources. Lignocellulosic fibers have many advantages such as low density, attractive cost, biodegradable, and non-abrasive. The present work presents the study of the alkaline treatment in açaí bark biomass that promotes the alteration of the surface of lignocellulosic fibers. Such fibers may be substituents of the commonly used fiberglass, in composites using as polymer matrix of thermoplastic matrices. In order to achieve a satisfactory adhesion between the fibers and the matrix, the fibers were subjected to alkaline treatments with 5% w/w NaOH and 1% w/w NaBH4 as a protective agent. In order to evaluate the properties of the fibers, the tests as specific mass and scanning electron microscopy (SEM) were performed. After drying the mass of açaí biomass that underwent alkaline treatment, a mass of 22 g was found. Thus, when compared to the initial value (30 g), a mass loss of 8 g occurred. This reduction in mass was expected, since alkaline treatment promotes the partial removal of lignin, hemicellulose, and other components present in natural biomass (eg, waxes, extractives, etc.). As expected, a variation of the average specific mass of the material after alkaline treatment (ρ = 1.2797g/cm³) occurred when compared to the in nature material (ρ = 1.3308 g/cm³). This decrease indicated that there was the extraction of lignocellulosic components of greater mass such as hemicelluloses (ρ = 1.52 g/cm3) due to alkaline treatment. With the alkali treatment with NaOH + NaBH4, the outer fibers presented a rough surface with the loose fibrils, due to the effect of lignin removal. Considering that lignin acts as a ligand between the fibrils, on being removed caused the process of fibrillation. Through the interpretation of scanning electron microscopy (SEM) micrographs, it can also be said that composites with treated biomass will tend to have a lower amount of voids and less amount of pull-out, suggesting greater adhesion with the polymer matrix than composites with untreated fibers. Thermal characterization via TGA and DSC showed that alkaline treatment promoted the removal of lignin. Thus, it can be concluded that the biomass of the açaí shell after undergoing the alkaline treatment with NaOH + NaBH4 can be an efficient alternative to be used as a reinforcing agent in thermoplastic polymer composites.
Keywords: composites, HIPS, açaí biomass, alkaline treatment, surface treatment.