Gizilene Maria de Carvalho

Bio: Gizilene Maria de Carvalho is an academic researcher from Universidade Estadual de Londrina. The author has contributed to research in topics: Starch & Reactive extrusion. The author has an hindex of 17, co-authored 33 publications receiving 744 citations. Previous affiliations of Gizilene Maria de Carvalho include Universidade Estadual de Maringá.

Mechanical properties of a polyurethane hybrid composite with natural lignocellulosic fibers

Abstract: Several low-cost hybrid composites composed of polyurethane and renewable natural fibers were developed and analyzed for their mechanical and physical properties. Composites were fabricated by replacing up to 20% w/w of the polyethylene glycol present in conventional polyurethane foams with one and the mixture of three natural fibers: sugarcane bagasse, sisal or rice husk. Prior to composite production, fibers were mercerized with sodium hydroxide and hydrogen peroxide to remove lignin and hemicellulose. A simplex-centroid mixture design model was used to evaluate the effects of the added fibers on composite properties such as resilience, elastic modulus and deformation under permanent compression. Obtained hybrid composites demonstrated up to 32% of resilience, 0.1 GPa of elastic modulus, and 7.32% of permanent deformation. In order to optimize these properties, fiber amounts were adjusted using a quadratic mathematical model, indicating that formulations containing only the rice husk or an 82/18 (% w/w) rice husk/sugarcane bagasse mixture will perform best. The obtained composite is a unique low cost material because is environmentally friendly and has a high potential for applications in shock absorption and padding materials, due its proven good resilience and elastic modulus.

Nanocellulose Produced from Rice Hulls and its Effect on the Properties of Biodegradable Starch Films

Abstract: Rice hull is a residue from agro-industry that can be used to produce nanocellulose. We produced nanocellulose from rice hulls through bleaching (with a 5% NaOH solution followed by a peracetic acid solution) and acid hydrolysis at a mild temperature (45oC) followed by ultrasonication. We investigated the microstructure, crystallinity and thermal stability of these materials and studied their effects on the properties of starch films. After bleaching, the compact structure around the cellulosic fibers was removed, and the lignin content of the residue decreased from 7.22 to 4.22%. The obtained nanocellulose presented a higher crystallinity (up 70%), higher thermal stability than the raw material and lignin contents below 0.35%. The nanocellulose formed interconnected webs of tiny fibers (< 100 nm in diameter), which decreased the opacity, water vapor permeability and improved the mechanical properties when added as reinforcement in the starch films.

Surface and Colloid Science

Abstract: 1: Magnetic Particles: Preparation, Properties and Applications: M. Ozaki. 2: Maghemite (gamma-Fe2O3): A Versatile Magnetic Colloidal Material C.J. Serna, M.P. Morales. 3: Dynamics of Adsorption and Oxidation of Organic Molecules on Illuminated Titanium Dioxide Particles Immersed in Water M.A. Blesa, R.J. Candal, S.A. Bilmes. 4: Colloidal Aggregation in Two-Dimensions A. Moncho-Jorda, F. Martinez-Lopez, M.A. Cabrerizo-Vilchez, R. Hidalgo Alvarez, M. Quesada-PMerez. 5: Kinetics of Particle and Protein Adsorption Z. Adamczyk.

Cu and Cu-Based Nanoparticles: Synthesis and Applications in Catalysis.

Abstract: The applications of copper (Cu) and Cu-based nanoparticles, which are based on the earth-abundant and inexpensive copper metal, have generated a great deal of interest in recent years, especially in the field of catalysis. The possible modification of the chemical and physical properties of these nanoparticles using different synthetic strategies and conditions and/or via postsynthetic chemical treatments has been largely responsible for the rapid growth of interest in these nanomaterials and their applications in catalysis. In addition, the design and development of novel support and/or multimetallic systems (e.g., alloys, etc.) has also made significant contributions to the field. In this comprehensive review, we report different synthetic approaches to Cu and Cu-based nanoparticles (metallic copper, copper oxides, and hybrid copper nanostructures) and copper nanoparticles immobilized into or supported on various support materials (SiO2, magnetic support materials, etc.), along with their applications i...

Polyurethane types, synthesis and applications – a review

Abstract: Polyurethanes (PUs) are a class of versatile materials with great potential for use in different applications, especially based on their structure–property relationships. Their specific mechanical, physical, biological, and chemical properties are attracting significant research attention to tailoring PUs for use in different applications. Enhancement of the properties and performance of PU-based materials may be achieved through changes to the production process or the raw materials used in their fabrication or via the use of advanced characterization techniques. Clearly, modification of the raw materials and production process through proper methods can produce PUs that are suitable for varied specific applications. The present study aims to shed light on the chemistry, types, and synthesis of different kinds of PUs. Some of the important research studies relating to PUs, including their synthesis method, characterization techniques, and research findings, are comprehensively discussed. Herein, recent advances in new types of PUs and their synthesis for various applications are also presented. Furthermore, information is provided on the environmental friendliness of the PUs, with a specific emphasis on their recyclability and recoverability.

Introduction to Spectroscopy

Abstract: Spectroscopy is the study of matter interacting with electromagnetic radiation (e.g., light). The electromagnetic spectrum in Figure 1 illustrates the many different types of electromagnetic radiation, including gamma rays (γ-rays), X-rays, ultraviolet (UV) radiation, visible light, infrared (IR) radiation, microwaves, and radio waves. The frequency (ν) and wavelength (λ) ranges associated with each form of radiant energy are also indicated in Figure 1.