Madalina Zanoaga - Academia.edu (original) (raw)

Papers by Madalina Zanoaga

Hybrid materials represent one of the most fascinating class of materials developed in recent yea... more Hybrid materials represent one of the most fascinating class of materials developed in recent years. The tremendous possibilities of combination of different properties in one material initiated extensive research on potential novel materials and high performance applications. The aviation and aerospace industry is an area of major interest in terms of new solutions and innovation. The spin-off effect for technology from the aerospace industry to other industrial sectors is particularly pronounced for materials technology which, in the wider sense including computer modelling, interfaces and surface science, is a key instrument to meet challenges. This paper is intended as an overview of the main issues concerning the design and structure-properties relationship of hybrid materials for aerospace applications.

Ecological Chemistry, 2005

Analele Stiintifice ale Universitatii "Alexandru Ioan Cuza" din Iasi Sec. II a. Genetica si Biologie Moleculara, Aug 10, 2007

Freezing, at least of the vegetable products, no matter of the anatomic part involved-root, stalk... more Freezing, at least of the vegetable products, no matter of the anatomic part involved-root, stalk, leaf, flower, fruit or seed-induces a biochemical changes manifested, implicitly, by modification of the tissular rH. More precisely, the more distant the native rH of the product under consideration is from a certain value-apparently the optimum/compatible to the animal, consuming organism-(rH ~ 26), the deeper are the transformations it suffers as a result of freezing, namely: if the native rH takes values below 26, the product gets oxidized by freezing while, in the opposite case, it is reduced, as if the whole group of vegetal products would tend to attain-by means of freezing-a (redox) homeostasis.

International Journal of Polymer Analysis and Characterization, Sep 28, 2018

The subject of this review is the study of the effects of compatibilizers on the properties of re... more The subject of this review is the study of the effects of compatibilizers on the properties of recycled plastic composites, effects monitored and evidenced through various specific methods of characterization, and validated by correlating experimental data and literature reports. In the present context, created by the environmental contamination due to the polymeric waste accumulation resulting from our daily single-life cycle plastic products, it is necessary to envisage new ways to up-cycle plastics. Conventional and reactive compatibilization strategies are among the most widely used methods, and the results are in good concordance with the envisaged applications of the new materials.

The objective of this study was to obtain and evaluate the thermal, mechanical and morphological ... more The objective of this study was to obtain and evaluate the thermal, mechanical and morphological characteristics, as well as the stability towards moisture, of some new green composites made of wood chips (W), as natural filler, and recycled polyethylene (rPE) or recovered statistic aliphatic copolyamide (coPA) as matrix, as well as rPE matrix with small amounts of coPA as compatibilizer. Experimental data confirmed the better dispersion of particles inside the matrix, as well as the improvement in the interfacial adhesion and tensile properties of rPE-W composites containing 5-20% coPA.

Springer Series on Polymer and Composite Materials, 2017

In the recent decades, bio-based polymers have gained increasing interest, especially for composi... more In the recent decades, bio-based polymers have gained increasing interest, especially for composite materials. These polymers and their respective monomers are derived from renewable resources, being thermoplastics or thermosetting resins which are biodegradable or non-biodegradable. Thermosettings are strong, rigid polymer materials and cannot be easily processed by melting after their hardening. At present, thermosetting resins are obtained using highly toxic and volatile petrochemicals, which require human and environmental safety monitoring. Considering the wide range of diverse renewable monomers available, vegetable oils (VOs) are especially well-suited when it comes to the synthesis of thermosetting resins due to their carbon-carbon double bonds, highly desirable for this type of application as these unsaturated bonds can be chemically modified in order to increase reactivity toward further polymerization. Thus, epoxidation, which consists of introducing a single oxygen atom to each non-saturated bond to yield in an epoxidic cycle, is a simple, effective method to modify these VOs. The resulted thermosetting resins exhibit improved toughness and environmental-friendly behavior. VOs, especially soybean oil which is abundant and cheap, are typically mixtures of unsaturated fatty acids with numerous bonds that can be easily converted into the more reactive oxirane rings through the reaction with peracids or

Bioplastics for Sustainable Development, 2021

Nowadays concerns over global warming favored research to focus on the environmental pollution an... more Nowadays concerns over global warming favored research to focus on the environmental pollution and waste accumulation and on the possibility to recycle and up-cycle the waste. A particular class of such waste consists of natural remains and by-products from agriculture and industries, such as forestry, pulp and paper, furniture, and food industry. There are various methods to upcycle and capitalize the agro-industrial waste: (1) anaerobic digestion for energy production; (2) thermal conversion for the resulting liquids and char that may be further used in obtaining other materials, bioplastics included; (3) industrial processing to obtain natural fibers, long or short, able to be employed as reinforcing materials in biocomposites (multicomponent systems where the matrix consists of polymers or polymer blends, either synthetic or natural; they may also contain emulsifiers, compatibilization agents, antioxidants, as well as inorganic, organic, metal, or metal oxides micro- and/or nanoparticles); and (4) composting. Composites based on agro-industrial waste displayed a level of performance high enough to grant their use in a wide variety of applications: furniture and civil constructions; interior design, fencing, and decking; automotive and aerospace industry; food and general packaging. To obtain such materials, it is necessary to consider specific issues, the most important being the compatibility between matrices and reinforcing material. Characteristics of the final material (mechanical, thermal, water sorption, weather resistance) strongly depend on a good compatibility. A critical assessment of the selected methodology is necessary as it is reflected in the final cost of production, which must be limited in relation to the envisaged application.

Handbook of Modern Coating Technologies, 2021

Abstract The demand for protective coatings for wood used in outdoor applications, able to preven... more Abstract The demand for protective coatings for wood used in outdoor applications, able to prevent or limit the weathering along with maintaining the wood aesthetical appearance, is increasing and motivated the R&D community to enhance efforts to provide new solutions. Some recent trends focused on the use of natural products, while others aimed at employing nanomaterials. This chapter offers an overview of the most recent data and a critical assessment of some particular issues. Thus the natural products used per se or in various formulations are presented herein divided in major classes. In the case of nanomaterials, due to the wide variety of formulations available, the type of protection provided was used as classification criterion. The behavior and performance of these particular coatings were evaluated in correlation with their complex formulation, the chemistry and compatibility between coatings and wood, processing, impact on the environment and human health, cost efficiency.

Freezing, at least of the vegetable products, no matter of the anatomic part involved – root, sta... more Freezing, at least of the vegetable products, no matter of the anatomic part involved – root, stalk, leaf, flower, fruit or seed – induces a biochemical changes manifested, implicitly, by modification of the tissular rH. More precisely, the more distant the native rH of the product under consideration is from a certain value – apparently the optimum/compatible to the animal, consuming organism – (rH ~ 26), the deeper are the transformations it suffers as a result of freezing, namely: if the native rH takes values below 26, the product gets oxidized by freezing while, in the opposite case, it is reduced, as if the whole group of vegetal products would tend to attain – by means of freezing – a (redox) homeostasis

Self-healing materials possess tremendous potential in increasing the longevity of structural mat... more Self-healing materials possess tremendous potential in increasing the longevity of structural materials. Consequently, a large number of academic and industrial research organizations have come forward to explore new concepts in design and synthesis of such materials. Though this field of innovative product research shows high promises, it has some practical limitations in understanding crack healing kinetics and stability of healing functionality. In this paper, different types of healing processes, design strategies and specific applications are reviewed.

Technologies for active carbons obtaining from vegetable by-products such as straw, nut shells, f... more Technologies for active carbons obtaining from vegetable by-products such as straw, nut shells, fruit stones, sawdust, hydrolysis products of corn cobs and sunflower husks have been developed. The physico-chemical characteristics, structural parameters and sorption characteristics of obtained active carbons were determined. The ability of carbonaceous adsorbents for detoxification of soil against pesticides, purification of surface waters and for removal of organic pollutants from wastewaters has been evaluated. The obtained results reveal the effectiveness of their use in a number of environmental technologies.

Journal of Optoelectronics and Advanced Materials, 2007

In order to understand the processing-mechanical-property relationships, the effects of adding a ... more In order to understand the processing-mechanical-property relationships, the effects of adding a small amount of maleated ethylene-propylene rubber (EP-g-MA) on the rheological properties of some copolyamide/EPDM blends were evaluated. The changes of the dynamic rheological parameters and some processing characteristics show that the blends with EP-g-MA display a different behavior from that of the homopolymer blend, viscoelastic measurements being sensitive to the composition of the blends. The obtained data showed the incompatibility of the binary coPA/EPDM blends due to the structural difference of the components. Better processability resulted because of high melt flow rate of coPA and increased mobility of elastomer macromolecules. The presence of EP-MA in the blend leads to the enhancement of the interfacial viscosity and adhesion due to the intermolecular interaction between the functional groups of the blend components produced during processing, the experimental curves corr...

Polymer Composites, 2021

A series of three copolyamide‐clay hybrid nanocomposites were prepared using three different smec... more A series of three copolyamide‐clay hybrid nanocomposites were prepared using three different smectite clays (bentonite, montmorillonite K10, and Nanomer I.30P) by a solventless melt mixing process. The influence of the nature of clays on the structural changes was critically assessed by comparison with the neat copolyamide. Nanocomposite samples were analyzed by scanning electron microscopy (SEM), wide angle X‐ray diffractometry (WAXD), UV–vis spectrometry and differential scanning calorimetry (DSC). The testing yielded in direct and indirect evidences of structural changes induced by the presence of clays in correlation with their characteristics, as nature of the clay, particle size, granulometric distribution, and particle dispersion into the matrix.

Environmental Engineering and Management Journal, 2004

In this study, the obtaining of some composite materials using wood chips as filler and a modifie... more In this study, the obtaining of some composite materials using wood chips as filler and a modified polyamidic polymer as thermoplastic matrix is presented. Characterization was carried out on composite samples by analysis of morphology, mechanical properties and thermal behaviour. It was observed that the tensile strength of composites decreased significantly with the increasing wood chips content. Still, even the bending strength is decreasing; it remains 2-8 times higher than that for the composites based on polyolefinic matrices. The thermal stability of the obtained composite materials is higher to that of the initial wood component.

Polymer Composites, 2019

Natural fiber composites have experienced a renaissance in the last two decades as a response to ... more Natural fiber composites have experienced a renaissance in the last two decades as a response to societal demands for developing eco‐friendly, biodegradable and recyclable materials. They are now being extensively used in everyday products as well as in automotive, packaging, sports and construction industries. Hemp fiber is being used in most of these products because of its superior mechanical properties. Like other natural fibers, hemp fibers require modifications in order to improve their properties and interfacial bonding with polymer matrices, and to reduce their hydrophilic character. These modification methods can be grouped into three major categories: chemical, physical and biological. Chemical methods use chemical reagents to reduce fibers' hydrophilic tendency and thus improve compatibility with the matrix. They also expose more reactive groups on the fiber surface to facilitate efficient coupling with the matrix. Physical methods change structural and surface proper...

International Journal of Biological Macromolecules, 2019

As fossil fuel resources dwindle and new regulations for a cleaner and safer environment come on ... more As fossil fuel resources dwindle and new regulations for a cleaner and safer environment come on stream, there is growing interest in developing new sustainable feedstocks for future fuels, chemicals, polymers and fibres. Therefore materials research is ever more focused on the production of green or bio-based materials and their composites. Lignocellulosic biomass has become the feedstock of choice for these new materials as cellulose and lignin are the most abundant biopolymers on the planet. Lignin is a phenolic macromolecule, the principal biological source of aromatic structures, with a complex structure which varies depending on plant species and its isolation process. Despite its high carbon content and its potential as a raw material, lignin remains underutilised. Between 40 and 50 million tons of lignin are produced worldwide per year; while some is being used for low-and medium-value applications, most is currently treated as a non-commercialized by-product or as low value fuel to produce energy. However, with the emergence of biorefinery projects larger amounts of lignin with the potential for valorisation are being produced. Here, we summarise some of the latest developments in the field.

Chemistry Journal of Moldova, 2014

New nanocomposites based on high density polyethylene (HDPE) and organically modified nanoclay (C... more New nanocomposites based on high density polyethylene (HDPE) and organically modified nanoclay (Cloisite 20A) were obtained by two different methods, namely melt compounding and solution blending, and their properties were comparatively studied by XRD, DSC, POM and SEM in order to establish the dependence of the clay degree of exfoliation/intercalation on the preparation procedure. Nanocomposites prepared in molten state under shear stress were found to posses the most extensive dispersion of nanometric clay particles and high levels of exfoliation.

Advanced Structured Materials, 2016

Multicomponent materials based on synthetic polymers were designed and used in a wide variety of ... more Multicomponent materials based on synthetic polymers were designed and used in a wide variety of common and hi-tech applications, including the outdoor applications as well. Therefore, their response to the UV radiation and complex weathering conditions (temperature, seasonal or freeze–thaw cycles, humidity, pH, pollutants, ozone, microorganisms) is a matter of utmost importance in terms of operational reliability and lifetime, protection of the environment and health safety. This chapter offers an overview of this subject and a critical assessment of more particular topics related to this issue. Thus, various types of multicomponent systems based on thermoplastic and thermosetting polymer matrices were subjected to natural and/or simulated UV radiation and/or weathering conditions. Their behavior was evaluated in correlation with their complex formulation and taking into consideration that the overall effect is a sum of the individual responses and interactions between components. The nature and type of the matrix, the nature, type and size distribution of the filler, the formation of the interphase and its characteristics, the interfacial adhesion and specific interfacial interactions, they all were considered as factors that influenced the materials behavior, and, at the same time, were used as classification criteria for this review.