Natural Organic Fillers Research Articles

Pyrolysis of natural rubber–cellulose composites: isoconversional kinetic analysis based on thermogravimetric data

Despite the current growing interest in rubber composites with natural organic fillers, there is a lack of kinetic analyses that describe the decomposition of these materials during pyrolysis. For this reason, the main objective of this study was the kinetic analysis and determination of formal kinetic parameters for the pyrolytic decomposition of NR–CEL composites with different cellulose content (0, 30, 45, and 55 phr). Thermogravimetric measurements were made at heating rates of 2, 4, 6, 8, 10, and 20 °C min–1 in the temperature range of 20–600 °C. First, Friedman and KAS model-free methods were applied. Therefore, model-based methods and the model-fitting procedure were used to find the optimal multi-step kinetic model. The proposed final model consists of two parallel processes, which are kinetically independent: A → B → C and D → E → F. For each step, a kinetic triplet was calculated: the apparent activation energy, the pre-exponential factor, and the kinetic parameters of the extended empirical Prout–Tompkins model. The master plots method was used to determine the kinetic decomposition mechanism of the individual steps. It was found that step A → B has the shape of an nth-order model, step B → C mainly follows the diffusion model, the mechanism of step D → E transfers from a random scission kinetics model to an nth-order model with an increasing amount of CEL, and step E → F obeys the chain scission mechanism.

Rheological properties and curing features of polymer materials filled with biowaste

AbstractBesides mechanical properties, the dynamic mechanical properties in a sensible range of temperature and rheological properties have to be taken into account for engineering applications. The rising concern towards the reduction in the use of petroleum‐based non‐renewable resources has led to increasing interests in natural polymer composites filled with natural organic fillers, i. e. they are from renewable and biodegradable sources. This work is focused on the use of biowaste, specifically wood flour as a plasticizer replacement in a rubber compound. Plasticizers (also called softener, extender or process oils) are common additives for polymers with a low molecular weight. An increasing content of a plasticizer usually leads to a decrease in the viscosity of the rubber mixture, and therefore, its processability can be improved. Based on the given fact, the experiment is aimed at the studies of the rheological properties. The scanning electron microscopy results can confirm the compatibility or incompatibility of the biowaste, specifically wood flour with rubber matrix. In the case of a successful replacement for plasticizer with wood flour, we expect a significant reduction in the cost of the mixtures production as well as a reduction in the environmental impact, compared with the petroleum products.

Green Composites: A Review of Adequate Materials for Automobile Applications

Increased interest in polymer composites filled with natural organic fillers, fillers derived from renewable sources and biodegradable, has resulted from growing concern about environmental concerns and, on the other hand, the desire for more adaptable polymer-based materials. The composites, which are often, referred to as "Green," have a wide range of industrial uses. This research conducts a literature assessment in the wide field of green composites in order to identify materials with the potential to be used on automobile body panels in the near future. Materials derived from renewable resources will be favoured over finite fossil goods from now on. When the polymer matrix is biodegradable and originates from renewable sources, these composites may be even more environmentally beneficial. This rapid overview (with no pretence of exhaustiveness over such a big issue) demonstrates the major routes and findings of study (both academic and industry) on this relevant subject, as well as acceptable sources for further in-depth studies.

Impact of microorganisms on mechanical properties changes of composite materials with organic filler

The beginning of the XXIst century is characterized by rapid development of polymer materials, including polymer composite materials, which consist of a natural organic filler (wood flour, sawdust, cellulose fiber, flax fiber, sisal fiber) and reinforcement carrier. In case of that kind of the fillers under the influence of weathering (humidity, temperature) they might be subject to biodegradation due to effect of microorganisms, including funguses, which are responsible for degradation of natural organic fillers. In case of the low melting temperature polymers (e.g. PE-LD) the processing temperature does not entirely eliminate some of the fungal spores. The paper has presented the research results of twelve months. The development of the microorganisms in the natural conditions was examined in a pure filler (sawdust) as well as in a composite. Simultaneously, change of one of the fundamental strength properties, which is the impact strength, was being tested. For the investigated composite the PE-LD as the matrix and a sawdust mixture of pine, larch and oak were used. The sawdust formed the composite in 30 %. The research results confirmed that in the natural conditions the microorganisms development depends on weathering which varies in the time of the year. The value of the V notch impact strength changed from 12.5 kJ/m2 for the composite in initial phase to the value of 6.7 kJ/m2 after twelve months operation, which is 50 %.

Flexural analysis of green composite material using CATIA V5 for tool carrier

The intensifying global distress towards the environmental problems and however, the demand for more versatile polymer-based materials has raised concerns about polymer composites containing natural organic fillers, i.e. fillers derived from renewable sources and biodegradable. The composites, which are often referred to as “green,” can be used in a variety of ways. Green composites are commonly listed as having possible applications in the automotive and construction industries, but an analysis of these applications shows that they are frequently an inappropriate fit for green composites' specific material properties. A concise summary of green composites is given, along with graphical comparisons of their relative benefits. In the present study flexural stress is calculated by using CATIA V5, AGMA and ANSYS. Designing a product is an important industrial activity that affects the quality of product, so because of this three dimensional objects is created, analysed and comparison among the three materials according to ASTM D 790 standard using modelling software CATIA V5. Coconut fiber reinforced with epoxy resin composite will have more life and durable because of its less deformation and high stress bearing capacity.

Composite Material Based on Plant Raw Materials

Modern global trends show the preferred low-rise construction, even in large cities. Lightweight concrete is the most common material for low-rise construction. Existing lightweight concrete with the wood residues addition have several disadvantages due to the properties of the aggregate. In the southern regions of Russia, walnut grows in large quantities. Only a small part of the shell is processed, the rest is buried in the ground or burned. The proposed aggregate from crushed walnut shell has several advantages compared to the traditional natural organic fillers: low water demand and decay, high strength. The nutshell in the composition has sugars, which are the cement poisons, there are no data in the literature on the crushed shell technical characteristics. Thus, it is required to determine the crushed shell technical characteristics, to choose a processing method reducing the water-soluble sugars amount in the shell, to select the lightweight concrete composition, ensuring its optimal characteristics. The new kind of lightweight concrete will have characteristics different from existing analogues.

Development of natural fibre reinforced polystyrene (NFRP) composites: Impact resistance study

The prevalent global issue on environmental pollution and the growing desire for polymer based composite materials has given rise to increasing research in the production of composite containing natural organic fillers. This study describes the optimization of impact strength of plastic composites developed from polystyrene and natural fibre wastes(sawdust and rice husk) using 3-level-factoral-design via hand lay-up method studying the effect of filler concentration (15 – 45 %), filler size (20 – 100 µm) and alkaline treatment concentration (2 – 6 %) on the impact strength of polystyrene fibre reinforced composite. Models were developed using response surface methodology to predict impact strength of the composite as a function of the process variables investigated. The optimization of the process parameters show that the optimum condition for obtaining high impact strength are 15% filler concentration, 100 µm filler size and 4% alkaline (NaOH) concentration in saw dust filled composite while a filler concentration of 15%, filler size of 31µm and an alkaline concentration of 2% for the rice husk filled composite. The recycled polystyrene in combination with wood dust and rice husk has produced a polymer composite with moderate impact strength applicable in various applications.

Mechanical, Thermomechanical and Reprocessing Behavior of Green Composites from Biodegradable Polymer and Wood Flour.

The rising concerns in terms of environmental protection and the search for more versatile polymer-based materials have led to an increasing interest in the use of polymer composites filled with natural organic fillers (biodegradable and/or coming from renewable resources) as a replacement for traditional mineral inorganic fillers. At the same time, the recycling of polymers is still of fundamental importance in order to optimize the utilization of available resources, reducing the environmental impact related to the life cycle of polymer-based items. Green composites from biopolymer matrix and wood flour were prepared and the investigation focused on several issues, such as the effect of reprocessing on the matrix properties, wood flour loading effects on virgin and reprocessed biopolymer, and wood flour effects on material reprocessability. Tensile, Dynamic-mechanical thermal (DMTA), differential scanning calorimetry (DSC) and creep tests were performed, pointing out that wood flour leads to an improvement of rigidity and creep resistance in comparison to the pristine polymer, without compromising other properties such as the tensile strength. The biopolymer also showed a good resistance to multiple reprocessing; the latter even allowed for improving some properties of the obtained green composites.

IMPROVING PERFORMANCE AND APPLICABILITY OF GREEN COMPOSITE MATERIALS BY HYBRIDIZATION

A growing concern over environmental issues and the common interest to find a viable alternative to the use of glass or carbon composite reinforcements has led to an increased attention in ecologically sustainable polymer composites. These „green” materials are made by natural fibers, as reinforcement, filled with natural-organic fillers, i.e. derived from renewable or biodegradable sources. At the same time, this relatively new class of materials faces several limits in comparison to traditional composites especially regarding the properties of resistance. This paper investigates the advantages of use of combination of natural fibers for improving mechanical proprieties of „green” composite materials. At the moment, the prevailing opinion is that green composites are not usable in structural applications, and, as a consequence, have to be relegated to unworthy applications (as fillers). On the contrary, there are several evidences that mixing different natural fibers (in practice usually called „hybridization”) leads to an improvement of these material properties. Although usually quite limited in terms of percentage, these improvements from time to time allow a new enlargement in the fields of applications for green composites. Following a large state-of-the-art on green composites, including potential benefits and limits of these materials, the paper proposes several examples of hybridization showing its effect on mechanical proprieties.

Lignocellulosic fibre mediated rubber composites: An overview

The rising concern towards the reduction in the use of petroleum-based, non-renewable resources and the need for more versatile polymer-based composite materials have led to increasing interests on natural polymer composites filled with natural organic fillers, i.e. coming from renewable and biodegradable sources. This paper reviews wood flour and other lignocellulosic fibres filled rubber composites, including cellulosic rubber composites, cellulosic thermoplastic elastomers, nanocellulose based rubber nanocomposites, with the aims at providing the most state of the art information for directing further scientific research, possible commercialization and design of cellulosic rubber composites. It has been found that 1) the surface properties of natural cellulose, hence the compatibility and interface of the natural cellulose and matrix rubber/plastics, are crucial for the successful development of the composites, such, physical and chemical modification and additives have been widely attempted to improve the incompatibility and poor interfacial adhesion between the filler and matrix; 2) the curing characteristics, mechanical properties, thermal stability and morphologies of the composites are complex but closely related to not only the interfacial properties, but also the compositions (e.g. the concentration of cellulosic materials) and other processing parameters; 3) the nature of hydrophilic cellulosic and hydrophobic matrix rubber and/or plastics requires an accurate introduction of coupling agent, one end of its structure shall be compatible to hydrophilic and the other to hydrophobic. The reviews on the main paths and results of study on the advanced nanocellulose reinforced rubber nanocomposites and sandwiches indicate much potentials and needs for further in-depth studies.

IMPROVING PERFORMANCE AND APPLICABILITY OF GREEN COMPOSITE MATERIALS BY HYBRIDIZATION

A growing concern over environmental issues and the common interest to find a viable alternative to the use of glass or carbon composite reinforcements has led to an increased attention in ecologically sustainable polymer composites. These „green” materials are made by natural fibers, as reinforcement, filled with natural-organic fillers, i.e. derived from renewable or biodegradable sources. At the same time, this relatively new class of materials faces several limits in comparison to traditional composites especially regarding the properties of resistance. This paper investigates the advantages of use of combination of natural fibers for improving mechanical proprieties of „green” composite materials. At the moment, the prevailing opinion is that green composites are not usable in structural applications, and, as a consequence, have to be relegated to unworthy applications (as fillers). On the contrary, there are several evidences that mixing different natural fibers (in practice usually called „hybridization”) leads to an improvement of these material properties. Although usually quite limited in terms of percentage, these improvements from time to time allow a new enlargement in the fields of applications for green composites. Following a large state-of-the-art on green composites, including potential benefits and limits of these materials, the paper proposes several examples of hybridization showing its effect on mechanical proprieties.

Mechanical Properties and Water Absorption Behavior of Polypropylene / Ijuk Fiber Composite by Using Silane Treatment

The rising concern towards environmental issues besides the need for more versatile polymer-based materials has led to increasing of interest in studying about the polymer composites filled with natural-organic fillers, which are coming from renewable sources. However, the bonds between polymeric materials and the organic fillers are not strong enough, by referring to mechanical properties. This study intends to the improvement in mechanical properties of polypropylene/ijuk fiber composite by pretreating the fiber using silane treatment. Vinyltrimethoxy silane was used for this silane treatment using immersion technique. Composites with 10wt%, 20wt%, and 30wt% fiber content were fabricated afterwards. The samples were tensile tested and the strength, modulus, and elongation were determined. The composite's water absorption was also tested. As the result, the silane treatment helps increasing the mechanical properties and decreasing the percentage of water absorption of the composites.

Biodegradation paths of Mater‐Bi®/kenaf biodegradable composites

AbstractComposites obtained from biodegradable polymers and natural–organic fillers are attracting increasing interest, thanks to the environmental advantages they promise. On the other hand, the real biodegradation performance of a biodegradable polymer/natural organic filler composite should be assessed by performing specific biodegradation tests. These are often carried out under laboratory conditions, but more realistic conditions should be taken into account. In this work, a systematic study on the biodegradation of kenaf fiber‐filled Mater‐Bi® composites in different environments is presented, and some interesting parameters for the understanding of the optimum way to obtain a fast degradation of the composites can be extrapolated. In particular, it was found that the presence of the fibers, the environmental conditions, and the manufacturing procedures of the composites can significantly affect the biodegradation behavior. The results can be used to determine the most suitable disposal environments for biodegradation of Mater‐Bi®‐based wastes. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Utilization of Agro-Waste <i>A. galanga</i> Natural Fibers in Composites

Utilization of locally abundant agro-waste Alpinia galanga (A. galanga) natural fibers in polyethylene (PE) was investigated. The results indicate that agro-waste fibers generally function as potential natural-organic fillers as well as show an attribute of reinforcement in PE-agro-waste composites at a certain fiber loading. Minimally reduced tensile strength from 28 MPa of unfilled PE, addition of agro-waste A. galanga natural fibers also resulted in reinforcement of up to 31 MPa at 6 wt% agro-waste fibers loading. Findings also reveal that alkali treatment was effective to impart surface modification of agro-waste A. galanga natural fibers and hence improved tensile strength, modulus of elasticity and thermal stability of PE-agro-waste composites.

Effect of the processing on the properties of biopolymer based composites filled with wood flour

Wood-polymer composites (WPCs) are well known today in the field of industrial applications, because of several advantages they can grant if compared with mineral filler-polymer composites. These advantages regard the low cost of wood based fillers, the reduced specific weight, the lower hazards for production workers in case of inhalation, the special aesthetic features, environmental issues. The scientific literature reports studies regarding polymer matrices like, for instance, polyethylene and polypropylene, in combination with several natural-organic fillers. However, a limit of these composites is represented by the fact that there is not a full biodegradability: this, in fact, regards only the filler, therefore the environmental performance is lower than expected. To overcome this limit, it is necessary to replace the traditional, nonbiodegradable polymer matrices (typically, polyolefins) with biodegradable ones. An available solution consists in the use of biodegradable polymers like, for instance, those belonging to the Mater-Bi® family.In this work, a biodegradable polymer matrix, coming from the Mater-Bi® class, was mixed with a naturalorganic filler, wood flour. The investigation was focussed on the comparison between different processing ways (single-screw extruder, twin-screw extruder; compression moulding, injection moulding), in particular the relationships between the mechanical properties and the processing method, the filler type, the humidity content of the components were analyzed. Morphological characterization was also carried out by SEM analysis, in order to get further indications regarding some different behaviours shown by the processing methods and the fillers.

Improving the properties of polypropylene–wood flour composites by utilization of maleated adhesion promoters

Polymer composites filled with natural organic fillers have gained a significant interest during the last few years, because of several advantages they can offer compared with properties of inorganic-mineral fillers. However, these composites (based, in most cases, on polyolefins) often show a reduction in some mechanical properties. This is mainly due to the problems regarding dispersion of the polar filler particles in the non-polar polymer matrix and their interfacial adhesion with polymer chains. In this work, polypropylene–wood flour composites were prepared and the effect of the addition of a maleated polypropylene was investigated. The two materials were compounded by an industrial co-rotating twin screw extruder, with two different compositions, without and with addition of Licomont AR504® (maleic anhydride-grafted polypropylene wax). The extruded material was then compression molded, which provided the specimens for tensile and impact tests. Water uptake was measured; the morphology of the fracture surfaces of the samples coming out from mechanical tests was investigated through SEM analysis. Rheological characterization was carried out as well. The addition of the adhesion promoter allowed a decrease in water uptake; mechanical properties were improved as well, especially elastic modulus and tensile strength; impact strength increased in the case of unnotched samples, while notched ones did not show remarkable differences. SEM analysis of the fracture surfaces also showed an overall change in the morphology as a consequence of the utilization of the adhesion promoter.

Mechanical properties of recycled polyethylene ecocomposites filled with natural organic fillers

AbstractThe use of natural organic fillers in addition to postconsumer recycled polymers is getting a growing interest during the last years; this is due to many advantages they can provide in terms of cost, aesthetic properties, environmental impact. In this work, several types of wood flour (differing each other with regard to production source and particle size) were added to a recycled polyethylene coming from films for greenhouses and the effects of filler type, content, and size were investigated. Investigation was then focused on the improvement of mechanical properties, through the addition of polar copolymers (ethylene‐co‐acrylic acid, ethylene‐vinyl acetate) and a maleic anhydride‐grafted‐grafted polyethylene (Licocene® PE MA 4351 TP), in order to try to overcome the poor adhesion between polar filler particles and nonpolar polymer chains. Investigation was also based on SEM micrographs. An overall positive influence of these additives was observed. Polym. Eng. Sci. 46:1131–1139, 2006. © 2006 Society of Plastics Engineers.

Modification of Wood Flour with Maleic Anhydride for Manufacture of Wood-Polymer Composites

Composites consisting of synthetic polymers and natural organic fillers have many applications. Plant-based materials, particularly wood, are used as fillers. Most frequently they are added to the polymer in the shape of wood flour or wood fibres. This type of polymer composite allows the possibility of modifying the components in accordance with the requirements of the application.Modifications to wood flour (WF) were carried out with a 10% solution of maleic anhydride (MA) in acetone in the presence of benzoyl peroxide and dicumene hydroperoxide. Lignin and cellulose were isolated from the WF and modified by the same method as the WF. They were characterized by Fourier Transform infrared spectroscopy and it was proved that there was a chemical reaction between the wood components and MA. This was confirmed by chemical analysis and by a determination of the hydroxyl groups in unmodified and modified WF.Composites of polypropylene and modified WF were obtained and studied by scanning electron microscopy, transmission electron microscopy, dynamic mechanical analysis and mechanical tests. They showed an improvement in adhesion between the polymer and the modified WF

Biodegradation of poly(vinyl alcohol) in soil environment: Influence of natural organic fillers and structural parameters

The biodegradation of PVA blends with natural polymers, such as gelatin, lignocellulosic by-products (sugar cane bagasse), as well as poly(vinyl acetate), was investigated in respirometric tests aimed at reproducing soil burial conditions. The observed behavior is discussed in terms of the influence of each blend component on the overall extent of mineralization, by assuming a simple additive behavior. The collected data evidenced that the biodegradation of PVA and PVA-based materials is rather limited under soil burial conditions. Additionally, PVA depresses the biodegradation of some of the investigated blends, particularly when mixed with gelatin. On the contrary, the hydrophobic character of the natural polymer component as well as the residual content of acetyl groups of the used PVA samples seem to have a positive effect on the biodegradation propensity of the blend. SEM micrograph (750 ×) of PVA/WG composite blend (Sample WGP20).