Novel Biocomposites Sheet Molding Compounds for Low Cost Housing Panel Applications

Biocomposites were made by a novel high volume processing technique named biocomposite sheet molding compound panel (BCSMCP) manufacturing process. This process design was inspired by the commercial glass fiber–polyester resin composite fabrication method called sheet molding compounding (SMC). This process yields continuous production of biocomposites on a large scale, and thus can be easily adopted in industries. A unique fiber dispersion method, which enabled uniform distribution of natural fibers, was used in this process. Consistency of the process was tested by evaluating the repeatability of the resultant materials mechanical properties. The low cost biocomposites produced as a result of the processing will be used for various panel applications such as housing and transportation. The molded samples were tested for various mechanical and thermal properties, in accordance with ASTM procedures. The biocomposites were made with various natural fibers including, big blue stem grass, jute, and industrial hemp. By combining different natural fibers in varying mass fractions, hybrid biocomposites were made using this process. Grass fiber reinforced polyester biocomposites processed by the SMC line showed very promising results.     

Soil Biodegradation of PHBV/Peach Palm Particles Biocomposites

There is great interest in developing eco-friendly green biocomposites from plant-derived natural fibers and crop-derived bioplastics attributable to their renewable resource-based origin and biodegradable nature. Fully biodegradable composites, made from both biodegradable polymeric matrices and natural fibers, should be advantageous in some applications, such as one way packaging. Polyhydroxyalkanoates (PHAs) are naturally occurring biodegradable polymers produced from a wide range of microorganisms, with poly(3-hydroxybutyrate) P(3HB) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) being important examples of PHAs. In this work, biocomposites of PHBV consisting of a PHBV matrix incorporating peach palm particles (PPp), [i.e., 100/0, 90/10, 80/20 and 75/25 (%w/w) PHBV/PPp] were processed by injection molding at 160 °C. The effect of PPp loading on the thermal and the mechanical properties, as well as on the morphological behavior of the PHBV/PPp biocomposites was investigated. Soil biodegradation tests were carried out by burying specimen beakers containing aged soil and kept under controlled temperature and humidity in accordance with ASTM G160-98. Degradation of the biocomposites was evaluated by visual analysis, scanning electron microscopy (SEM) and thermogravimetric analysis (TGA) following test exposures of up to 5 months. The addition of PPp reduced the maximum strength and the elongation at break of the biocomposites. On the other hand, the Young’s modulus improved with the PPp content. Micrographs of the fracture surfaces following tensile strength testing revealed a large distance between the PHBV matrix and PPp particles although a low interaction is expected. Where measured, these distances tended increase as the PPp content of the biocomposites increased. Soil biodegradation tests indicated that the biocomposites degraded faster than the neat polymer due to the presence of cavities that resulted from introduction of the PPp and that degradation increased with increasing PPp content. These voids allowed for enhanced water adsorption and greater internal access to the soil-borne degrader microorganisms.     

Study of Graft Copolymerization of Soy Protein-Methyl Methacrylate: Preparation and Characterization of Grafted Films

Hybrid materials represent the family of compounds comprising mixtures of natural and synthetic materials. The study of this field is in a marked expansion since their preparation represents a valid methodology for optimizing the insufficient properties exhibited by materials integrally formed from naturally-occurring sources. In the present work, we describe soy protein modification by grafting reaction with methyl methacrylate. The reaction was confirmed by Fourier Transform Infrared Analysis and Carbon Nuclear Magnetic Resonance. In addition, films were prepared with the material by heat compression. Films were physically and mechanically characterized by determining contact angle with water, total soluble matter, moisture content, swelling in water, water vapor permeability, tensile strength, elongation at break and Young’s modulus. These measurements suggest that the material increased its hydrophobic character as compared with that of the control film since marked reductions in water vapor permeability, swelling and water solubility were determined. Moreover, their mechanical properties were improved by obtaining a more rigid material. These results represent an interesting advance in the preparation of hybrid biocomposites.     

Environmental Impact Assessment of Polylactide(PLA)/Chicken Feathers Biocomposite Materials

The aim of this study is to analyse the environmental impacts (EIs) of the process of preparation of new biocomposite materials obtained from polylactide (PLA) and chicken feathers (CFs). Two CFs stabilization methods and different percentages of CFs have been studied. The EIs of these new composites were compared to the impact of virgin PLA. Cradle-to-gate life cycle inventories were assessed for 0–35% v/v of CFs in a CFs/PLA biocomposite. Two CFs stabilization processes, autoclave and surfactant, were tested and compared with the aim to prioritize one of them from the environmental point of view. A composite plate of 184?×?184?×?2.2 mm³ was defined as the functional unit. Autoclave stabilization process exhibited lower environmental impact compared with surfactant stabilization process mainly due to both the lower requirements of electricity and water and the reduced pollution loads of the generated wastewater. Thus, the autoclave process was selected as the standard method when comparing the EIs of the proposed CFs/PLA biocomposites. In this sense, the addition of CFs to PLA matrix proportionally reduces all the EIs compared to pure PLA due to the replacement of PLA with CFs. This behaviour can be explained because the PLA production accounts for the 99% of the impact of the biocomposite. Consequently, CFs conveniently stabilized might be an alternative raw material to prepare CFs/PLA biocomposites with less environmental impact compared to pure PLA.     

Comparative environmental assessment of natural and recycled aggregate concrete

Constant and rapid increase in construction and demolition (C&D) waste generation and consumption of natural aggregate for concrete production became one of the biggest environmental problems in the construction industry. Recycling of C&D waste represents one way to convert a waste product into a resource but the environment benefits through energy consumption, emissions and fallouts reductions are not certain. The main purpose of this study is to determine the potentials of recycled aggregate concrete (concrete made with recycled concrete aggregate) for structural applications and to compare the environmental impact of the production of two types of ready-mixed concrete: natural aggregate concrete (NAC) made entirely with river aggregate and recycled aggregate concrete (RAC) made with natural fine and recycled coarse aggregate. Based on the analysis of up-to-date experimental evidence, including own tests results, it is concluded that utilization of RAC for low-to-middle strength structural concrete and non-aggressive exposure conditions is technically feasible. The Life Cycle Assessment (LCA) is performed for raw material extraction and material production part of the concrete life cycle including transport. Assessment is based on local LCI data and on typical conditions in Serbia. Results of this specific case study show that impacts of aggregate and cement production phases are slightly larger for RAC than for NAC but the total environmental impacts depend on the natural and recycled aggregates transport distances and on transport types. Limit natural aggregate transport distances above which the environmental impacts of RAC can be equal or even lower than the impacts of NAC are calculated for the specific case study.     

Thermo-mechanical Characterization of New Natural Cellulose Fiber from Zmioculus Zamiifolia

Journal of Polymers and the Environment - The environmental impact on pollution has attracted the use of natural cellulose fibers as a replacement for synthetic materials due its ecofriendly nature...     

A Comparative Study of Doum fiber and Shrimp Chitin Based Reinforced Low Density Polyethylene Biocomposites

The aim of this paper was to study the effects of reinforcing low density polyethylene (LDPE) by using bio-fillers (Doum cellulose or Shrimp chitin) on the mechanical properties. Both, Doum cellulose extracted frsom Doum leaves and Shrimp chitin extracted from shrimp co-products were compounded with LPDE without and with compatibilizer. The biocomposites were prepared by melt blending in a twin-screw extruder. Torsion and flexural tests were performed to investigate the impact of each reinforcement on the biocomposite mechanical properties. The SEM was carried out to study the filler/polymer interface adhesion. The present study has demonstrated that Doum fibers and shrimp chitin succeed in improving the mechanical properties of LPDE bio-composites. The results also showed that the use of maleic anhydride-grafted polyethylene as a compatibilizer improves filler adhesion/matrix and mechanical properties. This study exhibits that polyethylene composites based on Doum fibers or shrimp chitin can be used to replace the polyethylene materials in several fields like packaging and automotive industries.     

A Critical Review on Natural Fibers Modifications by Graft Copolymerization for Wastewater Treatment

Graft copolymerization is a distinctive approach to modify the inherently cheap natural fibers (NFs) using different initiators to incorporate synthetic polymer side chains allowing development of novel types of hybrid materials. This method has been widely applied to develop a variety of NFs based adsorbents for decontamination of toxic pollutants from the aqueous environment. However, the development of high-performance adsorbents from NFs is steady challenged by the need to preserve the sustainability during graft modifications and applications. This article critically reviews the progress on modifications of NFs by graft copolymerization of polar monomers on NFs using various initiating methods and their applications in wastewater treatment. Particularly, the applications of the grafted NFs in removal of heavy metal ions, synthetic dyes, oil spills and extraction of precious metals from wastewater are elaborated. The critical challenges to the viability and sustainability of NFs-based adsorbents with respect to functionalization by graft copolymerization and environmental impacts are discussed and the future research directions are also outlined.

     

Tests for the evaluation of ammonium attenuation in MSW landfill leachate by adsorption into bentonite in a landfill liner

Uncontrolled leachate emissions are one of the key factors in the environmental impact of municipal solid waste (MSW) landfills. The concentration of ammonium, given the anaerobic conditions in traditional landfills, can remain significantly high for a very long period of time, as degradation does not take place and volatilisation is not significant (the pH is not high enough to considerably shift the equilibrium towards un-ionised ammonia). Recent years have witnessed a continuous enhancement of landfill technology in order to minimize uncontrolled emissions into the environment; bottom lining systems have been improved and more attention has been devoted to the study of the attenuation of the different chemicals in leachate in case of migration through the mineral barrier. Different natural materials have been considered for use as components of landfill liners in the last years and tested in order to evaluate the performance of the different alternatives. Among those materials, bentonite is often used, coupled with other materials in two different ways: in addition to in situ soil or in geocomposite clay liner (GCL). A lab-scale test was carried out in order to further investigate the influence of bentonite on the attenuation of ammonium in leachate passing through a landfill liner. Two different tests were conducted: a standardized batch test with pulverized bentonite and a batch test with compacted bentonite. The latter was proposed in order to better simulate the real conditions in a landfill liner. The two tests produced values for the partition coefficient K(d) higher than the average measured for other natural materials usually utilized as components of landfill liners. Moreover, the two tests showed similar results, thus providing a further validation of the suitability of the standard batch test with pulverized bentonite. A thorough knowledge of attenuation processes of ammonium in landfill liners is the basis for the application of risk analysis models for the evaluation of the failure of bottom liners or their components.     

Molding Method, Thermal and Mechanical Properties of Jute/PLA Injection Molding

Natural composites have been important materials system due to preservation of earth environments. Natural fibers such as jute, hemp, bagasse and so on are very good candidate of natural composites as reinforcements. On the other hand regarding matrix parts thermosetting polymer and thermoplastic polymer deriver form petrochemical products are not environmental friendly material, even if thermoplastic polymer can be recycled. In order to create fully environmental friendly material (FEFM) biodegradable polymer which can be deriver from natural resources is needed. Therefore poly(lactic acid) (PLA) polymer is very good material for the FEFM. In this paper jute fiber filled PLA resin (jute/PLA) composites was fabricated by injection moldings and mechanical properties were measured. It is believable that industries will have much attention to FEFM, so that injection molding was adopted to fabricate the composites. Long fiber pellet fabricated by pultrusion technique was adopted to prepare jute/PLA pellet. Because it is able to fabricate composite pellets with relative long length fibers for injection molding process, where, jute yarns were continuously pulled and coated with PLA resin. Here two kinds of PLA materials were used including the one with mold releasing agent and the other without it. After pass through a heated die whereby PLA resin impregnates into the jute yarns and sufficient cooling, the impregnated jute yarns were cut into pellets. Then jute/PLA pellets were fed into injection machine to make dumbbell shape specimens. In current study, the effects of temperature of PLA melting temperature i.e. impregnation temperature and the kinds of PLA were focused to get optimum molding condition. The volume fractions of jute fiber in pellet were measured by several measuring method including image analyzing, density measurement and dissolution methods. Additionally, thermal and mechanical properties were investigated. It is found that 250° is much suitable for jute/PLA long fiber pultrusion process because of its less heat degradation of jute, better impregnation, acceptable mechanical property and higher production efficiency. Additionally the jute fibers seem much effective to increase deflection temperature under load, tensile modulus and Izod strength.     

Use of rubble from building demolition in mortars

Because of increasing waste production and public concerns about the environment, it is desirable to recycle materials from building demolition. If suitably selected, ground, cleaned and sieved in appropriate industrial crushing plants, these materials can be profitably used in concrete. Nevertheless, the presence of masonry instead of concrete rubble is particularly detrimental to the mechanical performance and durability of recycled-aggregate concrete and the same negative effect is detectable when natural sand is replaced by fine recycled aggregate fraction. An alternative use of both masonry rubble and fine recycled material fraction could be in mortars. These could contain either recycled instead of natural sand or powder obtained by bricks crushing as partial cement substitution. In particular, attention is focused on the modification that takes place when either polypropylene or stainless steel fibers are added to these mortars. Polypropylene fibers are added in order to reduce shrinkage of mortars, stainless steel fibers for improving their flexural strength. The combined use of polypropylene fibers and fine recycled material from building demolition could allow the preparation of mortars showing good performance, in particular when coupled with bricks. Furthermore, the combined use of stainless steel fibers and mortars containing brick powder seems to be an effective way to guarantee a high flexural strength.     

Biopolymers Based Green Composites: Mechanical, Thermal and Physico-chemical Characterization

Natural cellulosic fibers are one of the smartest materials for use as reinforcement in polymers possessing a number of applications. Keeping in mind the immense advantages of the natural fibers, in present work synthesis of natural cellulosic fibers reinforced polymer composites through compression molding technique have been reported. Scanning Electron microscopy (SEM), Thermo gravimetric/Differential thermal/Derivative Thermogravimetry (TGA/DTA/DTG), absorption in different solvents, moisture absorbance, water uptake and chemical resistance measurements were used as characterization techniques for evaluating the different behaviour of cellulosic natural fibers reinforced polymer composites. Effect of fiber loading on mechanical properties like tensile strength, flexural strength, compressive strength and wear resistances has also been determined. Reinforcing of the polymer matrix with natural fibers was done in the form of short fiber. Present work indicates that green composites can be successfully fabricated with useful mechanical properties. These composites may be used in secondary structural applications in automotive, housing etc.     

Renewable Resource-Based Biocomposites of Various Surface Treated Banana Fiber and Poly Lactic Acid: Characterization and Biodegradability

Eco-friendly completely biodegradable biocomposites have been fabricated using polylactic acid (PLA) and banana fiber (BF) employing melt blending technique followed by compression moulding. BF??s were surface treated by NaOH and various silanes viz. 3-aminopropyltriethoxysilane and bis-(3-triethoxy silyl propyl) tetrasulfane (Si69) to improve the compatibility of the fibers within the matrix polymer. Characterization studies have been suggested that a better fiber matrix interaction because of the newly added functionalities on the BF surface as a result of chemical treatments. In comparison with the untreated BF biocomposite, an increase of 136% in tensile strength and 57% in impact strength has been observed for Si69 treated BF biocomposite. DSC thermograms of surface treated BF biocomposites revealed an increase in glass transition and melting transition due to the more restricted macromolecular movement as a result of better matrix fiber interaction. The thermal stability in the biocomposites also increased in case of biocomposite made up of BF treated with Si69. Viscoelastic measurements using DMA confirmed an increase of storage modulus and low damping values for the same biocomposite. Biodegradation studies of the biocomposites have been investigated in Burkholderia cepacia medium through morphological and weight loss studies.     

Life Cycle Assessment on a Bus Body Component Based on Hemp Fiber and PTP<Superscript>®</Superscript>

The application of renewable raw materials in the automotive sector became more and more interesting in the last years. For the first time, a material system based on natural fibers and PTP^®, a vegetable based thermoset resin, was produced and manufactured into a bus body component by Sheet-Moulding-Compound-technology. The Life Cycle Assessment on this component based on renewable raw materials shows advantages especially in the categories fossil resources and global warming. It can be expected that further concepts of development and optimization lead to a more efficient use of materials and so to an additional reduction of environmental impacts.     

Enzyme-Retted Flax Fiber and Recycled Polyethylene Composites

Municipal solid wastes generated each year contain potentially useful and recyclable materials for composites. Simultaneously, interest is high for the use of natural fibers, such as flax (Linum usitatissimum L.), in composites thus providing cost and environmental benefits. To investigate the utility of these materials, composites containing flax fibers with recycled high density polyethylene (HDPE) were created and compared with similar products made with wood pulp, glass, and carbon fibers. Flax was either enzyme- or dew-retted to observe composite property differences between diverse levels of enzyme formulations and retting techniques. Coupling agents would strengthen binding between fibers and HDPE but in this study fibers were not modified in anyway to observe mechanical property differences between natural fiber composites. Composites with flax fibers from various retting methods, i.e., dew- vs. enzyme-retting, behaved differently; dew-retted fiber composites resulted in both lower strength and percent elongation. The lowest level of enzyme-retting and the most economical process produces composites that do not appear to differ from the highest level of enzyme-retting. Flax fibers improved the modulus of elasticity over wood pulp and HDPE alone and were less dense than glass or carbon fiber composites. Likely, differences in surface properties of the various flax fibers, while poorly defined and requiring further research, caused various interactions with the resin that influenced composite properties.     

Leaching of inorganic contaminants from cement-based waste materials as a result of carbonation during intermittent wetting

Characterization of the leaching behavior of wastes is a crucial step in the environmental assessment for reuse or disposal scenarios. The release of inorganic contaminants from waste materials is typically evaluated by tank leaching of continuously water-saturated material. However, materials, in many field or management scenarios, experience cyclic wetting and drying under varied environmental conditions (i.e. variable relative humidity, atmospheric CO2 or CO2 from biologic activities). During periods of storage in an unsaturated environment, many processes may occur that can influence the release potential and release rate of inorganic constituents. The research presented here was carried out to examine how the phenomena of carbonation during drying influence the release of inorganic contaminants from Portland cement-based materials during cyclic wetting and storage. Batch equilibrium leaching tests were used to determine constituent solubility as a function of pH. Dynamic leaching tests on monolithic material were carried out to determine the rate of constituent release as a function of leaching time and intermittent storage conditions. This paper presents the results observed for three typical waste constituents, arsenic, cadmium and lead.     

Mechanical, Thermal and Water Absorption Properties of Kenaf-Fiber-Based Polypropylene and Poly(Butylene Succinate) Composites

The use of composites made from non-biodegradable conventional plastic materials (e.g., polypropylene, PP) is creating global environmental concern. Biodegradable plastics such as poly(butylene succinate) (PBS) are sought after to reduce plastic waste accumulation. Unfortunately, these types of plastics are very costly; therefore, natural lignocellulosic fibers are incorporated to reduce the cost. Kenaf fibers are also incorporated into PP and PBS for reinforcing purposes and they have low densities, high specific properties and renewable sourcing. However without good compatibilization, the interfacial adhesion between the matrix and the fibers is poor due to differences in polarity between the two materials. Maleic anhydride-grafted compatibilizers may be introduced into the system to improve the matrix-fiber interactions. The overall mechanical, thermal and water absorption properties of PP and PBS composites prepared with 30 vol.% short kenaf fibers (KFs) using a twin-screw extruder were being investigated in this study. The flexural properties for both types of composites were enhanced by the addition of compatibilizer, with improvements of 56 and 16 % in flexural strength for the PP/KF and PBS/KF composites, respectively. Good matrix-fiber adhesion was also observed by scanning electron microscopy. However, the thermal stability of the PBS/KF composites was lower than that of the PP/KF composites. This result was confirmed by both DSC and TGA thermal analysis tests. The water absorption at equilibrium of a PBS composite filled with KFs is inherently lower than of a PP/KF composite because the water molecules more readily penetrate the PP composites through existing voids between the fibers and the matrix. Based on this research, it can be concluded that PBS/KF composites are good candidates for replacing PP/KF composites in applications whereby biodegradability is essential and no extreme thermal and moisture exposures are required.     

Leaching assessment of road materials containing primary lead and zinc slags

Characterisation of the leaching behaviour of waste-containing materials is a crucial step in the environmental assessment for reuse scenarios. In our research we applied the multi-step European methodology ENV 12-920 to the leaching assessment of road materials containing metallurgical slag. A Zn slag from an imperial smelting furnace (ISF) and a Pb slag from a lead blast furnace (LBF) are investigated. The two slags contain up to 11.2 wt% of lead and 3.5 wt% of zinc and were introduced as a partial substitute for sand in two road materials, namely sand-cement and sand-bitumen. At the laboratory scale, a leaching assessment was performed first through batch equilibrium leaching tests. Second, the release rate of the contaminants was evaluated using saturated leaching tests on monolithic material. Third, laboratory tests were conducted on monolithic samples under intermittent wetting conditions. Pilot-scale tests were conducted for field testing of intermittent wetting conditions. The results show that the release of Pb and Zn from the materials in a saturated scenario was controlled by the pH of the leachates. For the intermittent wetting conditions, an additional factor, blocking of the pores by precipitation during the drying phase is proposed. Pilot-scale leaching behaviour only partially matched with the laboratory-scale test results: new mass transfer mechanisms and adapted laboratory leaching tests are discussed.     

Use of recycled fine aggregate in concretes with durable requirements

The use of construction waste materials as aggregates for concrete production is highly attractive compared to the use of non-renewable natural resources, promoting environmental protection and allowing the development of a new raw material. Several countries have recommendations for the use of recycled coarse aggregate in structural concrete, whereas the use of the fine fraction is limited because it may produce significant changes in some properties of concrete. However, during the last decade the use of recycled fine aggregates (RFA) has achieved a great international interest, mainly because of economic implications related to the shortage of natural sands suitable for the production of concrete, besides to allow an integral use of this type of waste. In this study, the durable behaviour of structural concretes made with different percentage of RFA (0%, 20%, and 30%) is evaluated. Different properties related to the durability of concretes such as absorption, sorptivity, water penetration under pressure, and carbonation are determined. In addition, the results of compressive strength, static modulus of elasticity and drying shrinkage are presented. The obtained results indicate that the recycled concretes have a suitable resistant and durable behaviour, according to the limits indicated by different international codes for structural concrete.     

Structure and Properties of Chicken Feather Barbs as Natural Protein Fibers

The structure and properties of chicken feather barbs makes them unique fibers preferable for several applications. The presence of hollow honeycomb structures, their low density, high flexibility and possible structural interaction with other fibers when made into products such as textiles provides them unique properties unlike any other natural or synthetic fibers. No literature is available on the physical structure and tensile properties of chicken feather barbs. In this study, we report the physical and morphological structure and the properties of chicken feather barbs for potential use as natural protein fibers. The morphological structure of chicken feather barbs is similar to that of the rachis but the physical structure of the protein crystals in chicken feather barbs is different than that reported for feather rachis keratin. The tensile properties of barbs in terms of their strength and modulus are similar but the elongation is lower than that of wool. Using the cheap and abundant feathers as protein fibers will conserve the energy, benefit the environment and also make the fiber industry more sustainable