Fly ash reinforced thermoplastic vulcanizates obtained from waste tire powder

Novel thermoplastic composites made from two major industrial and consumer wastes, fly ash and waste tire powder, have been developed. The effect of increasing fly ash loadings on performance characteristics such as tensile strength, thermal, dynamic mechanical and magnetic properties has been investigated. The morphology of the blends shows that fly ash particles have more affinity and adhesion towards the rubbery phase when compared to the plastic phase. The fracture surface of the composites shows extensive debonding of fly ash particles. Thermal analysis of the composites shows a progressive increase in activation energy with increase in fly ash loadings. Additionally, morphological studies of the ash residue after 90% thermal degradation shows extensive changes occurring in both the polymer and filler phases. The processing ability of the thermoplastics has been carried out in a Monsanto processability testing machine as a function of shear rate and temperature. Shear thinning behavior, typical of particulate polymer systems, has been observed irrespective of the testing temperatures. Magnetic properties and percolation behavior of the composites have also been evaluated.     

Rheological, Mechanical and Thermal Behaviour of Wood Polymer Composites Based on Recycled Polypropylene

The aim of this paper was to investigate the effect of recycled polypropylene (PP) on the rheological, mechanical and thermal properties of wood flour polypropylene composites. Beforehand, the influence of wood flour treated with a coupling agent on the rheological behaviour had been looked at. By analysing moduli and viscosity curves and studying the thermal and mechanical properties of samples with 10% filler it was possible to see that the recycled PP that was added change in either its physical properties or its rheology. In the other wood plastic composites (WPC) studied, slight changes in the rheology behaviour were observed. However, the same processing parameters may be used with and without recycled PP. Recycled PP is appropriate for these kinds of composites to maintain the optimal rheological properties that make it easier to process the material by extrusion. Furthermore, it is also possible to maintain the thermal and mechanical properties in comparison with the behaviour of virgin PP/wood flour composites.     

A Grey-Based Taguchi Approach for Characterization of Erosive Wear Phenomenon of Glass–Polyester Fly Ash Filled Composites

Fly ash is a solid waste generated in huge quantities from coal fired thermal power stations during the combustion of coal. In India, less than half of this is used as a raw material for concrete manufacturing and construction; the remaining is directly dumped on land side as land fill or simply piled up. Only a small fraction of it is used in development of high valued product. Due to environmental regulations, new ways of utilizing fly ash are being explored in order to safeguard the environment and provide useful ways for its utilization and disposal. With its richness in various metal oxides, it has tremendous potential to be utilized as a filler material in polymer composites. These days glass reinforced polyester composites find widespread application in erosive environment due to several advantages like high wear resistance, strength-to-weight ratio, and low cost. The cost of the composites can be further brought down using cheaper filler materials. To this end, this work uses fly ash in composite making and thereby suggests a new way of better utility of this industrial waste. It includes the processing, characterization and study of the erosion behavior of a class of such fly ash filled polyester-glass fiber composites. The engineering application of composites demands that it should have high wear resistance, low density and high tensile strength. In order to assess the behavior of composites satisfying multiple performance measures, a grey-based Taguchi approach has been adopted. After thorough analysis of factors, optimal factor settings have been suggested to improve multiple responses viz., erosive wear rate, density, flexural strength and tensile strength. This technique eliminates the need for repeated experiments; thus saves time and material. The systematic experimentation leads to determination of significant process parameters and material variables that predominantly influence the multiple responses.     

Modification of hydraulic conductivity in granular soils using waste materials

This paper evaluates the use of waste products such as silica fume and fly ash in modification of the granular soils in order to remove some environmental problems and create new useful findings in the field of engineering. It is known that silica fume and fly ash, as well as clay material, are used in geotechnical engineering because of their pozzolanic reactivity and fineness to improve the soil properties needed with respect to engineering purposes. The main objective of this research project was to investigate the use of these materials in geotechnical engineering and to improve the hydraulic properties of soils by means of grouting. For this reason, firstly, suitable grouts in suspension forms were prepared by using silica fume, fly ash, clay and cement in different percentages. The properties of these cement-based grouts were then determined to obtain the desired optimum values for grouting. After that, these grouts were penetrated into the soil samples under pressure. The experimental work indicates that these waste materials and clay improved the physical properties and the fluidity of the cement-based grouts and they also decreased the hydraulic conductivity of the grouted soil samples by sealing the voids of the soil. The results of this study have important findings concerning the use of these materials in soil treatment and the improvement of hydraulic conductivity of the soils.     

Utilization of Sunflower Stalk in Manufacture of Thermoplastic Composite

Dimensional stability and mechanical performance of polypropylene thermoplastic composites filled with sunflower stalk (SS) flour at 30, 40, 50, and 60 wt% contents of the SS flour were investigated. The thickness swelling and water absorption of the specimens increased with increasing SS flour content. The modulus in the flexural and tensile improved with increasing SS flour content while the tensile and flexural strengths of the specimens decreased. The use of maleic anhydride polypropylene (3 wt%) had a positive effect on the dimensional stability and mechanical properties of the polypropylene thermoplastic composites filled with SS flour. The melting temperature of polypropylene decreased with increasing content of the SS flour. The degree of crystallinity of filled polypropylene composites between fibre loading of 0–30 % by weight was higher than that of unfilled polypropylene composites. However, further increment in the filler content decreased the degree of crystallinity. The obtained results showed that SS flour could be potentially suitable raw material in the manufacture of polypropylene composites.     

Use of rubber and bentonite added fly ash as a liner material

In many countries regulations require all hazardous waste disposal facilities to be lined with suitable impermeable barriers to protect against contamination. In this study, a series of laboratory tests on rubber and bentonite added fly ash were conducted. The aim of the tests was to evaluate the feasibility of utilizing fly ash, rubber and bentonite as a low hydraulic conductivity liner material. Type C fly ash was obtained from Soma thermal power plant in Turkey; rubber in pulverized form was waste from the retreading industry. To investigate the properties of rubber and bentonite added fly ash, hydraulic conductivity, leachate analysis, unconfined compression, split tensile strength, one-dimensional consolidation, swell and freeze/thaw cycle tests were performed. The overall evaluation of results have revealed that rubber and bentonite added fly ash showed good promise and a candidate for construction of a liner.     

Synergistic Effect of Oil Palm Based Pozzolanic Materials/Oil Palm Waste on Polyester Hybrid Composite

This research work aims to investigate the synergistic effect of pozzolanic materials such as oil palm ash (OPA) and oil palm empty fruit bunch (OPEFB) on the developed hybrid polymer composites. The OPEFB and OPA fillers of different particle sizes (250, 150, and 75 µm) were mixed at OPEFB:OPA ratios of (0:100; 20:80; 40:60; 60:40; 80:20 and 100:0) and incorporated into an unsaturated polyester resin. Furthermore, both mechanical and morphological properties of the composites were analyzed and it was found that tensile, flexural, and impact properties were significantly improved at OPEFB:OPA of 75 µm particle size hybridization of the polymer. The increase of OPEFB to OPA filler ratio up to 80:20 significantly improved the tensile properties of the composites while 40:60 ratio of 75 µm gave the optimum filler ratio to obtain the highest flexural and impact properties of the composites among all studied samples. Scanning electron micrograph images showed strong particle dispersion of the embedded fillers with resin which explained the excellent mechanical strength enhancement of the composite.     

Effects of Filler Content and Compatibilizing Agents on Mechanical Behavior of the Particle-Reinforced Composites

The study was carried out to investigate the effects of filler content and two different compatibilizing agents (Eastman G-3003 and G-3216) on the mechanical properties of polypropylene reinforced with corn stalk and wood flour. In the sample preparation, three levels of filler loading (30, 40 and 50 wt%) and one level of compatibilizing agent content (2.5 wt%) were used. For overall trend, with addition of both grades of the compatibilizing agents, tensile and flexural properties of the composites significantly improved, as compared with the pure PP. Tensile and flexural properties reach a maximum at 40 wt% filler content and gradually decrease with a further increase in wood particle content. The composites treated with G-3003 gave better results in comparison with G-3216. This could be caused by the high melt viscosity of G-3003. In general, corn stalk flour filled composites showed superior mechanical properties.     

Characterization of poly(lactic acid) biocomposites filled with chestnut shell waste

The aim of this study was to determine thermal and mechanical properties and applicability of ground chestnut shell waste as a filler for poly(lactic acid) composites. The used amount of filler was ranging from 2.5 to 30 wt%. Spectroscopic analysis of composites and its ingredients was conducted by means of FT-IR method. The mechanical and thermal properties of the composites were determined in the course of static tensile test, Dynstat impact strength test, DMTA analysis, and DSC method. The fractured surface morphology of biocomposites was evaluated by SEM analysis. Incorporation of the filler influenced the overall mechanical properties of the composites characterized by high stiffness and lowered impact resistance. Fabricated composites with different amounts of non-reactive natural waste filler exhibited acceptable mechanical and thermal properties. Therefore, these composites can be used as eco-friendly, biodegradable materials for low-demanding applications.     

Characterization of composites based on expanded polystyrene wastes and wood flour

This paper aims to evaluate the potential for the use of recycled expanded polystyrene and wood flour as materials for the development of wood plastic composites. The effects of wood flour loading and coupling agent addition on the mechanical properties and morphology of wood thermoplastic composites were examined. In addition, a methodology for the thermo-mechanical recycling of expanded polystyrene waste was developed. The results show that the mechanical properties decreased as the wood flour loading increased. On the other hand, the use of poly(styrene-co-maleic anhydride), SMA, as a coupling agent improved the compatibility between the wood flour and polystyrene matrix and the mechanical properties subsequently improved. A morphological study revealed the positive effect of the coupling agent on the interfacial bonding. The density values obtained for the composites were compared with the theoretical values and showed agreement with the rule of mixtures. Based on the findings of this work, it appears that both recycled materials can be used to manufacture composites with high mechanical properties and low density.     

Influence of Filler Particle Size on Physical Properties and Biodegradation of Biocomposites Based on Low-Density Polyethylene and Lignocellulosic Fillers

This study examined biocomposites based on low-density polyethylene (LDPE) and lignocellulosic fillers [wood flour (WF) and oil flax straw (FS)] selecting four size fractions of each lignocellulosic material as fillers for the composites. The primary aim was to evaluate the influence of fraction size on the composites’ basic properties; to accomplish this, the composites’ mechanical properties, thermal oxidation, thermophysical characteristics, and water absorption capacity were examined. Then microphotographs of the samples were created and length-to-diameter (L/D) ratio of the fillers was calculated, finding that the L/D ratio increased with increasing particle size. The particle size influenced the oxidative degradation and water absorption processes in composites with oil flax but not in those with WF. Biodegradation tests performed on the recovered soil found that the loss of mass in composites based on LDPE and FS was higher than in the same composites with WF. Moreover, at the initial stage of composting, the biodegradation rate correlated with the size of filler particles (i.e., the larger the particles, the higher the degradation rate of the biocomposite).     

Effect of Fiber Surface Treatments on Thermo-Mechanical Behavior of Poly(Lactic Acid)/Phormium Tenax Composites

In the present study, Phormium Tenax fiber reinforced PLA composites were processed by injection molding and twin screw compounding with a fiber content ranging from 10 to 30 wt%. Three surface treatment methods have been used to improve the Phormium Tenax fiber-matrix interfacial bonding that are as follows: (1) aqueous alkaline solution, (2) silane coupling agent, and (3) a combination of alkaline and silane treatment. The mechanical, thermal and morphological properties of the resulting composites were investigated. The results have shown that the moduli of surface treated fiber reinforced composites are lower than the ones obtained for untreated composites (as a consequence of the decrease in fiber modulus caused by the chemical treatments) and no significant increase in strength was observed for any of the composites compared to neat PLA. SEM micrographs of composite fractured surfaces confirmed an improvement in the interfacial strength, which was insufficient nonetheless to significantly enhance the mechanical behavior of the resulting composites. Results from thermogravimetric analysis and differential scanning calorimetry suggest that surface treatment of Phormium affects the ability of PLA to cold crystallize, and the thermal stability of the composites at the different fiber contents was reduced with introduction of alkali and silane treated Phormium fibers.     

Injection Molded Wheat Straw and Corn Stem Filled Polypropylene Composites

Environmentally friendly composite materials can be prepared using wood fibers and/or various types of agro-derived fibers as reinforcements. In this study, agro-residues such as wheat straw and corn stem filled polypropylene were prepared and their suitability was investigated as a reinforcing filler in thermoplastics and as an alternative to the wood flour filled plastics. Effect of compounding techniques, compatibilizer and fungal treatment of agro-residues on the mechanical properties of the composites were evaluated. It was found that high shear compounding of wheat straw fibers exhibited similar properties to that produced by the milled wheat straw. This may be due to the extensive fiber breakage occurred during the high shear compounding that results in a similar aspect ratio to that of milled straw. Compatibilizer is needed for improving the strength properties of the agro-residue filled PP composites. Fungal treatment of milled wheat straw did not show much improvement in the strength properties of the composites. Comparison of mechanical properties of the agro-residue filled PP with that of the wood flour and the old newsprint filled PP showed the suitability of the agro-residues as alternative filler for thermoplastics.     

Thermal and Flame Retardancy Behavior of Oil Palm Based Epoxy Nanocomposites

The aim of present study was to investigate the thermal properties and flame retardancy behavior of flame retardant (FR) epoxy nanocomposites from chemically treated (bromine water and tin chloride) oil palm empty fruit bunch (OPEFB) nano filler at different filler loading (1, 3, 5%). Thermal properties were evaluated through thermogravimetry analyzer, derivative thermogravimetry and differential scanning calorimetry. FR properties of nanocomposites are evaluated through UL-94 vertical burning test and limiting oxygen index (LOI). The functional group analysis of all composites was made by FTIR spectroscopy. Thermal analysis shows that degradation temperature of epoxy composites shifts from 370 to 410 °C and char yield also increases for 3% loading. Furthermore LOI value of 29% and UL-94 rating of V-0 with no flame dripping and cotton ignition, revealed that 3% oil palm nano filler filled epoxy nanocomposites display satisfactory flame retardancy. The superior flame retardancy of epoxy nanocomposites are attributed to the chemical reactions occurred in the gaseous phases and the profound synergistic flame retardation effect of tin with bromine in the treated nano OPEFB filler. All the epoxy nanocomposites displayed almost similar FTIR spectra with the characteristics metal-halogen bond supporting the synergism. Homogeneous dispersion of 3% oil palm nano filler act as highly effective combustion chain terminating agent compared with 1 and 5% nano OPEFB/epoxy nanocomposites.     

Poly(lactic acid)/Cellulose Composites Obtained from Modified Cotton Fibers by Successive Acid Hydrolysis

This work is focused on the hydrolysis of cotton fibers from waste textiles to obtain micro and nanofibers to be used as reinforcements in polymer composites. To promote their compatibility with polymeric matrix, hydrolyzed cotton fibers were surface modified with various silane compounds. Thus, these fibers were mixed with commercial poly(lactic acid) (PLA) at 5% w/w loading by melt compounding. Acid treatments caused a decrease of the crystallinity index whereas the thermal stability was significantly improved, especially for cellulose fibers hydrolyzed in two steps. Morphological analysis revealed a reduction of the fibers diameter and a decrease of their length as a consequence of the hydrolysis. NMR analysis confirmed the silanization of the fibers by reaction with the silane agent. Tensile tests revealed that silanization treatments were able to increase the composite Young’s modulus and the stress at break with respect to the neat matrix, indicating that silanization improved the polymer/fiber compatibility interfacial adhesion. The overall results demonstrated that applying suitable surface modification strategies, waste cotton textiles can be effectively recycled as fillers in polymer based composites.     

Development and Application of Green Composites: Using Coffee Ground and Bamboo Flour

Environmental degradation and global warming are increasing as a result of the use of petroleum. Therefore, many industries are seeking more eco-friendly materials that will decrease the level of environmental contamination and economic cost. Recently, the level of coffee consumption has increased rapidly. Therefore, the amount of coffee grounds discarded is increasing. In this study, polylactic acid, coffee grounds and bamboo flour were compounded for green composites. Coffee grounds are used in the recycling of food waste. In addition, 4,4-methylene diphenyl diisocyanate (MDI) was used as a coupling agent. The mechanical strength of green composites decreased with increasing natural filler content. However, mechanical and thermal properties were increased by the addition of MDI as a coupling agent. The hydroxyl groups of natural fillers reacted with the isocyanate group of MDI, and a urethane linkage was created between the polymer and natural fillers.     

Sustainable alkali-activated binders with municipal solid waste incineration ashes as sand or fly ash replacement

The present study investigates the feasibility of using two types of municipality solid wastes incineration ashes, namely, fly ash and bottom ash in the production of sustainable alkali-activated binder. The ashes are collected from the incineration plant and characterized to determine their particle size distribution, specific gravity, chemical composition, and heavy metals content. The ashes are then used as either fly ash or sand replacement with five replacement ratios 0%, 5%, 10%, 15%, and 20% to produce the binder. The produced binder are characterized in terms of strength, workability, density, water absorption, thermal conductivity and stability, chemical composition, and heavy metals content. The results reflect the ability of producing sustainable alkali-activated binder with small dosage of MSWI ashes as either fly ash or sand replacement without negatively affecting its strength, workability, density, and water absorption. The ashes enhance the thermal insulation capability of the binder.

     

Sustainable Use of Coffee Husks For Reinforcing Polyethylene Composites

The utilization of the coffee husk fiber (CHF) from the coffee industry as a reinforcing filler in the preparation of a cost-effective thermoplastic based composite was explored in this study. The chemical composition and thermal properties of the CHF were investigated and compared with those of wood fiber (WF). CHF proved to be mainly composed of cellulose, hemicellulose and lignin, and exhibited similar thermal behavior to WF. High density polyethylene (HDPE) composites with CHF loadings of from 40 to 70% were prepared using melt processing and extrusion. The processing properties, mechanical behavior, water absorption and thermal performance of these composites were investigated. The effect of maleated polyethylene (MAPE) used as a coupling agent on the composite was explored. The experimental results showed that increasing the CHF loading in the HDPE matrix resulted in an increase in the modulus and thermal properties of the composites, but resulted in poor water resistance. The addition of a 4% MAPE significantly improved the interfacial behavior of the hydrophilic lignocellulosic fiber and the hydrophobic polymer matrix.     

Hybrid Composites from Waste Materials

Hybrid composites of thermoplastic biofiber reinforced with waste newspaper fiber (NF) and poplar wood flour (WF) were prepared. The weight ratio of the lignocellulosic materials to polymer was 30:70 (w:w). Polypropylene (PP) and maleic anhydride grafted polypropylene (MAPP) were also used as the polymer matrix and coupling agent, respectively. The mechanical properties, morphology and thermal properties were investigated. The obtained results showed that tensile and flexural modulus of the composites were significantly enhanced with addition of biofibers in both types (fiber and flour), as compared with pure PP. However, the increasing in WF content substantially reduced the tensile, flexural and impact modulus, but improved the thermal stability. This effect is explained by variations in fiber morphological properties and thermal degradation. Increasing fiber aspect ratio improved mechanical properties. The effect of fiber size on impact was minimal compared to the effects of fiber content. Scanning electron microscopy has shown that the composite, with coupling agent, promotes better fiber–matrix interaction. The largest improvement on the thermal stability of hybrid composites was achieved when WF was added more. In all cases, the degradation temperatures shifted to higher values after addition of MAPP. This work clearly showed that biofiber materials in both forms of fiber and flour could be effectively used as reinforcing elements in thermoplastic PP matrix.     

Behavior of Cellulose Reinforced Cross-Linked Starch Composite Films Made with Tartaric Acid Modified Starch Microparticles

Tartaric acid modified starch microparticles (TA-SM) previously obtained using the dry preparation technique were introduced as filler within glycerol plasticized-corn starch (GCS), the composites being prepared by casting process. The effects of cellulose addition within the TA-SM-GCS matrix on the structure, surface properties and water sorption, as well as mechanical and thermal properties of starch-based composite films were investigated. The water resistance and thermal stability were slightly improved through addition of high content of cellulose due to the inter-component H-bonding between components. The evaluation of mechanical properties evidenced a significant increase of the tensile strength of the composites with increasing the content level of cellulose.