Mixture Of Polypropylene Research Articles

Residual composite materials with applications in the industry of the construction

Ecological awareness as an ethical obligation is conceived. A product, a prototype or a process must culminate efficiently when incorporated into a production chain; its life cycle will depend, therefore; of its use, reuse and recycling. This project presents an industrial vision in conjunction with agriculture. For this, a general problem of interaction between products (agribusiness chain of the banana plant and reuse of conventional polymeric waste) that work within the same context has been addressed. Colombia has climatic conditions that weigh this country as one of the major producers in the banana zone. Today Colombia is recognized for its quality and for its exports, which reach a figure of 1,578,112 Tons of Banana as of December 31, 2017, and amount to 86.99 million boxes of approximately 18.14 Kg. Once the fruit is harvested, it is packed and exported; at the end of this process, the leaves and stems of the plant become waste. This residue called pseudostem has a mass percentage of about 51% with respect to the total plant. In economic terms, 1,667,000 metric tons per year correspond to this waste, an important economic factor in regions where bananas are high, as is the case in Risaralda. In response to this situation, we find that the banana pseudostem is a low-cost fiber, which increases its mechanical strength when mixed with medium density polymers. These characteristics allow mixing cellulosic residues with residual polymers such as polypropylene, the incorporation of load and reinforcement elements in thermoplastics has been a common practice in the plastics industry whose purpose is the reduction of production costs of molded products, and the improvement of thermo-mechanical properties of polymers. In this context, new materials are proposed based on the mixture of polypropylene and fiber with percentages of 10%, 20% and 30%. For these materials, the process variables were evaluated based on obtaining the pellets by extrusion and finally the samples to which the mechanical properties were estimated. On the other hand, the 3D design of the potential application in roof tiles for construction is reported and it is concluded that at 20 % fiber the degradation. There is a good consistency of pellets, but there is a drastic detriment of traction.

Hydrotreating of middle distillates with addition of pyrolysis oil from depolymerisation of waste plastics

The research work deals with the influence of the addition of alternative pyrolysis fractions as a component of feedstock processed in the hydrogenation of middle distillates. The alternative feedstocks are middle boiling fractions of oils derived from pyrolysis of sorted waste plastics, namely polystyrene (PyOil-PS) and mixture of polypropylene and polyethylene (PyOil-PP/PE). The down-flow testing reactor was used for simulation of hydrogenation process. The effects of the addition of alternative pyrolysis fractions on the quality of products as well as on the activity of the desulphurisation catalyst were studied. The testing was divided into three steps. The reaction temperature was subsequently changed to achieve the level of sulphur content of 10 mg.kg-1. In the first step, the feedstock was changed to the standard feedstock used in the hydrogenation unit. When the required level of sulphur content has been achieved, the feedstock was changed in the second step. The feedstock was changed to a standard feedstock with addition of 5 wt% of the mentioned alternative feedstock. The addition of alterna-tive pyrolysis fractions were compensated by an increase in reaction temperature by 6 °C to achieve the level of sulphur content of 10 mg.kg-1. In the third step, the feed-stock was changed to the standard feedstock. The addi-tions of recycled alternative materials resulted in higher deactivation of the catalyst, which had to be compensated by an increase in reaction temperature of 3 °C for PyOil-PS oil and 6 °C for PyOil-PP/PE. Pyrolysis oils used showed to be potential raw material for co-processing with conventional feedstock. The overall effect on activity of catalyst should be verified during long-term testing. Products meet requirements of standard ČSN 590.

Mechanical and structural properties for recycled thermoplastics from waste fishing ropes

To develop the utilization of recycled plastics made from fishing ropes waste, which have been drifted ashore on the seaside, mechanical and structural properties of the waste were analyzed. Fourier transform infrared spectrometry and differential scanning calorimetry measurements revealed that the fishing ropes waste used in this study was composed of polyethylene (PE) fiber or a mixture of PE and polypropylene (PP) fibers. The mechanical properties of the recycled PE plastic substantially changed after different heat treatment condition, i.e., quenching at 0 °C or heating at 70 and 110 °C. The results showed that this recycled material became stiffer and more brittle as the crystallinity increased. In contrast, the mechanical properties of the recycled PE/PP plastic were not dependent on the heat treatment; the mechanical properties of this material remained relatively low regardless of the selected heat treatment. This observed lack of improvement occurred because PE and PP are non-compatible, so the structure inside the material was phase-separated. By adding ground rice hull (RH) as a modifier to the PE/PP resin, the elastic modulus of the composites increased substantially, whereas the degree of elongation decreased. The improvement in mechanical properties was remarkable for the composites containing an average RH particle diameter of 17 μm.

Microwave pyrolysis of polystyrene and polypropylene mixtures using different activated carbon from biomass

In this study, microwave pyrolysis was experimented with mixed types of plastic waste. Two different plastic wastes polystyrene waste (PSW) and polypropylene waste (PPW) were used as feedstock. Carbon and activated carbon were synthesized from different biomass; rice husk (RH), corn husk (CH) and coconut sheath (CS) respectively which are used as microwave susceptors. The effect of impregnation on product yields was studied. Microwave pyrolysis at 900 W and with a polymer to an absorbent ratio of 10:1, produced the highest oil yield of 84.30 wt% when coconut sheath activated carbon (CSAC) was used as an absorbent. The reaction time was 10 min for the complete decomposition of polymer mixtures. Oil properties were determined and a high calorific value of 46.87 MJ kg−1 was obtained. These properties were compared to conventional fuel properties and the product oil has a density of 0.76 g ml−1 and viscosity of 2.4 cSt which is an equivalent fraction obtained to that of gasoline. Product oil has a styrene recovery of 67.58% from microwave pyrolysis. The results demonstrate that, microwave pyrolysis has a great potential for energy recovery from mixed plastic waste and the use of agricultural residues as absorbents enhanced the production efficiency of the process.

Ionic liquid- modified lignin as a bio- coupling agent for natural fiber- recycled polypropylene composites

In this study, the influence of ionic liquid-treated lignin as a bio coupling agent on the various properties of bagasse fiber-recycled polypropylene composites was investigated. For this purpose, extracted lignin from Bagasse Soda black liquor was modified with 1-ethyl-3-methylimidazolium acetate ([Emim][OAc]) ionic liquid and then different ratios of unmodified and modified lignin (0, 1, 3 and 5 wt%) were added to the bagasse fiber/recycled polypropylene mixture. The composites were then manufactured by injection molding after mixing mechanically of the bagasse fiber, virgin or modified lignin and recycled polypropylene. Structural and thermal properties of lignin after modification by ionic liquid along with physical (water absorption and thickness swelling) and mechanical (flexural modulus, flexural strength, tensile strength and impact strength) properties of the manufactured composites were measured according to ASTM standard methods. The FTIR analysis indicated lignin rearrangements showing that some bonds changed or formed after its modification with IL. The DSC analysis showed that the glass transition temperature (Tg) of lignin decreased from 92 °C to 80 °C by increasing the weight ratio of ionic liquid to lignin from 20 to 30 wt%. The panel testing results indicated that all physical and mechanical properties of the composites were continuously improved by increasing the lignin content from 1 to 5 wt%. Thus, the composites with IL-treated lignin presented higher dimensional stability and mechanical strength compared to those prepared with unmodified lignin. Scanning electron microscopy (SEM) showed that treatment with ionic liquid improves the uniform dispersion of lignin in the polymer matrix.

Combustibles alternativos para motores de combustión interna obtenidos a partir de residuos plásticos

Of the different methods for recycling plastic, pyrolysis offers the possibility to overcome the limitations of mechanical recycling, which requires large amounts of clean, separate and homogeneous plastic waste to ensure the quality of the final product. Pyrolysis is the chemical decomposition of plastic materials by thermal degradation in the absence of oxygen. The plastic waste is introduced into a chamber, where it is subjected to high temperatures, and the gases generated are condensed in order to obtain a distillate hydrocarbon. This paper presents the results obtained from the pyrolysis of plastic waste mixtures of polypropylene, high density polyethylene, and low density polyethylene. In a first stage, the plastic waste is subjected to a rapid pyrolysis process at temperatures of 440-450 °C, obtaining a mixture of heavy hydrocarbons. Subsequently, these hydrocarbons are subjected to a distillation process, first at a temperature of 180 °C, where a hydrocarbon with properties similar to those of gasoline is obtained, and then at a temperature of 360 °C, yielding a hydrocarbon with properties similar to those of diesel.

Determinación de la ruta crítica para la síntesis Química de hidroxiapatita nanométrica

Of the different methods for recycling plastic, pyrolysis offers the possibility to overcome the limitations of mechanical recycling, which requires large amounts of clean, separate and homogeneous plastic waste to ensure the quality of the final product. Pyrolysis is the chemical decomposition of plastic materials by thermal degradation in the absence of oxygen. The plastic waste is introduced into a chamber, where it is subjected to high temperatures, and the gases generated are condensed in order to obtain a distillate hydrocarbon. This paper presents the results obtained from the pyrolysis of plastic waste mixtures of polypropylene, high density polyethylene, and low density polyethylene. In a first stage, the plastic waste is subjected to a rapid pyrolysis process at temperatures of 440-450 °C, obtaining a mixture of heavy hydrocarbons. Subsequently, these hydrocarbons are subjected to a distillation process, first at a temperature of 180 °C, where a hydrocarbon with properties similar to those of gasoline is obtained, and then at a temperature of 360 °C, yielding a hydrocarbon with properties similar to those of diesel.

Value added hydrocarbons obtained by pyrolysis of contaminated waste plastics in horizontal tubular reactor: In situ upgrading of the products by chlorine capture

Abstract Municipal plastic waste (mixtures of high-density polyethylene, low-density polyethylene, polypropylene, and polyvinyl chloride) was pyrolyzed in a pilot-scale horizontal tubular reactor. To increase the yield of volatile and to improve the product properties (e.g. reduced chlorine content, better storage and transportation) red mud, calcium hydroxide, and nickel loaded zeolite catalysts were used. The nickel loaded synthetic zeolite catalysts were prepared by wet impregnation. Catalysts with high synthetic zeolite content can increase the yields of light oil roughly by 50%. The char formation was slight under the same used conditions. In case of catalyst free pyrolysis, the gases and light oil contained significant amount of chlorinated hydrocarbons, which can occur further corrosion problems. The stability of light oil was followed by aging test. Slight formations of polymerized compounds from unsaturated hydrocarbons were found after the treating in case of catalytic pyrolysis. However, the total acidic number was moderate-high without catalyst. Regarding the catalysts, the concentration of chlorinated compounds can be drastically reduced in the presence of catalysts. Especially, when high ratios of the red mud and calcium hydroxide were used. Therefore, the total acid number could be also reduced. Higher synthetic zeolite ratio in the catalyst mixture led to favorable hydrocarbon composition of products, e.g. higher concentration of branched compounds or lower C/H ratio.

Development of Two-Component Polymer-Polymeric Composites Based on UHMWPE-PP Blends for Additive Manufacturing

In order to develop extrudable polymer composites for additive manufacturing some mechanical and tribological properties of polymer-polymeric mixtures of ultra-high molecular weight polyethylene (UHMWPE) and polypropylene (PP) have been investigated. The problem of selecting rational compositions with the aim of improving the manufacturability (extrudability) of UHMWPE was solved. It is shown that extrudable 3D-printed UHMWPE composites over their tribomechanical properties (wear resistance, friction coefficient, elastic modulus, yield point, tensile strength, and elongation at break) exceed those of the hot pressing fabricated composite. This is related to more uniform ordered permolecular structure formation with increased crystallinity. It is shown that the composite ″UHMWPE + 20 wt.% PP″ is the most efficient from the standpoint of maintaining high tribomechanical properties and possessing acceptable melt flow rate (MFR) index.

Performance of hot bituminous mixes admixed with blended synthetic fibers

With increased traffic loads and climate changes, even well designed bituminous surfaced roads are fast deteriorating. Hence, in recent years, research has been focusing on the control of fracture and permanent deformations in flexible pavements. In order to address issues of rutting, fatigue, and low-temperature cracking, different types of polymer modifiers have been utilized. The use of blended synthetic fibers as a low cost modifier in bituminous pavement mix was found to be effective in improving performance compared to other modifiers, as an attractive option. In this study, a mixture of polypropylene and aramid fibers was introduced to evaluate the performance characteristics of a bituminous mixture. The objective of the study was to evaluate the mechanistic properties of conventional and fiber-reinforced bituminous mixtures and implications of fiber addition on thickness and cost reduction of bituminous layers. Effect of addition of fiber on pavement design has also been studied. The laboratory experimental program included indirect tensile strength tests, wet indirect tensile strength after water and MIST (Moisture Induced Sensitivity Test) conditioned, dynamic creep and resilient modulus at different temperatures. This paper reports of the reduction of thickness of pavement also cost analysis with the addition of fibers and resulting properties. Optimum fiber dosage was determined to be 0.05% by weight of mix based on laboratory performance of mix. The results show that fiber improved the mixture performance by a drop of rut depth up to 50% and adding fatigue resistance up to 400%. Moisture resistance and indirect tensile strength of fiber mixture is increased by 9 to 14% in comparison to conventional mix. While the addition of fibers resulted in 2% higher cost, manifold increase of performance and 13% reduction in pavement thickness would justify the act.

Enhancement of Percolation Threshold by Controlling the Structure of Composites Based on Nanostructured Carbon Filler

The effect of a multicomponent polymer binder composition on the electrical conductivity of composites filled with carbon black (CB) is reported. Composites based on a mixture of polypropylene and styrene-ethylene-butylene-styrene (SEBS), plasticized with industrial oil, and filled with electrically conductive CB, were prepared using a twin-roller mixer. The presence of various regions in the volume of the binder and the distributions of CB in binder regions was investigated by scanning electron microscopy. The formation of a special conductive network of CB is observed in the investigated composite. The electrical characteristics of the composites were investigated by means of impedance spectroscopy. On the basis of Raman spectroscopy, it was found that CB is predominantly located in the elastomer (in SEBS plasticized with industrial oil), which forms a continuous phase. It has been shown that the spatial distribution of CB (under constant loading of the filler) can change the conductivity of composites by as much as 5 orders of magnitude, and provides a low percolation threshold.

Friction stir welding of pure magnesium and polypropylene in a lap-joint configuration: Microstructure and mechanical properties

A hybrid joint with a satisfactory mixture of pure magnesium and polypropylene (PP) was achieved via friction stir joining (FSW) in a lap-joint configuration. The tool rotational and travel speeds used in this work were 500–700 r/min and 50–100 mm/min, respectively. The mechanical properties and microstructural analysis of the resultant hybrid Mg/PP joint were examined. The results show that the maximum tensile shear strength (22.5 MPa) of the joint was attained at 700 r/min and 75 mm/min due to the optimum percentage fraction of mechanical interlocking (48%) and the presence of magnesium oxide. The interfacial joint center exhibits the maximum microhardness values because of the presence of refined and intertwined Mg fragments and density dislocations in the matrix of the PP. The joint failed via two different modes: interfacial line and weld zone fractures, respectively.

Retarding the flammability of polypropylene based on the synergistic effect of montmorillonite and carbon nanotubes

The aim of this work is to reduce the flammability of polypropylene (PP) materials which are plenty used in a variety of industrial applications. For the first time, the efficiency of eco-friendly and low-cost flame retardant of CNTs prepared from rice straw on the flammability degree of PP/MMt composite is reported in this study. Mixtures of polypropylene/ montmorillonite /carbon nanotubes (PP/MMt/CNTs) were prepared by using different percentages of MMt and CNTs. The used CNTs sample was prepared from rice straw waste and the MMt was collected from Wadi El Hamadia, Egypt. The prepared samples were characterized by using Fourier transform infrared (FTIR) spectroscopy and scanning electron microscope (SEM), while the flammability properties were measured by using Limiting Oxygen Index (LOI). The results of FTIR and the photos of SEM showed that the MMt/CNTs composition is incorporated into the PP matrix. The LOI test revealed that LOI value of PP increased from 18.8% to 21.5 % in presence of MMt particles while the addition of 0.05 and 0.1 % of CNTs to PP/MMt significantly improved the LOI value to become 22.4 and 23.5%, respectively. This finding indicates that the addition of CNTs as co-nanofiller can improve the flame retardancy of PP/MMt composites. Thus the obtained MMt/CNTs composites act as synergist fillers to offer admirable and fire safe PP products.

Monitoring of abiotic degradation of photocrosslinked silicone acrylate coatings: the fate of the photoinitiator.

Photocrosslinked silicone acrylates are used in a variety of applications, such as printing inks, adhesives, or adhesive release liners. Their production requires the use of a photoinitiator. Even if the photoinitiator represents a minor mass in the photocurable formulation (2-10%), it is used in excess and residual amounts may therefore remain in the polymerized products and possibly migrate into the environment during the use of the products and/or at their end-of-life stage. Little is known on the possible degradation of silicone acrylate which may increase the potential release. The present study investigated the release of Darocur 1173, the most commonly used photoinitiator, from silicone matrix and the effect of accelerated photoageing on the extent of the phenomenon. Leaching tests in water were conducted on thin-coated plastic film (release liners) made of a mixture of polypropylene and polyethylene. Results showed that 44% of the Darocur 1173 photoinitiator initially used in silicone formulation was released from silicone matrix in the leaching test. Accelerated photoageing obtained by UV irradiation of the films for up to 200h was found to favor photoinitiator degradation but also induced a strong and fast oxidation of silicone-coated liners as compared to that of uncoated ones. Graphical abstract.

Environmentally-friendly technology for rapid on-line recycling of acrylonitrile-butadiene-styrene, polystyrene and polypropylene using near-infrared spectroscopy

The recovery of waste acrylonitrile-butadiene-styrene (ABS), polystyrene (PS) and polypropylene (PP) from waste white goods was inefficient due to their similar chemical and physical property. In this work, an environmental friendly equipment based on on-line dynamic recognition for recycling the waste white goods plastic stream (i.e. ABS, PS and PP mixture) was established. It included the recognition process utilizing the near infrared (NIR) range 1050 nm-1350 nm and separation process using the air ejection. In particular, NIR spectrum of waste plastic stream were acquired on-line and analyzed dynamically with the self-designed software. Results showed that although ABS, PS and PP share very similar chemical and physical property, it is possible to separate them with a high accuracy up to 99%. Meanwhile, the optimized operating parameters of the separation process were studied to guide the further industrial recycling process. The study revealed the potentiality of NIR technique as mechanical methods in recycling of plastics from the waste white goods.

Flexural Performance Evaluation of Fiber-Reinforced Concrete Incorporating Multiple Macro-Synthetic Fibers

Fiber-reinforced concrete (FRC) is a promising construction material mainly because of the crack-controlling mechanisms that discrete fibers can impart to inherently brittle concrete. Macrofibers, in particular, have been proven effective for providing post-crack ductility and toughness, while synthetic fibers are a promising solution to avoid corrosion-related durability issues. To assess the performance enhancement provided by macro-synthetic concrete fibers, this study performs flexural tests on FRC beams containing three different types of macro-synthetic fibers. The selected fibers include polypropylene (PP), polyvinyl alcohol (PVA), and alkali-resistant glass (ARG) macrofibers mixed at volume fractions of 0.5%, 1.0%, and 1.5%. Static and dynamic fresh properties are monitored using the vibrating Kelly ball (VKelly) test. Beam specimens are then placed under a third point bending configuration, as per ASTM C1609 Standard, to measure load versus mid-span deflection. Strength and toughness parameters are derived from the load–deflection data to assess the flexural performance of the FRC composite systems under consideration. The parameters of interest include first peak strength (pre-crack flexural strength) and post-crack residual strength and toughness provided by fiber addition. Of the mixtures tested, ARG fiber mixtures show the highest residual strength and toughness values, followed by PP and PVA fiber mixtures. ARG fibers produce the most workable mixtures at all fiber volumes, while PVA fibers show a tendency to encounter dispersion issues at higher volume doses. The outcome of this study is expected to facilitate the selection of fibers by giving insight into their relative contribution to fresh and hardened flexural properties of FRC.

Measurement of Dielectric and Thermal Properties of Leucaena Leucocephala Bio composite substrate with Different Composition Mixture

The measurements of dielectric and thermal properties for bio composite substrate conducted between the mixture of polypropylene (PP) and saw dust filler Leucaena Leucocephala (150μm). The high temperature Agilent 85070E dielectric probe and Quickline 30 Thermal properties analyser used as an instruments to measure the dielectric properties (εr) and handling temperature of the substrate for frequency range of 1GHz to 20 GHz that are suitable for radio frequency applications. The effect of increasing wood filler indicated that it will raise the DK value from 1.84 to 2.49 and decreases the thermal conductivity behaviour from 0.2 to 0.11w/m.k for all 5 mixture fabricated substrate (PP100, PB9010, PB8020, PB7030 and PB6040). In this research the composition of PP must be greater than the sawdust filler due to PP act as laminating and hold the composite structure. The result presented on this research will useful for planar antenna and microwave filter substrate up to frequency 20 GHz and it could support the technical and vocational education tanning (TVET) learning process that hybrid the knowledge among different field.

Effect of Sodium Chloride and Thiourea on Pollutant Formation during Combustion of Plastics

Thermal decomposition of different samples containing a mixture of plastics (polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), and nylon) combined with NaCl and metal oxides (Fe2O3, CuO) was studied under an air atmosphere at 850 °C using a reactor, followed by analysis of the evolved products. Combustion runs were performed to study how the presence of such compounds influences the production of pollutants. Here, we report the analyses of the emissions of the main gases, as well as volatiles and semivolatiles, including polyaromatic hydrocarbons (PAHs), polychlorinated benzenes and phenols, and polybrominated phenols. Results show that the production of chlorinated pollutants did not increase in the presence of NaCl, but the presence of other metals during the decomposition led to the production of a great amount of pollutants. In this regard, the emission of chlorinated phenols increased from 110 to ca. 250 mg/kg when the sample included a small quantity of a transition metal oxide. Additionally, the presence of an inhibitor—thiourea (TUA)—was tested. Results confirm that adding TUA to the sample reduced these emissions to a considerable extent, with the emission of chlorinated phenols amounting to 65 mg/kg.

Characterization of Polypropylene Modified by Blending Elastomer and Nano-Silica.

Polypropylene (PP) contains promising application prospects in thermoplastic cables for high voltage direct current (HVDC) power transmission because of its outstanding thermal and dielectric properties. However, the problem of poor toughness and space charge has restricted the application of pure PP in HVDC cables. In this paper, polyolefin elastomer (POE) and nano-silica were blended thoroughly and added into a PP mixture by a melting method. Scanning electron microscopy (SEM) was employed to observe the dispersion of POE and nanoparticles. Thermal properties were characterized by differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). Mechanical properties were evaluated by tensile tests. The elastomeric properties of composites were improved as the dispersed POE could transfer and homogenize external mechanical forces. DC breakdown results showed that the fail strength of composite with 10 phr POE and 1 phr nano-silica was obviously enhanced. The pulsed electro-acoustic (PEA) results showed that the injection and accumulation of space charge was increased by the introduction of POE, while it was restrained by the collective effect caused by nano-silica filling. X-ray diffraction (XRD) spectrograms showed that secondary ordered structures existed in the composites of PP, POE, and nano-silica, and that the ordered structure around the nanoparticles contributed to the enhancement of breakdown strength. The mechanical and dielectric properties were modified synergistically, which made the modified PP a propitious insulation material for HVDC cables.

Porous 3D Printed Scavenger Filters for Selective Recovery of Precious Metals from Electronic Waste

AbstractSelective laser sintering (SLS) 3D printing is used to fabricate highly macroporous ion scavenger filters for recovery of Pd and Pt from electronic waste. The scavengers are printed by using a mixture of polypropylene with 10 wt% of type‐1 anion exchange resin. Porosities and the flow‐through properties of the filters are controlled by adjusting the SLS printing parameters. The cylinder‐shaped filters are used in selective recovery of Pd and Pt from acidic leachate of electronic waste simply by passing the solution through the object. Under such conditions, the scavenger filters are able to capture Pd and Pt as anionic complexes with high efficiency from a solution containing mixture of different metal ions. By using the Pd/Pt scavenger together with previously reported, highly selective nylon‐based Au scavenger, precious metals, i.e., Au, Pd, and Pt could all be recovered from the electronic waste leachate in a single flow‐through process. One of the main advantages of the printed scavengers is that all recovered metals can be easily extracted from the filters as separate fractions by using aqueous solutions of thiourea or diluted nitric acid. After removal of the captured metals, the scavengers are reusable without significant loss of their ion‐capturing performance.