Industrial paper recycling process. Suitable micronization for additive polymer application

The traditional paper recycling process has problems related to the disposal of sludge and waste, the use of incinerators and water treatment. Because of that, an interesting alternative proposed from dep. of chemical and materials engineering of Sapienza University of Rome to Carlucci industrial typography, is using paper as filler in thermoplastics or recycled thermoplastic matrix composite. In this way it’s possible re-use paper, but it also possible reduces the amount of polymer with equal volume. The paper has to be subjected by grinding. The chosen grinding process is fundamental to obtain a suitable product for composite. After a pre-grinding process obtaining 5-10 mm of paper fragments, the charge have to be subjected to a micronization process. In this study are selected two different type of micronization: the superfine grinding mill SF, a micronization process based on system that uses simultaneously the impact and friction action, and a knife mill that uses instead the cutting and friction action. Thanks to the first process, it is possible obtaining fibres with diameters of about 15-20 microns and lengths of the order of 250-500micron: a product therefore suitable for the application of filler in composites. This process unfortunately causes the production of fluff, as will shown in figure 2, because of the interfibrillar bonds between the fibers: an optimal dispersion of the fibers is necessary to avoid agglomerates which would decrease the composite properties. From the second process it is possible to obtain both fiber than particles as illustrated in figure 3. This morphologies mix allows to achieve a higher fluency preventing agglomerates. The turbomixer equipment realizes the production process of the composite, this process allows to introduce a higher percentage of filler respect the traditional injection moulding technique. The resulting composite is subjected by a morphological and mechanical characterization: look at the SEM analysis of the fracture surface, the fiber-matrix interface is weak, in spite of this, however, from the tensile test there is a constant elastic modulus and in some cases growing respect to the matrix devoid of fibres. From these results, the importance of optimize the grinding and micronization processes is clear and there is the opportunity of additives introduction to improve fiber-matrix interface

Eco-friendly approach and potential biodegradable polymer matrix for WPC composite materials in outdoor application

Blends based on high density polyethylene (HDPE) and poly(lactic) acid (PLA) with different ratios of both polymers were produced: a blend with equal amounts of HDPE and PLA, hence 50 wt.% each, proved to be a useful compromise, allowing a high amount of bio-derived charge without this being too detrimental for mechanical properties and considering its possibility to biodegradation behaviour in outdoor application. In this way, an optimal blend suitable to produce a composite with cellulosic fillers is proposed. In the selected polymer blend, wood flour (WF) was added as natural filler in the proportion of 20, 30 and 40 wt.%, considering as 100 the weight of the polymer blend matrix. Two compatibilizers to modify both HDPE-PLA blend and wood-flour/polymer interfaces i.e. polyethylene grafted maleic anhydride and a random copolymer of ethylene and glycidyl methacrylate. The most suitable percentage of compatibilizer for HDPE-PLA blends appears to be 3 wt.%, which was selected also for use with wood flour. In order to evaluate properties of blends and composites tensile tests, scanning electron microscopy, differential scanning calorimetry, thermo-gravimetric analyses and infrared spectroscopy have been performed. Wood flour seems to affect heavy blend behaviour in process production of material suggesting that future studies are needed to reduce defectiveness

Dual morphology (fibres and particles) cellulosic filler for WPC materials

Wood-plastic composites (WPC) were fabricated by using a polyethylene (PE) matrix and filling it with wood flour in the amount of 30 wt.%, and compared with the same composites with further amount of 10 wt.% of cellulosic recycled fibres added. The materials were produced by turbomixing and subsequent moulding under pressure. Mechanical properties of both WPC and WPC with cellulosic recycled fibres were evaluated through mechanical and physical-chemical tests. Tensile tests clarified that a moderate reduction is strength is observed with the bare introduction of wood flour with respect to the neat PE matrix, whilst some recovery is offered by the addition of recycled cellulose fibres. Even more promisingly, the elastic modulus of PE matrix is substantially improved by the addition of wood flour (around 8% on average) and much more so with the further addition of recycled cellulose (around 20% on average). The fracture surfaces from the tensile test were analysed by scanning electron microscope (SEM) indicating a reduction in microporosity as an effect of added cellulose. The water absorption test and the hardness measure (Shore D) were also performed. SEM analysis underlined the weak interface between both wood particle and cellulosic recycled fibres and matrix. The water absorption test showed a higher mass variation for pure WPC than WPC with cellulosic recycled fibres. The hardness measurement showed that the presence of cellulosic recycled fibres improves both superficial hardness of the composite and temperature resistance. © 2016 Author(s)

Optimization of thermoplastic blend matrix HDPE/PLA with different types and levels of coupling agents

High-density polyethylene (HDPE) and poly(lactic) acid (PLA) blends with different ratios of both polymers, namely, 30:70, 50:50, and 70:30, were produced. Polyethylene-grafted maleic anhydride and a random copolymer of ethylene and glycidyl methacrylate were also considered as compatibilizers to modify HDPE/PLA optimal blends and were added in the amounts of 1, 3, and 5 wt.%. Different properties of the blends were evaluated by performing tensile tests and scanning electron microscopy to analyze blend and interfaces morphology. Moreover, thermomechanical analysis through differential scanning calorimetry, thermo-gravimetric analysis, and infrared spectroscopy were also performed. The blend containing equal amounts of HDPE and PLA seemed to present a good balance between amount of bio-derived charge and acceptable mechanical properties. This suggests that these blends have a good potential for the production of composites with lingo-cellulosic fillers

Lightweight metallic matrix composites. Development of new composites material reinforced with carbon structures

Carbon nano/micro-structures used as fillers in metallic lightweight alloys matrix composites are receiving considerable attention in scientific research and industrial applications. Aluminum and magnesium are the most studied light metals used as matrices in metal composites materials principally for their low density (respectively 2.7 g/cm3 and 1.7 g/cm3) and low melting temperature (around 660 °C for both metals). A good interaction between matrix and fillers is the first step to obtain an increase in bulk properties; furthermore, the manufacturing procedure of the composite is fundamental in terms of quality of fillers dispersion. In this work the influence of surface modifications for three classes of carbon fillers for aluminum and magnesium alloy (AZ63) as matrices is studied. In particular, the selected fillers are short carbon micro fibres (SCMFs), carbon woven fabrics (CWF) and unidirectional yarn carbon fibres (UYFs). The surface modification was carried out by a direct coating of pure nickel on fibres. The electroless pure nickel plating was chosen as coating technique and the use of hydrazine as reducing agent has prevented the co-deposition of other elements (such as P or B). SEM and EDS analyses were performed to study the effect of surface modifications. The mechanical properties of manufactured composites were evaluated by four point flexural tests according to ASTM C1161 (room temperature). Results confirm improved interactions between matrix and fillers, and the specific interaction was studied for any chosen reinforcement

Influence of wood flour and cellulose on the properties and the stability of formulations based on polyolefins and bio-based polymers

The objective of this research is the development of high-added value materials, with high amount of bio-derived fillers, resulting in a more eco-friendly product. The pursued strategy is based on both the introduction of natural fibres and the use of oil-based and bio-derived polymer blends as matrices, reducing the non-biodegradable amount in the material. The thesis project is based on the development of HDPE/PLA blends filled with natural fillers, such as wood flour and recycled paper fibres. High-density polyethylene has been chosen because it is one of the most representative recycled polymers on the market. Poly(lactic) acid has been selected as it is an important bio-degradable polymer on the market. The methodology developed here can be extended to other bio-degradable polymers, such as Soy Protein Isolate (SPI). Wood flour is a diffuse waste material, that can be used for production of Wood Plastic Composites. Recycled paper fibres are derived from industrial paper waste, which cannot be subjected to traditional recycling processes. Additives have been introduced in order to face the problem of different hydrophilicity between oil-based/bio-derived polymers with natural fillers. The optimal composition and production processes are challenges, not only for the use of these materials, but also for their disposal. The end-of-life of these samples can be evaluated through controlled bio-degradability and compostability, correlating material structure with the ability to biodegrade. The production of a material at reduced environmental impact with properties consistent with their applications is a first environmental advantage. Obtaining a controlled biodegradability, as a function of the applications, would give enhanced value to our materials. Several characterizations have been performed in order to analyse the effect of different compatibilizers and treatments such as: tensile tests, scanning electron microscopy, differential scanning calorimetry, thermogravimetric analyses, infrared spectroscopy, size exclusion chromatography and composting tests.L'objectif de cette recherche est le développement de matériaux à haute valeur ajoutée, avec une grande quantité de charges bio-dérivées, aboutissant à un produit plus écologique. La stratégie poursuivie est basée à la fois sur l'introduction de fibres naturelles et sur l'utilisation de mélanges de polymères à base d'huile et bio-dérivés comme matrices, réduisant la quantité non biodégradable dans le matériau. Le projet de thèse est basé sur le développement de mélanges HDPE / PLA remplis de charges naturelles, telles que la farine de bois et les fibres de papier recyclées. Le polyéthylène haute densité a été choisi car il est l'un des polymères recyclés les plus représentatifs du marché. L'acide poly (lactique) a été sélectionné car il s'agit d'un polymère biodégradable important sur le marché. La méthodologie développée ici peut être étendue à d'autres polymères biodégradables, tels que l'isolat de protéine de soja (SPI). La farine de bois est un déchet diffus qui peut être utilisé pour la production de composites bois-plastique. Les fibres de papier recyclées sont issues de déchets de papier industriels, qui ne peuvent pas être soumis aux procédés de recyclage traditionnels. Des additifs ont été introduits pour faire face au problème d'hydrophilie différente entre les polymères à base d'huile / bio-dérivés avec des charges naturelles. La composition et les processus de production optimaux sont des défis, non seulement pour l'utilisation de ces matériaux, mais aussi pour leur élimination. La fin de vie de ces échantillons peut être évaluée par une biodégradabilité et une compostabilité contrôlées, en corrélant la structure du matériau avec la capacité de se biodégrader. La production d'un matériau à impact environnemental réduit avec des propriétés cohérentes avec leurs applications est un premier avantage environnemental. L'obtention d'une biodégradabilité contrôlée, en fonction des applications, valoriserait nos matériaux. Plusieurs caractérisations ont été réalisées afin d'analyser l'effet de différents compatibilisants et traitements tels que: tests de traction, microscopie électronique à balayage, calorimétrie différentielle à balayage, analyses thermogravimétriques, spectroscopie infrarouge, chromatographie d'exclusion de taille et tests de compostage

Influence of wood flour and cellulose on the properties and the stability of formulations based on polyolefins and bio-based polymers

The objective of this research is the development of high-added value materials, with high amount of bio-derived fillers, resulting in a more eco-friendly product. The pursued strategy is based on both the introduction of natural fibres and the use of oil-based and bio-derived polymer blends as matrices, reducing the non-biodegradable amount in the material. The thesis project is based on the development of HDPE/PLA blends filled with natural fillers, such as wood flour and recycled paper fibres. High-density polyethylene has been chosen because it is one of the most representative recycled polymers on the market. Poly(lactic) acid has been selected as it is an important bio-degradable polymer on the market. The methodology developed here can be extended to other bio-degradable polymers, such as Soy Protein Isolate (SPI). Wood flour is a diffuse waste material, that can be used for production of Wood Plastic Composites. Recycled paper fibres are derived from industrial paper waste, which cannot be subjected to traditional recycling processes. Additives have been introduced in order to face the problem of different hydrophilicity between oil-based/bio-derived polymers with natural fillers. The optimal composition and production processes are challenges, not only for the use of these materials, but also for their disposal. The end-of-life of these samples can be evaluated through controlled bio-degradability and compostability, correlating material structure with the ability to biodegrade. The production of a material at reduced environmental impact with properties consistent with their applications is a first environmental advantage. Obtaining a controlled biodegradability, as a function of the applications, would give enhanced value to our materials. Several characterizations have been performed in order to analyse the effect of different compatibilizers and treatments such as: tensile tests, scanning electron microscopy, differential scanning calorimetry, thermogravimetric analyses, infrared spectroscopy, size exclusion chromatography and composting tests.L'objectif de cette recherche est le développement de matériaux à haute valeur ajoutée, avec une grande quantité de charges bio-dérivées, aboutissant à un produit plus écologique. La stratégie poursuivie est basée à la fois sur l'introduction de fibres naturelles et sur l'utilisation de mélanges de polymères à base d'huile et bio-dérivés comme matrices, réduisant la quantité non biodégradable dans le matériau. Le projet de thèse est basé sur le développement de mélanges HDPE / PLA remplis de charges naturelles, telles que la farine de bois et les fibres de papier recyclées. Le polyéthylène haute densité a été choisi car il est l'un des polymères recyclés les plus représentatifs du marché. L'acide poly (lactique) a été sélectionné car il s'agit d'un polymère biodégradable important sur le marché. La méthodologie développée ici peut être étendue à d'autres polymères biodégradables, tels que l'isolat de protéine de soja (SPI). La farine de bois est un déchet diffus qui peut être utilisé pour la production de composites bois-plastique. Les fibres de papier recyclées sont issues de déchets de papier industriels, qui ne peuvent pas être soumis aux procédés de recyclage traditionnels. Des additifs ont été introduits pour faire face au problème d'hydrophilie différente entre les polymères à base d'huile / bio-dérivés avec des charges naturelles. La composition et les processus de production optimaux sont des défis, non seulement pour l'utilisation de ces matériaux, mais aussi pour leur élimination. La fin de vie de ces échantillons peut être évaluée par une biodégradabilité et une compostabilité contrôlées, en corrélant la structure du matériau avec la capacité de se biodégrader. La production d'un matériau à impact environnemental réduit avec des propriétés cohérentes avec leurs applications est un premier avantage environnemental. L'obtention d'une biodégradabilité contrôlée, en fonction des applications, valoriserait nos matériaux. Plusieurs caractérisations ont été réalisées afin d'analyser l'effet de différents compatibilisants et traitements tels que: tests de traction, microscopie électronique à balayage, calorimétrie différentielle à balayage, analyses thermogravimétriques, spectroscopie infrarouge, chromatographie d'exclusion de taille et tests de compostage

Influence de la farine de bois et de la cellulose sur les propriétés et la stabilité des formulations à base de polyoléfines et de polymères biosourcés

L'objectif de cette recherche est le développement de matériaux à haute valeur ajoutée, avec une grande quantité de charges bio-dérivées, aboutissant à un produit plus écologique. La stratégie poursuivie est basée à la fois sur l'introduction de fibres naturelles et sur l'utilisation de mélanges de polymères à base d'huile et bio-dérivés comme matrices, réduisant la quantité non biodégradable dans le matériau. Le projet de thèse est basé sur le développement de mélanges HDPE / PLA remplis de charges naturelles, telles que la farine de bois et les fibres de papier recyclées. Le polyéthylène haute densité a été choisi car il est l'un des polymères recyclés les plus représentatifs du marché. L'acide poly (lactique) a été sélectionné car il s'agit d'un polymère biodégradable important sur le marché. La méthodologie développée ici peut être étendue à d'autres polymères biodégradables, tels que l'isolat de protéine de soja (SPI). La farine de bois est un déchet diffus qui peut être utilisé pour la production de composites bois-plastique. Les fibres de papier recyclées sont issues de déchets de papier industriels, qui ne peuvent pas être soumis aux procédés de recyclage traditionnels. Des additifs ont été introduits pour faire face au problème d'hydrophilie différente entre les polymères à base d'huile / bio-dérivés avec des charges naturelles. La composition et les processus de production optimaux sont des défis, non seulement pour l'utilisation de ces matériaux, mais aussi pour leur élimination. La fin de vie de ces échantillons peut être évaluée par une biodégradabilité et une compostabilité contrôlées, en corrélant la structure du matériau avec la capacité de se biodégrader. La production d'un matériau à impact environnemental réduit avec des propriétés cohérentes avec leurs applications est un premier avantage environnemental. L'obtention d'une biodégradabilité contrôlée, en fonction des applications, valoriserait nos matériaux. Plusieurs caractérisations ont été réalisées afin d'analyser l'effet de différents compatibilisants et traitements tels que: tests de traction, microscopie électronique à balayage, calorimétrie différentielle à balayage, analyses thermogravimétriques, spectroscopie infrarouge, chromatographie d'exclusion de taille et tests de compostage.The objective of this research is the development of high-added value materials, with high amount of bio-derived fillers, resulting in a more eco-friendly product. The pursued strategy is based on both the introduction of natural fibres and the use of oil-based and bio-derived polymer blends as matrices, reducing the non-biodegradable amount in the material. The thesis project is based on the development of HDPE/PLA blends filled with natural fillers, such as wood flour and recycled paper fibres. High-density polyethylene has been chosen because it is one of the most representative recycled polymers on the market. Poly(lactic) acid has been selected as it is an important bio-degradable polymer on the market. The methodology developed here can be extended to other bio-degradable polymers, such as Soy Protein Isolate (SPI). Wood flour is a diffuse waste material, that can be used for production of Wood Plastic Composites. Recycled paper fibres are derived from industrial paper waste, which cannot be subjected to traditional recycling processes. Additives have been introduced in order to face the problem of different hydrophilicity between oil-based/bio-derived polymers with natural fillers. The optimal composition and production processes are challenges, not only for the use of these materials, but also for their disposal. The end-of-life of these samples can be evaluated through controlled bio-degradability and compostability, correlating material structure with the ability to biodegrade. The production of a material at reduced environmental impact with properties consistent with their applications is a first environmental advantage. Obtaining a controlled biodegradability, as a function of the applications, would give enhanced value to our materials. Several characterizations have been performed in order to analyse the effect of different compatibilizers and treatments such as: tensile tests, scanning electron microscopy, differential scanning calorimetry, thermogravimetric analyses, infrared spectroscopy, size exclusion chromatography and composting tests

Polymeric matrix composites at reduced environmental impact

This work focused on the use of bio-derived charge, in order to reduce the environmental impact of traditional oil-based polymers (HDPE in this case). In fact, we introduced waste paper fibres and a starch-derived polymer in Wood Plastic Composites (WPC). We produced different materials: 10 wt% of recycled paper fibres (10F), 30 wt% of wood flour (30W) and a mix of two fillers (30W10F). Polyethylene-graft-maleic anhydride (MAPE) has been introduced as compatibilizer and a NaOH immersion treatment on both cellulosic filler has been done in order to improve composites properties. A starch-derived polymer was then added to the matrix to reduce HDPE amount (30W10F15S). Samples were produced through turbomixing followed by compression moulding technique, and then subjected to tensile tests, SEM analysis, water absorption tests and hardness tests (Shore D). Results evidenced a synergic effect of both cellulosic fillers, and the best results were obtained for 30 wt% wood, 10 wt% fibre of paper, and 3 wt% of MAPE, in which MAPE addition improved interfaces. Samples with starch-derived polymers have shown typical blends morphologies, and cellulosic fillers treated with NAOH revealed an effective attack. The hardness measure displayed that the presence of cellulosic recycled fibres increased both superficial hardness of the composite and temperature resistance, while the presence of starch-derived polymer and fibres treated with NaOH caused a higher softening effect. © 2017 Society of Plastics Engineers

Interactions between PLA, PE and wood flour: effects of compatibilizing agents and ionic liquids

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