Post-industrial Waste Research Articles

Effect of Hard Plastic Waste on the Quality of Recycled Polypropylene Blends

The recycling of plastic waste is undergoing fast growth due to environmental, health and economic issues, and several blends of post-consumer and post-industrial polymeric materials have been characterized in recent years. However, most of these researches have focused on plastic containers and packaging, neglecting hard plastic waste. This study provides the first experimental characterization of different blends of hard plastic waste and virgin polypropylene in terms of melt index, differential scan calorimetry (DSC), thermogravimetric analysis (TGA), mechanical properties (tensile, impact and Shore hardness) and Vicat softening test. Compared to blends based on packaging plastic waste, significant differences were observed in terms of melt flow index (about 10 points higher for hard plastic waste). Mechanical properties, in particular yield strain, were instead quite similar (between 5 and 9%), despite a higher standard deviation being observed, up to 10%, probably due to incomplete homogenization. Results demonstrate that these worse performances could be mainly attributed to the presence of different additives, as well as to the presence of impurities or traces of other polymers, other than incomplete homogenization. On the other hand, acceptable results were obtained for selected blends; the optimal blending ratio was identified as 78% post-consumer waste and 22% post-industrial waste, meeting the requirement for injection molding and thermoforming.

Optimisation of Shrinkage and Strength on Thick Plate Part Using Recycled LDPE Materials.

Achieving good quality of products from plastic injection moulding processes is very challenging, since the process comprises many affecting parameters. Common defects such as warpage are hard to avoid, and the defective parts will eventually go to waste, leading to unnecessary costs to the manufacturer. The use of recycled material from postindustrial waste has been studied by a few researchers. However, the application of an optimisation method by which to optimise processing parameters to mould parts using recycled materials remains lacking. In this study, Response Surface Methodology (RSM) and Particle Swarm Optimisation (PSO) methods were conducted on thick plate parts moulded using virgin and recycled low-density polyethylene (LDPE) materials (100:0, 70:30, 60:40 and 50:50; virgin to recycle material ratios) to find the optimal input parameters for each of the material ratios. Shrinkage in the x and y directions increased in correlation with the recycled ratio, compared to virgin material. Meanwhile, the tensile strength of the thick plate part continued to decrease when the recycled ratio increased. R30 (70:30) had the optimum shrinkage in the x direction with respect to R0 (100:0) material where the shrinkage increased by 24.49% (RSM) and 33.20% (PSO). On the other hand, the shrinkage in the y direction for R30 material increased by 4.48% (RSM) and decreased by 2.67% (PSO), while the tensile strength of R30 (70:30) material decreased by 0.51% (RSM) and 2.68% (PSO) as compared to R0 (100:0) material. Validation tests indicated that the optimal setting of processing parameter suggested by PSO and RSM for R0 (100:0), R30 (70:30), R40 (60:40) and R50 (50:50) was less than 10%.

Composites of Recycled Polypropylene from Cotton Swab Waste with Pyrolyzed Rice Husk

The manufacture of consumer goods from thermoplastic polymers leads to a considerable amount of scrap or off-specifications products, generating post-industrial waste that is typically landfilled. In present study, polypropylene (PP) wastes from the cotton swabs manufacture were used to the preparation of polymeric composites with agro-industrial waste of rice husk (RH). The RH was employed in the natural form as well as it was also treated by controlled pyrolysis for surface modification before incorporation to the PP. The PP/RH composites prepared by extrusion with contents from 2 to 20 wt% of non-pyrolyzed (NRH) and pyrolyzed (PRH) rice husk were submitted to the injection molding for preparation of tensile and impact specimens and characterized by mechanical testing, thermal analysis, melt flow rate, infrared spectroscopy and scanning electron microscopy. The controlled pyrolysis treatment on the RH caused significant changes in the thermal, chemical, rheological and mechanical properties of the PP/RH composites, mainly on the mechanical properties Young’s modulus, elongation at break and impact resistance that presented variation up to 100% when compared the composites containing NRH. The recycled PP/RH composites present suitable properties for several applications such as wood-plastic, furniture, doors and are an alternative for decrease the pollution generated by cotton swab waste.

Modification of post-industrial lignin by fungal strains of the genus Trichoderma isolated from different composting stages

One of the links in the environmental management chain is the environmentally friendly utilization of the emerging post-industrial waste and improvement of the methods of processing thereof. The aim and novelty of this research was to evaluate the potential of fungi to purify wastewater containing post-industrial lignin, i.e. waste originating from the pulp and paper industry. Trichoderma were dominant in the composts with different qualities and quantities of lignocellulosic compounds. The Trichoderma strains used in the research were isolated from two lignocellulosic composts at three different time points (from 10-, 20- and 30-week-old composting mass). Eighteen strains of the genus Trichoderma were tested for their ability to biodegrade 0.2% post-industrial lignin. It was evaluated by determination of decolorization, activities of ligninolytic enzymes, and concentration of phenolic compounds in the post-culture liquid. The Trichoderma strains isolated from 10-week-old compost I and 30-week-old compost II showed the highest decolorization activity and biotransformation of dark post-industrial lignin. All strains secreted horseradish-like peroxidase (HRP-like), superoxide dismutase-like (SOD-like), xylanase, and phenolic compounds. Strains isolated from 30-week-old compost I and from 10-week-old compost II released the greatest amounts of phenolic compounds into the culture liquid containing post-industrial lignin. The strains isolated from 10- and 20-week-old compost were characterized by high SOD-like and HRP-like activity, respectively. The concentration of phenolic compounds measured with HPLC in Trichoderma fungus culture VII from compost I corresponded with the decolorization degree and high HRP-like activity. The study results indicate that the genus Trichoderma with decolorization activity isolated from the first composting stages can be used in the biotransformation of post-industrial lignin waste.

Recycled poly(lactic acid)–based 3D printed sustainable biocomposites: a comparative study with injection molding

With the objective of giving a new economic life to postindustrial waste poly(lactic acid) (PLA), biocomposites based on recycled PLA were manufactured using conventional melt blending, and the strands produced were successfully used for three-dimensional (3D) printing of American Society for Testing and Materials (ASTM) samples by means of the fused deposition molding (FDM) method. This article further discusses the processing advantages and challenges associated with void formation, anisotropic behavior, and the quality of the 3D printed (3DP) samples in comparison with injection-molded (IM) counterparts. The blends were manufactured containing 30 wt % of recycled PLA in a matrix of virgin PLA. Similarly, blends were also prepared with addition of an epoxy-based chain extender (CE) and as well as with the CE and a reinforcing phase of microcrystalline cellulose (MCC). One of the limitations of recycled PLA in FDM-based 3D printing is its high melt flow due to the reduced molecular weight after recycling, which results in excessive material flow during extrusion, and hence limits its application in FDM-based 3D printing. Consequently, the main effect of the CE, Joncryl, was to control the Melt Flow Index (MFI) of the biocomposites containing the recycled PLA. The addition of CE also resulted in improvement of the impact strength of 3DP samples. In general, the CE in combination with the natural fibers (MCC) allowed the incorporation of postindustrial PLA. Data suggest that more recycled PLA may be incorporated by using this blend combination. In general, owing to the void formation, 3DP samples presented lower values of density (lightweight) and mechanical properties as compared with IM samples. However, the tensile strength, modulus and Izod impact strength of 3DP biocomposites were increased by up to 88%, 127%, and 11%, respectively, by the addition of 5 wt % MCC, as compared with 3DP samples based on postindustrial PLA without additives.

Separation and recycling of polymeric post-industrial waste from adhesive bandages

The use of polymer has been showing an increasing consumption in the industry for the production of several consumer goods, mainly for the manufacturing of disposable products that can involve the combination of polymers with other materials. Nowadays, the annual production of polymers in the world exceeds 300 million tons. The industrial processes for these materials lead to a wide production of post-industrial waste that are highly complex and challenging for mechanical recycling due to the difficulty in separation step of macro-contaminant for this kind of waste. In this sense, the aim of this current study was to research and develop an efficient separation process with low cost for recycling of post-industrial scraps generated from production of adhesive bandage, which consisted of multiple layer films containing polymers, copolymers and cellulose. The polymeric waste was submitted to the well-established process called hydro-pulping, which does not require the use of chemical additives, resulting in efficient separation of cellulose pulp, while the residual polymer has been submitted to the thermomechanical processing by extrusion and injection molding. The separation of the polymers from cellulose by hydro-pulping method was successful. Therefore, the mechanical recycling of adhesive bandage waste presents full conditions for practical use.

The Fatty Acid Composition and Quality of Oils from Post‐Industrial Waste of Quince Chaenomeles japonica

In the food industry, quince seeds are discarded as waste in the production process. Their use therefore creates added value and opens up the possibility of using no-waste processing technologies. Three types of waste were investigated: after juicing, after the manufacture of puree and syrup. The results showed that the yield of quince seeds (Chaenomeles japonica (Thunb.) Lindl. ex Spach from waste left after different production methods varies from 29.8 to 38.3 %. The cold pressed oil yield ranges from 4.9±0.03 to 7.1±0.06 %. The oil yield obtained by Soxhlet extraction varies from 14.6±0.64 to 17.3±0.9 %. Unsaturated fatty acid, especially polyunsaturated fatty acid is predominant in quince seed oil. The linoleic acid content of the quince seed oils was between 47.12 % and 58.49 % of the total fatty acids. The fatty acid composition of oils from post-industrial waste is more appropriate in the skin care industry than in the food industry because of the high ratio of omega-6/omega-3 and high linoleic acid content.

Production and characterization of low-energy Portland composite cement from post-industrial waste

Abstract The utilization of post-industrial waste materials is often challenging due to environmental regulations. Additionally, the scarcity of raw materials for producing cement is generating the demand for alternate sources of materials. The current study explores the production of cement and clinker on a large scale using post-industrial waste materials from different sources. Lime sludge generated by the paper mill industry and sponge iron produced during the processing of iron are used as primary source materials for producing clinker. A large-scale vertical kiln is used for clinkering. The unburnt carbon present in the sponge iron is used as an energy source for calcining the raw materials reducing the demand on external fuel. A Portland Composite Cement (PCC) is produced by inter-grinding the clinker with waste generated by the pharmaceutical industry, silico-manganese slag and fly ash. An evaluation of the clinker and the PCC is performed and compared with a commercially available Ordinary Portland Cement (OPC). Hydration studies and characterization of the materials are performed using different analytical techniques. This work provides the fundamental basis for an environmentally sustainable utilization of post-industrial waste in the production of clinker suitable for use in construction.

Heavy-metal tolerance of photobiont in pioneer lichens inhabiting heavily polluted sites

Heavy metals are known for their negative impact on the physiological processes of lichen photobiont. In spite of this, certain lichens are known to be effective pioneers of polluted sites. Cladonia cariosa, C. rei, and Diploschistes muscorum are prominent examples of lichens that spontaneously colonise post-industrial wastes. We examined the effect of total and intracellular Zn, Pb, Cd, As, Cu, and Ni accumulation in the thalli of these species on the physiological parameters of photobiont. Increased accumulation of Zn, Cd, Cu, and Ni in D. muscorum and of Zn and Ni in C. rei negatively affected contents of photosynthetic pigments, whereas concentrations of Pb had a positive effect in all lichen species. Moreover, pigment contents were positively associated with the concentrations of most examined elements in C. cariosa. The results indicate that even if chlorophyll contents reduced, its degradation does not progress. This suggests that metal stress may exert a negative effect on the synthesis rather than on the integrity of chlorophyll. Most importantly, lichen samples of each of the species from polluted sites proved to possess significantly higher FV/FM ratios than those from a reference site; moreover, the contents of elements of lichen thalli positively influenced this parameter. The efficient functioning of the algal component under heavy-metal stress conditions indicates that the examined lichens are well adapted to extremely contaminated substrates.

Tailoring PS/PPrecycled blends compatibilized with SEBS. Evaluation of rheological, mechanical, thermomechanical and morphological characters

The increasing consumption of polypropylene (PP) in several practical applications contributes to the production of a large amount of post-consumer and post-industrial waste contributing to environmental damages. The practice of material reusing is one of the feasible alternatives to overcome problems generated by these wastes/post-consumer products. Therefore, the effect of recycled polypropylene (PPr) addition in polystyrene (PS)/polypropylene (PPv) blends, compatibilized with styrene-(ethylene/butylene)-styrene (SEBS) was performed in this study. Blends were compounded in a co-rotational twin screw extruder; afterwards extruded granules were injection molded to produce specimens for tensile experiments. Blends were characterized by parallel plate rheometry, mechanical properties, impact strength, differential scanning calorimetry (DSC), thermogravimetry (TG), heat deflection temperature (HDT) and scanning electron microscopy (SEM). According to complex viscosity data blends behave as pseudoplastic fluid. An increase in impact strength, elongation at break, thermal stability (TG) and HDT was observed in relation to neat PS. Nevetheless, there were losses in the elastic modulus and tensile strength. The morphologies investigated by SEM are typical of immiscible blends corroborating Cole-Cole plots. In the range of investigated compositions for PPr (7, 14, 21 and 35% by mass), no significant differences in the blends properties were verified. Summing up, results collected with this work are valuable for recycling’s researches, which can lead to savings in the final product, since it was used up to 35% PPr, whereas keeping high performance and reconciling economic and environmental purposes.

Application of ashes as filling in reprocessed polypropylene: thermomechanical properties of composites

Abstract The life cycle of a product depends to a great extent on its reuse and ease of recycling. This work had developed of composite materials of reprocessed polypropylene composites with rice husk ash (RHA) and sugarcane bagasse ash (SBA) through the coextrusion and injection processes as main purpose. The polymeric matrix was reprocesed until six generations by the injection technique. The reprocessed PP was mixed in 80:20 proportions with respect to filler mineral, using maleic anhydride as coupling agent in a coextrusion machine. The new series of composite materials were analyzed thermal, mechanical, rheological and morphologically. The incorporation of ashes in the PP matrix achieved characteristics of improved tensile strength, conserving the thermal properties. For this reason, this work presents an alternative for the manufacture of composite materials from post-industrial waste.

How to identify opportunities for improvement in the use of reverse logistics in clothing industries? A case study in a Brazilian cluster

Waste disposal is a worldwide concern. In the case of the textile and clothing industries, consumption has increased steadily, especially in the clothing business, which generates large amounts of post-industrial waste. The objective of this article is to identify opportunities for improvement in the use of reverse logistics (RL) in clothing industries, as well as to list the existing strengths in the valuation of textile waste (TW) and minimize environmental impacts. To achieve this objective, a questionnaire was developed, validated and applied in a clothing cluster. The questionnaire assessed strengths and weaknesses in 8 dimensions using 32 assertions involving reverse logistics and management of textile waste. We identified in the research that: (i) there are no route facilitators between RL and TW in clothing industries; (ii) there are opportunities for the textile companies to increase the adoption of RL to combat TW; (iii) the main improvement opportunities for increasing cluster advancement in terms of RL and TW are: reuse of TW by the generating company and separating waste according to the composition of materials, which would facilitate the possibility of recycling and disclosing to consumers the importance of social and environmental practices. Conclusion remarks point that, despite the existence of strengths in the use of the RL for the TW valuing in the clothing industry, it is still required a readjustment of the destination of TW as a by-product to be used in a new cycle.

Plastic waste management, a matter for the 'community'.

Plastic waste management, a matter for the 'community'.

Narażenie mieszkańców Zabrza na metale ciężkie emitowane z hałd poprzemysłowych

Narażenie mieszkańców Zabrza na metale ciężkie emitowane z hałd poprzemysłowych

Examination of granulometry of ceramic dust which derogations while disposing waste sanitary ceramics for the use of their as addition to the concrete

The purpose of the research presented in this article was to assess the granulometry of ceramic dust in terms of their use as an additive to concrete. The material for testing came from postindustrial sanitary ceramic waste, which was subjected to a crushing process in jaw crushers. A research stand consisting of a Horoir LA-300 laser particle analyzer connected to a computer equipped with appropriate software was used to study the granulometric characteristics. As a side feature, the dust density was examined using a Le Chatelier flask. The results of the tests carried out were compared with the data obtained for the traditionally used concrete additive - silica volatile dusts.

Alkaline Activated Material as the Adsorbent for Uptake of High Concentration of Zinc from Wastewater

The use of wastes for developing of new materials is a sustainable approach. In current study filter media produced from industrial waste was tested for an ability to decrease high concentration of zinc in standard solution and industrial wastewater. The geopolymer production requires mixing of post-industrial waste with naturally occurred aluminosilicate materials by using binding agent at the ambient or slightly increased temperature in order to produce a long lasting eco-friendly cementitious material. The tested media decreased concentration of zinc in standard solution from 72,9 to 19,6 mg/L in 30 min showing similar performance as commercially available zeolite material. In experiments with wastewater the adsorption of Zn by AAM was much lower, which can be explained by the fact that wastewater contained generous amounts of different metal ions, organic substances and oils. Despite complex composition of wastewater AAM was able to immobilize at minimum 22 mg/L (32%) Zn from the solution.

Study of mechanical and physical properties of LLDPE-G-MA injection grade reinforced with coffee husk post-industrial waste

In this work, the evaluation of a post-industrial residue of coffee industry (coffee husk) as organic filler in functionalised linear low-density polyethylene matrix was investigated. The properties of these composites were compared with more widely used inorganic fillers, such as calcium carbonate and SiO2. All the composites were prepared by grafting of linear low-density polyethylene maleic anhydride and then by melt mixing of fillers. The rheological behaviour of the compounds during processing was established to evaluate the effects of a nanosized (SiO2), micron sized calcium carbonate and coffee husk fillers. Additionally, thermal, morphological and mechanical properties of the polymer composites were evaluated. The results indicated an increase in tensile modulus and tensile strength resulting from incorporation of fillers in the polymer matrix. Some relevant modifications of melting temperature and crystallinity degree for coffee husk composites were observed, but not observed for inorganic fillers composites. The properties of the composites prepared with coffee husk were comparable to those obtained with inorganic fillers, demonstrating that this coffee residue can be used as filler for obtaining composites for many possible applications.

Attitudes towards managing post-industrial apparel cuttings waste

By its origin, textile waste can be divided in two broad categories: post-consumer waste and post-industrial waste generated during the manufacturing process. The division of the clothing supply chain between developed consumer markets and developing countries where apparel production capacities are outsourced implies that post-consumer waste is present in the former countries, whereas the later generates more post-industrial waste. The purpose of this exploratory study was to determine how the attitudes of top management towards managing apparel cuttings waste influence their willingness to introduce apparel waste sorting. The proclivity to sort apparel cuttings was strongly influenced by two key factors – the ease and costs of introducing sorting operations and impediments to sorting such as lack of workforce, technology or market. Combining these two factors leads towards negative attitudes to introducing apparel sorting. Perception of impediments in the process of sorting leads towards negative attitudes regarding the ease of introducing sorting operations; however, it does not influence adversely the proclivity to sort.

Wood chile peppers stalks-plastic composite production

Nowadays, most common wood fibers used to produce wood plastic composites are from Oak and pine trees, rice hull, recycled paper, pallets and post-industrial oak fiber, furniture waste, or cedar wood chips. This paper is focused on a new wood plastic composites based on pre-dried New Mexico red chile stems and leafs with high-density polyethylene. The specimens were manufactured following ASTM 638-9 standard using injection molding. A series of experiments were designed to investigate how wood fiber length, geometry, and water absorption affects the microcellular structure of the new sustainable material. The effects of proportions and particle size on the strength of the resulting blend were analyzed. It was found that larger particle sizes of wood fiber showed higher mechanical properties. The blending of additives in the new sustainable material has shown to increase proper fiber dispersion improving the strength of the material.

Tensile and Fatigue Evaluation of a Glass Reinforced Recycled Nylon Blend: Effect of Polypropylene Contamination

ABSTRACTTensile strength was measured on 30 wt% glass fiber-reinforced postconsumer waste and postindustrial waste recycled nylon blends. Fatigue tests were performed under load control at a stress ratio of 0.1 at temperatures of 24 and 120°C. It was found that increasing temperature led to a significant decrease in both tensile strength and fatigue life. For unwelded postindustrial waste/postconsumer waste blends, the endurance ratio was approximately 50% regardless of the temperature. For welded postindustrial waste/postconsumer, a similar endurance ratio was observed at room temperature, but it decreased to 33% at 120°C due to the presence of polypropylene found in the postconsumer component.