Yes / Real time measurement of melt rheology has been investigated as a Process Analytical Technology (PAT) to monitor hot melt extrusion of an Active Pharmaceutical Ingredient (API) in a polymer matrix. A developmental API was melt mixed with a commercial copolymer using a heated twin screw extruder at different API loadings and set temperatures. The extruder was equipped with an instrumented rheological slit die which incorporated three pressure transducers flush mounted to the die surface. Pressure drop measurements within the die at a range of extrusion throughputs were used to calculate rheological parameters such as shear viscosity and exit pressure, related to shear and elastic melt flow properties respectively. Results showed that the melt exhibited shear thinning behavior whereby viscosity decreased with increasing flow rate. Increase in drug loading and set extrusion temperature resulted in a reduction in melt viscosity. Shear viscosity and exit pressure measurements were found to be sensitive to API loading. These findings suggest that this technique could be used as a simple tool to measure material attributes in-line, to build better overall process understanding for hot melt extrusion.

The mixing of additives into a plastic is an extremely important step in the plastics industry, necessary for the manufacture of almost every conceivable product. Therefore the costs in developing new products can prove very expensive as the testing is usually carried out using full scale machines, usually using twin screw extruders because they are able to provide good dispersive and distributive mixing. This is particularly important when compounding difficult to disperse additives and nano-additives. What is required is a machine that can replicate the mixing abilities of a twin-screw extruder but on a laboratory scale. There have been attempts by industry to develop smaller machines, such as the Thermo Scientific HAAKE Minilab II Micro Compounder which processes on the scale of 7 cm3 of material volume. This can be too small for some needs and therefore a machine is required to produce material on the 10g to 100g scale. To this end a laboratory mixer of novel design was devised and its mixing performance was assessed using conductive carbon black and compared against the Thermo Scientific HAAKE Minilab II Micro Compounder, a 19 mm co-rotating twin-screw extruder and a 40 mm co-rotating twin-screw extruder. Carbon black was used because mixing performance can be assessed by measuring the minimum carbon loading necessary to induce electrical conductivity. It was found that the minimixer was able to induce electrical conductivity at loading of 5.75% but the comparison with the other machines proved difficult as the achievement of the threshold at which semi-conductivity occurred appeared independent of shear rate and mixing duration.

Aujourd’hui le développement de nouveaux matériaux polymères ayant de bonnes propriétés repose de plus en plus sur des procédés de mélange ou de compoundage de polymères au lieu de recourir à la synthèse de nouvelles molécules. L’action du mélange peut fortement influer sur la morphologie des matériaux polymères multi-constituants. Les extrudeuses bi-vis (TSE) sont souvent utilisées comme mélangeurs/réacteurs pour des procédés de mélange, de compoundage et d’extrusion réactive. Cependant, l’étude sur la qualité du mélange dans les TSE demeure un grand défi en raison de la complexité géométrique et du caractère transitoire de l’écoulement. Cette thèse a pour objet de développer un nouvel instrument en line pour mesurer en temps réel la distribution des temps de séjour (DTS) qui caractérise la performance du mélange axial et la capacité de convoyage de différents types d’éléments de vis basées sur l’analyse de l’écoulement transitoire et l’évaluation systématique de la théorie de mélange dans les TSE. Le mélange distributif des polymères fondus est caractérisé par la génération de l’aire des interfaces, un paramètre difficile à mesurer expérimentalement. Alors on fait appel à des simulations numériques de type CFD / The development of new materials with improved properties seems to rely nowadays more on blending and compounding than on the synthesis of chemically new polymers. Mixing may have a great effect on the morphology and structure of multi-component polymer materials. Twin-screw extruders (TSE) are widely used as mixers/reactors for blending, compounding, and reactive processing. This work aimed at developing a new instrument to measure in real time the residence time distribution (RTD) which characterizes the axial mixing and transport abilities of different screw elements based on the analysis of the transient flow pattern and systematic evaluation of mixing theory in TSE. Distributive mixing of polymer melts is characterized by the generation of interfacial area, which is experimentally much more difficult to measure. This 3D numerical simulation based on CFD is adopted

Aujourd’hui le développement de nouveaux matériaux polymères ayant de bonnes propriétés repose de plus en plus sur des procédés de mélange ou de compoundage de polymères au lieu de recourir à la synthèse de nouvelles molécules. L’action du mélange peut fortement influer sur la morphologie des matériaux polymères multi-constituants. Les extrudeuses bi-vis (TSE) sont souvent utilisées comme mélangeurs/réacteurs pour des procédés de mélange, de compoundage et d’extrusion réactive. Cependant, l’étude sur la qualité du mélange dans les TSE demeure un grand défi en raison de la complexité géométrique et du caractère transitoire de l’écoulement. Cette thèse a pour objet de développer un nouvel instrument en line pour mesurer en temps réel la distribution des temps de séjour (DTS) qui caractérise la performance du mélange axial et la capacité de convoyage de différents types d’éléments de vis basées sur l’analyse de l’écoulement transitoire et l’évaluation systématique de la théorie de mélange dans les TSE. Le mélange distributif des polymères fondus est caractérisé par la génération de l’aire des interfaces, un paramètre difficile à mesurer expérimentalement. Alors on fait appel à des simulations numériques de type CFD / The development of new materials with improved properties seems to rely nowadays more on blending and compounding than on the synthesis of chemically new polymers. Mixing may have a great effect on the morphology and structure of multi-component polymer materials. Twin-screw extruders (TSE) are widely used as mixers/reactors for blending, compounding, and reactive processing. This work aimed at developing a new instrument to measure in real time the residence time distribution (RTD) which characterizes the axial mixing and transport abilities of different screw elements based on the analysis of the transient flow pattern and systematic evaluation of mixing theory in TSE. Distributive mixing of polymer melts is characterized by the generation of interfacial area, which is experimentally much more difficult to measure. This 3D numerical simulation based on CFD is adopted

O objetivo deste trabalho é avaliar a viabilidade técnica do desenvolvimento de uma miniextrusora dupla-rosca corrotativa que, além de processar a matéria-prima, possa exercer a função de um cabeçote de impressão 3D. Os avanços tecnológicos na área da manufatura relacionados à impressão 3D têm gerado grande entusiasmo nos últimos 10 anos, na medida em que possibilitam a fabricação de formas geométricas de alta complexidade diretamente a partir de arquivos digitais, agilizando a cadeia de produção e reduzindo custos de ferramental associados. Apesar das inúmeras vantagens, a Manufatura Aditiva (MA) ainda é uma tecnologia em desenvolvimento e, portanto, apresenta desafios para que possa realmente atender às novas demandas criadas pela comunidade científica e industrial, muitos deles relacionados com a busca por novos materiais de impressão, com a melhoria dos materiais utilizados, das estratégias de deposição visando menor tempo de fabricação e maior precisão dimensional e com a ausência de padronização para os processos. As tendências no desenvolvimento de materiais para as técnicas de MA por extrusão apontam tanto para a elaboração de compósitos de matriz polimérica e blendas capazes de conferir propriedades mecânicas mais apropriadas às impressões e/ou proporcionar novas funcionalidades, quanto para o desenvolvimento de sistemas que possibilitem a deposição de matérias-primas diferenciadas ou a incorporação de soluções de pós-processamento para compor sistemas híbridos de manufatura. Nesse contexto, a principal motivação deste trabalho é a ausência de um equipamento para produção de compósitos poliméricos e blendas a partir pequenas quantidades de material em pó (cerca de 200 g) e que também seja capaz de estruturar objetos tridimensionais por meio da deposição de camadas sucessivas de material fundido. A fim de obter o conjunto de parâmetros geométricos e operacionais fundamentais para a definição e avaliação da miniextrusora dupla-rosca, houve a necessidade de se desenvolver um procedimento sistemático integrando conceitos de projeto de máquinas, processo de extrusão dupla-rosca e reologia aplicados ao contexto da MA. O método de projeto resultante considera requisitos funcionais e restrições geométricas específicas, conciliando a necessidade de manter uma folga constante entre as roscas com a desejada ação de autolimpeza obtida por meio da interpenetração das mesmas. A capacidade de processar o material viscoso com o torque fornecido às roscas, requisito crítico a ser atendido, foi avaliada teoricamente para o ABS (acrilonitrila butadieno estireno) virgem e validada experimentalmente para três sistemas baseados em ABS com auxílio de um reômetro de torque. Ao final do estudo, foi obtido um modelo geométrico virtual de dimensões reduzidas (69,6x75x201 mm) e na sequência foi construído um mock-up com auxílio da impressão 3D para avaliação das tolerâncias dimensionais, cinemática e funcionalidades básicas do conjunto. Estima-se que a miniextrusora projetada, operando a 10 rpm, seja capaz de processar até 0,2 kg/h e gerar 60% do calor necessário para a fusão (ABS), mostrando-se viável para aplicação como cabeçote intercambiável de impressão 3D destinado à pesquisa de novos materiais para MA. / The objective of this document is accessing the development feasibility of a mini co-rotating twin-screw extruder capable of mixing different materials and performing the function of 3D printhead. The technological progress in the manufacturing context related to 3D printing have generated great enthusiasm in the last 10 years, as it enables fabricating complex geometric shapes directly from digital files, speeding up production chain and reducing associated tooling costs. Despite the many advantages, Additive Manufacturing (AM) is still an emerging technology and must overcome challenges to effectively meet the new demands created by scientific and industrial communities, many of them related to the search for new building materials, improving current materials and deposition strategies, in order to achieve faster fabrication and increased dimensional precision, as well as the lack of process standardization. Tendencies towards material development to AM techniques based in extrusion points to the formulation of different polymer matrix composites and blends capable of imparting more appropriate mechanical properties to the 3D prints and/or provide new functionalities, as well as to the development of systems capable of depositing special raw materials or to the incorporation of post processing solutions composing hybrid manufacture systems. In that context, the main motivation for this work is the lack of an equipment for producing polymer composites and blends from small amounts of powder material (about 200 g) that is also capable of structuring three-dimensional objects depositing successive layers of fused material. In order to obtain the fundamental geometric and operational parameters set to define and access the mini twin-screw extruder, it was necessary to develop a systematic procedure integrating concepts from machine design, twin-screw extrusion and rheology applied to the AM context. The resulting design method considers specific functional requisites and geometric constraints, conciliating the need for a constant clearance between the screws and the desired self-cleaning action obtained with closely intermeshing screws. The capacity to process viscous material with the torque provided to the screws, a critical requisite to be met, was theoretically evaluated considering ABS resin (acrylonitrile butadiene styrene) and experimentally validated to three polymer systems based in ABS with a torque rheometer. At the end of the study, a virtual geometric model with reduced dimensions (69.6x75x201 mm) was obtained and then a mock-up was 3D printed in order to evaluate dimensional tolerances, cinematics and basic functionalities. It is estimated that the mini twin-screw extruder designed is able to process up to 0.2 kg/h running at 10 rpm and generate 60% of the heat necessary to melt the polymer (ABS), showing to be feasible to its application as an interchangeable 3D printhead for research of new materials in AM.

Esse trabalho apresenta um modelo termodinâmico de uma bomba multifásica do tipo duplo parafuso. Para uma dada condição de operação, o modelo calcula a potência consumida, as condições do fluido na descarga e o perfil de pressão ao longo da bomba. Ao invés de simular diretamente o escoamento dentro da bomba, simulou-se os processos que ocorrem dentro das suas câmaras. Para tanto, dividiu-se o processo de bombeamento multifásico em uma seqüência de processos simples, facilitando-se a construção do modelo no simulador de processos Hysys.Process v2.1. Os resultados de potência e temperatura de descarga obtidos com a simulação mostram uma boa concordância com valores experimentais, principalmente para FVG’s baixos. Para FVG’s elevados, o modelo passa a superestimar a potência consumida indicando que as fendas, nesses casos, já não se encontram totalmente preenchidas com líqüido. Dos resultados obtidos para o refluxo, conclui-se que, das equações sugeridas na literatura, aquelas para escoamento turbulento liso são mais adequadas para os números de Reynolds envolvidos. O perfil de pressão e a vazão de refluxo quando o escoamento é multifásico aproxima-se qualitativamente das medições experimentais. Estudou-se a influência de diversos parâmetros na eficiência exergética da bomba. Os resultados mostram que a otimização da eficiência depende das condições de operação da bomba: FVG, tipo de líqüido, diferença de pressão, entre outros. / The goal of this project was to develop a thermodynamic model of a twin-screw multiphase pump. With given operation conditions the model can determine the absorbed power, discharge conditions and the pressure profile along the screw. An alternative approach was suggested to overcome the complex flow problem and the processes inside the pump were simulated instead of direct simulation of the flow. For this purpose, the multiphase pumping process was divided in a sequence of simple processes so the model could be developed in an easier way. The power and temperature values calculated by the model are in good agreement with experimental data, mainly when the gas fraction is low. With higher gas fractions, the model overestimates the absorbed power indicating that screw gaps are not completely filled with liquid anymore. Concerning about the backflow rate, the results show that the equations for turbulent flow in smooth ducts fits better the Reynolds number range in the gaps. The pressure profile and backflow rate for multiphase flow agree qualitatively with experimental results. The influence of several parameters in the exergetic eficiency of the pump were analysed and results show that the efficiency optimization depends on pump operation conditions: gas fraction, liquid type, pressure difference and others.

Esse trabalho apresenta um modelo termodinâmico de uma bomba multifásica do tipo duplo parafuso. Para uma dada condição de operação, o modelo calcula a potência consumida, as condições do fluido na descarga e o perfil de pressão ao longo da bomba. Ao invés de simular diretamente o escoamento dentro da bomba, simulou-se os processos que ocorrem dentro das suas câmaras. Para tanto, dividiu-se o processo de bombeamento multifásico em uma seqüência de processos simples, facilitando-se a construção do modelo no simulador de processos Hysys.Process v2.1. Os resultados de potência e temperatura de descarga obtidos com a simulação mostram uma boa concordância com valores experimentais, principalmente para FVG’s baixos. Para FVG’s elevados, o modelo passa a superestimar a potência consumida indicando que as fendas, nesses casos, já não se encontram totalmente preenchidas com líqüido. Dos resultados obtidos para o refluxo, conclui-se que, das equações sugeridas na literatura, aquelas para escoamento turbulento liso são mais adequadas para os números de Reynolds envolvidos. O perfil de pressão e a vazão de refluxo quando o escoamento é multifásico aproxima-se qualitativamente das medições experimentais. Estudou-se a influência de diversos parâmetros na eficiência exergética da bomba. Os resultados mostram que a otimização da eficiência depende das condições de operação da bomba: FVG, tipo de líqüido, diferença de pressão, entre outros. / The goal of this project was to develop a thermodynamic model of a twin-screw multiphase pump. With given operation conditions the model can determine the absorbed power, discharge conditions and the pressure profile along the screw. An alternative approach was suggested to overcome the complex flow problem and the processes inside the pump were simulated instead of direct simulation of the flow. For this purpose, the multiphase pumping process was divided in a sequence of simple processes so the model could be developed in an easier way. The power and temperature values calculated by the model are in good agreement with experimental data, mainly when the gas fraction is low. With higher gas fractions, the model overestimates the absorbed power indicating that screw gaps are not completely filled with liquid anymore. Concerning about the backflow rate, the results show that the equations for turbulent flow in smooth ducts fits better the Reynolds number range in the gaps. The pressure profile and backflow rate for multiphase flow agree qualitatively with experimental results. The influence of several parameters in the exergetic eficiency of the pump were analysed and results show that the efficiency optimization depends on pump operation conditions: gas fraction, liquid type, pressure difference and others.

The objective of this work is to determine the effect of four process variables on the properties of blends composed of bisphenol-A polycarbonate (PC) and poly (butylene terephthalate) (PBT) polymers which are compounded using a large scale commercial extruder. The four variables studied are blend composition, specific energy consumption, residence time and shear rate. The last three factors were varied using the extruder screw speed and feed rate. The PC/PBT blends, commercially known as XENOY, were compounded using a WP ZSK 58 mm co-rotating twin screw extruder at the facility of SABIC Innovative Plastics in Cobourg Ontario. The extruder was instrumented to measure online the die pressure, specific energy consumption and blend temperature. The blends were characterized using differential scanning calorimetry, (DSC), scanning electron microscopy, (SEM), gel permeation chromatography, (GPC), and melt volume flow rate, (MVR). After processing, the blend properties determined were melting temperature, glass transition temperature, crystallinity, amorphous phase weight fraction, amorphous phase composition, phase morphology, PBT-rich-phase size, blend molecular weight distribution, and MVR. Using principles available in the literature, a linear regression model was developed to relate the process variables with the online measured properties and output blend properties. Fitting this model allowed the relative importance of each process variable to be estimated for each property. An attempt was also made to identify the general type of PC/PBT blend studied and how it compares with published PC/PBT blend data. It was found that the blends studied were well stabilized since there was no evidence of significant co-polymer formation during processing. Small decreases in molecular weight were attributed to mechanical degradation. Blending increased the crystallization and melting temperatures, as well as blend crystallinity. No practically significant difference in melting temperatures was observed between the different processing conditions. Analysis of glass transitions indicated that the blend components were partially miscible. The amorphous phase compositions were unaffected by blend composition or processing; however, the weight fraction PC-rich-phase present in the blend was strongly influenced by the screw speed. The phase structure of as-extruded blends could not be resolved using the SEM. Therefore, the blends were annealed to coarsen the phases. After annealing, a continuous PC-rich-phase and a discrete PBT-rich-phase were observed. The PBT phase size increased with increasing PBT content. No other statistically significant effects on phase size were observed but this is not conclusive due to the large scatter in the measurements. MVR was primarily influenced by blend composition and specific energy consumption, with the effects of composition being dominant. Further study using higher imaging resolution is required if the phase structures of as received blend pellets are to be characterized. Contrary to current practice, it is recommended that the Utracki-Jukes equation be used rather than the Fox equation for determining amorphous phase composition from glass transition data in PC/PBT blends.

The objective of this work is to determine the effect of four process variables on the properties of blends composed of bisphenol-A polycarbonate (PC) and poly (butylene terephthalate) (PBT) polymers which are compounded using a large scale commercial extruder. The four variables studied are blend composition, specific energy consumption, residence time and shear rate. The last three factors were varied using the extruder screw speed and feed rate. The PC/PBT blends, commercially known as XENOY, were compounded using a WP ZSK 58 mm co-rotating twin screw extruder at the facility of SABIC Innovative Plastics in Cobourg Ontario. The extruder was instrumented to measure online the die pressure, specific energy consumption and blend temperature. The blends were characterized using differential scanning calorimetry, (DSC), scanning electron microscopy, (SEM), gel permeation chromatography, (GPC), and melt volume flow rate, (MVR). After processing, the blend properties determined were melting temperature, glass transition temperature, crystallinity, amorphous phase weight fraction, amorphous phase composition, phase morphology, PBT-rich-phase size, blend molecular weight distribution, and MVR. Using principles available in the literature, a linear regression model was developed to relate the process variables with the online measured properties and output blend properties. Fitting this model allowed the relative importance of each process variable to be estimated for each property. An attempt was also made to identify the general type of PC/PBT blend studied and how it compares with published PC/PBT blend data. It was found that the blends studied were well stabilized since there was no evidence of significant co-polymer formation during processing. Small decreases in molecular weight were attributed to mechanical degradation. Blending increased the crystallization and melting temperatures, as well as blend crystallinity. No practically significant difference in melting temperatures was observed between the different processing conditions. Analysis of glass transitions indicated that the blend components were partially miscible. The amorphous phase compositions were unaffected by blend composition or processing; however, the weight fraction PC-rich-phase present in the blend was strongly influenced by the screw speed. The phase structure of as-extruded blends could not be resolved using the SEM. Therefore, the blends were annealed to coarsen the phases. After annealing, a continuous PC-rich-phase and a discrete PBT-rich-phase were observed. The PBT phase size increased with increasing PBT content. No other statistically significant effects on phase size were observed but this is not conclusive due to the large scatter in the measurements. MVR was primarily influenced by blend composition and specific energy consumption, with the effects of composition being dominant. Further study using higher imaging resolution is required if the phase structures of as received blend pellets are to be characterized. Contrary to current practice, it is recommended that the Utracki-Jukes equation be used rather than the Fox equation for determining amorphous phase composition from glass transition data in PC/PBT blends.

Submitted by Ronildo Prado (ronisp@ufscar.br) on 2017-08-23T13:47:40Z No. of bitstreams: 1 DissRB.pdf: 6420019 bytes, checksum: 9a9303246e3fd99e5635cc0d40d684d5 (MD5) / Approved for entry into archive by Ronildo Prado (ronisp@ufscar.br) on 2017-08-23T13:47:48Z (GMT) No. of bitstreams: 1 DissRB.pdf: 6420019 bytes, checksum: 9a9303246e3fd99e5635cc0d40d684d5 (MD5) / Approved for entry into archive by Ronildo Prado (ronisp@ufscar.br) on 2017-08-23T13:47:53Z (GMT) No. of bitstreams: 1 DissRB.pdf: 6420019 bytes, checksum: 9a9303246e3fd99e5635cc0d40d684d5 (MD5) / Made available in DSpace on 2017-08-23T13:48:00Z (GMT). No. of bitstreams: 1 DissRB.pdf: 6420019 bytes, checksum: 9a9303246e3fd99e5635cc0d40d684d5 (MD5) Previous issue date: 2017-03-08 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / The present study investigated the utilization efficiency of an intermeshing co-rotating twin-screw extruder (ICTSE) in the devulcanization of natural rubber compounds (NR), evaluating the physical, chemical and mechanical characteristics of these materials in each project step. Three accelerated compounds with different sulfur concentrations were submitted to torque rheometry and vulcanized according these results aiming the achievement of elastomers with different crosslinks densities. The influences on the characteristics of the devulcanized material caused by the variation of the extruder barrel temperature, screw rotation, thermoplastics addition and material stiffness were evaluated. Thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), infrared spectroscopy (FTIR), soluble fraction extraction and crosslink density were performed, evaluating the devulcanized compound. Horikx's theory was also used as an indicator of selective crosslink cleavage, defining the compounds to be revulcanized for comparison with the virgin pure material. The revulcanization was carried out with the mixture of the devulcanized compound with the pure, in the proportions of 30/70 w/w, respectively, and in the devulcanized compound singularly, with addition of complementary vulcanization system in both cases. The mechanical, dynamic-mechanical and crosslink density properties of the revulcanized compounds were characterized and evaluated in relation to the properties of the pure compounds. The increase in the concentration of uncrosslinked BN chains and the concentration of sulfur compounds in the extruded samples was observed by thermal tests and spectrocopy, together with the verification of a high level of devulcanization percentage, according to Flory-Rehner, evidencing the regeneration of the natural rubber existent. Also, satisfactory mechanical properties were found in the revulcanized compounds, especially when using auxiliary thermoplastics, revealing the great potential of ERDCI processing for the reuse of discarded BN compounds. / O presente estudo avaliou a eficiência de utilização de uma extrusora com rosca dupla co-rotacional e interpenetrante (ERDCI) na desvulcanização de compostos de borracha natural (BN), avaliando as características físicas, químicas e mecânicas destes materiais em cada fase do projeto. Três compostos acelerados com diferentes concentrações de enxofre foram submetidos a reometria de torque, e vulcanizados de acordo com a curva reométrica, para obtenção de elastômeros com diferentes densidades de ligações cruzadas. Foram avaliadas as influências nas características do material desvulcanizado, causadas pela variação da temperatura do barril da extrusora, velocidade de rotação das roscas, adição de termoplásticos e módulo elástico do material. Análises de termogravimetria (TGA), calorimetria exploratória diferencial (DSC), espectroscopia no infravermelho (FTIR), fração solúvel (FS) e densidade de ligações cruzadas foram realizadas, avaliandose o composto desvulcanizado. A teoria de Horikx também foi utilizada como indicativa da seletividade de ruptura de ligações cruzadas, definindo os compostos a serem revulcanizados para comparação com o material virgem. A revulcanização foi realizada com a mistura de 30 %(m/m) do composto desvulcanizado e 70 %(m/m) do puro, e também com 100 % do composto desvulcanizado, e adição de sistema de vulcanização complementar. Caracterizou-se os compostos revulcanizados quanto às suas propriedades mecânicas, dinâmico-mecânicas e densidade de ligações cruzadas. Através dos ensaios TGA, DSC, FTIR e a verificação de alto nível de percentual de desvulcanização pela teoria de Flory- Rehner, foi observado o aumento da concentração de cadeias de BN não reticuladas e da concentração de compostos de enxofre nas amostras extrudadas, evidenciando a regeneração da BN presente nos compostos. Também foram encontradas propriedades mecânicas satisfatórias nos compostos revulcanizados, principalmente quando utilizados termoplásticos auxiliares, revelando o grande potencial do processamento por ERDCI para a reutilização de compostos de BN descartados.