Development of a constitutive model for the compaction of recovered polyethylene terephthalate packages

[EN] To date, PET (polyethylene terephthalate) is the most widely used plastic in packaging and also one of the most recycled polymers worldwide. However, the high transport costs and stagnated prices of recycled PET undermine recycling process profits. Transport costs can lower through compaction, which is still not a completely wellknown process. Due to heterogeneous designs, the output density of the compaction process varies. This poses problems during equipment design, selection or operation processes as recovery costs sharply increase if the required density is not met. In this manuscript, the authors develop a constitutive model for the compaction of recovered PET packaging. This experimentally validated model, based on the elasto-plastic behaviour of PET packages, allows the output density range to be predicted according to the compression pressure during PET compaction. Unlike other generic compaction models that need more than two parameters, this model uses only one and better correlates with the experimental results. Unlike existing generic models, the model parameters have a physical meaning, which allows the influence of different factors on the compaction process to be assessed. Finally as a result of the model analysis, we provide some tips to enhance compaction equipment efficiency.Funding for open access charge: CRUE-Universitat Politecnica de Valencia.Sanchez-Caballero, S.; Sellés, M.; Peydro, MA.; H.P. Cherukuri (2021). Development of a constitutive model for the compaction of recovered polyethylene terephthalate packages. Waste Management. 133:89-98. https://doi.org/10.1016/j.wasman.2021.07.028S899813

The Potential of an Itaconic Acid Diester as EnvironmentallyFriendly Plasticizer for Injection-Molded Polylactide Parts

[EN] This work reports on the use of dibutyl itaconate (DBI) as an environmentallyfriendly plasticizer for polylactide (PLA) with different proportions of DBI inthe 2.5¿20 wt% (weight content) range. A co-rotating twin-screw extrusionprocess followed by injection molding is employed for the manufacturing ofthe samples. The results show that the plasticized PLA formulation with10 wt% DBI offers the most balanced overall properties, with a noticeableincrease in the elongation at break from 4.6% (neat PLA) up to 322%, with atensile modulus of 1572 MPa, and a tensile strength of 23.8 MPa. In the caseof 15 and 20 wt% DBI formulations, PLA reaches the saturation point with nomore increase in the elongation at break and a clear decrease in the tensilemodulus. DBI also decreases the glass transition temperature (Tg)from61.3°C (neat PLA) down to 23.4°C for plasticized PLA formulation containing20 wt% DBI, thus showing the high plasticization efficiency of DBI.J.I.-M. wants to thank FPU19/01759 grant funded by MCIN/AEI/10.13039/501100011033 and by ESF Investing in your future. J.G.-C. wants to thank Generalitat Valenciana-GVA, for his FPI grant (ACIF/2021/185) and grant FPU20/01732 funded by MCIN/AEI/10.13039/501100011033 and by ESF Investing in your future. Also, Microscopy Services at UPV are also acknowledged by their help in collecting and analyzing images. This research is a part of the grant PID2020-116496RB-C22 funded by MCIN/AEI/10.13039/501100011033, and the grant AICO/2021/025 funded by Generalitat Valenciana-GVAIvorra-Martínez, J.; Peydro, MA.; Gómez-Caturla, J.; Boronat, T.; Balart, R. (2022). The Potential of an Itaconic Acid Diester as EnvironmentallyFriendly Plasticizer for Injection-Molded Polylactide Parts. Macromolecular Materials and Engineering. 307(12):1-15. https://doi.org/10.1002/mame.2022003601153071

An Efficient COVID-19 Prediction Model Validated with the Cases of China, Italy and Spain: Total or Partial Lockdowns?

[EN] The present work develops an accurate prediction model of the COVID-19 pandemic, capable not only of fitting data with a high regression coefficient but also to predict the overall infections and the infection peak day as well. The model is based on the Verhulst equation, which has been used to fit the data of the COVID-19 spread in China, Italy, and Spain. This model has been used to predict both the infection peak day, and the total infected people in Italy and Spain. With this prediction model, the overall infections, the infection peak, and date can accurately be predicted one week before they occur. According to the study, the infection peak took place on 23 March in Italy, and on 29 March in Spain. Moreover, the influence of the total and partial lockdowns has been studied, without finding any meaningful difference in the disease spread. However, the infected population, and the rate of new infections at the start of the lockdown, seem to play an important role in the infection spread. The developed model is not only an important tool to predict the disease spread, but also gives some significant clues about the main factors that affect to the COVID-19 spread, and quantifies the effects of partial and total lockdowns as well.Sanchez-Caballero, S.; Sellés Cantó, MÁ.; Peydro, MA.; Pérez Bernabeu, E. (2020). An Efficient COVID-19 Prediction Model Validated with the Cases of China, Italy and Spain: Total or Partial Lockdowns?. Journal of Clinical Medicine. 9(5):1-18. https://doi.org/10.3390/jcm9051547S11895Huang, C., Wang, Y., Li, X., Ren, L., Zhao, J., Hu, Y., … Cao, B. (2020). Clinical features of patients infected with 2019 novel coronavirus in Wuhan, China. The Lancet, 395(10223), 497-506. doi:10.1016/s0140-6736(20)30183-5Al-qaness Mohammed A. A., Ewees, A. A., Fan, H., & Abd El Aziz, M. (2020). Optimization Method for Forecasting Confirmed Cases of COVID-19 in China. Journal of Clinical Medicine, 9(3), 674. doi:10.3390/jcm9030674Roosa, K., Lee, Y., Luo, R., Kirpich, A., Rothenberg, R., Hyman, J. M., … Chowell, G. (2020). Short-term Forecasts of the COVID-19 Epidemic in Guangdong and Zhejiang, China: February 13–23, 2020. Journal of Clinical Medicine, 9(2), 596. doi:10.3390/jcm9020596Shao, N., Zhong, M., Yan, Y., Pan, H., Cheng, J., & Chen, W. (2020). Dynamic models for Coronavirus Disease 2019 and data analysis. Mathematical Methods in the Applied Sciences, 43(7), 4943-4949. doi:10.1002/mma.6345Sun, K., Chen, J., & Viboud, C. (2020). Early epidemiological analysis of the coronavirus disease 2019 outbreak based on crowdsourced data: a population-level observational study. The Lancet Digital Health, 2(4), e201-e208. doi:10.1016/s2589-7500(20)30026-1Zhao, S., & Chen, H. (2020). Modeling the epidemic dynamics and control of COVID-19 outbreak in China. Quantitative Biology, 8(1), 11-19. doi:10.1007/s40484-020-0199-0Kuniya, T. (2020). Prediction of the Epidemic Peak of Coronavirus Disease in Japan, 2020. Journal of Clinical Medicine, 9(3), 789. doi:10.3390/jcm9030789Coronavirus COVID-19 Global Cases by the Center for Systems Science and Engineeringhttps://github.com/CSSEGISandData/COVID-19Wuhan Lockdown “Unprecedented”, Shows Commitment to Contain Virus: WHO Representative in Chinahttps://www.reuters.com/article/us-china-health-who-idUSKBN1ZM1G9First Case of Coronavirus Confirmed in Spainhttps://edition.cnn.com/asia/live-news/coronavirus-outbreak-02-01-20-intl-hnk/h_afcf3a4665521aab11c721c8cc80dd03Coronavirus Confirmed as Pandemic by World Health Organizationhttps://www.bbc.com/news/world-51839944MWC 2020: Smartphone Showcase Cancelled over Coronavirus Fearshttps://www.bbc.com/news/technology-51474116Capacity of the First League Stadiums in Spainhttps://www.enterat.com/actualidad/estadios-futbol-espana.phpMore than 550,000 People Demonstrating for Women Rights in Madrid and Barcelonahttps://www.elmundo.es/espana/2019/03/08/5c82a5da21efa09e348b469c.htmlMadrid Locksdown the Education System and Recommends Teleworkinghttps://www.lavanguardia.com/local/madrid/20200309/474061897680/madrid-ordena-cierre-colegios-coronavirus.htmlAll of Italy Placed under Coronavirus Lockdownhttps://www.bbc.com/news/world-europe-51810673State of Alarm Conditionshttps://www.boe.es/eli/es/rd/2020/03/14/463/conMerkel Says ‘Let’s Get through This’ as Shops, Bars and Churches Shuthttps://www.reuters.com/article/us-health-coronavirus-germany-economy/merkel-says-lets-get-through-this-as-shops-bars-and-churches-shut-idUSKBN213178Coronavirus: Europe Plans Full Border Closure in Virus Battlehttps://www.bbc.com/news/world-europe-51918596Italy Tightens Virus Lockdown after Worst Daily Death Tollhttps://www.bloomberg.com/news/articles/2020-03-19/italy-is-now-world-s-deadliest-hotspot-in-the-virus-pandemicChina to Lift Lockdown on Wuhan, Ground Zero of Coronavirus Pandemichttps://edition.cnn.com/2020/03/24/asia/coronavirus-wuhan-lockdown-lifted-intl-hnk/index.htmlCoronavirus: Strict New Curbs on Life in UK Announced by PMhttps://www.bbc.com/news/uk-52012432State of Alarm Thighteninghttps://www.boe.es/buscar/doc.php?id=BOE-A-2020-4166Coronavirus: Sharp increase in Deaths and Cases in Hubeihttps://www.bbc.com/news/world-asia-china-51482994Kampf, G., Todt, D., Pfaender, S., & Steinmann, E. (2020). Persistence of coronaviruses on inanimate surfaces and their inactivation with biocidal agents. Journal of Hospital Infection, 104(3), 246-251. doi:10.1016/j.jhin.2020.01.022Coronavirus Disease (COVID-2019) Situation Reportshttps://www.who.int/emergencies/diseases/novel-coronavirus-2019/situation-reports

Failure analysis of a plastic modular belt in-service

[EN] In this study, an analysis of the possible causes of the failure in-service of a section of a plastic modular belt was conducted. The study begins with a reproduction of the service conditions in a traction gear. An analysis of the fracture surfaces revealed the existence of defects in the interior of the parts. With the aim of determining the origin of the imperfections and their influence on the failure, an exhaustive mechanical and rheological characterization of the material was carried out. The development of an FE Analysis established that the reduction of the tensile strength of the part due to internal defects was around 70%. Tests also showed that the most stressed area was the area where the most defects appeared. A simulation of the injection process showed that the defects are caused by the geometry of the part, leading to the conclusion that its failure was caused by bad dimensioning of thicknesses.Sanchez-Caballero, S.; Sellés Cantó, MÁ.; Ferrándiz Bou, S.; Peydro, MA.; Oliver, B. (2018). Failure analysis of a plastic modular belt in-service. Engineering Failure Analysis. 93:13-25. https://doi.org/10.1016/j.engfailanal.2018.06.019S13259

The effects of processing parameters on mechanical properties of 3D-printed polyhydroxyalkanoates parts

[EN] The crystallisation process of polyhydroxyalkanoates (PHA) polymers plays a key role on final properties of manufactured parts due to most PHA are highly sensitive to physical aging which leads to embrittlement. The secondary crystallisation associated with the aging process can be partially controlled by the cooling process during manufacturing or, even, by heat treatments such as annealing. A critical parameter in additive manufacturing is the difficulty to achieve good adhesion of the material to the printing bed. The bed temperature plays a key role on PHBH crystallisation, which leads to shrinkage having a negative effect on polymer-to-bed adhesion. In this work, a study of the effect of different processing parameters such as the printing temperature, the bed temperature, the cooling conditions, as well as raster direction on the final properties of PHBH 3D-printed parts is carried out.This research is a part of the grant PID2020-116496RB-C22 funded by MCIN/AEI/10.13039/501100011033. Authors also thank Generalitat Valenciana-GVA for funding this research through the grant numbers AICO/2021/025 and CIGE/2021/ 094. Wants to thank the Ministerio de Ciencia e Innovación and Universities for his FPU grant (FPU19/01759). Wants to thank Generalitat Valenciana-GVA, for his FPI grant (ACIF/2021/ 185) and grant FPU20/01732 funded by MCIN/AEI/10.13039/ 501100011033 and by ESF Investing in your future. Funding for open access charge: Universitat Politècnica de València.Ivorra-Martinez, J.; Peydro, MA.; Gómez-Caturla, J.; Sanchez-Nacher, L.; Boronat, T.; Balart, R. (2023). The effects of processing parameters on mechanical properties of 3D-printed polyhydroxyalkanoates parts. Virtual and Physical Prototyping (Online). 18(1). https://doi.org/10.1080/17452759.2022.216473418

Research on the Friction Properties of DP600 Stainless Steel as a Function of Bending Angle and Pin Diameter

[EN] The rapid evolution of materials and manufacturing processes, driven by global competition and new safety and environmental regulations has had an impact on automotive structures (Body In White; BIW) manufacturing. The need for lighter vehicles, with more equipment, that are safer and eco-friendly at the same time, relates to the entire life cycle of the car. Car and steelmakers agree that weight reduction is possible, and the solution involves the use of new advanced high-strength steels. Thinner and stronger materials lead to higher demands on stamping, the most used manufacturing in BIW parts. The use of advanced high-strength steels raises new challenges, especially concerning the lubrication between the die and the sheet. To study the lubrication conditions of the stamping process, a sheet metal forming a simulator was developed. The simulator consists of two cylinders that pull the strip of steel and a pin in between. The angle between the cylinders can be adjusted from 0 to 90 degrees, which allows analysis of the effect of the stamping angle. The pull force and velocity can be set and measured, and the peripheric pin velocity, the strain, and the strain velocity can be measured as well. In this work, the tribological properties of Dual-Phase 600 stainless steel using different processing conditions have been analyzed. To this end, a factorial experiments design with twelve parameters that compare the behavior of different angles and diameters was run. The results showed that the friction coefficient increases by increasing the bending angle and decreases with pin diameter.Sanchez-Caballero, S.; Sellés, M.; Pla-Ferrando, R.; Segui Llinares, VJ.; Peydro, MA. (2021). Research on the Friction Properties of DP600 Stainless Steel as a Function of Bending Angle and Pin Diameter. Materials Proceedings. 3(1):1-7. https://doi.org/10.3390/IEC2M-09248173

Study and analysis of injection molding of thermoplastic polymeric materials

[EN] This article aims at analyzing the injection molding of thermoplastic polymeric materials by examining their current situation from the perspective of industrial production, the evolution of technology and modeling of the injection process.[ES] El presente artículo tiene como objetivo el análisis del moldeo por inyección de materiales poliméricos termoplásticos, estudiando su situación actual desde la perspectiva de la producción industrial, la evolución de la técnica y la modelización del proceso de inyección.Authors thank “Ministerio de Ciencia y Tecnología”, Ref: DPI2007-66849-C02-02 and Generalitat Valenciana FPA/2010/027 for financial support.Juárez Varón, D.; Balart, R.; Peydro, MA.; Ferrándiz Bou, S. (2012). Estudio y análisis del moldeo por inyección de materiales poliméricos termoplásticos. 3c Tecnologia. (3):40-53. http://hdl.handle.net/10251/33135S4053

Calculation of loss of mechanical properties (wt%) through reprocessing and presence of impurities

[EN] Recycled materials are characterized by having endured different reprocessing cycles that cause thermal degradation and by containing often a number of impurities from different sources. In this paper, is studied the calculation of which of these two factors analyzed has more weight in the fall of mechanical properties. To carry out such work has investigated an ABS recycled from alarm systems used in Textile garments sector with presence of impurities of a 4% of PE. The results show that in the case studied, for an ABS reprocessed twice with a presence of 4% of impurities, is obtained that the thermal degradation factor has a weight of 25%, meanwhile, the presence of impurities has a weight of 75% in the fall of its properties.[ES] Los materiales reciclados se caracterizan por haber soportado diferentes ciclos de reprocesados que provocan degradación térmica y por contener frecuentemente una serie de impurezas de distinta procedencia. En este trabajo se expone el cálculo de cuál de estos dos factores tiene más peso en la caída de propiedades mecánicas. Para la realización de dicho trabajo se ha investigado un ABS reciclado procedente de sistemas de alarma utilizadas en prendas del sector Textil con una presencia de impurezas del 4% de PE. Los resultados muestran que en el caso estudiado, un ABS reprocesado dos veces y con una presencia de impurezas del 4%, el factor de la degradación térmica tiene un peso de un 25%, mientras que el otro factor, la presencias de impurezas tiene un peso del 75% en la caída de propiedades.Peydro, MA.; Parres, F.; Navarro Vidal, R.; Juárez Varón, D. (2015). Cálculo de pérdida de propiedades mecánicas (%) a través de reprocesado y presencia de impurezas. 3C Tecnología. 4(2):45-53. http://hdl.handle.net/10251/65402S45534

Estudio de compatibilización de las mezclas PET/HDPE

[ES] En el presente trabajo se ha realizado un estudio de compatibilización del sistema de mezclas PET/HDPE. Para ello se realiza una caracterización mecánica y reológica del sistema binario PET/HDPE (70/30 wt%) y posteriormente se añade SEBS (2.5 - 30 wt%) como compatibilzador de modo que nos permita recuperar alguna de las propiedades mecánicas, al mismo tiempo que nos ajuste las propiedades reológicas de la mezcla al proceso de inyección. La adición de SEBS como compatibilizador al sistema PET/HDPE más desfavorable (70/30), ha permitido una recuperación progresiva de las propiedades mecánicas. La adición de un 2.5% de SEBS al sistema PET/HDPE (70/30) produce un incremento de los valores de viscosidad en todo el rango de velocidades de cizalla estudiado, lo que confirma el efecto compatibilizador para bajos contenidos de SEBS. Esta compatibilización se observa en la sección de rotura mediante la desaparición del efecto skin-core. Esta mezcla presenta unas propiedades mecánicas aceptables y un comportamiento reológico adecuado para el proceso de inyección.Los autores desean agradecer Al VIDI de la Universitat Politècnica de València por la ayuda concedida al proyecto “Utilización del polietilén tereftalato reciclado (PET-R) en el sector del juguete”, Ref. 003-306 dentro del programa Primeros Proyectos de Investigación.Navarro Vidal, R.; Parres, F.; Peydro, MA.; Crespo Amorós, JE. (2013). Estudio de compatibilización de las mezclas PET/HDPE. Compobell, S.L. http://hdl.handle.net/10251/74083

Industrial applications of phase change materials

[EN] This study identifies the different industrial applications of phase change materials, in order to identify those thar are potentially viable for addition with thermoplastic materials.[ES] El presente estudio pretende identificar las diferentes aplicaciones industriales de materiales con cambio de fase, para identificar aquellos que son potencialmente viables para su adición en materiales termoplásticos.Juárez Varón, D.; Ferrándiz Bou, S.; Peydro, MA.; Mengual Recuerda, A. (2015). Aplicaciones industriales de los materiales con cambio de fase. 3C Tecnología. 4(1):32-41. http://hdl.handle.net/10251/65311S32414