Green Polymer Materials for Circular Economy and Sustainable Development

Topic Information

Dear Colleagues,

Producing more than 2.5 billion tonnes of waste a year, the European Union has forced the European Parliament to take appropriate legal measures and promote the transition to a more sustainable model known as a circular economy. This means using raw materials more efficiently, keeping waste to a minimum, and extending the life cycle of products through repeated use (repair, reuse, recycling, and remanufacture). Green polymer materials made from (bio)degradable and/or renewable and/or recycled raw materials can help to prevent and partially reduce waste and contribute to more sustainable life cycles. Furthermore, carbon-neutral energy should be used to produce such polymers, and the end products can be reused or recycled, including organic recycling (processed into compost or biogas). (Bio)degradable and/or renewable and/or recyclable plastics have a lower carbon footprint and may, in some cases, exhibit more favorable material properties in many applications. This Topic welcomes papers that address interdisciplinary approaches aimed at the development of (bio)degradable and/or renewable and/or recyclable polymer materials for environmental, packaging, and medical needs.

Dr. Joanna Rydz
Dr. Marta Musioł
Dr. Barbara Zawidlak-Węgrzyńska
Dr. Alena Opálková Šišková
Dr. Cristian Peptu
Prof. Dr. Darinka Christova
Topic Editors

Keywords

Participating Journals

Journal Name	Impact Factor	CiteScore	Launched Year	First Decision (median)	APC
Biomolecules biomolecules	5.5	8.3	2011	16.9 Days	CHF 2700	Submit
International Journal of Molecular Sciences ijms	5.6	7.8	2000	16.3 Days	CHF 2900	Submit
Materials materials	3.4	5.2	2008	13.9 Days	CHF 2600	Submit
Nanomaterials nanomaterials	5.3	7.4	2010	13.6 Days	CHF 2900	Submit
Pharmaceutics pharmaceutics	5.4	6.9	2009	14.2 Days	CHF 2900	Submit
Polymers polymers	5.0	6.6	2009	13.7 Days	CHF 2700	Submit

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Published Papers (5 papers)

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All Biomolecules IJMS Materials Nanomaterials Pharmaceutics Polymers

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17 pages, 4608 KiB  

Open AccessArticle

Comparative Analysis of the Effects of Incorporating Post-Industrial Recycled LLDPE and Post-Consumer PE in Films: Macrostructural and Microstructural Perspectives in the Packaging Industry

by Ricardo Ballestar de las Heras, Xavier Colom and Javier Cañavate

Polymers 2024, 16(7), 916; https://doi.org/10.3390/polym16070916 - 27 Mar 2024

Viewed by 613

Abstract

In accordance with the Circular Economy Package of the European directive, the Spanish government compels manufacturers of plastic bags to include into their products a minimum of 70% of polyethylene (PE) waste. Following this mandate can be challenging and requires a deep knowledge [...] Read more.

In accordance with the Circular Economy Package of the European directive, the Spanish government compels manufacturers of plastic bags to include into their products a minimum of 70% of polyethylene (PE) waste. Following this mandate can be challenging and requires a deep knowledge of the alterations produced by the recycling in the main components of a plastic bag film: lineal low-density polyethylene (LLDPE), the LLDPE recycled post-industry, generated as waste from an industrial process (rLLDPE) and the PE recycled from post-consumer use (rPE), that has been picked up, cleaned, and reprocessed. This study provides insight in the macro and microstructural changes produced by several cycles of recycling in these materials. Specimens in the form of film for supermarket bags formed with these polymers have been subjected to several recycling sequences. The process closely mimics industrial processes. Four cycles have been applied to the samples. The evolution of mechanical properties, including tensile strength, elongation at break, and tear and impact tests, shows an obvious decrease due to degradation that is not an impediment for practical use after the four cycles of recycling according to the main specifications defined by the producer. Colorimetric measurements reveal no significant variations in the color of the films. The results of the FTIR and TGA analysis show degradation phenomena and changes in crystallinity in branching and the apparition of crosslinking that are in consonance with the mechanical data. There is also a difference between both types of recycled PE. In general, rLLDPE is more affected by the recycling than rPE. According to our findings, the limiting property would be the tearing. By comparing these values with bags available in the market, manufactured from 70–80% recycled material, we can infer that while two reprocessing cycles can lead to good results, a maximum of four cycles of recycling is advisable. Full article

(This article belongs to the Topic Green Polymer Materials for Circular Economy and Sustainable Development)

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20 pages, 3724 KiB  

Open AccessArticle

Ductile Copolyesters Prepared Using Succinic Acid, 1,4-Butanediol, and Bis(2-hydroxyethyl) Terephthalate with Minimizing Generation of Tetrahydrofuran

by Sang Uk Park, Hyeon Jeong Seo, Yeong Hyun Seo, Ju Yong Park, Hyunjin Kim, Woo Yeon Cho, Pyung Cheon Lee and Bun Yeoul Lee

Polymers 2024, 16(4), 519; https://doi.org/10.3390/polym16040519 - 14 Feb 2024

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Abstract

Poly(1,4-butylene succinate) (PBS) is a promising sustainable and biodegradable synthetic polyester. In this study, we synthesized PBS-based copolyesters by incorporating 5–20 mol% of –O₂CC₆H₄CO₂– and –OCH₂CH₂O– units through the polycondensation of [...] Read more.

Poly(1,4-butylene succinate) (PBS) is a promising sustainable and biodegradable synthetic polyester. In this study, we synthesized PBS-based copolyesters by incorporating 5–20 mol% of –O₂CC₆H₄CO₂– and –OCH₂CH₂O– units through the polycondensation of succinic acid (SA) with 1,4-butanediol (BD) and bis(2-hydroxyethyl) terephthalate (BHET). Two different catalysts, H₃PO₄ and the conventional catalyst (nBuO)₄Ti, were used comparatively in the synthesis process. The copolyesters produced using the former were treated with M(2-ethylhexanoate)₂ (M = Mg, Zn, Mn) to connect the chains through ionic interactions between M²⁺ ions and either –CH₂OP(O)(OH)O⁻ or (–CH₂O)₂P(O)O⁻ groups. By incorporating BHET units (i.e., –O₂CC₆H₄CO₂– and –OCH₂CH₂O–), the resulting copolyesters exhibited improved ductile properties with enhanced elongation at break, albeit with reduced tensile strength. The copolyesters prepared with H₃PO₄/M(2-ethylhexanoate)₂ displayed a less random distribution of –O₂CC₆H₄CO₂– and –OCH₂CH₂O– units, leading to a faster crystallization rate, higher T_m value, and higher yield strength compared to those prepared with (nBuO)₄Ti using the same amount of BHET. Furthermore, they displayed substantial shear-thinning behavior in their rheological properties due to the presence of long-chain branches of (–CH₂O)₃P=O units. Unfortunately, the copolyesters prepared with H₃PO₄/M(2-ethylhexanoate)₂, and hence containing M²⁺, –CH₂OP(O)(OH)O⁻, (–CH₂O)₂P(O)O⁻ groups, did not exhibit enhanced biodegradability under ambient soil conditions. Full article

(This article belongs to the Topic Green Polymer Materials for Circular Economy and Sustainable Development)

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16 pages, 4910 KiB  

Open AccessArticle

Comparative Study of Different Pretreatment and Combustion Methods on the Grindability of Rice-Husk-Based SiO₂

by Yunhai Ma, Shengwang Yuan, Zichao Ma, Yihao Hou, Shichao Niu, Li Lekai, Guoqin Liu and Feipeng Cao

Nanomaterials 2023, 13(22), 2951; https://doi.org/10.3390/nano13222951 - 15 Nov 2023

Cited by 1 | Viewed by 698

Abstract

The rice husk (RH) combustion pretreatment method plays a crucial role in the extraction of nanoscale SiO₂ from RH as a silicon source. This study examined the effects of diverse pretreatment methods and combustion temperatures on the particle size distribution of nanoscale [...] Read more.

The rice husk (RH) combustion pretreatment method plays a crucial role in the extraction of nanoscale SiO₂ from RH as a silicon source. This study examined the effects of diverse pretreatment methods and combustion temperatures on the particle size distribution of nanoscale high-purity amorphous SiO₂ extracted from rice husk ash (RHA) post RH combustion. The experiment was structured using the Taguchi method, employing an L9 (2¹ × 3³) orthogonal mixing table. The median diameter (D50) served as the output response parameter, with the drying method (A), combustion temperature (B), torrefaction temperature (C), and pretreatment method (D) as the input parameters. The results showed the torrefaction temperature (C) as being the predominant factor affecting the D50, which decreased with an increasing torrefaction temperature (C). The optimal parameter combination was identified as A2B2C3D2. The verification test revealed that roasting could improve the abrasiveness of Rh-based silica and reduce the average particle size. Torrefaction at medium temperatures might narrow the size distribution range of RHA-SiO₂. We discovered that the purity of silica increased with an increasing roasting temperature by evaluating the concentration of silica in the sample. The production of RHA with silica concentrations up to 92.3% was investigated. X-ray diffraction analysis affirmed that SiO₂’s crystal structure remained unaltered across different treatment methods, consistently presenting as amorphous. These results provide a reference for extracting high-value products through RH combustion. Full article

(This article belongs to the Topic Green Polymer Materials for Circular Economy and Sustainable Development)

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18 pages, 3510 KiB  

Open AccessArticle

Alternative Solid Activators from Waste Glass for One-Part Alkali-Activated Fly Ash/Red Mud Cements

by Nicolaie Marin, Cristina Orbeci, Liliana Bobiricǎ, Ileana Rău, Calin Deleanu, Elena Iuliana Bîru, Paul Octavian Stănescu, Andrei Constantin Berbecaru, Ecaterina Matei and Constantin Bobiricǎ

Materials 2023, 16(20), 6707; https://doi.org/10.3390/ma16206707 - 16 Oct 2023

Viewed by 880

Abstract

Solid activators based on waste glass for the manufacture of one-part alkali-activated fly ash/red mud materials were synthesized, characterized, and tested in this work. The synthesis was carried out via alkaline fusion with sodium hydroxide at different reaction temperatures and at different sodium [...] Read more.

Solid activators based on waste glass for the manufacture of one-part alkali-activated fly ash/red mud materials were synthesized, characterized, and tested in this work. The synthesis was carried out via alkaline fusion with sodium hydroxide at different reaction temperatures and at different sodium hydroxide/waste glass mass ratios. The results showed that the reaction temperature decisively influences the properties of the obtained solid activators. Thus, the best results regarding the water solubility of solid activators were obtained for the synthesis temperature of 600 °C, regardless of the sodium hydroxide/waste glass mass ratio. Also, the use of these assortments of solid activators led to obtaining the best compressive strength of one-part alkali-activated fly ash/red mud materials. The best results were obtained for the solid activator synthesized at a temperature of 600 °C and a sodium hydroxide/glass waste mass ratio of two. Full article

(This article belongs to the Topic Green Polymer Materials for Circular Economy and Sustainable Development)

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16 pages, 18189 KiB  

Open AccessArticle

Influence of Pyrolytic Carbon Black Derived from Waste Tires at Varied Temperatures within an Industrial Continuous Rotating Moving Bed System

by Haibin Fang, Zhanfeng Hou, Lingdi Shan, Xiaohui Cai and Zhenxiang Xin

Polymers 2023, 15(16), 3460; https://doi.org/10.3390/polym15163460 - 18 Aug 2023

Cited by 3 | Viewed by 1097

Abstract

Nowadays, waste tires have emerged as one of the most significant sources of environmental pollution. To address this issue, pyrolysis has become a widely adopted method. The continuous rotary kiln reactor has particularly gained popularity in industrial production for pyrolysis due to its [...] Read more.

Nowadays, waste tires have emerged as one of the most significant sources of environmental pollution. To address this issue, pyrolysis has become a widely adopted method. The continuous rotary kiln reactor has particularly gained popularity in industrial production for pyrolysis due to its suitability. In order to guide the development of new industrial continuous rotary kiln reactors and achieve high-performance pyrolytic carbon black (CBp), this study was conducted to investigate the relationship between the physical and chemical characteristics of CBp and pyrolysis temperature. The elevated-temperature procedure led to a reduction in DBP values from 90 to 70 mL/100 mg, accompanied by a rise in the specific surface area from 63 to 77 m²/g. The augmentation of pyrolysis temperature was noted to induce the agglomeration of CBp particles, thereby negatively impacting their dispersion within polymer matrices. CBp particles at 550 °C exhibited greater structural order, as determined by Raman spectroscopy, which can be attributed to the elevated temperature proximate to the cylinder wall surface. Furthermore, the potential of CBp for reinforcement in natural rubber (NR) was taken into consideration. The pronounced propensity of high-temperature CBps to agglomerate led to uneven dispersion within the polymer, consequently causing heightened heat accumulation and the emergence of the Payne effect. Based on a thorough analysis of the outcomes, the optimal pyrolysis temperature for CBp synthesis within the continuous reactor was ascertained. Full article

(This article belongs to the Topic Green Polymer Materials for Circular Economy and Sustainable Development)

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