| 1. |
- Rusli, Andri, et al.
(author)
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Eco-Friendly fabrication of nanoplastic particles and fibrils using polymer blends as templates
- 2024
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In: Chemical Engineering Journal. - : Elsevier BV. - 1385-8947 .- 1873-3212. ; 495
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Journal article (peer-reviewed)abstract
- Plastic pollution poses a critical global environmental challenge, and within this context, nanoplastics (NPs), the smallest plastic fragments, remain poorly understood. The progress in studying NP toxicity and developing analytical methods highly depends on access to well-defined NP materials. Herein, a straightforward and eco-friendly method for fabricating NP particles and fibrils using polymer blends as templates is presented. The process began with blending plastics with a water-soluble polymer (polyvinyl alcohol (PVA)), followed by the dissolution of the PVA matrix in water and the isolation of the NPs through a two-stage filtration process. NP materials from three widely used plastics, polyethylene, polypropylene, and polystyrene, were prepared, underscoring the versatility of this method. The resulting NPs were primarily submicron in size, and their size distribution was tuned by varying the blend ratio. Furthermore, by incorporating a stretch operation during the extrusion, the NP shape could be varied, enabling the fabrication of NP fibril materials. This method, which does not rely heavily on specialized equipment and avoids the use of harsh solvents, offers a viable and eco-friendly approach to fabricating NP samples suitable for a broad range of research applications.
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| 2. |
- Wei, Xin-Feng, et al.
(author)
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Microplastics Originating from Polymer Blends : An Emerging Threat?
- 2021
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In: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 55:8, s. 4190-4193
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Journal article (peer-reviewed)abstract
- No one can have missed the growing global environmental problems with plastics ending up as microplastics in food, water, and soil, and the associated effects on nature, wildlife, and humans. A hitherto not specifically investigated source of microplastics is polymer blends. A 1 g polymer blend can contain millions to billions of micrometer-sized species of the dispersed phase and therefore aging-induced fragmentation of the polymer blends can lead to the release of an enormous amount of microplastics. Especially if the stability of the dispersed material is higher than that of the surrounding matrix, the risk of microplastic migration is notable, for instance, if the matrix material is biodegradable and the dispersed material is not. The release can also be much faster if the matrix polymer is biodegradable. The purpose of writing this feature article is to arise public and academic attention to the large microplastic risk from polymer blends during their development, production, use, and waste handling.
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| 3. |
- Wei, Xin-Feng, et al.
(author)
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Risk for the release of an enormous amount of nanoplastics and microplastics from partially biodegradable polymer blends
- 2022
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In: Green Chemistry. - : Royal Society of Chemistry (RSC). - 1463-9262 .- 1463-9270. ; 24:22, s. 8742-8750
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Journal article (peer-reviewed)abstract
- Nanoplastics and microplastics (NMPs) in natural environments are an emerging global concern and understanding their formation processes from macro-plastic items during degradation/weathering is critical for predicting their quantities and impacts in different ecological systems. Here, we show the risk of enormous emissions of NMPs from polymer blends, a source that has not been specifically studied, by taking immiscible (most common case) partially biodegradable polymer blends as an example. The blends have the common “sea-island” morphology, where the minor non-biodegradable polymer phase (polyethylene and polypropylene) is dispersed as NMP particles in the major continuous biodegradable matrix (poly(ϵ-caprolactone)). The dispersed NMP particles with spherical and rod-like shapes are gradually liberated and released to the surrounding aquatic environment during the biodegradation of the matrix polymer. Strikingly, the number of released NMPs from the blend is very high. The blend film surface erosion process, induced by enzymatic hydrolysis of the matrix, involving fragmentation, hole formation, and hole wall detachment, was systematically investigated to reveal the NMP release process. Our findings present direct evidence and detailed insights into the high risk of emissions of NMPs from partially biodegradable immiscible polymer blends with a widespread “sea-island” morphology. Efforts from authorities, developers, manufacturers, and the public are needed to avoid the use of non-biodegradable polymers in blends with biodegradable polymers.
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| 4. |
- Wu, Jian, 1988-, et al.
(author)
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Hollow IF-MoS2/r-GO Nanocomposite Filled Polyimide Coating with Improved Mechanical, Thermal and Tribological Properties
- 2021
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In: Coatings. - : MDPI. - 2079-6412. ; 11:1
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Journal article (peer-reviewed)abstract
- Polyimide (PI) is one of the most excellent polymers for coating. However, the high friction coefficient and the high wear rate of pure PI limit its further applications. In this work, the hollow inorganic fullerene-like MoS2/reduced graphene oxide (HIF-MoS2/r-GO) nanocomposite filled PI coating is prepared by in situ polymerization. Reinforcement in mechanical strength and thermal stability is realized on the PI composite coating with incorporation of HIF-MoS2/r-GO, which performs better than carbon nanofiber (CNF). Reduced elastic modulus and hardness of HIF-MoS2/r-GO/PI coating is increased by 8.3% and 4.8%, respectively. The addition of HIF-MoS2/r-GO also results in 24% higher residual mass at 800 °C than CNF. Tribological study indicates that, HIF-MoS2/r-GO/PI achieves a wear rate reduction of 79% compared with pure PI under dry sliding condition, which is much more effective than other nanofillers including CNF, r-GO nanosheets and MoS2 nanoparticles. Under ionic liquid-lubricated condition, the presence of HIF-MoS2/r-GO in PI results in a 30% reduction in wear rate and 10% reduction in friction coefficient as compared to pure PI. It is thought that the HIF-MoS2/r-GO in PI can be slowly released to the frictional interface and form a protective film during sliding, in this way the aggregation problem is successfully solved.
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| 5. |
- Wu, Jian, et al.
(author)
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Turning the solubility and lubricity of ionic liquids by absorbing CO2
- 2018
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In: Tribology International. - : Elsevier. - 0301-679X .- 1879-2464. ; 121, s. 223-230
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Journal article (peer-reviewed)abstract
- Ionic liquids (ILs) attract high interest as lubricants or lubricant additives due to their special physicochemical characteristics. CO2 is a widely distributed gas. In many situations, its influence on lubricants cannot be avoided. In this work, three ILs are synthesized from choline and amino acids of glycine, l-proline and lysine, respectively. The influence of CO2 absorption on their solubility and lubricity is investigated. In general, it is interesting to find that the solubility is decreased and their lubricity is obviously improved after absorbing CO2, which is strongly related to their functional group (amino group) interactions with CO2. The formation of carbamate groups greatly increases the viscosity resulting in less solid contacts, and strengthens the interfacial adhesion between ILs and solids.
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| 6. |
- Yin, Xiang, et al.
(author)
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Right Way of Using Graphene Oxide Additives for Water-Lubricated PEEK : Adding in Polymer or Water?
- 2018
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In: Tribology letters. - : Springer. - 1023-8883 .- 1573-2711. ; 66:3
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Journal article (peer-reviewed)abstract
- Water-lubricated polymer is attracting more and more interest from the industry. Adding nanoparticles is considered to be an effective way to improve the tribological performance. In this work, water-lubricated Polyetheretherketone (PEEK)-steel contacts were employed as the objects of study. A careful comparative study was made by investigating the effect of adding graphene oxide (GO) into water or into PEEK. Results show that adding GO into water can significantly reduce the wear and friction coefficient of pure PEEK, which is much more effective than adding GO into PEEK. Under the lubrication of GO aqueous dispersion, the wear of PEEK remains very low even under a harsh condition where the pressure reaches 50 MPa and the linear sliding speed is 0.7 m/s. Neat PEEK and GO/PEEK composites in pure water exhibit serious wear under this harsh condition. The excellent lubricating properties of GO aqueous dispersion are attributed to GO nanosheets entering into solid contacts, which can not only form a protective layer on steel counterpart repairing the worn surface, but also strongly adhere to the PEEK matrix resulting in an in situ-formed GO coating and prevent the scratch by steel counterpart.
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