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24 pages, 1335 KiB

Open AccessArticle

Design for 4D Printing of Biodegradable Shape Memory Polymers for Disposable UAV Systems

by Mary Ebeid and Sagil James

Polymers 2023, 15(17), 3562; https://doi.org/10.3390/polym15173562 - 27 Aug 2023

Cited by 2 | Viewed by 1401

Abstract

The use of bio-based smart materials is vital for achieving the desired morphing characteristics while improving the efficiency of disposable Unmanned Aerial Vehicle (UAV) systems. Smart materials combine the structure and actuator into a single element without discrete moving parts, thereby minimizing the [...] Read more.

The use of bio-based smart materials is vital for achieving the desired morphing characteristics while improving the efficiency of disposable Unmanned Aerial Vehicle (UAV) systems. Smart materials combine the structure and actuator into a single element without discrete moving parts, thereby minimizing the weight and mechanical complexity of the UAV system. Biodegradable smart materials facilitate the realization of smart actuation concepts that help in potentially improving system reliability and reducing the risk of potential component failure. However, the manufacturing of biodegradable smart materials is a huge challenge. Recent advances in 3D printing technologies have opened new possibilities for manufacturing biodegradable smart materials. The 3D printing technologies have been further extended to 4D printing, which essentially involves fabricating 3D smart structures. The goal of this research is to investigate the manufacturing challenges involved in the 4D printing of biodegradable smart polymer materials for disposable UAV systems. The manufacturing process consists of a combination of biodegradable smart polymer materials in conjunction with SLA-based 3D printing technology. The study will involve extensive theoretical investigations followed by experimental studies. The results of this study are expected to open up new possibilities for using biodegradable smart polymer materials at commercial scales. Full article

(This article belongs to the Special Issue Eco-Friendly Polymers: Synthesis, Characterization and Applications)

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13 pages, 3955 KiB

Open AccessArticle

Biocompatible Palladium Nanoparticles Prepared Using Vancomycin for Colorimetric Detection of Hydroquinone

by Shoubei Gao, Kai Liu, Xianbing Ji, Yanshuai Cui, Ruyu Li, Guanglong Ma, Yongqiang Zhang and Longgang Wang

Polymers 2023, 15(14), 3148; https://doi.org/10.3390/polym15143148 - 24 Jul 2023

Cited by 1 | Viewed by 1751

Abstract

Hydroquinone poses a major threat to human health and is refractory to degradation, so it is important to establish a convenient detection method. In this paper, we present a novel colorimetric method for the detection of hydroquinone based on a peroxidase-like Pd nanozyme. [...] Read more.

Hydroquinone poses a major threat to human health and is refractory to degradation, so it is important to establish a convenient detection method. In this paper, we present a novel colorimetric method for the detection of hydroquinone based on a peroxidase-like Pd nanozyme. The vancomycin-stabilized palladium nanoparticles (Van-Pd_n NPs, n = 0.5, 1, 2) were prepared using vancomycin as a biological template. The successful synthesis of Van-Pd_n NPs (n = 0.5, 1, 2) was demonstrated by UV-vis spectrophotometry, transmission electron microscopy, and X-ray diffraction. The sizes of Pd nanoparticles inside Van-Pd_0.5 NPs, Van-Pd₁ NPs, and Van-Pd₂ NPs were 2.6 ± 0.5 nm, 2.9 ± 0.6 nm, and 4.3 ± 0.5 nm, respectively. Furthermore, Van-Pd₂ NPs exhibited excellent biocompatibility based on the MTT assay. More importantly, Van-Pd₂ NPs had good peroxidase-like activity. A reliable hydroquinone detection method was established based on the peroxidase-like activity of Van-Pd₂ NPs, and the detection limit was as low as 0.323 μM. Therefore, vancomycin improved the peroxidase-like activity and biocompatibility of Van-Pd₂ NPs. Van-Pd₂ NPs have good application prospects in the colorimetric detection of hydroquinone. Full article

(This article belongs to the Special Issue Eco-Friendly Polymers: Synthesis, Characterization and Applications)

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12 pages, 2090 KiB

Open AccessArticle

Amidated Pectic Polysaccharides (Pectin) as Methane Hydrate Inhibitor at Constant Cooling and Isobaric Condition

by Adam Daniel Effendi, Muhammad Aslam Md Yusof, Nor Fariza Abd Mutalib and Chee Wee Sia

Polymers 2023, 15(9), 2080; https://doi.org/10.3390/polym15092080 - 27 Apr 2023

Cited by 1 | Viewed by 1352

Abstract

This study aims to address the environmental impact of using common commercial hydrate inhibitors such as Methanol (MeOH) in extremely cold oil and gas environments. As a greener alternative, Pectic Polysaccharides (pectin) can act as a kinetic hydrate inhibitor (KHI) to delay hydrate [...] Read more.

This study aims to address the environmental impact of using common commercial hydrate inhibitors such as Methanol (MeOH) in extremely cold oil and gas environments. As a greener alternative, Pectic Polysaccharides (pectin) can act as a kinetic hydrate inhibitor (KHI) to delay hydrate formation. We evaluated the performance of amidated pectin (AMP), a type of pectin with higher electronegative functional groups, using a high-pressure micro-differential scanning calorimeter (HP µ-DSC) under isobaric conditions with constant cooling. We compared AMP to low-methoxylated pectin (LMP) and high-methoxylated pectin (HMP) and found that AMP was the best KHI among the tested pectin types. At a concentration of 1.0 wt.%, the AMP Relative Inhibitor Performance (RIP) was 0.10, and at 0.1 wt.%, it had an RIP of 0.07, which were the only positive RIPs obtained amongst the tested KHIs. The results suggest that AMP can be a sustainable KHI option in extremely cold environments where the KHI effectiveness typically declines. Full article

(This article belongs to the Special Issue Eco-Friendly Polymers: Synthesis, Characterization and Applications)

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18 pages, 13527 KiB

Open AccessArticle

Investigation of Morphological, Chemical, and Thermal Properties of Biodegradable Food Packaging Films Synthesised by Direct Utilisation of Cassava (Monihot esculanta) Bagasse

by Vindya Thathsaranee Weligama Thuppahige, Lalehvash Moghaddam, Zachary G. Welsh and Azharul Karim

Polymers 2023, 15(3), 767; https://doi.org/10.3390/polym15030767 - 2 Feb 2023

Cited by 3 | Viewed by 2899

Abstract

The utilisation of edible sources of starch such as corn, wheat, potato, and cassava has become the common approach to develop biodegradable food packaging. However, the future food security issue from the wide application of such edible starch sources has become a major [...] Read more.

The utilisation of edible sources of starch such as corn, wheat, potato, and cassava has become the common approach to develop biodegradable food packaging. However, the future food security issue from the wide application of such edible starch sources has become a major concern. Consequently, exploring non-edible sources of starch for starch-based biodegradable food packaging and their property enhancement have become one of the common research interests. Although there has been a great potentials of synthesising biodegradable food packaging by direct utilisation of agro-industrial waste cassava bagasse, there have been very limited studies on this. In this context, the current study investigated the potential of developing biodegradable food packaging by directly using cassava bagasse as an alternative matrix. Two film-forming mixtures were prepared by incorporating glycerol (30% and 35%), powdered cassava bagasse and water. The films were hot-pressed at 60 °C, 100 °C, and 140 °C temperatures under 0.28 t pressure for 6 min. The best film-forming mixture and temperature combination was further tested with 0.42 t and 0.84 t pressures, followed by analysing their morphology, functional group availability and the thermal stability. Accordingly, application of 35% glycerol, with 100 °C, 0.42 t temperature and pressure, respectively, were found to be promising for film preparation. The absence of starch agglomerates in film surfaces with less defects suggested satisfactory dispersion and compatibility of starch granules and glycerol. The film prepared under 0.42 t exhibited slightly higher thermal stability. Synthesised prototypes of food packaging and the obtained characterisation results demonstrated the high feasibility of direct utilisation of cassava bagasse as an alternative, non-edible matrix to synthesise biodegradable food packaging. Full article

(This article belongs to the Special Issue Eco-Friendly Polymers: Synthesis, Characterization and Applications)

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16 pages, 2490 KiB

Open AccessArticle

Extraction and Characterization of Fiber and Cellulose from Ethiopian Linseed Straw: Determination of Retting Period and Optimization of Multi-Step Alkaline Peroxide Process

by Kibrom Feleke, Ganesh Thothadri, Habtamu Beri Tufa, Ali A. Rajhi and Gulam Mohammed Sayeed Ahmed

Polymers 2023, 15(2), 469; https://doi.org/10.3390/polym15020469 - 16 Jan 2023

Cited by 23 | Viewed by 9302

Abstract

Flax is a commercial crop grown in many parts of the world both for its seeds and for its fibers. The seed-based flax variety (linseed) is considered less for its fiber after the seed is extracted. In this study, linseed straw was utilized [...] Read more.

Flax is a commercial crop grown in many parts of the world both for its seeds and for its fibers. The seed-based flax variety (linseed) is considered less for its fiber after the seed is extracted. In this study, linseed straw was utilized and processed to extract fiber and cellulose through optimization of retting time and a multi-step alkaline peroxide extraction process using the Taguchi design of experiment (DOE). Effects of retting duration on fiber properties as well as effects of solvent concentration, reaction temperature, and time on removal of non-cellulosic fiber components were studied using the gravimetric technique, Fourier transform infrared (FTIR) spectroscopy and thermal studies. Based on these findings, retting for 216 h at room temperature should offer adequate retting efficiency and fiber characteristics; 70% cellulose yield was extracted successfully from linseed straw fiber using 75% ethanol–toluene at 98 °C for 4 h, 6% NaOH at 75 °C for 30 min, and 6% H₂O₂ at 90 °C for 120 min. Full article

(This article belongs to the Special Issue Eco-Friendly Polymers: Synthesis, Characterization and Applications)

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24 pages, 26167 KiB

Open AccessArticle

Influence of Herbal Fillers Addition on Selected Properties of Silicone Subjected to Accelerated Aging

by Sara Sarraj, Małgorzata Szymiczek and Sebastian Jurczyk

Polymers 2023, 15(1), 42; https://doi.org/10.3390/polym15010042 - 22 Dec 2022

Cited by 2 | Viewed by 1734

Abstract

This work aims to assess the impact of the type and percentage of powdered herbs on selected properties of silicone-based composites. The matrix was an addition cross-linked platinum-cured polydimethylsiloxane. The fillers were powdered thyme and sage, which were introduced at 5, 10, and [...] Read more.

This work aims to assess the impact of the type and percentage of powdered herbs on selected properties of silicone-based composites. The matrix was an addition cross-linked platinum-cured polydimethylsiloxane. The fillers were powdered thyme and sage, which were introduced at 5, 10, and 15 wt.%. The introduced fillers differed in composition, morphology, and grain size. The grain morphology showed differences in the size and shape of the introduced fillers. The qualitative and quantitative assessment resulting from the incorporation was conducted based on tests of selected properties: density, wettability, rebound resilience, hardness, and tensile strength. The incorporation slightly affected the density and wettability of the silicone. Rebound resilience and hardness results differed depending on the filler type and fraction. However, tensile strength decreased, which may be due to the matrix’s distribution of fillers and their chemical composition. Antibacterial activity evaluation against S. aureus proved the bacteriostatic properties of the composites. Accelerated aging in PBS solution further deteriorated the mechanical properties. FTIR and DSC have demonstrated the progressive aging of the materials. In addition, the results showed an overall minimal effect of fillers on the silicone chemical backbone and melting temperature. The developed materials can be used in applications that do not require high mechanical properties. Full article

(This article belongs to the Special Issue Eco-Friendly Polymers: Synthesis, Characterization and Applications)

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18 pages, 8906 KiB

Open AccessArticle

Deformation and Simulation of the Cellular Structure of Foamed Polypropylene Composites

by Wei Gong, Di Zhang, Chun Zhang, Xiangbu Zeng, Li He and Tuanhui Jiang

Polymers 2022, 14(23), 5103; https://doi.org/10.3390/polym14235103 - 24 Nov 2022

Viewed by 1425

Abstract

Foamed Polymer is an important polymer material, which is one of the most widely used polymer materials and plays a very important role in the polymer industry. In this work, foamed polypropylene (PP) composites are prepared by injection molding, and the cell deformation [...] Read more.

Foamed Polymer is an important polymer material, which is one of the most widely used polymer materials and plays a very important role in the polymer industry. In this work, foamed polypropylene (PP) composites are prepared by injection molding, and the cell deformation process within them is studied by combining visualization technology and COMSOL software simulation. The results shows that the deformation of isolated cells depends in temperature, and there is no macroscopic deformation. There was no significant difference between the stress around adjacent cells at different temperatures, but the stress at different positions around the adjacent cells has obvious changes, and the maximum stress at the center of the adjacent cells was 224.18 N·m⁻², which was easy to cause a lateral deformation of the cells. With the increase in temperature, the displacement around the adjacent cell gradually increased, the maximum displacement of the upper and lower symmetrical points of the cell was 14.62 μm, which is most likely to cause longitudinal deformation of the cell; the deviation of the cell deformation parameter gradually increased, which led to deformation during the growth of the cell easily. The simulation results were consistent with the visualized cell deformation behaviors of the foamed PP composites. Full article

(This article belongs to the Special Issue Eco-Friendly Polymers: Synthesis, Characterization and Applications)

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12 pages, 2851 KiB

Open AccessArticle

Preparation of Mannitol-Modified Loofah and Its High-Efficient Adsorption of Cu(II) Ions in Aqueous Solution

by Guangtian Liu, Jianjian Liang and Jie Zhang

Polymers 2022, 14(22), 4883; https://doi.org/10.3390/polym14224883 - 12 Nov 2022

Cited by 3 | Viewed by 1439

Abstract

Adsorption is considered the most favorable method for heavy metal removal. In this paper, a low-cost, high-efficiency heavy metal adsorbent, mannitol-modified loofah (MML) was prepared. Some characterization methods are used to characterize the structure of MML, such as Fourier transform infrared spectroscopy (FTIR), [...] Read more.

Adsorption is considered the most favorable method for heavy metal removal. In this paper, a low-cost, high-efficiency heavy metal adsorbent, mannitol-modified loofah (MML) was prepared. Some characterization methods are used to characterize the structure of MML, such as Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The adsorption behavior of MML for Cu(II) ions was explored under different conditions, such as the amount of adsorbent, pH, initial concentration of Cu(II) ions, and adsorption time. The results indicated that the adsorption capacity of MML for Cu(II) ions was greatly improved. When the initial concentration of Cu(II) ions was 900 mg/L and the pH is 5.0, the adsorption capacity (Q_e) was 888.9 mg/g at 298K, which was significantly higher than that of some other modified cellulose adsorbents. Isothermal adsorption results showed that the adsorption process was consistent with the Freundlich model. The adsorption kinetics conformed to the pseudo-second-order equation. Furthermore, the regeneration capability of MML indicates that MML is a cheap and excellent adsorbent for Cu(II) ions removal in wastewater treatment. Full article

(This article belongs to the Special Issue Eco-Friendly Polymers: Synthesis, Characterization and Applications)

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12 pages, 2728 KiB

Open AccessArticle

Thermally Conductive and Antistatic Properties of Silicone Rubber Reinforced by the Modified Graphene Oxide

by Deling Li, Liming Dong, Ying Chen, Congcong Luo, Jun Zhou, Guangtian Liu and Haidong Ren

Polymers 2022, 14(21), 4703; https://doi.org/10.3390/polym14214703 - 3 Nov 2022

Cited by 8 | Viewed by 2419

Abstract

Silicone rubber (SR)/vinyl-graphene oxide (vinyl-GO) nanocomposites were prepared through the hydrosilylation reaction of silicon hydrogen polydimethylsiloxane (H-PDMS) with vinyl polydimethylsiloxane (vinyl-PDMS), in which vinyl-GO was used as a nano filler. The thermally conductive and antistatic properties of the nanocomposites, and their tensile strength [...] Read more.

Silicone rubber (SR)/vinyl-graphene oxide (vinyl-GO) nanocomposites were prepared through the hydrosilylation reaction of silicon hydrogen polydimethylsiloxane (H-PDMS) with vinyl polydimethylsiloxane (vinyl-PDMS), in which vinyl-GO was used as a nano filler. The thermally conductive and antistatic properties of the nanocomposites, and their tensile strength and thermal stability were evaluated. The thermally conductive and antistatic properties increased naturally when the nanocomposites had eight to nine parts of vinyl-GO. The addition of 9 parts of vinyl-GO increased the thermal conductivity to 0.44 from 0.17 W/m⁻¹·K⁻¹ of neat SR and the surface resistance value to 10⁸ from 10¹⁴ Ω of neat SR. Vinyl-GO is effective in improving the tensile strength and toughness of the nanocomposites. The tensile strength and elongation at break of the nanocomposites were much higher than that of neat SR, especially for 10 parts of vinyl-GO in the nanocomposite, and the tensile strength was 1.84 MPa and the elongation at break was 314.1%. Additionally, compared with neat SR, the nanocomposites had a much higher thermal stability. For eight parts of vinyl-GO in the nanocomposites, H-PDMS with the selected silicon hydrogen content and vinyl-PDMS with the selected vinyl content could offer an appropriate cross-linking degree that suits the character of GO. When the nanocomposite had eight parts of vinyl-GO, its scanning electron microscope exhibited a monolayer GO with folded, twisted, and local surface folds. However, there was a certain amount of multilayer aggregation of GO for 10 parts of vinyl-GO in the nanocomposite. Full article

(This article belongs to the Special Issue Eco-Friendly Polymers: Synthesis, Characterization and Applications)

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19 pages, 5735 KiB

Open AccessArticle

Experimental Study on Interfacial Friction Characteristics of Reinforced Clay

by Chenyang Zhang, Hong Mei, Guochang Hu, Jin Liu, Jian Xue, Xiaoyong Zhu, Hongning Lu, Zezhuo Song and Wenyue Che

Polymers 2022, 14(21), 4626; https://doi.org/10.3390/polym14214626 - 31 Oct 2022

Cited by 2 | Viewed by 1812

Abstract

Clay is one of the important base materials in slope restoration. The adhesion of clay–rock interface plays a decisive role in the repairing effect on rock slopes. Fibers and polymers are widely used as a clay improvement method in rock slope repair. In [...] Read more.

Clay is one of the important base materials in slope restoration. The adhesion of clay–rock interface plays a decisive role in the repairing effect on rock slopes. Fibers and polymers are widely used as a clay improvement method in rock slope repair. In this paper, the friction effect of sisal fiber and polyvinyl acetate (PVAc)-reinforced clay was studied through the design of an indoor rock-like interface sliding model test. Using modelled test results and scanning electron microscope (SEM) images, the reinforced clay was analyzed. The test results showed that the critical sliding angle and maximum static friction force of clay decreased with the increase of moisture content. An excess of fiber content and moisture content weakens the coupling effect of fiber-anchoring clay. Fiber content of 0.8% and PVAc content of 2% had the best effect on enhancing the sliding resistance of clay and provided good adhesion for dangerous interfaces of rock slope at 35° and 45°, respectively. PVAc formed a three-dimensional networked elastic membrane structure to improve the skid resistance and dynamic friction coefficient of the clay. The results provide an effective way for soil improvement and ecological restoration. Full article

(This article belongs to the Special Issue Eco-Friendly Polymers: Synthesis, Characterization and Applications)

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12 pages, 3394 KiB

Open AccessArticle

Water−Processed Organic Solar Cell with Efficiency Exceeding 11%

by Chen Xie, Songqiang Liang, Guangye Zhang and Shunpu Li

Polymers 2022, 14(19), 4229; https://doi.org/10.3390/polym14194229 - 9 Oct 2022

Cited by 12 | Viewed by 2863

Abstract

Water processing is an ideal strategy for the ecofriendly fabrication of organic photovoltaics (OPVs) and exhibits a strong market−driven demand. Here, we report a state−of−the−art active material, namely PM6:BTP−eC9, for the synthesis of water−borne nanoparticle (NP) dispersion towards ecofriendly OPV fabrication. The surfactant−stripping [...] Read more.

Water processing is an ideal strategy for the ecofriendly fabrication of organic photovoltaics (OPVs) and exhibits a strong market−driven demand. Here, we report a state−of−the−art active material, namely PM6:BTP−eC9, for the synthesis of water−borne nanoparticle (NP) dispersion towards ecofriendly OPV fabrication. The surfactant−stripping technique, combined with a poloxamer, facilitates purification and eliminates excess surfactant in water−dispersed organic semiconducting NPs. The introduction of 1,8−diiodooctane (DIO) for the synthesis of surfactant−stripped NP (ssNP) further promotes a percolated microstructure of the polymer and NFA in each ssNP, yielding water−processed OPVs with a record efficiency of over 11%. The use of an additive during water−borne ssNP synthesis is a promising strategy for morphology optimization in NP OPVs. It is believed that the findings in this work will engender more research interest and effort relating to water−processing in preparation of the industrial production of OPVs. Full article

(This article belongs to the Special Issue Eco-Friendly Polymers: Synthesis, Characterization and Applications)

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12 pages, 2029 KiB

Open AccessArticle

Comparison and Optimization: Research on the Structure of the PET Bottle Bottom Based on the Finite Element Method

by Shangjie Ge-Zhang, Mingbo Song, Zehang Huang, Maodan Li and Liqiang Mu

Polymers 2022, 14(15), 3174; https://doi.org/10.3390/polym14153174 - 3 Aug 2022

Cited by 5 | Viewed by 2988

Abstract

The polyethylene terephthalate (PET) beverage bottle is one of the most common beverage packages in the world, but the bottom of the PET bottle tends to crack due to excessive stress. In this paper, through numerical simulation and finite element analysis, the mechanical [...] Read more.

The polyethylene terephthalate (PET) beverage bottle is one of the most common beverage packages in the world, but the bottom of the PET bottle tends to crack due to excessive stress. In this paper, through numerical simulation and finite element analysis, the mechanical properties of four typical geometric models of bottle bottom are studied, and it is determined that “claw flap bottle bottom (CF-bottom)” has the best structure. Then, the shapes of four bottle bottom structures are fine-tuned by using the automatic optimization method. Under the premise of the same material quality, the surface maximum principal stress, the overall maximum principal stress, and the total elastic strain energy of the bottle bottom are reduced by 46.39–71.81%, 38.16–71.50%, and 38.56–61.38%, respectively, while the deformation displacement is also reduced by 0.63 mm–3.43 mm. In contrast to other papers, this paper dispenses with the manual adjustment of various variables, instead adopting automatic shape optimization to obtain a more accurate model. The percentage of maximum principal stress reduction is remarkable, which provides a feasible theoretical guidance for the structural optimization of PET bottle bottom in the production process. Full article

(This article belongs to the Special Issue Eco-Friendly Polymers: Synthesis, Characterization and Applications)

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16 pages, 2185 KiB

Open AccessArticle

Acetylation Modification, Characterization, and Anticomplementary Activity of Polysaccharides from Rhododendron dauricum Leaves

by Zhengyu Hu, Jinfeng Sun, Long Jin, Tieqiang Zong, Yuanqi Duan, Hongli Zhou, Wei Zhou and Gao Li

Polymers 2022, 14(15), 3130; https://doi.org/10.3390/polym14153130 - 31 Jul 2022

Cited by 9 | Viewed by 2131

Abstract

This study focuses on the acetylation modification of polysaccharides from Rhododendron dauricum leaves (RDPs) with a high degree of substitution (DS) and then discusses their characterization and biological activity. The optimum acetylation conditions of RDPs were optimized by response surface methodology, which were [...] Read more.

This study focuses on the acetylation modification of polysaccharides from Rhododendron dauricum leaves (RDPs) with a high degree of substitution (DS) and then discusses their characterization and biological activity. The optimum acetylation conditions of RDPs were optimized by response surface methodology, which were reaction time 3 h, reaction temperature 50 °C, and the liquid-solid ratio 16 mL/g. Under the optima schemes, two eco-friendly acetylated polysaccharides from R. dauricum leaves (AcRDP-1 with DS of 0.439 ± 0.025 and AcRDP-2 with DS of 0.445 ± 0.022) were prepared. The results of structural characterization showed that the AcRDP-1 (9.3525 × 10³ kDa) and AcRDP-2 (4.7016 × 10³ kDa) were composed of mannose, glucose, galactose, and arabinose with molar ratios of 1.00:5.01:1.17:0.15 and 1.00:4.47:2.39:0.88, respectively. Compared with unmodified polysaccharides, the arabinose content and molecular weight of the two acetylated polysaccharides decreased, and their triple helix conformation disappeared, and further improved their anticomplementary activity. The two acetylated polysaccharides showed stronger a complement inhibition effect than the positive drug by blocking C2, C3, C4, C5, C9, and factor B targets in the classical and alternative pathways. This research indicated that acetylation modification could effectively enhance the anticomplementary activity of RDPs, which is beneficial for the development and utilization of R. dauricum leaves. Full article

(This article belongs to the Special Issue Eco-Friendly Polymers: Synthesis, Characterization and Applications)

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12 pages, 1680 KiB

Open AccessArticle

Computer Simulation of Polyethylene Terephthalate Carbonated Beverage Bottle Bottom Structure Based on Manual–Automatic Double-Adjustment Optimization

by Shangjie Ge-Zhang, Xiaoli Chen, Haotong Zhu, Yuan Song, Yuyang Ding and Jingang Cui

Polymers 2022, 14(14), 2845; https://doi.org/10.3390/polym14142845 - 13 Jul 2022

Cited by 5 | Viewed by 2344

Abstract

PET bottlesare often used as airtight containers for filling carbonated drinks. Because carbonated drinks contain large volumes of CO₂ gas, the container needs to bear a tremendous pressure from the inside of the bottle.If the stress exceeds the bearing limit, the material [...] Read more.

PET bottlesare often used as airtight containers for filling carbonated drinks. Because carbonated drinks contain large volumes of CO₂ gas, the container needs to bear a tremendous pressure from the inside of the bottle.If the stress exceeds the bearing limit, the material will show the phenomenon of local cracking and liquid overflow.For the structural design, the method of manual adjustment before automatic adjustment was adopted. First, through manual optimization, the initial optimal parameter combination was as follows:the inner diameter of the bottle bottom was 17 mm, the dip angle of the valley bottom was 81°, the deepest part of the valley bottom was 25 mm, and the outer diameter was 27 mm. Comsol software was used for automatic optimization. Compared with the original bottle bottom, the total maximum principal stress and total elastic strain energy in the bottle bottom after manual–automatic double optimization decreased by 69.4% and 40.0%, respectively, and the displacement caused by deformation decreased by 0.60 mm (74.1%). The extremely high reduction ratio was caused by manual–automatic double optimization. Full article

(This article belongs to the Special Issue Eco-Friendly Polymers: Synthesis, Characterization and Applications)

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10 pages, 1880 KiB

Open AccessArticle

Daptomycin-Biomineralized Silver Nanoparticles for Enhanced Photothermal Therapy with Anti-Tumor Effect

by Jie Zhang, Jing Wang, Guixiu Fan, Bingjie Zhang, Guanglong Ma, Haiyan Xiao and Longgang Wang

Polymers 2022, 14(14), 2787; https://doi.org/10.3390/polym14142787 - 7 Jul 2022

Cited by 5 | Viewed by 2202

Abstract

Silver nanoparticles as photothermal agents have the problems of low stability and low photothermal conversion efficiency. Amphiphilic daptomycin can improve the stability of silver nanoparticles, thereby improving their photothermal conversion efficiency. Herein, daptomycin-biomineralized silver nanoparticles (Dap-AgNPs) were prepared by reducing silver nitrate with [...] Read more.

Silver nanoparticles as photothermal agents have the problems of low stability and low photothermal conversion efficiency. Amphiphilic daptomycin can improve the stability of silver nanoparticles, thereby improving their photothermal conversion efficiency. Herein, daptomycin-biomineralized silver nanoparticles (Dap-AgNPs) were prepared by reducing silver nitrate with sodium borohydride in the presence of daptomycin as a stabilizer and biomineralizer. The Dap-AgNPs had good solution stability and peroxidase-like activity. Furthermore, the photothermal conversion efficiency of the Dap-AgNPs was as high as 36.8%. The Dap-AgNPs displayed good photothermal stability under irradiation. More importantly, the Dap-AgNPs showed good cell compatibility with HeLa cells and HT-29 cells without irradiation by 808-nanometer near-infrared light at a concentration of 0.5 mM, and the cell viability was greater than 85.0%. However, the Dap-AgNPs displayed significant anti-tumor ability with irradiation by 808-nanometer near-infrared light, which was due to the increasing temperature of the culture medium caused by the Dap-AgNPs. In conclusion, Dap-AgNPs have potential applications as photothermal agents in the treatment of tumors. Full article

(This article belongs to the Special Issue Eco-Friendly Polymers: Synthesis, Characterization and Applications)

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16 pages, 4698 KiB

Open AccessArticle

Unfilled Natural Rubber Compounds Containing Bio-Oil Cured with Different Curing Systems: A Comparative Study

by Chesidi Hayichelaeh, Phattarawadee Nun-Anan, Mili Purbaya and Kanoktip Boonkerd

Polymers 2022, 14(12), 2479; https://doi.org/10.3390/polym14122479 - 18 Jun 2022

Cited by 9 | Viewed by 2732

Abstract

This study focuses on the properties of unfilled natural rubber compounds containing bio-oils cured with a peroxide curing system and then discusses the comparisons to those cured using the sulfur system from our previous work. Two types of bio-oils, i.e., palm oil and [...] Read more.

This study focuses on the properties of unfilled natural rubber compounds containing bio-oils cured with a peroxide curing system and then discusses the comparisons to those cured using the sulfur system from our previous work. Two types of bio-oils, i.e., palm oil and soybean oil, were used, and distillate aromatic extract (DAE)-based petroleum oil was employed as a reference. The bio-oils caused no significant change in the vulcanization of rubber compounds cured using peroxide. However, the compounds containing bio-oils and cured with sulfur showed a faster vulcanization than the ones with DAE. The bio-oils strongly affected the crosslink density of rubber compounds in both curing systems. The use of bio-oils caused a low crosslink density due to the possible implication of curing agents to bio-oil molecules. The properties of rubber compounds dependent on the different levels of crosslink density were also investigated. The results revealed that when the crosslink density increased, the modulus, tensile strength, and hardness of the rubber compounds increased and the elongation at break and compression set decreased. The use of bio-oils in the rubber compounds cured with different curing systems gave low modulus at 300% strain, tensile strength, and hardness but high elongation at break and compression set when compared to the ones with DAE. However, no significant change was observed for the compression set of the rubber compounds cured using sulfur. With the presence of bio-oils, the properties of rubber compounds cured with sulfur system deteriorated less than those of the ones cured with peroxide. Full article

(This article belongs to the Special Issue Eco-Friendly Polymers: Synthesis, Characterization and Applications)

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16 pages, 1989 KiB

Open AccessArticle

Biosorption of Cr(VI) Using Cellulose Nanocrystals Isolated from the Waterless Pulping of Waste Cotton Cloths with Supercritical CO₂: Isothermal, Kinetics, and Thermodynamics Studies

by Siti Hajar Mohamed, Md. Sohrab Hossain, Mohamad Haafiz Mohamad Kassim, Venugopal Balakrishnan, Mohamed A. Habila, Azham Zulkharnain, Muzafar Zulkifli and Ahmad Naim Ahmad Yahaya

Polymers 2022, 14(5), 887; https://doi.org/10.3390/polym14050887 - 23 Feb 2022

Cited by 19 | Viewed by 2576

Abstract

In the present study, supercritical carbon dioxide (scCO₂) was utilized as a waterless pulping for the isolation of cellulose nanocrystals (CNCs) from waste cotton cloths (WCCs). The isolation of CNCs from the scCO₂-treated WCCs’ fiber was carried out using [...] Read more.

In the present study, supercritical carbon dioxide (scCO₂) was utilized as a waterless pulping for the isolation of cellulose nanocrystals (CNCs) from waste cotton cloths (WCCs). The isolation of CNCs from the scCO₂-treated WCCs’ fiber was carried out using sulphuric acid hydrolysis. The morphological and physicochemical properties analyses showed that the CNCs isolated from the WCCs had a rod-like structure, porous surface, were crystalline, and had a length of 100.03 ± 1.15 nm and a width of 7.92 ± 0.53 nm. Moreover, CNCs isolated from WCCs had a large specific surface area and a negative surface area with uniform nano-size particles. The CNCs isolated from WCCs were utilized as an adsorbent for the hexavalent chromium [Cr(VI)] removal from aqueous solution with varying parameters, such as treatment time, adsorbent doses, pH, and temperature. It was found that the CNCs isolated from the WCCs were a bio-sorbent for the Cr(VI) removal. The maximum Cr(VI) removal was determined to be 96.97% at pH 2, 1.5 g/L of adsorbent doses, the temperature of 60 °C, and the treatment time of 30 min. The adsorption behavior of CNCs for Cr(VI) removal was determined using isothermal, kinetics, and thermodynamics properties analyses. The findings of the present study revealed that CNCs isolated from the WCCs could be utilized as a bio-sorbent for Cr(VI) removal. Full article

(This article belongs to the Special Issue Eco-Friendly Polymers: Synthesis, Characterization and Applications)

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Advances in Polyethylene Terephthalate Beverage Bottle Optimization: A Mini Review

by Shangjie Ge-Zhang, Huixin Liu, Mingbo Song, Yanzhi Wang, Hong Yang, Haobo Fan, Yuyang Ding and Liqiang Mu

Polymers 2022, 14(16), 3364; https://doi.org/10.3390/polym14163364 - 17 Aug 2022

Cited by 9 | Viewed by 3841

Abstract

Compared with other materials, polyethylene terephthalate (PET) has high transparency, excellent physical and mechanical properties in a wide temperature range and good hygiene and safety, so it is widely used in the packaging industry, especially in the packaging of beverages and foods. The [...] Read more.

Compared with other materials, polyethylene terephthalate (PET) has high transparency, excellent physical and mechanical properties in a wide temperature range and good hygiene and safety, so it is widely used in the packaging industry, especially in the packaging of beverages and foods. The optimization of PET bottles is mainly reflected in three aspects: material optimization, structure optimization and process optimization, among which there is much research on material optimization and process optimization, but there is no complete overview on structure optimization. A summary of structural optimization is necessary. Aiming at structural optimization, the finite element method is a useful supplement to the beverage packaging industry. By combining the computer-aided design technology and using finite element software for finite element simulation, researchers can replace the experimental test in the pre-research design stage, predict the effect and save cost. This review summarizes the development of PET bottles for beverage packaging, summarizes various optimization methods for preventing stress cracking in beverage packaging, and especially focuses on comparing and evaluating the effects of several optimization methods for packaging structure. Finally, the future development of all kinds of optimization based on structural optimization in the field of beverage packaging is comprehensively discussed, including personalized design, the combination of various methods and the introduction of actual impact factor calculation. Full article

(This article belongs to the Special Issue Eco-Friendly Polymers: Synthesis, Characterization and Applications)

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