M. Bustamante-Torres, Belén Arcentales-Vera, Jocelyne Estrella-Nuñez, Heidi Yánez-Vega, E. Bucio
Microorganisms have developed a resistance against some of the most conventional antibiotics. These microorganisms can be self-assembled, forming a microbial biofilm. A microbial biofilm formation is an inherent event on almost any surface, causing countless side effects on human health and the environment. Therefore, multiple scientific proposals have been developed based on renewable sources such as natural polymers. Natural polymers or biopolymers include cellulose, chitosan, starch, collagen, gelatin, hyaluronic acid, alginates, fibrin, and pectin, which are widely found in nature. The biopolymers have displayed many interesting properties, including biocompatibility and biodegradability. Nonetheless, these materials usually have no antimicrobial properties (except for the chitosan) by themselves. Therefore, antimicrobial agents have been incorporated into the natural polymeric matrix, providing an antimicrobial property to the biocomposite. Biocomposites consist of two different materials (one of natural origin) studied as biocompatible and biodegradable drug carriers of antimicrobial agents. In addition, due to the incorporation of antimicrobial agents, biocomposites can inhibit biofilm formation and bacteria proliferation on many surfaces. This review describes this using natural polymers as a platform of antimicrobial agents to form a biocomposite to eliminate or reduce biofilm formation on different surfaces.
{"title":"Antimicrobial Activity of Composites-Based on Biopolymers","authors":"M. Bustamante-Torres, Belén Arcentales-Vera, Jocelyne Estrella-Nuñez, Heidi Yánez-Vega, E. Bucio","doi":"10.3390/macromol2030018","DOIUrl":"https://doi.org/10.3390/macromol2030018","url":null,"abstract":"Microorganisms have developed a resistance against some of the most conventional antibiotics. These microorganisms can be self-assembled, forming a microbial biofilm. A microbial biofilm formation is an inherent event on almost any surface, causing countless side effects on human health and the environment. Therefore, multiple scientific proposals have been developed based on renewable sources such as natural polymers. Natural polymers or biopolymers include cellulose, chitosan, starch, collagen, gelatin, hyaluronic acid, alginates, fibrin, and pectin, which are widely found in nature. The biopolymers have displayed many interesting properties, including biocompatibility and biodegradability. Nonetheless, these materials usually have no antimicrobial properties (except for the chitosan) by themselves. Therefore, antimicrobial agents have been incorporated into the natural polymeric matrix, providing an antimicrobial property to the biocomposite. Biocomposites consist of two different materials (one of natural origin) studied as biocompatible and biodegradable drug carriers of antimicrobial agents. In addition, due to the incorporation of antimicrobial agents, biocomposites can inhibit biofilm formation and bacteria proliferation on many surfaces. This review describes this using natural polymers as a platform of antimicrobial agents to form a biocomposite to eliminate or reduce biofilm formation on different surfaces.","PeriodicalId":18139,"journal":{"name":"Macromol","volume":"1146 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87923500","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Non-woven materials feature unique properties that allow them to be used in different applications, such as the automotive sector that is increasingly seeking lightweight and sustainable materials. The aim of this work was to investigate the influence of reinforcement type and porosity on the properties of commingled, partially compacted composites based on polypropylene (PP) and polylactic acid (PLA). Furthermore, a model was applied to predict the properties of such composites, i.e., the elastic modulus, to aid materials development. It was found that high properties could be achieved using flax as reinforcement for partially compacted fleece biocomposites. Porosity is an important factor influencing these types of composites and was influenced by the compaction grade achieved as a result of stacking different numbers of layers during the consolidation of the composites. The modeling of the elastic modulus was found to be adequate for both PP-flax and PLA-flax composites for porosities under 20 vol.%.
{"title":"Partially Compacted Commingled PLA-Flax Biocomposites","authors":"B. Lekube, C. Burgstaller","doi":"10.3390/macromol2030017","DOIUrl":"https://doi.org/10.3390/macromol2030017","url":null,"abstract":"Non-woven materials feature unique properties that allow them to be used in different applications, such as the automotive sector that is increasingly seeking lightweight and sustainable materials. The aim of this work was to investigate the influence of reinforcement type and porosity on the properties of commingled, partially compacted composites based on polypropylene (PP) and polylactic acid (PLA). Furthermore, a model was applied to predict the properties of such composites, i.e., the elastic modulus, to aid materials development. It was found that high properties could be achieved using flax as reinforcement for partially compacted fleece biocomposites. Porosity is an important factor influencing these types of composites and was influenced by the compaction grade achieved as a result of stacking different numbers of layers during the consolidation of the composites. The modeling of the elastic modulus was found to be adequate for both PP-flax and PLA-flax composites for porosities under 20 vol.%.","PeriodicalId":18139,"journal":{"name":"Macromol","volume":"57 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88570005","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Meimoun, Audrey Favrelle-Huret, J. Winter, P. Zinck
Organocatalysis for polymer chemistry has become a subject of significant interest in the last two decades. In this contribution, we have studied the evolution of the microstructure of poly(L-lactide) in solution in toluene at 105 °C in the presence of various organocatalysts. Weak bases such as triethylamine and DMAP (4-dimethylaminopyridine) lead to a low extent of epimerization and a chain scission reaction. The DBU (1,8-diazabicyclo[5.4.0]undec-7-ene) amidine induces in turn important extents of both epimerization (up to 37% D-stereoisomer formation) and chain scission. This has been tentatively attributed to a nucleophilic mechanism. Cinchona alkaloids lead to only a modest amount of epimerization. Phosphazene bases are in turn rather active, especially for high catalytic loadings (>1 mol %). The chain scission observed in this case is proposed to occur via a base-catalyzed hydrolysis mechanism. Finally, it is shown that combining an organic base with an acid can lead to a synergistic effect regarding notably the chain scission reaction.
{"title":"Poly(L-lactide) Epimerization and Chain Scission in the Presence of Organic Bases","authors":"J. Meimoun, Audrey Favrelle-Huret, J. Winter, P. Zinck","doi":"10.3390/macromol2020016","DOIUrl":"https://doi.org/10.3390/macromol2020016","url":null,"abstract":"Organocatalysis for polymer chemistry has become a subject of significant interest in the last two decades. In this contribution, we have studied the evolution of the microstructure of poly(L-lactide) in solution in toluene at 105 °C in the presence of various organocatalysts. Weak bases such as triethylamine and DMAP (4-dimethylaminopyridine) lead to a low extent of epimerization and a chain scission reaction. The DBU (1,8-diazabicyclo[5.4.0]undec-7-ene) amidine induces in turn important extents of both epimerization (up to 37% D-stereoisomer formation) and chain scission. This has been tentatively attributed to a nucleophilic mechanism. Cinchona alkaloids lead to only a modest amount of epimerization. Phosphazene bases are in turn rather active, especially for high catalytic loadings (>1 mol %). The chain scission observed in this case is proposed to occur via a base-catalyzed hydrolysis mechanism. Finally, it is shown that combining an organic base with an acid can lead to a synergistic effect regarding notably the chain scission reaction.","PeriodicalId":18139,"journal":{"name":"Macromol","volume":"17 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78610891","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
X. Ding, Jian Wu, Yonggang Wang, B. Cui, S. An, B. Su, Youshan Wang
Due to the hydrodynamic pressure effect, the bearing capacity of the oil film on the surface of a textured friction pair is greater than that of a smooth surface. In this paper, the effects of PTFE surface texture parameters (shape, depth, width, and area ratio) on the oil film bearing capacity and leakage of the sealing system under lubrication are studied using the FLURNT simulation. It is found in this present study that greater texture depths do not necessarily lead to better sealing performance. When the texture depth exceeds a certain level, a reverse flow occurs at the bottom of the texture, thereby weakening the hydrodynamic pressure effect. An optimal texture depth of 5–10 μm maximizes the oil film bearing capacity. Within a certain range, the oil film bearing capacity increases along with texture widths. In addition, leakage of the rectangular texture rises significantly with growing texture widths. Larger texture area ratios result in higher leakage, but the bearing capacity first rises and then falls with an increase in the area ratio, with a maximum value of 70–80%. Considering the influence of texture parameters on oil film bearing capacity and leakage, selecting the most appropriate texture parameters for surface texture treatment optimizes the performance of the sealing system. The findings of this paper provide a theoretical basis for improving the sealing performance of high-end aviation equipment using texture treatment, thereby enabling the application of surface texture technology to improve the tribological properties of materials.
{"title":"Influence of Surface Texture on Sealing Performance of PTFE Materials","authors":"X. Ding, Jian Wu, Yonggang Wang, B. Cui, S. An, B. Su, Youshan Wang","doi":"10.3390/macromol2020015","DOIUrl":"https://doi.org/10.3390/macromol2020015","url":null,"abstract":"Due to the hydrodynamic pressure effect, the bearing capacity of the oil film on the surface of a textured friction pair is greater than that of a smooth surface. In this paper, the effects of PTFE surface texture parameters (shape, depth, width, and area ratio) on the oil film bearing capacity and leakage of the sealing system under lubrication are studied using the FLURNT simulation. It is found in this present study that greater texture depths do not necessarily lead to better sealing performance. When the texture depth exceeds a certain level, a reverse flow occurs at the bottom of the texture, thereby weakening the hydrodynamic pressure effect. An optimal texture depth of 5–10 μm maximizes the oil film bearing capacity. Within a certain range, the oil film bearing capacity increases along with texture widths. In addition, leakage of the rectangular texture rises significantly with growing texture widths. Larger texture area ratios result in higher leakage, but the bearing capacity first rises and then falls with an increase in the area ratio, with a maximum value of 70–80%. Considering the influence of texture parameters on oil film bearing capacity and leakage, selecting the most appropriate texture parameters for surface texture treatment optimizes the performance of the sealing system. The findings of this paper provide a theoretical basis for improving the sealing performance of high-end aviation equipment using texture treatment, thereby enabling the application of surface texture technology to improve the tribological properties of materials.","PeriodicalId":18139,"journal":{"name":"Macromol","volume":"36 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82447131","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Syed Muhammad Imran, Gwang-Myeong Go, M. Hussain, M. Al‐harthi
Thermoplastic polyurethane (TPU) is a widely used polymer for a variety of pressure sensing applications because of its softness and shape memory. This work reports the synthesis of novel TPU-based three-dimensional structured (3D) pressure-sensitive composites via the melt mixing method. Poly-methyl methacrylate (PMMA) microbeads of different sizes (5, 10, and 20 µm) were first coated with multi-walled carbon nanotubes (MWCNT) and then incorporated into the TPU matrix for achieving an early electro conductive percolation threshold compared to without PMMA beads. The addition of MWCNT coated PMMA beads reduced the TPU insulated areas by creating a 3D conductive network that finally reflected the early percolation threshold during external pressure. Raman microscopy and XRD results confirmed the MWCNT coated nicely on the surface of PMMA beads. The pressure sensitivity results also confirmed the decrease in resistance of the composites with the increase in the applied external pressure. Composites with 10 µm PMMA bead size showed the most linear responses to the decrease in resistance with increasing pressure and showed a higher strain gauge factor value (3.15) as compared to other composites, which had values of 2.78 and 2.42 for 20 and 5 µm, respectively. Microstructure analysis of the composites by SEM, capacitance, permeability, and thermal conductivity measurements was also investigated to support the above evidence. The results support the suitability of this novel composite as a potential candidate for pressure sensing applications.
{"title":"Multiwalled Carbon Nanotube-Coated Poly-Methyl Methacrylate Dispersed Thermoplastic Polyurethane Composites for Pressure-Sensitive Applications","authors":"Syed Muhammad Imran, Gwang-Myeong Go, M. Hussain, M. Al‐harthi","doi":"10.3390/macromol2020014","DOIUrl":"https://doi.org/10.3390/macromol2020014","url":null,"abstract":"Thermoplastic polyurethane (TPU) is a widely used polymer for a variety of pressure sensing applications because of its softness and shape memory. This work reports the synthesis of novel TPU-based three-dimensional structured (3D) pressure-sensitive composites via the melt mixing method. Poly-methyl methacrylate (PMMA) microbeads of different sizes (5, 10, and 20 µm) were first coated with multi-walled carbon nanotubes (MWCNT) and then incorporated into the TPU matrix for achieving an early electro conductive percolation threshold compared to without PMMA beads. The addition of MWCNT coated PMMA beads reduced the TPU insulated areas by creating a 3D conductive network that finally reflected the early percolation threshold during external pressure. Raman microscopy and XRD results confirmed the MWCNT coated nicely on the surface of PMMA beads. The pressure sensitivity results also confirmed the decrease in resistance of the composites with the increase in the applied external pressure. Composites with 10 µm PMMA bead size showed the most linear responses to the decrease in resistance with increasing pressure and showed a higher strain gauge factor value (3.15) as compared to other composites, which had values of 2.78 and 2.42 for 20 and 5 µm, respectively. Microstructure analysis of the composites by SEM, capacitance, permeability, and thermal conductivity measurements was also investigated to support the above evidence. The results support the suitability of this novel composite as a potential candidate for pressure sensing applications.","PeriodicalId":18139,"journal":{"name":"Macromol","volume":"14 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84531556","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study reports the first attempt to employ a potassium–graphite intercalation compound (KC24) as an initiator for the one-pot synthesis of a multi-block copolymer. The results obtained show that KC24 successfully initiated the copolymerization, leading to a copolymer consisting of poly(styrene), poly(methyl methacrylate) and poly(ethylene oxide) blocks. When all three comonomers were introduced simultaneously or in a specific sequence, the resulting copolymers had molecular masses in the range between 170,000 Da and 280,000 Da. Their composition was investigated by size-exclusion chromatography with triple detection (dRI/UV/IR) and 1H-NMR. The analyses indicated that all copolymers were enriched in methyl methacrylate (50–66 mol%) despite the fact that the comonomers were added in equimolar amounts. Due to the layered structure of the initiator, the polymerization took place in the graphite interlayer spaces and lead to extensive delamination, indicating at the potential to produce in situ graphite/copolymer composite materials.
{"title":"Polymerization Initiated by Graphite Intercalation Compounds Revisited: One-Pot Synthesis of Amphiphilic Pentablock Copolymers","authors":"N. Vladimirov, I. Gitsov","doi":"10.3390/macromol2020012","DOIUrl":"https://doi.org/10.3390/macromol2020012","url":null,"abstract":"This study reports the first attempt to employ a potassium–graphite intercalation compound (KC24) as an initiator for the one-pot synthesis of a multi-block copolymer. The results obtained show that KC24 successfully initiated the copolymerization, leading to a copolymer consisting of poly(styrene), poly(methyl methacrylate) and poly(ethylene oxide) blocks. When all three comonomers were introduced simultaneously or in a specific sequence, the resulting copolymers had molecular masses in the range between 170,000 Da and 280,000 Da. Their composition was investigated by size-exclusion chromatography with triple detection (dRI/UV/IR) and 1H-NMR. The analyses indicated that all copolymers were enriched in methyl methacrylate (50–66 mol%) despite the fact that the comonomers were added in equimolar amounts. Due to the layered structure of the initiator, the polymerization took place in the graphite interlayer spaces and lead to extensive delamination, indicating at the potential to produce in situ graphite/copolymer composite materials.","PeriodicalId":18139,"journal":{"name":"Macromol","volume":"126 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88139908","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Polyethylenes (PE) are the most commonly occurring ingredients for post-consumer recyclates (PCR). The structure–property relationships of different types of model PE-based blends are established using multiple thermo-rheological analyses. Although considered “simple”, the complex behavior of model PE-based blends is experimentally demonstrated for the first time for metallocene-catalyzed, linear, low-density polyethylenes (mLLDPE) with different microstructures that are commonly encountered in PCR. During non-isothermal crystallization, the microstructure of mLLDPE predominantly influences the interaction between mLLDPE and LDPE. Based on the mLLDPE microstructure, the molten LDPE phase acts either as a nucleating agent or as a crystallization rate promoting agent. Both rheological and thermal analyses show that higher activation energy is required for the reptation or movement of polymer chains in a highly branched microstructure with long chain branching (LCB) compared to a linear microstructure with short chain branching (SCB). The quasi-melt response, as measured by thermal analysis under non-isothermal conditions, is distinctly different and sensitive to both the SCB and LCB present in the LLDPE/LDPE blends.
{"title":"Influence of Ethylene-1-Alkene Copolymers Microstructure on Thermo-Rheological Behavior of Model Blends for Enhanced Recycling","authors":"G. Galgali, S. Kaliappan, Tej Pandit","doi":"10.3390/macromol2020011","DOIUrl":"https://doi.org/10.3390/macromol2020011","url":null,"abstract":"Polyethylenes (PE) are the most commonly occurring ingredients for post-consumer recyclates (PCR). The structure–property relationships of different types of model PE-based blends are established using multiple thermo-rheological analyses. Although considered “simple”, the complex behavior of model PE-based blends is experimentally demonstrated for the first time for metallocene-catalyzed, linear, low-density polyethylenes (mLLDPE) with different microstructures that are commonly encountered in PCR. During non-isothermal crystallization, the microstructure of mLLDPE predominantly influences the interaction between mLLDPE and LDPE. Based on the mLLDPE microstructure, the molten LDPE phase acts either as a nucleating agent or as a crystallization rate promoting agent. Both rheological and thermal analyses show that higher activation energy is required for the reptation or movement of polymer chains in a highly branched microstructure with long chain branching (LCB) compared to a linear microstructure with short chain branching (SCB). The quasi-melt response, as measured by thermal analysis under non-isothermal conditions, is distinctly different and sensitive to both the SCB and LCB present in the LLDPE/LDPE blends.","PeriodicalId":18139,"journal":{"name":"Macromol","volume":"8 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78662122","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
C. Sergi, Libera Vitiello, P. Russo, J. Tirillò, F. Sarasini
The automotive sector covers almost 40% of polyamide (PA) total demand. A suitable solution to improve the sustainability of this sector is the exploitation of PA matrices sourced from renewable origins, such as PA11, and their reinforcement with natural fibers such as vegetable flax and mineral basalt. A preliminary study on the quasi-static properties of PA11-based composites reinforced with an intraply flax/basalt hybrid fabric demonstrated their feasibility for semi-structural purposes in the transportation field, but their application needs to be validated against dynamic loading. In this regard, this work investigated the low-velocity impact performance of PA11 flax/basalt hybrid composites (10 J, 20 J and 30 J) as a function of temperature (room temperature and +80 °C) and plasticizer addition (butyl-benzene-sulfonamide). The results proved that plasticized PA11 is endowed with a lower glass transition temperature (~15 °C, from DMA) and melting temperature (~10 °C, from DSC), which simplifies manufacturing and processing, but also possesses a higher toughness which delays penetration phenomena and reduces permanent indentation at room temperature between 20.5% and 42.8% depending on impact energy. The occurrence of matrix plasticization at +80 °C caused a more flexible and tougher response from the laminates with a decrease in linear stiffness and a delay in penetration phenomena which made the plasticizer effect less prominent.
{"title":"Toughened Bio-Polyamide 11 for Impact-Resistant Intraply Basalt/Flax Hybrid Composites","authors":"C. Sergi, Libera Vitiello, P. Russo, J. Tirillò, F. Sarasini","doi":"10.3390/macromol2020010","DOIUrl":"https://doi.org/10.3390/macromol2020010","url":null,"abstract":"The automotive sector covers almost 40% of polyamide (PA) total demand. A suitable solution to improve the sustainability of this sector is the exploitation of PA matrices sourced from renewable origins, such as PA11, and their reinforcement with natural fibers such as vegetable flax and mineral basalt. A preliminary study on the quasi-static properties of PA11-based composites reinforced with an intraply flax/basalt hybrid fabric demonstrated their feasibility for semi-structural purposes in the transportation field, but their application needs to be validated against dynamic loading. In this regard, this work investigated the low-velocity impact performance of PA11 flax/basalt hybrid composites (10 J, 20 J and 30 J) as a function of temperature (room temperature and +80 °C) and plasticizer addition (butyl-benzene-sulfonamide). The results proved that plasticized PA11 is endowed with a lower glass transition temperature (~15 °C, from DMA) and melting temperature (~10 °C, from DSC), which simplifies manufacturing and processing, but also possesses a higher toughness which delays penetration phenomena and reduces permanent indentation at room temperature between 20.5% and 42.8% depending on impact energy. The occurrence of matrix plasticization at +80 °C caused a more flexible and tougher response from the laminates with a decrease in linear stiffness and a delay in penetration phenomena which made the plasticizer effect less prominent.","PeriodicalId":18139,"journal":{"name":"Macromol","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83389344","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Elijah Cook, Qiaxian R. Johnson, Gurjeet Longia, Gurpreet Longia, B. Chauhan
This research presents a new approach to the dispersion and stabilization of gold nanoparticles from aqueous to organic solution through the use of alkylsilanes. The unique phase activity of poly(hydro)silanes inspired the investigation of monomeric hydrosilanes as transfer agents. This method utilizes n-butylsilane, hexylsilane, octylsilane, and octadecylsilane as transfer agents to complete a ligand exchange, allowing the nanoparticles to flow into organic solution. These reactions were monitored and characterized through UV-Vis Spectrometry (UV-Vis), Fourier Transform Infrared Spectroscopy (FTIR), and Transmission Electron Microscopy (TEM). The gold and silver nanoparticles transferred using this protocol maintained their size and shape throughout the reaction. This phase-transfer reaction successfully transferred 2-AST stabilized gold and silver nanoparticles to a variety of organic solvents which remained stable for prolonged periods.
{"title":"Long-Chain Hydrosilanes Mediated Phase Transfer of Aqueous Metal Nanoparticles","authors":"Elijah Cook, Qiaxian R. Johnson, Gurjeet Longia, Gurpreet Longia, B. Chauhan","doi":"10.3390/macromol2020009","DOIUrl":"https://doi.org/10.3390/macromol2020009","url":null,"abstract":"This research presents a new approach to the dispersion and stabilization of gold nanoparticles from aqueous to organic solution through the use of alkylsilanes. The unique phase activity of poly(hydro)silanes inspired the investigation of monomeric hydrosilanes as transfer agents. This method utilizes n-butylsilane, hexylsilane, octylsilane, and octadecylsilane as transfer agents to complete a ligand exchange, allowing the nanoparticles to flow into organic solution. These reactions were monitored and characterized through UV-Vis Spectrometry (UV-Vis), Fourier Transform Infrared Spectroscopy (FTIR), and Transmission Electron Microscopy (TEM). The gold and silver nanoparticles transferred using this protocol maintained their size and shape throughout the reaction. This phase-transfer reaction successfully transferred 2-AST stabilized gold and silver nanoparticles to a variety of organic solvents which remained stable for prolonged periods.","PeriodicalId":18139,"journal":{"name":"Macromol","volume":"143 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74776056","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Bérengère Aubry, F. Dumur, M. Lansalot, E. Bourgeat‐Lami, Emmanuel Lacôte, J. Lalevée
In this work, two new water-soluble photoinitiators based on the α-alkoxy-arylketone scaffold have been synthesized and investigated for their ability to initiate photopolymerization for the preparation of hydrogels. The efficiency of these new Type I photoinitiators was compared to that of benchmark ones (2-hydroxy-4′-(2-hydroxyethoxy)-2-methylpropiophenone—Irgacure 2959 and 2-hydroxy-2-methyl propiophenone—Irgacure 1173). In combination with additive (carbene-borane), a good initiating ability was found under air. Mechanical properties of the prepared hydrogels were investigated by tensile tests and dynamic mechanical analysis (DMA). Markedly, hydrogels could be prepared with the newly proposed initiating systems in mild conditions (i.e., under air, using low light intensity @405 or 395 nm and without specialized glassware) and exhibited similar properties to those prepared by harsher approaches (thermal treatment or UV light).
{"title":"Development of Water-Soluble Type I Photoinitiators for Hydrogel Synthesis","authors":"Bérengère Aubry, F. Dumur, M. Lansalot, E. Bourgeat‐Lami, Emmanuel Lacôte, J. Lalevée","doi":"10.3390/macromol2010008","DOIUrl":"https://doi.org/10.3390/macromol2010008","url":null,"abstract":"In this work, two new water-soluble photoinitiators based on the α-alkoxy-arylketone scaffold have been synthesized and investigated for their ability to initiate photopolymerization for the preparation of hydrogels. The efficiency of these new Type I photoinitiators was compared to that of benchmark ones (2-hydroxy-4′-(2-hydroxyethoxy)-2-methylpropiophenone—Irgacure 2959 and 2-hydroxy-2-methyl propiophenone—Irgacure 1173). In combination with additive (carbene-borane), a good initiating ability was found under air. Mechanical properties of the prepared hydrogels were investigated by tensile tests and dynamic mechanical analysis (DMA). Markedly, hydrogels could be prepared with the newly proposed initiating systems in mild conditions (i.e., under air, using low light intensity @405 or 395 nm and without specialized glassware) and exhibited similar properties to those prepared by harsher approaches (thermal treatment or UV light).","PeriodicalId":18139,"journal":{"name":"Macromol","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88365647","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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