As final attributes of dosage form largely depend on the properties of excipients used, understanding the effect of physicochemical properties of excipients is important. In the present study, six grades of L-HPC with varying degrees of particle size and hydroxypropyl content and the influence of the grade on compaction as well as disintegration behavior were studied. All grades of L-HPC were compressed at different compression loads to achieve different tablet porosity. Compressibility and compactibility of L-HPC grades were evaluated using a modified Heckel equation and percolation model. Further effects of particle size and hydroxypropyl content of L-HPC on tablet porosity and disintegration time were evaluated using a 32 full-factorial design. From compaction studies, it was found that compressibility of L-HPC largely depends upon the particle size with lower particle size grade showing lower compressibility. Whereas consolidation/bonding behavior of L-HPC is independent of particle size and % hydroxypropyl content. By factorial design, it was found that particle size and % hydroxypropyl content have a significant effect on the disintegration behavior of L-HPC. It was found that smaller particle sizes and higher hydroxypropyl content of L-HPC show longer disintegration time. Thus, careful consideration of excipients selection should be made to achieve desired quality attribute of the product.
{"title":"Effect of Physical Properties and Chemical Substitution of Excipient on Compaction and Disintegration Behavior of Tablet: A Case Study of Low-Substituted Hydroxypropyl Cellulose (L-HPC)","authors":"Saurabh M Mishra, Andreas Sauer","doi":"10.3390/macromol2010007","DOIUrl":"https://doi.org/10.3390/macromol2010007","url":null,"abstract":"As final attributes of dosage form largely depend on the properties of excipients used, understanding the effect of physicochemical properties of excipients is important. In the present study, six grades of L-HPC with varying degrees of particle size and hydroxypropyl content and the influence of the grade on compaction as well as disintegration behavior were studied. All grades of L-HPC were compressed at different compression loads to achieve different tablet porosity. Compressibility and compactibility of L-HPC grades were evaluated using a modified Heckel equation and percolation model. Further effects of particle size and hydroxypropyl content of L-HPC on tablet porosity and disintegration time were evaluated using a 32 full-factorial design. From compaction studies, it was found that compressibility of L-HPC largely depends upon the particle size with lower particle size grade showing lower compressibility. Whereas consolidation/bonding behavior of L-HPC is independent of particle size and % hydroxypropyl content. By factorial design, it was found that particle size and % hydroxypropyl content have a significant effect on the disintegration behavior of L-HPC. It was found that smaller particle sizes and higher hydroxypropyl content of L-HPC show longer disintegration time. Thus, careful consideration of excipients selection should be made to achieve desired quality attribute of the product.","PeriodicalId":18139,"journal":{"name":"Macromol","volume":"33 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89464044","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. P. Sagini, P. Arantes, Conrado Pedebos, R. Ligabue-Braun
Arboviral diseases have a high incidence in Brazil and constitute a serious public health problem. Rocio virus (ROCV) is an arbovirus belonging to the family Flaviviridae. It was responsible for the emergence of an outbreak of encephalitis on the São Paulo state coast in the late 1970s. Although no recent case of this virus has been reported, data suggest the circulation of ROCV throughout the Brazilian territory. Given these indications and the strong presence of fundamental factors for the resurgence of emerging diseases in Brazil, we conducted this study using virtual screenings to identify targets and therapeutic molecules that could be redirected to fight infections related to ROCV. Herein, we demonstrated that the National List of Essential Medicines of the Brazilian Unified Health System (SUS) has several molecules that could be redirected to combat this flavivirus, namely simeprevir, daclatasvir, iloprost, and itraconazole. Among them, itraconazole was found to be an interesting candidate since it interacts with both structural and nonstructural proteins of this virus and it is a strong binder to the NS1 protein, as confirmed by molecular simulations.
{"title":"Rocio Virus Encephalitis: In Silico Evidence for Drug Repurposing","authors":"J. P. Sagini, P. Arantes, Conrado Pedebos, R. Ligabue-Braun","doi":"10.3390/macromol2010006","DOIUrl":"https://doi.org/10.3390/macromol2010006","url":null,"abstract":"Arboviral diseases have a high incidence in Brazil and constitute a serious public health problem. Rocio virus (ROCV) is an arbovirus belonging to the family Flaviviridae. It was responsible for the emergence of an outbreak of encephalitis on the São Paulo state coast in the late 1970s. Although no recent case of this virus has been reported, data suggest the circulation of ROCV throughout the Brazilian territory. Given these indications and the strong presence of fundamental factors for the resurgence of emerging diseases in Brazil, we conducted this study using virtual screenings to identify targets and therapeutic molecules that could be redirected to fight infections related to ROCV. Herein, we demonstrated that the National List of Essential Medicines of the Brazilian Unified Health System (SUS) has several molecules that could be redirected to combat this flavivirus, namely simeprevir, daclatasvir, iloprost, and itraconazole. Among them, itraconazole was found to be an interesting candidate since it interacts with both structural and nonstructural proteins of this virus and it is a strong binder to the NS1 protein, as confirmed by molecular simulations.","PeriodicalId":18139,"journal":{"name":"Macromol","volume":"110 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87715313","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}
Moorthy Maruthapandi, A. Saravanan, Akanksha Gupta, J. Luong, A. Gedanken
Conducting polymers, mainly polyaniline (PANI) and polypyrrole (PPY) with positive charges bind to the negatively charged bacterial membrane to interfere with bacterial activities. After this initial electrostatic adherence, the conducting polymers might partially penetrate the bacterial membrane and interact with other intracellular biomolecules. Conducting polymers can form polymer composites with metal, metal oxides, and nanoscale carbon materials as a new class of antimicrobial agents with enhanced antimicrobial properties. The accumulation of elevated oxygen reactive species (ROS) from composites of polymers-metal nanoparticles has harmful effects and induces cell death. Among such ROS, the hydroxyl radical with one unpaired electron in the structure is most effective as it can oxidize any bacterial biomolecules, leading to cell death. Future endeavors should focus on the combination of conducting polymers and their composites with antibiotics, small peptides, and natural molecules with antimicrobial properties. Such arsenals with low cytotoxicity are expected to eradicate the ESKAPE pathogens: Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp.
{"title":"Antimicrobial Activities of Conducting Polymers and Their Composites","authors":"Moorthy Maruthapandi, A. Saravanan, Akanksha Gupta, J. Luong, A. Gedanken","doi":"10.3390/macromol2010005","DOIUrl":"https://doi.org/10.3390/macromol2010005","url":null,"abstract":"Conducting polymers, mainly polyaniline (PANI) and polypyrrole (PPY) with positive charges bind to the negatively charged bacterial membrane to interfere with bacterial activities. After this initial electrostatic adherence, the conducting polymers might partially penetrate the bacterial membrane and interact with other intracellular biomolecules. Conducting polymers can form polymer composites with metal, metal oxides, and nanoscale carbon materials as a new class of antimicrobial agents with enhanced antimicrobial properties. The accumulation of elevated oxygen reactive species (ROS) from composites of polymers-metal nanoparticles has harmful effects and induces cell death. Among such ROS, the hydroxyl radical with one unpaired electron in the structure is most effective as it can oxidize any bacterial biomolecules, leading to cell death. Future endeavors should focus on the combination of conducting polymers and their composites with antibiotics, small peptides, and natural molecules with antimicrobial properties. Such arsenals with low cytotoxicity are expected to eradicate the ESKAPE pathogens: Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp.","PeriodicalId":18139,"journal":{"name":"Macromol","volume":"73 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79160970","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}
Rizos Bikiaris, N. Ainali, Evi Christodoulou, N. Nikolaidis, D. Lambropoulou, G. Papageorgiou
In the present study, a series of aliphatic polyesters based on succinic acid and several diols with 2, 4, 6, 8, and 10 methylene groups, namely poly(ethylene succinate) (PESu), poly(butylene succinate) (PBSu), poly(hexylene succinate) (PHSu), poly(octylene succinate) (POSu), and poly(decylene succinate) (PDeSu), were prepared via a two-stage melt polycondensation method. All polyesters were semicrystalline materials with Tm ranging from 64.2 to 117.8 °C, while their Tg values were progressively decreasing by increasing the methylene group number in the used diols. Thermogravimetric analysis (TGA) revealed that the synthesized poly(alkylene succinate)s present high thermal stability with maximum decomposition rates at temperatures 420–430 °C. The thermal decomposition mechanism was also evaluated with the aid of Pyrolysis–Gas chromatography/Mass spectrometry (Py–GC/MS), proving that all the studied polyesters decompose via a similar pathway, with degradation taking place mainly via β–hydrogen bond scission and less extensive with homolytic scission.
{"title":"Thermal Stability and Decomposition Mechanism of Poly(alkylene succinate)s","authors":"Rizos Bikiaris, N. Ainali, Evi Christodoulou, N. Nikolaidis, D. Lambropoulou, G. Papageorgiou","doi":"10.3390/macromol2010004","DOIUrl":"https://doi.org/10.3390/macromol2010004","url":null,"abstract":"In the present study, a series of aliphatic polyesters based on succinic acid and several diols with 2, 4, 6, 8, and 10 methylene groups, namely poly(ethylene succinate) (PESu), poly(butylene succinate) (PBSu), poly(hexylene succinate) (PHSu), poly(octylene succinate) (POSu), and poly(decylene succinate) (PDeSu), were prepared via a two-stage melt polycondensation method. All polyesters were semicrystalline materials with Tm ranging from 64.2 to 117.8 °C, while their Tg values were progressively decreasing by increasing the methylene group number in the used diols. Thermogravimetric analysis (TGA) revealed that the synthesized poly(alkylene succinate)s present high thermal stability with maximum decomposition rates at temperatures 420–430 °C. The thermal decomposition mechanism was also evaluated with the aid of Pyrolysis–Gas chromatography/Mass spectrometry (Py–GC/MS), proving that all the studied polyesters decompose via a similar pathway, with degradation taking place mainly via β–hydrogen bond scission and less extensive with homolytic scission.","PeriodicalId":18139,"journal":{"name":"Macromol","volume":"26 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78572947","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}
Given the fossil fuel crisis and the steady consumption of finite resources, the use of green polymers is becoming necessary. However, the term “green” describes materials that present green properties (such as biological origin and/or biodegradability) and are produced via sustainable processes conducted under mild conditions and not requiring the use of chemical catalysts, toxic solvents or reagents. Truly green materials must combine these characteristics; consequently, enzymatically synthesized bio-based and/or biodegradable polymers can be characterized as truly green. The present review focuses on the most promising, commercially available aliphatic and alipharomatic polyesters that can be synthesized enzymatically. In particular, the recent developments in the enzymatic polymerization of PLA and PBS and alipharomatic furan-based polyesters (e.g., PBF) are herein analyzed. Based on this analysis, it can be concluded that important steps have been taken toward synthesizing sustainably green polymers. Still, it is necessary to evaluate the applied methods regarding their capability to be used on an industrial scale.
{"title":"Enzymatic Polymerization as a Green Approach to Synthesizing Bio-Based Polyesters","authors":"Christina Gkountela, S. Vouyiouka","doi":"10.3390/macromol2010003","DOIUrl":"https://doi.org/10.3390/macromol2010003","url":null,"abstract":"Given the fossil fuel crisis and the steady consumption of finite resources, the use of green polymers is becoming necessary. However, the term “green” describes materials that present green properties (such as biological origin and/or biodegradability) and are produced via sustainable processes conducted under mild conditions and not requiring the use of chemical catalysts, toxic solvents or reagents. Truly green materials must combine these characteristics; consequently, enzymatically synthesized bio-based and/or biodegradable polymers can be characterized as truly green. The present review focuses on the most promising, commercially available aliphatic and alipharomatic polyesters that can be synthesized enzymatically. In particular, the recent developments in the enzymatic polymerization of PLA and PBS and alipharomatic furan-based polyesters (e.g., PBF) are herein analyzed. Based on this analysis, it can be concluded that important steps have been taken toward synthesizing sustainably green polymers. Still, it is necessary to evaluate the applied methods regarding their capability to be used on an industrial scale.","PeriodicalId":18139,"journal":{"name":"Macromol","volume":"310 9 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86607778","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}
Amol Batra, Feng-yuan Yang, Michael Kogan, A. Sosnowik, C. Usher, Eugene W. Oldham, Ningyi Chen, Kamaru Lawal, Yunxia Bi, T. Dürig
High-molecular-weight hypromellose (HPMC) and hydroxypropyl cellulose (HPC) are widely known, extended-release polymers. Conventional high-molecular-weight HPMCs are preferred in extended-release applications but not widely used in twin-screw melt granulation due to processability difficulties at low operating temperatures and potential drug degradation if high processing temperatures are used. Conversely, high-molecular-weight grade HPC (Klucel®) can be used in melt granulation processes. The purpose of this study was to evaluate the processability and dissolution behavior of HPC GXF ((Klucel® GXF) and a recently introduced type of hot-melt extrudable HPMC (Affinisol®) in extended-release metformin hydrochloride formulations using twin-screw melt granulation. Powder blends were prepared with 75% w/w metformin HCl and 25% w/w polymeric binder. Blends were granulated at processing temperatures of 160, 140, 120 and 100 °C. HPMC HME 4M (Affinisol® 4M) provided a fine powder, indicating minimum granulation at processing temperatures lower than 160 °C, and the tablets obtained with these granules capped during tableting. In contrast, acceptable tablets could be obtained with HPC GXF at all processing temperatures. Rheological studies including capillary rheometry to measure steady shear rate viscosity, and rotational rheometry to obtain time and temperature superposition data, showed that HPC GXF had a greater thermoplasticity than HPMC HME 4M, which made granulation possible with HPC GXF at low temperatures. Tablets compressed with granules obtained at 160 °C with both binders showed comparable dissolution profiles. High-molecular-weight HPC GXF provided a better processability at low temperatures and adequate tablet strength for the melt granulation of metformin HCl.
{"title":"Comparison of Hydroxypropylcellulose and Hot-Melt Extrudable Hypromellose in Twin-Screw Melt Granulation of Metformin Hydrochloride: Effect of Rheological Properties of Polymer on Melt Granulation and Granule Properties","authors":"Amol Batra, Feng-yuan Yang, Michael Kogan, A. Sosnowik, C. Usher, Eugene W. Oldham, Ningyi Chen, Kamaru Lawal, Yunxia Bi, T. Dürig","doi":"10.3390/macromol2010001","DOIUrl":"https://doi.org/10.3390/macromol2010001","url":null,"abstract":"High-molecular-weight hypromellose (HPMC) and hydroxypropyl cellulose (HPC) are widely known, extended-release polymers. Conventional high-molecular-weight HPMCs are preferred in extended-release applications but not widely used in twin-screw melt granulation due to processability difficulties at low operating temperatures and potential drug degradation if high processing temperatures are used. Conversely, high-molecular-weight grade HPC (Klucel®) can be used in melt granulation processes. The purpose of this study was to evaluate the processability and dissolution behavior of HPC GXF ((Klucel® GXF) and a recently introduced type of hot-melt extrudable HPMC (Affinisol®) in extended-release metformin hydrochloride formulations using twin-screw melt granulation. Powder blends were prepared with 75% w/w metformin HCl and 25% w/w polymeric binder. Blends were granulated at processing temperatures of 160, 140, 120 and 100 °C. HPMC HME 4M (Affinisol® 4M) provided a fine powder, indicating minimum granulation at processing temperatures lower than 160 °C, and the tablets obtained with these granules capped during tableting. In contrast, acceptable tablets could be obtained with HPC GXF at all processing temperatures. Rheological studies including capillary rheometry to measure steady shear rate viscosity, and rotational rheometry to obtain time and temperature superposition data, showed that HPC GXF had a greater thermoplasticity than HPMC HME 4M, which made granulation possible with HPC GXF at low temperatures. Tablets compressed with granules obtained at 160 °C with both binders showed comparable dissolution profiles. High-molecular-weight HPC GXF provided a better processability at low temperatures and adequate tablet strength for the melt granulation of metformin HCl.","PeriodicalId":18139,"journal":{"name":"Macromol","volume":"11 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73819644","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}
Owed to current environmental concerns and crude oil price fluctuations, the design of feasible substitutes to petroleum-based polymeric materials is a major challenge. A lot of effort has been focused on transforming natural vegetable oils (VOs), which are inexpensive, abundant, and sustainable, into polymeric materials. Different nanofillers have been combined with these bio-based polymer matrices to improve their thermal, mechanical, and antibacterial properties. The development of multifunctional nanocomposites materials facilitates their application in novel areas such as sensors, medical devices, coatings, paints, adhesives, food packaging, and other industrial appliances. In this work, a brief description of current literature on polymeric nanocomposites from vegetable oils reinforced with carbon nanomaterials is provided, in terms of preparation, and properties. Different strategies to improve the nanomaterial state of dispersion within the biopolymer matrix are discussed, and a correlation between structure and properties is given. In particular, the mechanical, thermal, and electrical properties of these natural polymers can be considerably enhanced through the addition of small quantities of single-walled carbon nanotubes (SWCNTs), multi-walled carbon nanotubes (MWCNTs), graphene (G), or its derivatives such as graphene oxide (GO) or fullerenes (C60). Finally, some current and potential future applications of these materials in diverse fields are briefly discussed.
{"title":"Composites of Vegetable Oil-Based Polymers and Carbon Nanomaterials","authors":"A. Díez-Pascual, A. Rahdar","doi":"10.3390/macromol1040019","DOIUrl":"https://doi.org/10.3390/macromol1040019","url":null,"abstract":"Owed to current environmental concerns and crude oil price fluctuations, the design of feasible substitutes to petroleum-based polymeric materials is a major challenge. A lot of effort has been focused on transforming natural vegetable oils (VOs), which are inexpensive, abundant, and sustainable, into polymeric materials. Different nanofillers have been combined with these bio-based polymer matrices to improve their thermal, mechanical, and antibacterial properties. The development of multifunctional nanocomposites materials facilitates their application in novel areas such as sensors, medical devices, coatings, paints, adhesives, food packaging, and other industrial appliances. In this work, a brief description of current literature on polymeric nanocomposites from vegetable oils reinforced with carbon nanomaterials is provided, in terms of preparation, and properties. Different strategies to improve the nanomaterial state of dispersion within the biopolymer matrix are discussed, and a correlation between structure and properties is given. In particular, the mechanical, thermal, and electrical properties of these natural polymers can be considerably enhanced through the addition of small quantities of single-walled carbon nanotubes (SWCNTs), multi-walled carbon nanotubes (MWCNTs), graphene (G), or its derivatives such as graphene oxide (GO) or fullerenes (C60). Finally, some current and potential future applications of these materials in diverse fields are briefly discussed.","PeriodicalId":18139,"journal":{"name":"Macromol","volume":"74 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79171864","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}
Removal of dyes through adsorption from wastewater has gained substantial interest in recent years, especially in development of hydrogel based adsorbents, owing to their easy use and economical nature. The aim of the present study was to design a super-adsorbent hydrogel based on sodium styrenesulfonate (NaSS) monomer for removal of dyes like methylene blue (MB). NaSS displays both an aromatic ring and strongly ionic group in its monomer structure that can enhance adsorption capacity. Poly(sodium styrenesulfonate-co-dimethylacrylamide) hydrogels were prepared by solution free radical polymerization using gelatin methacryloyl (GelMA) as crosslinker, creating a highly porous, three-dimensionally crosslinked polymer network contributing to higher swelling ratios of up to 27,500%. These super-adsorbent hydrogels exhibited high adsorption capacity of 1270 mg/g for MB adsorption with above 98% removal efficiency. This is the first report for such a high adsorption capacity for dye absorbance for NaSS-based hydrogels. Additionally, the adsorption kinetics using a pseudo-first-order and the Freundlich adsorption isotherm models for multilayer, heterogeneous adsorption processes has been reported. The adsorbents’ reusability was confirmed through 4 repeated cycles of desorption-adsorption. The results discussed herein illustrate that NaSS based chemistries can be used as an efficient option for removal of organic dyes from contaminated wastewater.
{"title":"Super-Adsorbent Hydrogels for Removal of Methylene Blue from Aqueous Solution: Dye Adsorption Isotherms, Kinetics, and Thermodynamic Properties","authors":"Buddhabhushan Salunkhe, T. Schuman","doi":"10.3390/macromol1040018","DOIUrl":"https://doi.org/10.3390/macromol1040018","url":null,"abstract":"Removal of dyes through adsorption from wastewater has gained substantial interest in recent years, especially in development of hydrogel based adsorbents, owing to their easy use and economical nature. The aim of the present study was to design a super-adsorbent hydrogel based on sodium styrenesulfonate (NaSS) monomer for removal of dyes like methylene blue (MB). NaSS displays both an aromatic ring and strongly ionic group in its monomer structure that can enhance adsorption capacity. Poly(sodium styrenesulfonate-co-dimethylacrylamide) hydrogels were prepared by solution free radical polymerization using gelatin methacryloyl (GelMA) as crosslinker, creating a highly porous, three-dimensionally crosslinked polymer network contributing to higher swelling ratios of up to 27,500%. These super-adsorbent hydrogels exhibited high adsorption capacity of 1270 mg/g for MB adsorption with above 98% removal efficiency. This is the first report for such a high adsorption capacity for dye absorbance for NaSS-based hydrogels. Additionally, the adsorption kinetics using a pseudo-first-order and the Freundlich adsorption isotherm models for multilayer, heterogeneous adsorption processes has been reported. The adsorbents’ reusability was confirmed through 4 repeated cycles of desorption-adsorption. The results discussed herein illustrate that NaSS based chemistries can be used as an efficient option for removal of organic dyes from contaminated wastewater.","PeriodicalId":18139,"journal":{"name":"Macromol","volume":"219 0 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79559224","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}
N. Ainali, Dimitrios Kalaronis, E. Evgenidou, D. Bikiaris, D. Lambropoulou
During the past two decades, immobilization of titanium dioxide (TiO2), a well-known photocatalyst, on several polymeric substrates has extensively gained ground since it limits the need of post-treatment separation stages. Taking into account the numerous substrates tested for supporting TiO2 photocatalysts, the use of biodegradable polymer seems a hopeful option owing to its considerable merits, including the flexible nature, low price, chemical inertness, mechanical stability and wide feasibility. The present review places its emphasis on recently published research articles (2011–2021) and exhibits the most innovative studies facilitating the eco-friendly biodegradable polymers to fabricate polymer-based photocatalysts, while the preparation details, photocatalytic performance and reuse of the TiO2/polymer photocatalysts is also debated. The biodegradable polymers examined herein comprise of chitosan (CS), cellulose, alginate, starch, poly(lactid acid) (PLA), polycaprolactone (PCL) and poly(lactide-co-glycolide) (PLGA), while an emphasis on the synthetical pathway (dip-coating, electrospinning, etc.) of the photocatalysts is provided.
{"title":"Insights into Biodegradable Polymer-Supported Titanium Dioxide Photocatalysts for Environmental Remediation","authors":"N. Ainali, Dimitrios Kalaronis, E. Evgenidou, D. Bikiaris, D. Lambropoulou","doi":"10.3390/macromol1030015","DOIUrl":"https://doi.org/10.3390/macromol1030015","url":null,"abstract":"During the past two decades, immobilization of titanium dioxide (TiO2), a well-known photocatalyst, on several polymeric substrates has extensively gained ground since it limits the need of post-treatment separation stages. Taking into account the numerous substrates tested for supporting TiO2 photocatalysts, the use of biodegradable polymer seems a hopeful option owing to its considerable merits, including the flexible nature, low price, chemical inertness, mechanical stability and wide feasibility. The present review places its emphasis on recently published research articles (2011–2021) and exhibits the most innovative studies facilitating the eco-friendly biodegradable polymers to fabricate polymer-based photocatalysts, while the preparation details, photocatalytic performance and reuse of the TiO2/polymer photocatalysts is also debated. The biodegradable polymers examined herein comprise of chitosan (CS), cellulose, alginate, starch, poly(lactid acid) (PLA), polycaprolactone (PCL) and poly(lactide-co-glycolide) (PLGA), while an emphasis on the synthetical pathway (dip-coating, electrospinning, etc.) of the photocatalysts is provided.","PeriodicalId":18139,"journal":{"name":"Macromol","volume":"62 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74402092","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}
The current study is focused on the development of highly stable drug nanocarriers by encapsulating losartan potassium (LSR) into an amphiphilic biocompatible poly(2-methyl-2-oxazoline)-grad-poly(2-phenyl-2-oxazoline) (PMeOxz72-grad-PPhOxz28) gradient copolymer (GC). Based on dynamic light scattering (DLS), the PMeOxz72-grad-PPhOxz28 (where the subscripts denote %wt composition of the components) GC formed micelles and aggregates of 13 nm and 96 nm in aqueous milieu. The presence of hydrophobic LSR molecules altered the structural characteristics of the GC, modulating the organization of the polymeric components and revealing the formation of hyper micellar nanostructures in addition to micelles. The 2D-NOESY experiments evidenced intermolecular interactions between the phenyl ring of LSR with the phenyl group of PPhOxz and eminent correlations between the butyl chain of LSR with the phenyl group of PPhOxz and methylene group of PMeOxz, respectively. Additionally, NMR studies as a function of temperature demonstrated that the presence of hydrophilic PMeOxz segments in the gradient core of PMeOxz72-grad-PPhOxz28 nanoassemblies induced an increased fluidity of the core matrix, especially upon heating, thus causing water penetration, resulting in increased proton mobility. Lastly, the ultrasound release profile of LSR signified that a great amount of the encapsulated LSR is tightly bound to the PMeOxz72-grad-PPhOxz28 nanoassemblies.
{"title":"Poly(2-oxazoline)-Based Amphiphilic Gradient Copolymers as Nanocarriers for Losartan: Insights into Drug–Polymer Interactions","authors":"A. Chroni, T. Mavromoustakos, S. Pispas","doi":"10.3390/MACROMOL1030014","DOIUrl":"https://doi.org/10.3390/MACROMOL1030014","url":null,"abstract":"The current study is focused on the development of highly stable drug nanocarriers by encapsulating losartan potassium (LSR) into an amphiphilic biocompatible poly(2-methyl-2-oxazoline)-grad-poly(2-phenyl-2-oxazoline) (PMeOxz72-grad-PPhOxz28) gradient copolymer (GC). Based on dynamic light scattering (DLS), the PMeOxz72-grad-PPhOxz28 (where the subscripts denote %wt composition of the components) GC formed micelles and aggregates of 13 nm and 96 nm in aqueous milieu. The presence of hydrophobic LSR molecules altered the structural characteristics of the GC, modulating the organization of the polymeric components and revealing the formation of hyper micellar nanostructures in addition to micelles. The 2D-NOESY experiments evidenced intermolecular interactions between the phenyl ring of LSR with the phenyl group of PPhOxz and eminent correlations between the butyl chain of LSR with the phenyl group of PPhOxz and methylene group of PMeOxz, respectively. Additionally, NMR studies as a function of temperature demonstrated that the presence of hydrophilic PMeOxz segments in the gradient core of PMeOxz72-grad-PPhOxz28 nanoassemblies induced an increased fluidity of the core matrix, especially upon heating, thus causing water penetration, resulting in increased proton mobility. Lastly, the ultrasound release profile of LSR signified that a great amount of the encapsulated LSR is tightly bound to the PMeOxz72-grad-PPhOxz28 nanoassemblies.","PeriodicalId":18139,"journal":{"name":"Macromol","volume":"219 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89113810","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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