This study aims to confer autohesive strength to polyethylene (PE) plates by swelling the grafted layers, which were formed on the PE plates grafted with alkyl (meth)acrylate monomers, with 1,4-dioxane, and subsequently heat-pressing them. For the methyl methacrylate (MMA)-grafted PE (PE-g-PMMA) plates, the location of grafting was restricted to the outer surface region and the grafted layer with higher densities of grafted PMMA chains was composed. When the grafted PE plates were immersed in 1,4-dioxane, and then heat-pressed while applying the load, autohesion was developed. The substrate failure was observed for the PE-g-PMMA plates and the grafted amount at which the substrate failure was observed decreased with the procedures that decreased the methanol concentration of the solvent, the MMA concentration, the grafting temperature, and the heat-press temperature, and/or increased the load. The lowest grafted amount of 45 μmol/cm2 for the substrate failure was obtained under the conditions where the PE-g-PMMA plate prepared at 0.75 M and 60 °C in a 70 vol% aqueous methanol solution was heat-pressed at 60 °C while applying the load of 2.0 kg/cm2. The swelling of the grafted layers with 1,4-dioxane considerably contributed to the development of autohesion, bringing the inter-diffusion of grafted PMMA chains and coincident entanglement of grafted PMMA chains during the heat-pressing. The fact that the substrate failure occurred indicates that an autohesive strength higher than the ultimate strength of the used PE plate was obtained. Our approach provides a novel procedure to develop the water-resistant autohesion of PE plates.
本研究旨在通过膨胀接枝层来赋予聚乙烯(PE)板自粘强度，接枝层是在用烷基(甲基)丙烯酸酯单体接枝的PE板上形成的，然后用1,4-二恶烷进行热压。对于甲基丙烯酸甲酯(MMA)接枝PE (PE-g-PMMA)板，接枝位置被限制在外表面区域，形成了具有较高接枝PMMA链密度的接枝层。接枝的PE板浸泡在1,4-二氧六烷中，然后在施加载荷的同时进行热压，形成自粘。通过降低溶剂的甲醇浓度、MMA浓度、接枝温度和热压温度，以及/或增加负载，可以观察到PE-g-PMMA板的底物破坏，接枝量随着接枝量的减少而减少。在0.75 M, 60℃条件下制备的PE-g-PMMA板，在70 vol%的甲醇水溶液中，施加2.0 kg/cm2的负载，在60℃下进行热压，接枝量最低，为45 μmol/cm2。在热压过程中，1,4-二恶烷对接枝层的膨胀极大地促进了自粘的发展，导致接枝PMMA链的相互扩散和接枝PMMA链的重合缠结。基材发生破坏的事实表明，所获得的自粘强度高于所用PE板的极限强度。我们的方法为开发PE板的防水自粘提供了一种新的方法。
{"title":"Development of Water-Resistant Autohesive Strength of Polyethylene Plates with Photografting of Alkyl (Meth)Acrylates","authors":"Kazunori Yamada, Y. Kazama, Y. Kimura","doi":"10.3390/macromol3030032","DOIUrl":"https://doi.org/10.3390/macromol3030032","url":null,"abstract":"This study aims to confer autohesive strength to polyethylene (PE) plates by swelling the grafted layers, which were formed on the PE plates grafted with alkyl (meth)acrylate monomers, with 1,4-dioxane, and subsequently heat-pressing them. For the methyl methacrylate (MMA)-grafted PE (PE-g-PMMA) plates, the location of grafting was restricted to the outer surface region and the grafted layer with higher densities of grafted PMMA chains was composed. When the grafted PE plates were immersed in 1,4-dioxane, and then heat-pressed while applying the load, autohesion was developed. The substrate failure was observed for the PE-g-PMMA plates and the grafted amount at which the substrate failure was observed decreased with the procedures that decreased the methanol concentration of the solvent, the MMA concentration, the grafting temperature, and the heat-press temperature, and/or increased the load. The lowest grafted amount of 45 μmol/cm2 for the substrate failure was obtained under the conditions where the PE-g-PMMA plate prepared at 0.75 M and 60 °C in a 70 vol% aqueous methanol solution was heat-pressed at 60 °C while applying the load of 2.0 kg/cm2. The swelling of the grafted layers with 1,4-dioxane considerably contributed to the development of autohesion, bringing the inter-diffusion of grafted PMMA chains and coincident entanglement of grafted PMMA chains during the heat-pressing. The fact that the substrate failure occurred indicates that an autohesive strength higher than the ultimate strength of the used PE plate was obtained. Our approach provides a novel procedure to develop the water-resistant autohesion of PE plates.","PeriodicalId":18139,"journal":{"name":"Macromol","volume":"14 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83714170","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}
G. G. Flores-Rojas, Bélen Gómez-Lazaro, F. López-Saucedo, R. Vera-Graziano, E. Bucio, E. Mendizábal
Tissue engineering and regenerative medicine have emerged as innovative approaches to enhance clinical outcomes by addressing tissue lesions and degenerations that can significantly impair organ function. Since human tissues have limited regenerative capacity, the field of regenerative medicine aims to restore damaged tissues and their functionalities. Recent decades have witnessed remarkable progress in materials science, tissue engineering, and medicine, leading to the development of regenerative engineering. This interdisciplinary field has revolutionized the production of artificial matrices, enabling the design of anatomically accurate structures with enhanced biocompatibility, bioabsorption, and cell adhesion. Among the techniques utilized for fabricating cellular scaffolds, the electrospinning of fibers stands out as an ideal approach due to its ability to mimic the characteristics of the extracellular matrix (ECM). Electrospun scaffolds exhibit distinct advantages, including a high surface area-to-volume ratio, exceptional porosity, uniformity, compositional diversity, structural flexibility, and the ease of functionalization with bioactive molecules for controlled release. These versatile properties allow for the creation of nanofiber scaffolds that closely resemble the architecture of the ECM. Consequently, they facilitate the transport of nutrients and oxygen to cells as well as the incorporation of growth factors to stimulate cell growth. These advancements open up a wide range of applications in the field of regenerative medicine.
{"title":"Electrospun Scaffolds for Tissue Engineering: A Review","authors":"G. G. Flores-Rojas, Bélen Gómez-Lazaro, F. López-Saucedo, R. Vera-Graziano, E. Bucio, E. Mendizábal","doi":"10.3390/macromol3030031","DOIUrl":"https://doi.org/10.3390/macromol3030031","url":null,"abstract":"Tissue engineering and regenerative medicine have emerged as innovative approaches to enhance clinical outcomes by addressing tissue lesions and degenerations that can significantly impair organ function. Since human tissues have limited regenerative capacity, the field of regenerative medicine aims to restore damaged tissues and their functionalities. Recent decades have witnessed remarkable progress in materials science, tissue engineering, and medicine, leading to the development of regenerative engineering. This interdisciplinary field has revolutionized the production of artificial matrices, enabling the design of anatomically accurate structures with enhanced biocompatibility, bioabsorption, and cell adhesion. Among the techniques utilized for fabricating cellular scaffolds, the electrospinning of fibers stands out as an ideal approach due to its ability to mimic the characteristics of the extracellular matrix (ECM). Electrospun scaffolds exhibit distinct advantages, including a high surface area-to-volume ratio, exceptional porosity, uniformity, compositional diversity, structural flexibility, and the ease of functionalization with bioactive molecules for controlled release. These versatile properties allow for the creation of nanofiber scaffolds that closely resemble the architecture of the ECM. Consequently, they facilitate the transport of nutrients and oxygen to cells as well as the incorporation of growth factors to stimulate cell growth. These advancements open up a wide range of applications in the field of regenerative medicine.","PeriodicalId":18139,"journal":{"name":"Macromol","volume":"43 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89641350","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 review considers the recent investigations in the scope of biodegradability of synthetic polymers, spanning polyethylene (PE), polypropylene (PP), and their corresponding composites, with a focus on the influence of oxo-additives (mostly transition metal salts). The types of oxo-additives and the mechanisms of oxidation acceleration are discussed. Furthermore, the influence of oxo-additives on both physicochemical and biological stages of degradation is evaluated (laboratory and field experiments with microorganisms/fungi action) with recent standards suggested for degradation estimation. Comparisons of the metal salts are given with respect to catalysis, as well as the synergetic influence of additives. The additives presented on the commercial market are also discussed.
{"title":"Oxo-Additives for Polyolefin Degradation: Kinetics and Mechanism","authors":"E. A. Mamin, P. Pantyukhov, A. A. Olkhov","doi":"10.3390/macromol3030029","DOIUrl":"https://doi.org/10.3390/macromol3030029","url":null,"abstract":"This review considers the recent investigations in the scope of biodegradability of synthetic polymers, spanning polyethylene (PE), polypropylene (PP), and their corresponding composites, with a focus on the influence of oxo-additives (mostly transition metal salts). The types of oxo-additives and the mechanisms of oxidation acceleration are discussed. Furthermore, the influence of oxo-additives on both physicochemical and biological stages of degradation is evaluated (laboratory and field experiments with microorganisms/fungi action) with recent standards suggested for degradation estimation. Comparisons of the metal salts are given with respect to catalysis, as well as the synergetic influence of additives. The additives presented on the commercial market are also discussed.","PeriodicalId":18139,"journal":{"name":"Macromol","volume":"47 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84760561","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}
In this work, a simple and environmentally friendly process combining low pressure (vacuum) and mechanical compression is proposed to convert recycled polypropylene (PP) foams (28 kg/m3) into low density foams (90–131 kg/m3) having negative tensile and compressive Poisson’s ratios (NPR). The main objective of the work was to determine the effect of processing conditions (vacuum time, temperature and mechanical pressure). Based on the optimized conditions, the tensile Poisson’s ratio of the resulting auxetic foams reached −1.50, while the minimum compressive Poisson’s ratio was −0.32 for the same sample. The foam structure was characterized via morphological analysis (SEM) to determine any changes related to the treatment applied. Finally, the tensile and compressive properties (Young’s modulus, strain energy, energy dissipation and damping capacity) are also presented and discussed. It was observed that the mechanical properties of the resulting auxetic foams were improved compared to the original PP foam (PP-O) for all tensile properties in terms of modulus (19.9 to 59.8 kPa), strength (0.298 to 1.43 kPa) elongation at break (28 to 77%), energy dissipation (14.4 to 56.3 mJ/cm3) and damping capacity (12 to 19%). Nevertheless, improvements were also observed under compression in terms of the energy dissipation (1.6 to 3.6 mJ/cm3) and the damping capacity (13 to 19%). These auxetic foams can find applications in sport and military protective equipment, as well as any energy mitigation system.
{"title":"Conversion of Polypropylene (PP) Foams into Auxetic Metamaterials","authors":"Xiao-Yuan Chen, D. Rodrigue","doi":"10.3390/macromol3030028","DOIUrl":"https://doi.org/10.3390/macromol3030028","url":null,"abstract":"In this work, a simple and environmentally friendly process combining low pressure (vacuum) and mechanical compression is proposed to convert recycled polypropylene (PP) foams (28 kg/m3) into low density foams (90–131 kg/m3) having negative tensile and compressive Poisson’s ratios (NPR). The main objective of the work was to determine the effect of processing conditions (vacuum time, temperature and mechanical pressure). Based on the optimized conditions, the tensile Poisson’s ratio of the resulting auxetic foams reached −1.50, while the minimum compressive Poisson’s ratio was −0.32 for the same sample. The foam structure was characterized via morphological analysis (SEM) to determine any changes related to the treatment applied. Finally, the tensile and compressive properties (Young’s modulus, strain energy, energy dissipation and damping capacity) are also presented and discussed. It was observed that the mechanical properties of the resulting auxetic foams were improved compared to the original PP foam (PP-O) for all tensile properties in terms of modulus (19.9 to 59.8 kPa), strength (0.298 to 1.43 kPa) elongation at break (28 to 77%), energy dissipation (14.4 to 56.3 mJ/cm3) and damping capacity (12 to 19%). Nevertheless, improvements were also observed under compression in terms of the energy dissipation (1.6 to 3.6 mJ/cm3) and the damping capacity (13 to 19%). These auxetic foams can find applications in sport and military protective equipment, as well as any energy mitigation system.","PeriodicalId":18139,"journal":{"name":"Macromol","volume":"32 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80935790","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. Santos, L. P. Albuquerque, Marcus M. R. de Amorim, Juliane Nancy de Oliveira Silva, T. F. Procópio, Patryck Érmerson Monteiro Dos Santos, P. Paiva, M. R. Barros, T. Napoleão, E. V. Pontual
In this study, we evaluated the susceptibility of Alphitobius diaperinus larvae and adults to saline extract (SE), lectin-rich fraction (FR), and isolated lectin (MvRL) from Microgramma vacciniifolia rhizomes. To determine immediate effects, larvae and adults were exposed to SE (10.5 mg/mL), FR (7.5 mg/mL), or MvRL (1.0 mg/mL) for 48 h. Live insects were evaluated for acetylcholinesterase (AChE) activity. The delayed effects of SE (10.5 mg/mL), FR (7.5 mg/mL), and MvRL (0.2 and 0.4 mg/mL) were checked by incubating the adults for 16 days with a diet containing the preparations. In vitro effects on gut digestive enzymes were investigated. All preparations showed immediate larvicidal effect but had no effect on adult survival. Extracts from FR-treated larvae showed higher AChE activity than control insects. In the delayed effect assay, the adults lost biomass after consuming SE and FR. FR was the most effective inhibitory agent of trypsin-like and amylase activities (88% and 65% inhibition, respectively). All preparations inhibited endoglucanase activity in 94–98%, while SE and FR inhibited exoglucanase activity in 93.2 and 94.1%, respectively. In conclusion, M. vacciniifolia rhizomes contain compounds (including MvRL) that affect the survival and physiology of A. diaperinus, acting as potential natural insecticides for controlling this pest.
{"title":"Effects of Lectin Preparations from Microgramma vacciniifolia Rhizomes on the Survival, Digestive Enzymes, and Acetylcholinesterase Activity of Alphitobius diaperinus (Panzer) (Coleoptera: Tenebrionidae)","authors":"N. Santos, L. P. Albuquerque, Marcus M. R. de Amorim, Juliane Nancy de Oliveira Silva, T. F. Procópio, Patryck Érmerson Monteiro Dos Santos, P. Paiva, M. R. Barros, T. Napoleão, E. V. Pontual","doi":"10.3390/macromol3030027","DOIUrl":"https://doi.org/10.3390/macromol3030027","url":null,"abstract":"In this study, we evaluated the susceptibility of Alphitobius diaperinus larvae and adults to saline extract (SE), lectin-rich fraction (FR), and isolated lectin (MvRL) from Microgramma vacciniifolia rhizomes. To determine immediate effects, larvae and adults were exposed to SE (10.5 mg/mL), FR (7.5 mg/mL), or MvRL (1.0 mg/mL) for 48 h. Live insects were evaluated for acetylcholinesterase (AChE) activity. The delayed effects of SE (10.5 mg/mL), FR (7.5 mg/mL), and MvRL (0.2 and 0.4 mg/mL) were checked by incubating the adults for 16 days with a diet containing the preparations. In vitro effects on gut digestive enzymes were investigated. All preparations showed immediate larvicidal effect but had no effect on adult survival. Extracts from FR-treated larvae showed higher AChE activity than control insects. In the delayed effect assay, the adults lost biomass after consuming SE and FR. FR was the most effective inhibitory agent of trypsin-like and amylase activities (88% and 65% inhibition, respectively). All preparations inhibited endoglucanase activity in 94–98%, while SE and FR inhibited exoglucanase activity in 93.2 and 94.1%, respectively. In conclusion, M. vacciniifolia rhizomes contain compounds (including MvRL) that affect the survival and physiology of A. diaperinus, acting as potential natural insecticides for controlling this pest.","PeriodicalId":18139,"journal":{"name":"Macromol","volume":"13 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78326634","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}
Maurice Brendan Dalton, F. Ebrahimi, Han Xu, Ke Gong, G. Fehrenbach, E. Fuenmayor, E. Murphy, I. Major
The use of biodegradable polymers in tissue engineering has been widely researched due to their ability to degrade and release their components in a controlled manner, allowing for the potential regeneration of tissues. Melt blending is a common method for controlling the degradation rate of these polymers, which involves combining these materials in a molten state to create a homogenous mixture with tailored properties. In this study, polycaprolactone (PCL) was melt blended with hydrophilic poly (ethylene oxide) (PEO) of different molecular weights to assess its effect on PCL material performance. Hydrolytic degradation, thermal and viscoelastic properties, and surface hydrophilicity were performed to contrast the properties of the blends. DSC, DMA, and FTIR were performed on selected degraded PCL/PEO specimens following mass loss studies. The results showed that adding PEO to PCL reduced its melt viscosity-torque and melt temperature while increasing its hydrophilicity, optimizing PCL/PEO blend for soft tissue engineering applications and could contribute to the development of more effective and biocompatible materials for soft tissue regeneration.
{"title":"The Influence of the Molecular Weight of Poly(Ethylene Oxide) on the Hydrolytic Degradation and Physical Properties of Polycaprolactone Binary Blends","authors":"Maurice Brendan Dalton, F. Ebrahimi, Han Xu, Ke Gong, G. Fehrenbach, E. Fuenmayor, E. Murphy, I. Major","doi":"10.3390/macromol3030026","DOIUrl":"https://doi.org/10.3390/macromol3030026","url":null,"abstract":"The use of biodegradable polymers in tissue engineering has been widely researched due to their ability to degrade and release their components in a controlled manner, allowing for the potential regeneration of tissues. Melt blending is a common method for controlling the degradation rate of these polymers, which involves combining these materials in a molten state to create a homogenous mixture with tailored properties. In this study, polycaprolactone (PCL) was melt blended with hydrophilic poly (ethylene oxide) (PEO) of different molecular weights to assess its effect on PCL material performance. Hydrolytic degradation, thermal and viscoelastic properties, and surface hydrophilicity were performed to contrast the properties of the blends. DSC, DMA, and FTIR were performed on selected degraded PCL/PEO specimens following mass loss studies. The results showed that adding PEO to PCL reduced its melt viscosity-torque and melt temperature while increasing its hydrophilicity, optimizing PCL/PEO blend for soft tissue engineering applications and could contribute to the development of more effective and biocompatible materials for soft tissue regeneration.","PeriodicalId":18139,"journal":{"name":"Macromol","volume":"1 4 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79641304","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 degradation patterns of bacterial poly-3-hydroxybutyrate (PHB) in chloroform solution under the action of thionyl chloride in the presence of zinc chloride were studied. When 2.5.mol of zinc chloride and 100 mmol of thionyl chloride were introduced into the solution of 25 mmol PHB, a decrease in the molecular weight of the polymer was observed. During the reaction, a relatively rapid decrease in the molecular weight of the polymer was noted in the first hour of the experiment; thus, the values of the weight-average molecular weight decreased from 840 kDa to 483, 167, 58.6, and 16.7 kDa after 1, 5, 24, and 96 h of the experiment, respectively. The polydispersity also gradually decreased from 2.69 at the beginning to 1.92 at the end of the experiment. Oligomers of PHB containing 3-chlorobutyric acid and 3-hydroxybutyryl chloride residues at the O and C ends of the polymer chain, respectively, were obtained. The results confirm the ability of thionyl chloride to interact with aliphatic esters in the presence of zinc compounds, and demonstrate the possibility of using this reaction to produce oligomeric derivatives of polyesters bearing chloralkyl and acid chloride functional groups.
{"title":"Reaction of Bacterial Poly-3-Hydroxybutyrate with Thionyl Chloride in the Presence of Zinc Chloride, and the Preparation of Chlorine-Containing Oligomers","authors":"A. Boyandin","doi":"10.3390/macromol3030025","DOIUrl":"https://doi.org/10.3390/macromol3030025","url":null,"abstract":"The degradation patterns of bacterial poly-3-hydroxybutyrate (PHB) in chloroform solution under the action of thionyl chloride in the presence of zinc chloride were studied. When 2.5.mol of zinc chloride and 100 mmol of thionyl chloride were introduced into the solution of 25 mmol PHB, a decrease in the molecular weight of the polymer was observed. During the reaction, a relatively rapid decrease in the molecular weight of the polymer was noted in the first hour of the experiment; thus, the values of the weight-average molecular weight decreased from 840 kDa to 483, 167, 58.6, and 16.7 kDa after 1, 5, 24, and 96 h of the experiment, respectively. The polydispersity also gradually decreased from 2.69 at the beginning to 1.92 at the end of the experiment. Oligomers of PHB containing 3-chlorobutyric acid and 3-hydroxybutyryl chloride residues at the O and C ends of the polymer chain, respectively, were obtained. The results confirm the ability of thionyl chloride to interact with aliphatic esters in the presence of zinc compounds, and demonstrate the possibility of using this reaction to produce oligomeric derivatives of polyesters bearing chloralkyl and acid chloride functional groups.","PeriodicalId":18139,"journal":{"name":"Macromol","volume":"30 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89864963","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}
Nanocellulose can be obtained from low-cost sources and has been extensively studied in the last decades due to its biodegradability, biocompatibility, low weight, large specific surface area, and good mechanical and optical properties. The nanocellulose properties palette can be greatly expanded by incorporating different metals, metal oxides or carbon nanomaterials, with the formation of multifunctional hybrids. Nanocellulose–nanocarbon hybrids are emerging nanomaterials that can respond to many current challenges in areas such as water purification, energy storage and conversion, or biomedicine for drug delivery, tissue engineering, antitumor and antimicrobial therapies, and many others. Although nanocellulose–nanodiamonds hybrids are still in their infancy, these nanomaterials are extremely promising for applications requiring good thermal conductivity and mechanical strength along with optical transparency. A strong increase in the thermal conductivity of a nanocellulose film of about 150 times was obtained after the addition of 90 wt% single-crystal nanodiamonds and a 70% increase in the Young’s modulus of nanocellulose films was produced by the addition of 5 wt% nanodiamonds. Therefore, in this review, data related to the manufacturing routes, main properties, and applications of nanocellulose–nanodiamonds hybrids are presented and discussed. This review paves the way for new methods and procedures to obtain nanocellulose–nanodiamonds hybrids better adapted to practical needs.
{"title":"Nanocellulose/Nanodiamond Hybrids: A Review","authors":"C. Uşurelu, D. Panaitescu","doi":"10.3390/macromol3020024","DOIUrl":"https://doi.org/10.3390/macromol3020024","url":null,"abstract":"Nanocellulose can be obtained from low-cost sources and has been extensively studied in the last decades due to its biodegradability, biocompatibility, low weight, large specific surface area, and good mechanical and optical properties. The nanocellulose properties palette can be greatly expanded by incorporating different metals, metal oxides or carbon nanomaterials, with the formation of multifunctional hybrids. Nanocellulose–nanocarbon hybrids are emerging nanomaterials that can respond to many current challenges in areas such as water purification, energy storage and conversion, or biomedicine for drug delivery, tissue engineering, antitumor and antimicrobial therapies, and many others. Although nanocellulose–nanodiamonds hybrids are still in their infancy, these nanomaterials are extremely promising for applications requiring good thermal conductivity and mechanical strength along with optical transparency. A strong increase in the thermal conductivity of a nanocellulose film of about 150 times was obtained after the addition of 90 wt% single-crystal nanodiamonds and a 70% increase in the Young’s modulus of nanocellulose films was produced by the addition of 5 wt% nanodiamonds. Therefore, in this review, data related to the manufacturing routes, main properties, and applications of nanocellulose–nanodiamonds hybrids are presented and discussed. This review paves the way for new methods and procedures to obtain nanocellulose–nanodiamonds hybrids better adapted to practical needs.","PeriodicalId":18139,"journal":{"name":"Macromol","volume":"81 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72961394","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}
R. R. Silva, C. Marques, T. R. Arruda, Samiris Côcco Teixeira, T. V. de Oliveira
Nowadays, sustainable and biodegradable bioplastics are gaining significant attention due to resource depletion and plastic pollution. An increasing number of environmentally friendly plastics are being introduced to the market with the aim of addressing these concerns. However, many final products still contain additives or mix non-biodegradable polymers to ensure minimum performance, which often undermines their ecological footprint. Moreover, there is a lack of knowledge about all stages of biodegradation and their accuracy in classifying products as biodegradable. Therefore, this review provides an overview of biodegradable polymers, elucidating the steps and mechanisms of polymer biodegradation. We also caution readers about the growing marketing practice of “greenwashing” where companies or organizations adopt green marketing strategies to label products with more environmental benefits than they have. Furthermore, we present the main standards for evaluating biodegradation, tools, and tests capable of measuring the biodegradation process. Finally, we suggest strategies and perspectives involving concepts of recycling and the circularity of polymers to make them more environmentally friendly and sustainable. After all, “throwing away” plastics should not be an option because there is no outside when there is only one planet.
{"title":"Biodegradation of Polymers: Stages, Measurement, Standards and Prospects","authors":"R. R. Silva, C. Marques, T. R. Arruda, Samiris Côcco Teixeira, T. V. de Oliveira","doi":"10.3390/macromol3020023","DOIUrl":"https://doi.org/10.3390/macromol3020023","url":null,"abstract":"Nowadays, sustainable and biodegradable bioplastics are gaining significant attention due to resource depletion and plastic pollution. An increasing number of environmentally friendly plastics are being introduced to the market with the aim of addressing these concerns. However, many final products still contain additives or mix non-biodegradable polymers to ensure minimum performance, which often undermines their ecological footprint. Moreover, there is a lack of knowledge about all stages of biodegradation and their accuracy in classifying products as biodegradable. Therefore, this review provides an overview of biodegradable polymers, elucidating the steps and mechanisms of polymer biodegradation. We also caution readers about the growing marketing practice of “greenwashing” where companies or organizations adopt green marketing strategies to label products with more environmental benefits than they have. Furthermore, we present the main standards for evaluating biodegradation, tools, and tests capable of measuring the biodegradation process. Finally, we suggest strategies and perspectives involving concepts of recycling and the circularity of polymers to make them more environmentally friendly and sustainable. After all, “throwing away” plastics should not be an option because there is no outside when there is only one planet.","PeriodicalId":18139,"journal":{"name":"Macromol","volume":"57 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84065059","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}
Keran Zhou, Farah Alwani Azaman, Zhi-nong Cao, Margaret Brennan Fournet, D. Devine
A large bone defect is defined as a defect that exceeds the regenerative capacity of the bone. Nowadays, autologous bone grafting is still the gold standard treatment. In this study, a hybrid bone tissue engineering scaffold (BTE) was designed with biocompatibility, biodegradability and adequate mechanical strength as the primary objectives. Chitosan (CS) is a biocompatible and biodegradable polymer that can be used in a wide range of applications in bone tissue engineering. Hydroxyapatite (HAp) and fluorapatite (FAp) have the potential to improve the mechanical properties of CS. In the present work, different volumes of acetic acid (AA) and different ratios of HAp and FAp scaffolds were prepared and UV cross-linked to form a 3D structure. The properties of the scaffolds were characterised by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, swelling studies and compression testing. The cytotoxicity result was obtained by the MTT assay. The degradation rate was tested by weight loss after the scaffold was immersed in SBF. The results showed that a crosslinked structure was formed and that bonding occurred between different materials within the scaffold. Additionally, the scaffolds not only provided sufficient mechanical strength but were also cytocompatibility, depending on their composition. The scaffolds were degraded gradually within a 6-to-8-week testing period, which closely matches bone regeneration rates, indicating their potential in the BTE field.
{"title":"Bone Tissue Engineering Scaffold Optimisation through Modification of Chitosan/Ceramic Composition","authors":"Keran Zhou, Farah Alwani Azaman, Zhi-nong Cao, Margaret Brennan Fournet, D. Devine","doi":"10.3390/macromol3020021","DOIUrl":"https://doi.org/10.3390/macromol3020021","url":null,"abstract":"A large bone defect is defined as a defect that exceeds the regenerative capacity of the bone. Nowadays, autologous bone grafting is still the gold standard treatment. In this study, a hybrid bone tissue engineering scaffold (BTE) was designed with biocompatibility, biodegradability and adequate mechanical strength as the primary objectives. Chitosan (CS) is a biocompatible and biodegradable polymer that can be used in a wide range of applications in bone tissue engineering. Hydroxyapatite (HAp) and fluorapatite (FAp) have the potential to improve the mechanical properties of CS. In the present work, different volumes of acetic acid (AA) and different ratios of HAp and FAp scaffolds were prepared and UV cross-linked to form a 3D structure. The properties of the scaffolds were characterised by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, swelling studies and compression testing. The cytotoxicity result was obtained by the MTT assay. The degradation rate was tested by weight loss after the scaffold was immersed in SBF. The results showed that a crosslinked structure was formed and that bonding occurred between different materials within the scaffold. Additionally, the scaffolds not only provided sufficient mechanical strength but were also cytocompatibility, depending on their composition. The scaffolds were degraded gradually within a 6-to-8-week testing period, which closely matches bone regeneration rates, indicating their potential in the BTE field.","PeriodicalId":18139,"journal":{"name":"Macromol","volume":"52 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87904658","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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