Chitosan is a natural polymer derived from the deacetylation of chitin. It is mainly derived from crustaceans and fungal sources. It has many intrinsic properties, such as biocompatibility, biodegradability, cationic nature, and nontoxicity. These features of chitosan have made it an attractive material for various applications. Furthermore, these unique properties have found significant biomedical applications, such as in drug delivery, tissue engineering, antimicrobial agent, and wound healing. However, it has its drawbacks, such as the raw material source being seasonal and localized, the extraction procedure being time-consuming, costly, and involving the use of harsh chemicals in substantial amounts, and the quality of chitosan obtained from marine sources being variable. Furthermore, studies are needed to increase the yield and utilization of chitosan for various industrial purposes. Technological improvements, such as gene modification will enhance the yield and application of chitosan. This review focuses primarily on the numerous applications of chitosan in the biomedical field, including tissue engineering, wound dressing, drug delivery, and others.
{"title":"Study on the Physicochemical Properties of Chitosan and their Applications in the Biomedical Sector","authors":"Digafe Alemu, Efrata Getachew, A. Mondal","doi":"10.1155/2023/5025341","DOIUrl":"https://doi.org/10.1155/2023/5025341","url":null,"abstract":"Chitosan is a natural polymer derived from the deacetylation of chitin. It is mainly derived from crustaceans and fungal sources. It has many intrinsic properties, such as biocompatibility, biodegradability, cationic nature, and nontoxicity. These features of chitosan have made it an attractive material for various applications. Furthermore, these unique properties have found significant biomedical applications, such as in drug delivery, tissue engineering, antimicrobial agent, and wound healing. However, it has its drawbacks, such as the raw material source being seasonal and localized, the extraction procedure being time-consuming, costly, and involving the use of harsh chemicals in substantial amounts, and the quality of chitosan obtained from marine sources being variable. Furthermore, studies are needed to increase the yield and utilization of chitosan for various industrial purposes. Technological improvements, such as gene modification will enhance the yield and application of chitosan. This review focuses primarily on the numerous applications of chitosan in the biomedical field, including tissue engineering, wound dressing, drug delivery, and others.","PeriodicalId":14283,"journal":{"name":"International Journal of Polymer Science","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2023-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47660852","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Sucharitha, Reena Thomas, B. Jyothi, Edeh Michael Onyema, Gashaw Bekele
Stretchable circuit is a technological innovation that has transformed the microelectronic landscape due to its enormous applications in the field of medicine. The consistency or durability of health monitoring devices can increase the dependability with which non-invasive clinical measures are collected. Metal–conductive polymer (CP) hybrid interconnects and metal–polyimide dual-layered interconnects were all produced as stretchable interconnections. Stretchable substrate for all of the interconnects was selected as soft elastomer polydimethylsiloxane (PDMS). However, the PDMS substrate presents challenges because it is temperature sensitive, limiting the process temperature. The extreme hydrophobic nature of the PDMS surface makes it difficult to deposit components that contain water and results in poor adhesion with different metals. Following the development of processes for fabricating materials on the PDMS substrate, methods for resolving these issues were investigated.
{"title":"Design and Fabrication of Metallic-Conductive Polymer-Based Hybrid Film Interconnections for Stretchable Electronic Devices","authors":"M. Sucharitha, Reena Thomas, B. Jyothi, Edeh Michael Onyema, Gashaw Bekele","doi":"10.1155/2023/1392115","DOIUrl":"https://doi.org/10.1155/2023/1392115","url":null,"abstract":"Stretchable circuit is a technological innovation that has transformed the microelectronic landscape due to its enormous applications in the field of medicine. The consistency or durability of health monitoring devices can increase the dependability with which non-invasive clinical measures are collected. Metal–conductive polymer (CP) hybrid interconnects and metal–polyimide dual-layered interconnects were all produced as stretchable interconnections. Stretchable substrate for all of the interconnects was selected as soft elastomer polydimethylsiloxane (PDMS). However, the PDMS substrate presents challenges because it is temperature sensitive, limiting the process temperature. The extreme hydrophobic nature of the PDMS surface makes it difficult to deposit components that contain water and results in poor adhesion with different metals. Following the development of processes for fabricating materials on the PDMS substrate, methods for resolving these issues were investigated.","PeriodicalId":14283,"journal":{"name":"International Journal of Polymer Science","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2023-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41697273","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cooperation of essential oil into film formation results in active packaging materials, which can improve the quality and freshness of the foods and extend the shelf life. In the present study, extraction of starch and essential oil was performed. The active films were developed through the solvent casting method. The influence of avocado seed starch and orange peel essential oil was investigated and optimized using response surface methodology and an artificial neural network on the tensile strength, water vapor permeability, and antimicrobial properties of active films. The results showed that both models performed reasonably well, but trained artificial neural networks have more modeling capability rather than the response surface method. The optimum conditions were found to be orange peel oil of 0.57 g and 30% w/w of avocado seed starch with the values of the corresponding responses of 3.94 MPa, 3.098 × 10 − 10 g/ms Pa, and 17.273 mm for tensile strength, water vapor permeability, and inhibition zone, respectively. Generally, the orange peel extract had an effective and promising alternative for the commercial production of antimicrobial packaging films.
{"title":"ANN and RSM Modeling for the Synthesis of Avocado Seed Starch Combined Orange Peel Extract Antimicrobial Packaging Film","authors":"Yasin Ahmed Waday, Ermias Girma Aklilu","doi":"10.1155/2023/8877598","DOIUrl":"https://doi.org/10.1155/2023/8877598","url":null,"abstract":"Cooperation of essential oil into film formation results in active packaging materials, which can improve the quality and freshness of the foods and extend the shelf life. In the present study, extraction of starch and essential oil was performed. The active films were developed through the solvent casting method. The influence of avocado seed starch and orange peel essential oil was investigated and optimized using response surface methodology and an artificial neural network on the tensile strength, water vapor permeability, and antimicrobial properties of active films. The results showed that both models performed reasonably well, but trained artificial neural networks have more modeling capability rather than the response surface method. The optimum conditions were found to be orange peel oil of 0.57 g and 30% w/w of avocado seed starch with the values of the corresponding responses of 3.94 MPa, \u0000 \u0000 3.098\u0000 ×\u0000 \u0000 \u0000 10\u0000 \u0000 \u0000 −\u0000 10\u0000 \u0000 \u0000 \u0000 g/ms Pa, and 17.273 mm for tensile strength, water vapor permeability, and inhibition zone, respectively. Generally, the orange peel extract had an effective and promising alternative for the commercial production of antimicrobial packaging films.","PeriodicalId":14283,"journal":{"name":"International Journal of Polymer Science","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2023-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45998600","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kaihua Chen, Xiaobao Zhu, G. Zhao, J. Chen, Shenghui Guo
Investigating the curing kinetics of a fiber prepreg system is beneficial to the controlling of prepreg laminate curing process. In the present work, a dicyandiamide (DICY)-cured carbon fiber/epoxy prepreg system was investigated by non-isothermal differential scanning calorimetry (DSC) at 2, 5, 10, and 20°C/min to attain the glass transition temperature for uncured prepreg and fully cured sample, which were estimated to be 7.6°C and 106.2°C, respectively. The activation energy (Ea) of the prepreg system was evaluated by Kissinger and Ozawa methods, and Friedman method was also employed to reveal the evolution of Ea as a function of curing degree. The kinetic parameters were determined by fitting the average Ea value obtained by Friedman method into Málek methodology, and the two parameters Šesták–Berggren model was found to best describe the curing kinetic of the prepreg system. The preexponential factor was calculated to be 6.0 × 10 8 min−1, with the overall reaction order at nearly 2.5. The prediction curves, based on Friedman method and autocatalytic model, were in good agreement with the experimental data.
{"title":"Cure Kinetics of a Carbon Fiber/Epoxy Prepreg by Dynamic Differential Scanning Calorimetry","authors":"Kaihua Chen, Xiaobao Zhu, G. Zhao, J. Chen, Shenghui Guo","doi":"10.1155/2023/5244722","DOIUrl":"https://doi.org/10.1155/2023/5244722","url":null,"abstract":"Investigating the curing kinetics of a fiber prepreg system is beneficial to the controlling of prepreg laminate curing process. In the present work, a dicyandiamide (DICY)-cured carbon fiber/epoxy prepreg system was investigated by non-isothermal differential scanning calorimetry (DSC) at 2, 5, 10, and 20°C/min to attain the glass transition temperature for uncured prepreg and fully cured sample, which were estimated to be 7.6°C and 106.2°C, respectively. The activation energy (Ea) of the prepreg system was evaluated by Kissinger and Ozawa methods, and Friedman method was also employed to reveal the evolution of Ea as a function of curing degree. The kinetic parameters were determined by fitting the average Ea value obtained by Friedman method into Málek methodology, and the two parameters Šesták–Berggren model was found to best describe the curing kinetic of the prepreg system. The preexponential factor was calculated to be \u0000 \u0000 6.0\u0000 ×\u0000 \u0000 \u0000 10\u0000 \u0000 \u0000 8\u0000 \u0000 \u0000 \u0000 min−1, with the overall reaction order at nearly 2.5. The prediction curves, based on Friedman method and autocatalytic model, were in good agreement with the experimental data.","PeriodicalId":14283,"journal":{"name":"International Journal of Polymer Science","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2023-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46868022","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Bioprinting is fast emerging as a viable technique for organ fabrication. Though various types of bioprinting methods have been developed, the most commonly used bioprinting is extrusion-based bioprinting (EBB). Bioinks are extruded layer-by-layer forming a 3D multicellular construct and scaled up to dimensions depending upon the specific tissue to be regenerated. Among various bioinks, alginate, a natural polysaccharide, has been extensively used because of its good printability in physiologically amenable conditions. Though alginate possesses good printability properties, it promotes little cell–material interaction resulting in limited biofunctionality. Therefore, it becomes necessary to blend/modify alginate to improve the biological properties of bioink without compromising printability. This paper presents a review of the various approaches used to optimize bioprinting with alginate bioinks and their limitations.
{"title":"Advantage of Alginate Bioinks in Biofabrication for Various Tissue Engineering Applications","authors":"S. Datta","doi":"10.1155/2023/6661452","DOIUrl":"https://doi.org/10.1155/2023/6661452","url":null,"abstract":"Bioprinting is fast emerging as a viable technique for organ fabrication. Though various types of bioprinting methods have been developed, the most commonly used bioprinting is extrusion-based bioprinting (EBB). Bioinks are extruded layer-by-layer forming a 3D multicellular construct and scaled up to dimensions depending upon the specific tissue to be regenerated. Among various bioinks, alginate, a natural polysaccharide, has been extensively used because of its good printability in physiologically amenable conditions. Though alginate possesses good printability properties, it promotes little cell–material interaction resulting in limited biofunctionality. Therefore, it becomes necessary to blend/modify alginate to improve the biological properties of bioink without compromising printability. This paper presents a review of the various approaches used to optimize bioprinting with alginate bioinks and their limitations.","PeriodicalId":14283,"journal":{"name":"International Journal of Polymer Science","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2023-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41868891","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Muhammad Zaman, A. Iqbal, H. S. Sarwar, M. H. Butt, M. Iqbal, Naveed Nissar, A. Mumtaz, Hafiza Yusra Nazeer, A. Alshammari, Muhammad Shahid Riaz
Currently, the solid lipid nanoparticles (SLNs) are utilized as a novel approach for the controlled drug delivery system (CDDS). Tacrolimus (TCM), a lipophilic drug, can easily be encapsulated in the hydrophobic core of these SLNs using nanoprecipitation technique. The current aim was to develop the controlled release Poloxamer (PLX) facilitated TCM loaded SLNs (PLX/TCM-SLNs), followed by their physicochemical evaluations, including chemical compatibility, particle size, surface charge, surface morphology, nature of SLNs, loading efficiency (LE), entrapment efficiency (EE), in vitro drug release studies, release kinetic modeling, and statistical evaluation. Here we also evaluate physicochemical properties of TCM and investigate solubility profile for improvement and dissolution rate of PLX/TCM-SLNs. PLX was used in the process as a polymer due to its low toxicity and weak immunogenic properties. The prepared formulation was characterized by scanning electron microscopy (SEM) images, and Fourier transform infrared spectroscopy (FTIR) has confirmed the compatibility of the selected ingredients, whereas particle size analysis showed that prepared PLX/TCM-SLNs were of nanosized ( 120.6 ± 9 nm) having zeta potential of −21.3 Mv. On the other hand, SEM had revealed the smooth and uniform surface of the particle, while X-ray diffraction (XRD) confirmed the uniform surface as crystalline structure of TCM in PLX/TCM-SLNs masked. A satisfactory level of EE ( 94.5 ± 2.74 %) has also been noticed. Furthermore, in vitro drug release studies have explored the controlled release of drug during 8 hours, following zero order release kinetics and diffusion type of release mechanism. Outcomes of the studies have advocated the successful preparation of SLNs, as controlled release PLX/TCM-SLNs have been prepared efficiently.
{"title":"Application of Nanoprecipitation Technique to Develop Poloxamer-407 Facilitated Solid Lipid Nanoparticles for the Controlled Delivery of Tacrolimus","authors":"Muhammad Zaman, A. Iqbal, H. S. Sarwar, M. H. Butt, M. Iqbal, Naveed Nissar, A. Mumtaz, Hafiza Yusra Nazeer, A. Alshammari, Muhammad Shahid Riaz","doi":"10.1155/2023/7356899","DOIUrl":"https://doi.org/10.1155/2023/7356899","url":null,"abstract":"Currently, the solid lipid nanoparticles (SLNs) are utilized as a novel approach for the controlled drug delivery system (CDDS). Tacrolimus (TCM), a lipophilic drug, can easily be encapsulated in the hydrophobic core of these SLNs using nanoprecipitation technique. The current aim was to develop the controlled release Poloxamer (PLX) facilitated TCM loaded SLNs (PLX/TCM-SLNs), followed by their physicochemical evaluations, including chemical compatibility, particle size, surface charge, surface morphology, nature of SLNs, loading efficiency (LE), entrapment efficiency (EE), in vitro drug release studies, release kinetic modeling, and statistical evaluation. Here we also evaluate physicochemical properties of TCM and investigate solubility profile for improvement and dissolution rate of PLX/TCM-SLNs. PLX was used in the process as a polymer due to its low toxicity and weak immunogenic properties. The prepared formulation was characterized by scanning electron microscopy (SEM) images, and Fourier transform infrared spectroscopy (FTIR) has confirmed the compatibility of the selected ingredients, whereas particle size analysis showed that prepared PLX/TCM-SLNs were of nanosized (\u0000 \u0000 120.6\u0000 ±\u0000 9\u0000 \u0000 nm) having zeta potential of −21.3 Mv. On the other hand, SEM had revealed the smooth and uniform surface of the particle, while X-ray diffraction (XRD) confirmed the uniform surface as crystalline structure of TCM in PLX/TCM-SLNs masked. A satisfactory level of EE (\u0000 \u0000 94.5\u0000 ±\u0000 2.74\u0000 \u0000 %) has also been noticed. Furthermore, in vitro drug release studies have explored the controlled release of drug during 8 hours, following zero order release kinetics and diffusion type of release mechanism. Outcomes of the studies have advocated the successful preparation of SLNs, as controlled release PLX/TCM-SLNs have been prepared efficiently.","PeriodicalId":14283,"journal":{"name":"International Journal of Polymer Science","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43739985","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Software-based mold flow analysis is often performed to confirm optimized resin pipe arrangements. In this study, the GeoDict software and reverse scanning were employed to develop a method for performing rapid porosity and permeability estimation. A comparison of the results from one-dimensional resin flow and Easyperm tests revealed a 10% variation in the porosity and permeability parameters obtained through the proposed rapid estimation method. In addition, the obtained parameters were substituted into a Moldex3D model to simulate the resin flow on the personal watercraft hull during vacuum-assisted resin transfer molding (VARTM). A comparison of simulation results and hull infusion results revealed that the integration of the proposed rapid estimation method with Moldex3D allowed for the accurate simulation of the resin flow in large fiber-reinforced-plastic (FRP) products (variation <8%). The proposed method can be applied to large wind turbine FRP parts and large FRP yacht components to increase process planning efficiency and product stability.
{"title":"Acquisition of Key Vacuum-Assisted Resin Transfer Molding Parameters through Reverse Scanning for Application in the Manufacturing of Large Fiber-Reinforced-Plastic Products","authors":"G. Luo, Kai-Lin Chen, Chen-Ting Hsu","doi":"10.1155/2023/7927196","DOIUrl":"https://doi.org/10.1155/2023/7927196","url":null,"abstract":"Software-based mold flow analysis is often performed to confirm optimized resin pipe arrangements. In this study, the GeoDict software and reverse scanning were employed to develop a method for performing rapid porosity and permeability estimation. A comparison of the results from one-dimensional resin flow and Easyperm tests revealed a 10% variation in the porosity and permeability parameters obtained through the proposed rapid estimation method. In addition, the obtained parameters were substituted into a Moldex3D model to simulate the resin flow on the personal watercraft hull during vacuum-assisted resin transfer molding (VARTM). A comparison of simulation results and hull infusion results revealed that the integration of the proposed rapid estimation method with Moldex3D allowed for the accurate simulation of the resin flow in large fiber-reinforced-plastic (FRP) products (variation <8%). The proposed method can be applied to large wind turbine FRP parts and large FRP yacht components to increase process planning efficiency and product stability.","PeriodicalId":14283,"journal":{"name":"International Journal of Polymer Science","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2023-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46405330","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Syrille Brice Tchinwoussi Youbi, O. Harzallah, N. R. S. Tagne, P.W.M. Huisken, T. T. Stanislas, J. Drean, S. Bistac, E. Njeugna
This study evaluates the effects of lengths and reinforcement ratio of Raphia vinifera fibres (RVFs) on the physical and mechanical properties of an epoxy matrix composite. Three volume fractions (20%, 30%, and 40%) and three lengths (5, 10, and 15 mm) of fibres were used to produce the composite, and the samples were subjected to the absolute and apparent density, porosity, water absorption rate, and tensile and flexural strength. The probability of failure of the composite is described by the means of two-factor Weibull model. In addition, a theoretical approach to predict mechanical characteristics based on empirical models was carried out. The results show that the addition of RVF decreases the density of the composite, while the porosity and absorption rate increase. The mechanical test shows that the tensile and flexural stress and Young’s modulus of the composite are lowered compared to those of the resin alone. Multivariate analysis of variance (MANOVA) and Tukey test showed that fibre lengths and reinforcement ratio significantly lower the mechanical properties of the composite. The distribution of strength and Young’s modulus follows Weibull’s law. Furthermore, the Cox–Krenkel mathematical model has the best approximated model for the experimental results after the tensile test. Based on these results, this material could be used as reinforcement parts for vehicle backrests or interior decoration in the construction industry.
{"title":"Effect of Raphia vinifera Fibre Size and Reinforcement Ratio on the Physical and Mechanical Properties of an Epoxy Matrix Composite: Micromechanical Modelling and Weibull Analysis","authors":"Syrille Brice Tchinwoussi Youbi, O. Harzallah, N. R. S. Tagne, P.W.M. Huisken, T. T. Stanislas, J. Drean, S. Bistac, E. Njeugna","doi":"10.1155/2023/5591108","DOIUrl":"https://doi.org/10.1155/2023/5591108","url":null,"abstract":"This study evaluates the effects of lengths and reinforcement ratio of Raphia vinifera fibres (RVFs) on the physical and mechanical properties of an epoxy matrix composite. Three volume fractions (20%, 30%, and 40%) and three lengths (5, 10, and 15 mm) of fibres were used to produce the composite, and the samples were subjected to the absolute and apparent density, porosity, water absorption rate, and tensile and flexural strength. The probability of failure of the composite is described by the means of two-factor Weibull model. In addition, a theoretical approach to predict mechanical characteristics based on empirical models was carried out. The results show that the addition of RVF decreases the density of the composite, while the porosity and absorption rate increase. The mechanical test shows that the tensile and flexural stress and Young’s modulus of the composite are lowered compared to those of the resin alone. Multivariate analysis of variance (MANOVA) and Tukey test showed that fibre lengths and reinforcement ratio significantly lower the mechanical properties of the composite. The distribution of strength and Young’s modulus follows Weibull’s law. Furthermore, the Cox–Krenkel mathematical model has the best approximated model for the experimental results after the tensile test. Based on these results, this material could be used as reinforcement parts for vehicle backrests or interior decoration in the construction industry.","PeriodicalId":14283,"journal":{"name":"International Journal of Polymer Science","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2023-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41318907","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Many catalysts containing various elements at their active sites have been reported for the ring-opening polymerization (ROP) of cyclic esters. However, to our knowledge, silicon-based catalysts for ROP have never been reported. Here we report the ROP of cyclic esters and cyclic carbonates catalyzed by the derivatives of bis(perchlorocatecholato)silane (Si(catCl)2), which is a neutral silicon-based Lewis acid recently reported by Greb et al. The catalyst systems show high activity for the ROP of seven- and six-membered ring monomers such as ε-caprolactone, δ-valerolactone, and trimethylene carbonate to produce the polymers with molecular weights up to 32 kg/mol. The matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and nuclear magnetic resonance analysis of the obtained polymers indicates the predominant formation of cyclic polymers.
{"title":"Ring-Opening Polymerization of Lactones Catalyzed by Silicon-Based Lewis Acid","authors":"Y. Nakayama, Keiya Katagi, R. Tanaka, T. Shiono","doi":"10.1155/2023/4391372","DOIUrl":"https://doi.org/10.1155/2023/4391372","url":null,"abstract":"Many catalysts containing various elements at their active sites have been reported for the ring-opening polymerization (ROP) of cyclic esters. However, to our knowledge, silicon-based catalysts for ROP have never been reported. Here we report the ROP of cyclic esters and cyclic carbonates catalyzed by the derivatives of bis(perchlorocatecholato)silane (Si(catCl)2), which is a neutral silicon-based Lewis acid recently reported by Greb et al. The catalyst systems show high activity for the ROP of seven- and six-membered ring monomers such as ε-caprolactone, δ-valerolactone, and trimethylene carbonate to produce the polymers with molecular weights up to 32 kg/mol. The matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and nuclear magnetic resonance analysis of the obtained polymers indicates the predominant formation of cyclic polymers.","PeriodicalId":14283,"journal":{"name":"International Journal of Polymer Science","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2023-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43164869","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Complex forms may be easily created with additive manufacturing methods, but managing surface roughness remains a difficulty, even for flat surfaces, because surface quality is dependent on numerous parameters. This research investigates the effect of some printing factors on surface roughness in 3D printing methods. The purpose of this study is to quantify the most influential input printing factors on surface roughness in 3D printing processes. Polyacrylic acid thermoplastic was used to print workpieces, and mathematical models were generated using the regression method to analyze the relationship between process parameters and surface roughness. The exponential model fits the experimental data slightly better than the linear model. Only Ra-90 met all surface roughness classification requirements, while surface roughness measurements in the 0 and 45-degree directions did not meet the requirements and cannot be used to describe the surface roughness. The study highlights the importance of considering input printing parameters when optimizing surface roughness in 3D printing processes, providing valuable insights into the impact of process parameters on surface roughness.
{"title":"Surface Roughness Modeling of Material Extrusion PLA Flat Surfaces","authors":"Kaltrine Jakupi, V. Dukovski, G. Hodolli","doi":"10.1155/2023/8844626","DOIUrl":"https://doi.org/10.1155/2023/8844626","url":null,"abstract":"Complex forms may be easily created with additive manufacturing methods, but managing surface roughness remains a difficulty, even for flat surfaces, because surface quality is dependent on numerous parameters. This research investigates the effect of some printing factors on surface roughness in 3D printing methods. The purpose of this study is to quantify the most influential input printing factors on surface roughness in 3D printing processes. Polyacrylic acid thermoplastic was used to print workpieces, and mathematical models were generated using the regression method to analyze the relationship between process parameters and surface roughness. The exponential model fits the experimental data slightly better than the linear model. Only Ra-90 met all surface roughness classification requirements, while surface roughness measurements in the 0 and 45-degree directions did not meet the requirements and cannot be used to describe the surface roughness. The study highlights the importance of considering input printing parameters when optimizing surface roughness in 3D printing processes, providing valuable insights into the impact of process parameters on surface roughness.","PeriodicalId":14283,"journal":{"name":"International Journal of Polymer Science","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2023-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45954028","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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