The catalyst synthesis of salicylaldimine Ni(II) complexes with bulky imide moieties, ethylene polymerization, and characterization of synthesized polyethylenes are described in this paper. These Ni(II) complexes are designed to bear 2-aminobiphenyl and 4-tritylaniline. Results confirmed relatively high activity (up to 4 × 10 4 g PE mol Ni-1 h-1) of these catalysts in ethylene polymerization. Moreover, Ni(II) complexes demonstrated enhanced thermal stability, maintaining activity level up to 80°C. The generated polyethylenes possess moderate branching density and high melting temperatures. Less bulky 2-aminobiphenyl group resulted in higher branch content, while in Ni(II) complexes bearing 4-tritylaniline, more linear structure was observed. These semicrystalline polyethylenes showed mechanical properties similar to thermoplastics.
介绍了水杨醛二胺大体积亚胺配合物的催化剂合成、乙烯聚合及合成聚乙烯的表征。这些Ni(II)配合物被设计为含有2-氨基联苯和4-三苯胺。结果表明，这些催化剂在乙烯聚合中具有较高的活性(最高可达4 × 10 4 g PE mol Ni-1 h-1)。此外，Ni(II)配合物表现出增强的热稳定性，在80°C下保持活性水平。生成的聚乙烯具有中等的分支密度和较高的熔融温度。2-氨基联苯基体积较小，支链含量较高，而含4-三苯胺的Ni(II)配合物具有更多的线性结构。这些半结晶聚乙烯表现出与热塑性塑料相似的机械性能。
{"title":"Ethylene Polymerization through Neutral Nickel Complexes Bearing Cyclic Imides","authors":"Hassan Arabi, M. S. Beheshti, A. Manteghi","doi":"10.1155/2022/8788585","DOIUrl":"https://doi.org/10.1155/2022/8788585","url":null,"abstract":"The catalyst synthesis of salicylaldimine Ni(II) complexes with bulky imide moieties, ethylene polymerization, and characterization of synthesized polyethylenes are described in this paper. These Ni(II) complexes are designed to bear 2-aminobiphenyl and 4-tritylaniline. Results confirmed relatively high activity (up to \u0000 \u0000 4\u0000 ×\u0000 \u0000 \u0000 10\u0000 \u0000 \u0000 4\u0000 \u0000 \u0000 \u0000 g PE mol Ni-1 h-1) of these catalysts in ethylene polymerization. Moreover, Ni(II) complexes demonstrated enhanced thermal stability, maintaining activity level up to 80°C. The generated polyethylenes possess moderate branching density and high melting temperatures. Less bulky 2-aminobiphenyl group resulted in higher branch content, while in Ni(II) complexes bearing 4-tritylaniline, more linear structure was observed. These semicrystalline polyethylenes showed mechanical properties similar to thermoplastics.","PeriodicalId":7372,"journal":{"name":"Advances in Polymer Technology","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2022-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49019389","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The glass transition of amorphous polymers determines the mobility of polymer chains and the time scale of relaxation processes. The glass transition temperature is reduced by the presence of low molecular weight molecules, e.g., dissolved gases or organic solvents. The quantitative knowledge of reduction of the glass transition temperature caused by the addition of carbon dioxide in a polymer melt is highly relevant for foam extrusion. However, measurement of the reduction of glass transition temperature caused by gas loading has to be performed under elevated pressure which implies high experimental efforts. In this work, we discuss and compare three methods for determination of the influence of carbon dioxide on thermal properties of amorphous polymers, i.e., calorimetric measurements, creep tests, and rheological experiments. The advantages and disadvantages of these methods are elucidated. Furthermore, the influence of molecular structure of the styrenic and vinylpyridine polymers on the glass transition temperature is discussed. Polystyrene generally shows the highest reduction of glass transition temperature. Poly(2-vinylpyridine) and poly(4-vinylpyridine) show a slightly less pronounced behaviour in comparison to polystyrene because of the lower polarity of polystyrene. Poly(α-methyl styrene) is associated with a different dependence of glass transition temperature on gas loading in calorimetric and rheological experiments.
{"title":"Influence of Carbon Dioxide on the Glass Transition of Styrenic and Vinyl Pyridine Polymers: Comparison of Calorimetric, Creep, and Rheological Experiments","authors":"Felix Harden, M. Kargar, U. A. Handge","doi":"10.1155/2022/5602902","DOIUrl":"https://doi.org/10.1155/2022/5602902","url":null,"abstract":"The glass transition of amorphous polymers determines the mobility of polymer chains and the time scale of relaxation processes. The glass transition temperature is reduced by the presence of low molecular weight molecules, e.g., dissolved gases or organic solvents. The quantitative knowledge of reduction of the glass transition temperature caused by the addition of carbon dioxide in a polymer melt is highly relevant for foam extrusion. However, measurement of the reduction of glass transition temperature caused by gas loading has to be performed under elevated pressure which implies high experimental efforts. In this work, we discuss and compare three methods for determination of the influence of carbon dioxide on thermal properties of amorphous polymers, i.e., calorimetric measurements, creep tests, and rheological experiments. The advantages and disadvantages of these methods are elucidated. Furthermore, the influence of molecular structure of the styrenic and vinylpyridine polymers on the glass transition temperature is discussed. Polystyrene generally shows the highest reduction of glass transition temperature. Poly(2-vinylpyridine) and poly(4-vinylpyridine) show a slightly less pronounced behaviour in comparison to polystyrene because of the lower polarity of polystyrene. Poly(α-methyl styrene) is associated with a different dependence of glass transition temperature on gas loading in calorimetric and rheological experiments.","PeriodicalId":7372,"journal":{"name":"Advances in Polymer Technology","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2022-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46922363","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R. Alshgari, M. Prasad, B. K. Srivastava, Mohammed Saleh Al Ansari, Parul Gupta, A. Sivakumar, S. Wabaidur, M. Islam, Abdi Diriba
This work is about making hybrid composite materials out of carbon fiber mats and basalt fiber mats that are 40% reinforced with a 60% epoxy polymer matrix. Traditional hand layup has been used for the fabrication process to make five laminates of these two fibers. The mechanical properties of the hybrid composite were evaluated by measuring its tensile strength, flexural strength, impact energy, and hardness. The results showed that adding more carbon fiber layers to the composite made a big difference in its mechanical properties. In sample A, the tensile strength is 280 MPa, the flexural strength is 247 MPa, and the basalt fiber can keep more impact energy of 24 J in sample E, along with the carbon fiber and epoxy matrix. A scanning electron microscope was used to figure out how carbon/basalt fiber composite laminates break down.
{"title":"Mechanical Evaluation on Carbon/Basalt Fiber-Reinforced Hybrid Polymer Matrix Composite","authors":"R. Alshgari, M. Prasad, B. K. Srivastava, Mohammed Saleh Al Ansari, Parul Gupta, A. Sivakumar, S. Wabaidur, M. Islam, Abdi Diriba","doi":"10.1155/2022/7742349","DOIUrl":"https://doi.org/10.1155/2022/7742349","url":null,"abstract":"This work is about making hybrid composite materials out of carbon fiber mats and basalt fiber mats that are 40% reinforced with a 60% epoxy polymer matrix. Traditional hand layup has been used for the fabrication process to make five laminates of these two fibers. The mechanical properties of the hybrid composite were evaluated by measuring its tensile strength, flexural strength, impact energy, and hardness. The results showed that adding more carbon fiber layers to the composite made a big difference in its mechanical properties. In sample A, the tensile strength is 280 MPa, the flexural strength is 247 MPa, and the basalt fiber can keep more impact energy of 24 J in sample E, along with the carbon fiber and epoxy matrix. A scanning electron microscope was used to figure out how carbon/basalt fiber composite laminates break down.","PeriodicalId":7372,"journal":{"name":"Advances in Polymer Technology","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2022-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42507179","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this work, the effects of amino silane-grafted areca fibre and papaya slice biochar particle on the mechanical, thermal conductivity, and dielectric properties of epoxy resin biocomposite were shown. The goal of the study was to find out how the way fibres are treated affects their properties and how those properties affect the composite as a whole. The acid hydrolysis process is used to treat the raw chopped fibre and slice-dried particles with amino silane and then air-dry them in an oven. The oven-dried areca nut fibre and charcoal particles are then used with a hand-layup method to make composites that meet ASTM standards. According to the results, the tensile and flexural strengths got better by 64% and 50%, respectively, and the impact resistance got better by 93%. The use of reinforcing materials gradually improved the dielectric properties and the way heat moved through the material.
{"title":"Mechanical Properties of Epoxy Composite Using Papaya Slice Biochar and Areca Nut Chopped Fibre","authors":"T. Lakshmana Kishore, Kuma Gowwomsa Erko","doi":"10.1155/2022/4733375","DOIUrl":"https://doi.org/10.1155/2022/4733375","url":null,"abstract":"In this work, the effects of amino silane-grafted areca fibre and papaya slice biochar particle on the mechanical, thermal conductivity, and dielectric properties of epoxy resin biocomposite were shown. The goal of the study was to find out how the way fibres are treated affects their properties and how those properties affect the composite as a whole. The acid hydrolysis process is used to treat the raw chopped fibre and slice-dried particles with amino silane and then air-dry them in an oven. The oven-dried areca nut fibre and charcoal particles are then used with a hand-layup method to make composites that meet ASTM standards. According to the results, the tensile and flexural strengths got better by 64% and 50%, respectively, and the impact resistance got better by 93%. The use of reinforcing materials gradually improved the dielectric properties and the way heat moved through the material.","PeriodicalId":7372,"journal":{"name":"Advances in Polymer Technology","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2022-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43010949","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The vibration attenuation mechanism of shear thickening fluid- (STF-) filled sandwich structures was investigated in this study. Structural equivalent damping, stiffness, and mass increased simultaneously with the increase in the volume fraction of shear thickening fluid. However, the damping ratio decreased and natural frequency increased with the increase in structural mass. Thus, the damping ratio was not a monotonically increasing function of the volume fraction of STF. A modified shear strain model of the damping layer was developed based on the following conditions: (1) under the condition of small strain, shear thickening fluid was regarded as linear viscoelastic material, and (2) the warpage of the sandwich beam was considered during deformation and the influence of STF on the shear strain of sandwich beam. According to the modified shear strain model of the damping layer, the shear thickening occurred at 1 Hz to 20 Hz during vibration. Therefore, the resonance point of the structure shifted to the left. The predictions were in excellent agreement with the experimental results. The results demonstrated that shear thickening fluid improved the vibration damping performance of the sandwich structure, while the thickening ability was not the higher, the better.
{"title":"Vibration Characteristics of Shear Thickening Fluid-Based Sandwich Structures","authors":"Ping Wang, Zhiyuan Chen, K. Qian, Kejing Yu","doi":"10.1155/2022/6959485","DOIUrl":"https://doi.org/10.1155/2022/6959485","url":null,"abstract":"The vibration attenuation mechanism of shear thickening fluid- (STF-) filled sandwich structures was investigated in this study. Structural equivalent damping, stiffness, and mass increased simultaneously with the increase in the volume fraction of shear thickening fluid. However, the damping ratio decreased and natural frequency increased with the increase in structural mass. Thus, the damping ratio was not a monotonically increasing function of the volume fraction of STF. A modified shear strain model of the damping layer was developed based on the following conditions: (1) under the condition of small strain, shear thickening fluid was regarded as linear viscoelastic material, and (2) the warpage of the sandwich beam was considered during deformation and the influence of STF on the shear strain of sandwich beam. According to the modified shear strain model of the damping layer, the shear thickening occurred at 1 Hz to 20 Hz during vibration. Therefore, the resonance point of the structure shifted to the left. The predictions were in excellent agreement with the experimental results. The results demonstrated that shear thickening fluid improved the vibration damping performance of the sandwich structure, while the thickening ability was not the higher, the better.","PeriodicalId":7372,"journal":{"name":"Advances in Polymer Technology","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2022-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47344626","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We present a method and several applications for the synthesis of hydrogel-crosslinked microneedle arrays utilizing microwave-assisted drying, ensuring a significant reduction in reaction preparation time while maintaining quality. We demonstrate the feasibility of drying hydrogels using microwaves and thus extend to crosslinked microneedle fabrication. Crosslinking was performed using 1,4-butanediol diglycidyl ether (BDDE) as a crosslinking agent. Infrared spectra of the microneedle arrays were measured with attenuated total reflection-Fourier transform infrared (ATR-FTIR). The surface morphology of the microneedle arrays was observed with scanning electron microscopy (SEM). The microneedle arrays were evaluated in terms of mechanical strength, swelling kinetics, rheological properties, degradation rate, and glucose iontophoresis. The results show that this method can shorten the reaction preparation time by 5 hours, and the prepared crosslinked microneedle array has better crosslinking efficiency, swelling effect, and greater mechanical strength than traditional methods.
{"title":"Hydrogel-Crosslinked Microneedles Based on Microwave-Assisted Drying Method","authors":"Dongyu Chen, Yu Zhang, Xiaoke Chen, Qiyao He, Tianwei Wu, Xiaoping Cao, Jing Liu, Xueqiu You","doi":"10.1155/2022/2220918","DOIUrl":"https://doi.org/10.1155/2022/2220918","url":null,"abstract":"We present a method and several applications for the synthesis of hydrogel-crosslinked microneedle arrays utilizing microwave-assisted drying, ensuring a significant reduction in reaction preparation time while maintaining quality. We demonstrate the feasibility of drying hydrogels using microwaves and thus extend to crosslinked microneedle fabrication. Crosslinking was performed using 1,4-butanediol diglycidyl ether (BDDE) as a crosslinking agent. Infrared spectra of the microneedle arrays were measured with attenuated total reflection-Fourier transform infrared (ATR-FTIR). The surface morphology of the microneedle arrays was observed with scanning electron microscopy (SEM). The microneedle arrays were evaluated in terms of mechanical strength, swelling kinetics, rheological properties, degradation rate, and glucose iontophoresis. The results show that this method can shorten the reaction preparation time by 5 hours, and the prepared crosslinked microneedle array has better crosslinking efficiency, swelling effect, and greater mechanical strength than traditional methods.","PeriodicalId":7372,"journal":{"name":"Advances in Polymer Technology","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2022-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43721714","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R. Alshgari, N. Hemalatha, A. Suryavanshi, D. Prasad, R. Subalakshmi, M. Abirami, M. Amudha, S. Wabaidur, M. Islam, David Christopher
Composites that were made stronger with jute fiber and glass fiber were used to test the performance of filament wound abaca fiber composites. Tensile, bending, and dynamic mechanical analyses were used to figure out the mechanical properties of the composites. Fiber composites and glass-fiber composites were found to have higher density and mechanical properties than abaca fiber-based composites. This is because resin did not get into the cell cavity of the fiber’s inner tissue structure. The abaca fiber composites that worked the worst were those in which the fibers were pulled out while the fibers on the surface were torn. The fiber-reinforced epoxy circumferential composite interface junction in the twisting abaca fiber circumferential composite was found to be more flexible and have a higher glass transition temperature than any of the other composites (6000 MPa). We found that twisting abaca fiber-naval ordnance laboratory and twisting abaca fiber-prepared circumferential composite had the lowest frequency dependence and performance variability. To improve composite properties, both the outside and inside structures of twisting abaca fiber need to be fixed. There is also a rise in fiber-to-resin contact and a rise in fiber surface area. The diameter of the fibers also gets smaller.
{"title":"Investigation on Physical and Mechanical Properties of Abaca Fiber Composites Using Filament Winding","authors":"R. Alshgari, N. Hemalatha, A. Suryavanshi, D. Prasad, R. Subalakshmi, M. Abirami, M. Amudha, S. Wabaidur, M. Islam, David Christopher","doi":"10.1155/2022/5000547","DOIUrl":"https://doi.org/10.1155/2022/5000547","url":null,"abstract":"Composites that were made stronger with jute fiber and glass fiber were used to test the performance of filament wound abaca fiber composites. Tensile, bending, and dynamic mechanical analyses were used to figure out the mechanical properties of the composites. Fiber composites and glass-fiber composites were found to have higher density and mechanical properties than abaca fiber-based composites. This is because resin did not get into the cell cavity of the fiber’s inner tissue structure. The abaca fiber composites that worked the worst were those in which the fibers were pulled out while the fibers on the surface were torn. The fiber-reinforced epoxy circumferential composite interface junction in the twisting abaca fiber circumferential composite was found to be more flexible and have a higher glass transition temperature than any of the other composites (6000 MPa). We found that twisting abaca fiber-naval ordnance laboratory and twisting abaca fiber-prepared circumferential composite had the lowest frequency dependence and performance variability. To improve composite properties, both the outside and inside structures of twisting abaca fiber need to be fixed. There is also a rise in fiber-to-resin contact and a rise in fiber surface area. The diameter of the fibers also gets smaller.","PeriodicalId":7372,"journal":{"name":"Advances in Polymer Technology","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2022-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44158535","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Onruthai Srirodpai, J. Wootthikanokkhan, S. Nawalertpanya
Vanadium dioxide (VO2) particles were modified by grafting with poly(styrene sulfonate) (PSS) and poly(3,4-ethylenedioxythiophene) (PEDOT) via surface-initiated atom transfer radical polymerization (SI-ATRP). Critical transition temperature ( T c ) of the modified VO2 ranging between 77 and 79°C was obtained. After mixing with acrylic-based emulsion, dispersion of the VO2 particles in the polymer matrix was significantly improved. The visible light transmittance through the composite films above 75% was maintained if a concentration of the modified VO2 particles loaded into acrylic polymer film was no greater than 1.0 wt%. The NIR transmittance through the acrylic/VO2@PSS : PEDOT also dropped by 9-10%, compared with that of the pure acrylic film (without any particles). Finally, glass substrates coated with the acrylic/VO2@PSS : PEDOT composite films could reduce the temperature inside a model house by 5-6°C, compared with that of the control system (pure acrylic coating film without VO2 particles). Overall, this work demonstrated that it was possible to improve the dispersion of VO2 particles in polymer films without sacrificing its NIR shielding ability by grafting the surface of VO2 particles with PSS : PEDOT chains, while providing the optimum grafting density and particle loading.
{"title":"Synthesis, Characterizations, and Thermochromic Properties of VO2 Particles Grafted with PSS : PEDOT","authors":"Onruthai Srirodpai, J. Wootthikanokkhan, S. Nawalertpanya","doi":"10.1155/2022/1866280","DOIUrl":"https://doi.org/10.1155/2022/1866280","url":null,"abstract":"Vanadium dioxide (VO2) particles were modified by grafting with poly(styrene sulfonate) (PSS) and poly(3,4-ethylenedioxythiophene) (PEDOT) via surface-initiated atom transfer radical polymerization (SI-ATRP). Critical transition temperature (\u0000 \u0000 \u0000 \u0000 T\u0000 \u0000 \u0000 c\u0000 \u0000 \u0000 \u0000 ) of the modified VO2 ranging between 77 and 79°C was obtained. After mixing with acrylic-based emulsion, dispersion of the VO2 particles in the polymer matrix was significantly improved. The visible light transmittance through the composite films above 75% was maintained if a concentration of the modified VO2 particles loaded into acrylic polymer film was no greater than 1.0 wt%. The NIR transmittance through the acrylic/VO2@PSS : PEDOT also dropped by 9-10%, compared with that of the pure acrylic film (without any particles). Finally, glass substrates coated with the acrylic/VO2@PSS : PEDOT composite films could reduce the temperature inside a model house by 5-6°C, compared with that of the control system (pure acrylic coating film without VO2 particles). Overall, this work demonstrated that it was possible to improve the dispersion of VO2 particles in polymer films without sacrificing its NIR shielding ability by grafting the surface of VO2 particles with PSS : PEDOT chains, while providing the optimum grafting density and particle loading.","PeriodicalId":7372,"journal":{"name":"Advances in Polymer Technology","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2022-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42322069","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this study, a series of polyoxymethylene copolymers are synthesized by bulk cationic ring-opening polymerization by 1,3,5-trioxane (TOX) with 1,3-dioxolane (DOX), octamethylcyclotetrasiloxane (D4), and cyclohexane oxide (CHO) as the second monomer using phosphotungstic acid (PTA) as an initiator. The polymer products were characterized by hydrogen nuclear magnetic resonance (1H-NMR), infrared spectroscopy (IR), thermogravimetry (TG), and differential scanning calorimetry (DSC). And the copolymerization energy barrier was calculated at the b3lyp/6-31g(d) calculation level using density functional theory (DFT) to explore the copolymerization ability of the second monomer with 1,3,5-trioxane. The results showed that CHO as the second monomer more easily participated in the copolymerization reaction, and the copolymers showed better thermal stability.
{"title":"Study on Ring-Opening Copolymerization of Trioxymethylene and Second Monomer Initiated by Phosphotungstic Acid","authors":"Yanhong Li, Y. Jin, Hongjuan Li, Xiang Li, Yatao Wang, Ruofan Liu, Yibo Wu","doi":"10.1155/2022/5094734","DOIUrl":"https://doi.org/10.1155/2022/5094734","url":null,"abstract":"In this study, a series of polyoxymethylene copolymers are synthesized by bulk cationic ring-opening polymerization by 1,3,5-trioxane (TOX) with 1,3-dioxolane (DOX), octamethylcyclotetrasiloxane (D4), and cyclohexane oxide (CHO) as the second monomer using phosphotungstic acid (PTA) as an initiator. The polymer products were characterized by hydrogen nuclear magnetic resonance (1H-NMR), infrared spectroscopy (IR), thermogravimetry (TG), and differential scanning calorimetry (DSC). And the copolymerization energy barrier was calculated at the b3lyp/6-31g(d) calculation level using density functional theory (DFT) to explore the copolymerization ability of the second monomer with 1,3,5-trioxane. The results showed that CHO as the second monomer more easily participated in the copolymerization reaction, and the copolymers showed better thermal stability.","PeriodicalId":7372,"journal":{"name":"Advances in Polymer Technology","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2022-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45078346","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Despite carbon nanotubes (CNTs) have garnered tremendous research interests for enhancing the electrical and thermal conductivity of polymers, it is still a considerable challenge to achieve the uniform dispersion of carbon nanotubes in polymer matrix. Herein, inspired by the mussel-inspired chemistry, we adopted the strategy of coating CNTs with polydopamine. And the polysilsesquioxane-modified CNTs (CNTs-PSQ) were obtained based on the click chemistry reaction. The FT-IR, Raman, XRD, and TGA collectively demonstrated the successful modification of PSQ on the surface of CNTs. The incorporation of PSQ could significantly improve the dispersion of CNTs in the silicon rubbers, and a strong interfacial interaction was formed between CNTs-PSQ and silicon rubber matrix, as observed from TEM images of silicon rubber/CNTs-PSQ nanocomposites. Meanwhile, compared with the nanocomposites with neat CNTs, the ones with CNTs-PSQ exhibited simultaneously improved electrical conductivity and insulating performance. This strategy proposed for the preparation of PSQ-modified CNTs provides insights toward highly insulating and thermal conducting polymers.
{"title":"Well-Distributed Polysilsesquioxane-Modified Carbon Nanotubes for Thermal Conductive Insulating Silicone Rubbers","authors":"L. Han, Zhaobo Wang, Jing Hua, Jieting Geng","doi":"10.1155/2022/9115873","DOIUrl":"https://doi.org/10.1155/2022/9115873","url":null,"abstract":"Despite carbon nanotubes (CNTs) have garnered tremendous research interests for enhancing the electrical and thermal conductivity of polymers, it is still a considerable challenge to achieve the uniform dispersion of carbon nanotubes in polymer matrix. Herein, inspired by the mussel-inspired chemistry, we adopted the strategy of coating CNTs with polydopamine. And the polysilsesquioxane-modified CNTs (CNTs-PSQ) were obtained based on the click chemistry reaction. The FT-IR, Raman, XRD, and TGA collectively demonstrated the successful modification of PSQ on the surface of CNTs. The incorporation of PSQ could significantly improve the dispersion of CNTs in the silicon rubbers, and a strong interfacial interaction was formed between CNTs-PSQ and silicon rubber matrix, as observed from TEM images of silicon rubber/CNTs-PSQ nanocomposites. Meanwhile, compared with the nanocomposites with neat CNTs, the ones with CNTs-PSQ exhibited simultaneously improved electrical conductivity and insulating performance. This strategy proposed for the preparation of PSQ-modified CNTs provides insights toward highly insulating and thermal conducting polymers.","PeriodicalId":7372,"journal":{"name":"Advances in Polymer Technology","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2022-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46314576","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：