Superabsorbent polymer (SAP) is a new water-retaining and nutrient-holding material with the potential to improve soil properties and promote crop growth in arid and semiarid areas. This study investigated the effects of multifunctional SAP on the sandy soil properties and maize productivity in Yanghuang irrigated area of Ningxia where residue incorporation was a common agricultural practice, we tested multifunctional SAP at different doses of 0, 30, 60, 90, and 120 kg ha–1 under the residue incorporation to the field. The soil bulk density in the 0–0.40 m layer was significantly lower by 6.2–8.2% under SAP at 60–120 kg ha–1 compared with no SAP, but the total soil porosity was improved significantly by 8.5–11.2%, where the SAP at 90 and 120 kg ha–1 had the greatest effects. The applications of SAP at 60 and 90 kg ha–1 significantly improved soil organic matter, and available P and K contents in the 0–0.40 m soil layer. The soil water storage (0–1.0 m) under SAP at 60–120 kg ha–1 was significantly increased by 17.1–18.7% compared with no SAP throughout the whole maize growing season. The SAP at 60–90 kg ha–1 significantly promoted crop growth and maize yield formation, and increased grain yield, whereas the net income were the highest with applying SAP at 30–60 kg ha–1. In combination with the soil physicochemical property, crop productivity and economic benefit comprehensive analysis of this two-year study, we recommended that the application of multifunctional SAP at 30–60 kg ha–1 under residue incorporation significantly improved the sandy soil properties, as well as increasing maize growth, crop productivity, and obtain the higher net income for farmers in Yanghuang irrigation area of Ningxia, China.
{"title":"Multifunctional Superabsorbent Polymer under Residue Incorporation Increased Maize Productivity through Improving Sandy Soil Properties","authors":"Rong-Ping Li, X. Hou, Pei Li, Xi’na Wang","doi":"10.1155/2022/6554918","DOIUrl":"https://doi.org/10.1155/2022/6554918","url":null,"abstract":"Superabsorbent polymer (SAP) is a new water-retaining and nutrient-holding material with the potential to improve soil properties and promote crop growth in arid and semiarid areas. This study investigated the effects of multifunctional SAP on the sandy soil properties and maize productivity in Yanghuang irrigated area of Ningxia where residue incorporation was a common agricultural practice, we tested multifunctional SAP at different doses of 0, 30, 60, 90, and 120 kg ha–1 under the residue incorporation to the field. The soil bulk density in the 0–0.40 m layer was significantly lower by 6.2–8.2% under SAP at 60–120 kg ha–1 compared with no SAP, but the total soil porosity was improved significantly by 8.5–11.2%, where the SAP at 90 and 120 kg ha–1 had the greatest effects. The applications of SAP at 60 and 90 kg ha–1 significantly improved soil organic matter, and available \u0000 \u0000 P\u0000 \u0000 and \u0000 \u0000 K\u0000 \u0000 contents in the 0–0.40 m soil layer. The soil water storage (0–1.0 m) under SAP at 60–120 kg ha–1 was significantly increased by 17.1–18.7% compared with no SAP throughout the whole maize growing season. The SAP at 60–90 kg ha–1 significantly promoted crop growth and maize yield formation, and increased grain yield, whereas the net income were the highest with applying SAP at 30–60 kg ha–1. In combination with the soil physicochemical property, crop productivity and economic benefit comprehensive analysis of this two-year study, we recommended that the application of multifunctional SAP at 30–60 kg ha–1 under residue incorporation significantly improved the sandy soil properties, as well as increasing maize growth, crop productivity, and obtain the higher net income for farmers in Yanghuang irrigation area of Ningxia, China.","PeriodicalId":7372,"journal":{"name":"Advances in Polymer Technology","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2022-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45180787","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}
A novel type of polyimide foams (PIFs) with chemically inserted flexible aliphatic diamine (1,6-diaminohexane (HMDA)) segments was successfully synthesized and characterized in this research. The aliphatic HMDA segments were randomly incorporated in the long chain aromatic imide bonds. The obtained PIFs containing various HMDA contents (0 to 20 mol%) exhibited different morphologies such as lowered density and larger cell diameter (with higher HMDA content), and open cell ratio was increased as well. HMDA rendered flexibility to the copolymer leading to decreased rigidity. Compared to using 4,4 ′ -oxydianiline (ODA) as the sole diamine source, incorporating low cost of HMDA would increase the PIF’s flexibility and improve its processibility while making the production more cost effective. Within some range of compromised thermal and mechanical properties, this proposed method could be feasible for industrial applications.
{"title":"Novel Synthesis of Polyimide Foams with Aromatic and 1,6-Diaminohexane Imide Bonding","authors":"Dong Chen, Chun-Hua Chen, W. Whang, Chunping Su","doi":"10.1155/2022/3859792","DOIUrl":"https://doi.org/10.1155/2022/3859792","url":null,"abstract":"A novel type of polyimide foams (PIFs) with chemically inserted flexible aliphatic diamine (1,6-diaminohexane (HMDA)) segments was successfully synthesized and characterized in this research. The aliphatic HMDA segments were randomly incorporated in the long chain aromatic imide bonds. The obtained PIFs containing various HMDA contents (0 to 20 mol%) exhibited different morphologies such as lowered density and larger cell diameter (with higher HMDA content), and open cell ratio was increased as well. HMDA rendered flexibility to the copolymer leading to decreased rigidity. Compared to using 4,4\u0000 \u0000 ′\u0000 \u0000 -oxydianiline (ODA) as the sole diamine source, incorporating low cost of HMDA would increase the PIF’s flexibility and improve its processibility while making the production more cost effective. Within some range of compromised thermal and mechanical properties, this proposed method could be feasible for industrial applications.","PeriodicalId":7372,"journal":{"name":"Advances in Polymer Technology","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2022-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42747515","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}
Salt water exposure conditions relevant to carbon-fibre-reinforced polymer (CFRP) prestressed concrete structures in marine environments are investigated. The diffusion into relatively small diameter CFRP tendons can be a lengthy process so the prediction of the long-term moisture uptake using short-term experiments on thin films of epoxy would be advantageous. However, the fibre inclusions within a composite introduce complexities, and factors are typically required for correlation with pure epoxy specimens. Diffusion parameters based on moisture uptake result from CFRP tendons exposed to salt water solution at 20°C and 60°C are compared with those obtained using equivalent thin film specimens. The higher temperature is selected to accelerate the moisture uptake. It is found that the measured ratios of tendon and epoxy diffusivity were temperature dependent, and the combination of the higher temperature and salt solution leads to an increased propensity for moisture uptake in the tendon. Existing analytical models to predict the CFRP tendon diffusivity from that of a thin film of epoxy did not appear to capture the observed trends. However, predictions using a unit cell with a fibre interface zone suggest that this may be due to an increased diffusivity in the interphase region.
{"title":"Solution Uptake in Cylindrical Carbon-Fibre-Reinforced Polymer (CFRP) Tendons","authors":"P. Scott, Eleni Toumpanaki, J. Lees","doi":"10.1155/2022/1981256","DOIUrl":"https://doi.org/10.1155/2022/1981256","url":null,"abstract":"Salt water exposure conditions relevant to carbon-fibre-reinforced polymer (CFRP) prestressed concrete structures in marine environments are investigated. The diffusion into relatively small diameter CFRP tendons can be a lengthy process so the prediction of the long-term moisture uptake using short-term experiments on thin films of epoxy would be advantageous. However, the fibre inclusions within a composite introduce complexities, and factors are typically required for correlation with pure epoxy specimens. Diffusion parameters based on moisture uptake result from CFRP tendons exposed to salt water solution at 20°C and 60°C are compared with those obtained using equivalent thin film specimens. The higher temperature is selected to accelerate the moisture uptake. It is found that the measured ratios of tendon and epoxy diffusivity were temperature dependent, and the combination of the higher temperature and salt solution leads to an increased propensity for moisture uptake in the tendon. Existing analytical models to predict the CFRP tendon diffusivity from that of a thin film of epoxy did not appear to capture the observed trends. However, predictions using a unit cell with a fibre interface zone suggest that this may be due to an increased diffusivity in the interphase region.","PeriodicalId":7372,"journal":{"name":"Advances in Polymer Technology","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2022-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47116268","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}
S. S. Nahar, M. Rahaman, R. Samadder, F. R. Shagor, R. K. Chadni, M. Rahaman, Mubarak A. Khan
To manage the polycotton textile-waste fabric (PCWF), a modified alkaline hydrolysis method is used for decolorization and separation of polyester as terephthalic acid (TPA). The effects of optimum conditions on TPA yield (%) have been determined to be 97.66 ± 1.94 % . Dye degradations and K/S values are measured by UV-visible spectrophotometer. K/S value of PCWF is 37.06 and separated cotton fabric (SCF) is 0.035, respectively. The chemical functionalities and crystallinity of PCWF, SCF, and TPA are determined by using FTIR and XRD. FTIR peak values are 1684 cm-1, 1574 cm-1, 1512 cm-1, 1280 cm-1, and 1425 cm-1 that prove transformation of polyester to TPA. XRD peaks confirm polyester conversion to TPA, and the values are 17.4, 25.13, 28.12, 29.09, and 38.7. TGA, SEM, and EDX data showed the thermal stability, morphology, and elemental composition of TPA.
{"title":"A Modified Hydrolysis Method of Decolorizing Reactive-Dyed Polycotton Waste Fabric and Extraction of Terephthalic Acid: A Perspective to Reduce Textile Solid Waste","authors":"S. S. Nahar, M. Rahaman, R. Samadder, F. R. Shagor, R. K. Chadni, M. Rahaman, Mubarak A. Khan","doi":"10.1155/2022/4325506","DOIUrl":"https://doi.org/10.1155/2022/4325506","url":null,"abstract":"To manage the polycotton textile-waste fabric (PCWF), a modified alkaline hydrolysis method is used for decolorization and separation of polyester as terephthalic acid (TPA). The effects of optimum conditions on TPA yield (%) have been determined to be \u0000 \u0000 97.66\u0000 ±\u0000 1.94\u0000 %\u0000 \u0000 . Dye degradations and K/S values are measured by UV-visible spectrophotometer. K/S value of PCWF is 37.06 and separated cotton fabric (SCF) is 0.035, respectively. The chemical functionalities and crystallinity of PCWF, SCF, and TPA are determined by using FTIR and XRD. FTIR peak values are 1684 cm-1, 1574 cm-1, 1512 cm-1, 1280 cm-1, and 1425 cm-1 that prove transformation of polyester to TPA. XRD peaks confirm polyester conversion to TPA, and the values are 17.4, 25.13, 28.12, 29.09, and 38.7. TGA, SEM, and EDX data showed the thermal stability, morphology, and elemental composition of TPA.","PeriodicalId":7372,"journal":{"name":"Advances in Polymer Technology","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2022-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47507069","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}
Rapid and reliable optimal control of injection molding machines (IMMs) is critical for the effective production of injection-molded goods, especially in the situation of restricted computer resources of embedded equipment in IMMs. In this paper, an optimal tracking injection velocity control problem arising in a typical IMM is studied. An effective hybrid intelligent control approach with less computing resources for real-time implementation based on the deep learning (DL) method to mimic the classical model predictive control rule is developed to deal with the tracking control of the injection speed. The proposed method utilizes the gated recurrent unit neural network to learn and predict the optimal time series control process data produced by the traditional model predictive controller. The benefits of this approach over the conventional optimization method are illustrated through simulation results, which show that the convergent DL-based controller can effectively avoid the complex calculation in the control process of IMMs and meet the requirements of more robustness and resist environmental uncertainty to a certain level and can be potentially implemented in embedded hardware much more efficiently and conveniently with a smaller memory footprint and faster computation time.
{"title":"Deep Learning-Based Predictive Control of Injection Velocity in Injection Molding Machines","authors":"Zhigang Ren, Yao Li, Zongze Wu, Shengli Xie","doi":"10.1155/2022/7662264","DOIUrl":"https://doi.org/10.1155/2022/7662264","url":null,"abstract":"Rapid and reliable optimal control of injection molding machines (IMMs) is critical for the effective production of injection-molded goods, especially in the situation of restricted computer resources of embedded equipment in IMMs. In this paper, an optimal tracking injection velocity control problem arising in a typical IMM is studied. An effective hybrid intelligent control approach with less computing resources for real-time implementation based on the deep learning (DL) method to mimic the classical model predictive control rule is developed to deal with the tracking control of the injection speed. The proposed method utilizes the gated recurrent unit neural network to learn and predict the optimal time series control process data produced by the traditional model predictive controller. The benefits of this approach over the conventional optimization method are illustrated through simulation results, which show that the convergent DL-based controller can effectively avoid the complex calculation in the control process of IMMs and meet the requirements of more robustness and resist environmental uncertainty to a certain level and can be potentially implemented in embedded hardware much more efficiently and conveniently with a smaller memory footprint and faster computation time.","PeriodicalId":7372,"journal":{"name":"Advances in Polymer Technology","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2022-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41819784","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}
Wenzai Shi, Jin Zhao, Xiao-Rui Liu, Yuan Ming, Yong-Miao Shen
Polymer materials are widely used in medical materials, food packaging, coatings, and other fields. However, the surface of the materials is easily contaminated by microorganisms, resulting in serious problems. To solve this issue, a new type of antibacterial polymer fluorescent coating was successfully synthesized by copolymerization of divinylbenzene with 7-methacryloxy-4-methyl coumarin, dodecafluoroheptyl methacrylate, and other monomers. The surface structure and thermal stability of the coating were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, and thermogravimetric analysis. Fluorine was polymerized into the polymer, improving the thermal stability compared to polystyrene and polydivinylbenzene. The bactericidal and antibacterial adhesion properties of the coating materials were studied by a contact germicidal test and antibacterial adhesion test. The polymer had a strong inhibitory effect on Staphylococcus aureus. After immersion in room temperature water, the film maintained its strong inhibitory effect on S. aureus fluorescence intensity and had high fluorescence stability.
{"title":"Synthesis and Characterization of a Coumarin Antimicrobial Polymer Fluorescent Coating","authors":"Wenzai Shi, Jin Zhao, Xiao-Rui Liu, Yuan Ming, Yong-Miao Shen","doi":"10.1155/2022/6213187","DOIUrl":"https://doi.org/10.1155/2022/6213187","url":null,"abstract":"Polymer materials are widely used in medical materials, food packaging, coatings, and other fields. However, the surface of the materials is easily contaminated by microorganisms, resulting in serious problems. To solve this issue, a new type of antibacterial polymer fluorescent coating was successfully synthesized by copolymerization of divinylbenzene with 7-methacryloxy-4-methyl coumarin, dodecafluoroheptyl methacrylate, and other monomers. The surface structure and thermal stability of the coating were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, and thermogravimetric analysis. Fluorine was polymerized into the polymer, improving the thermal stability compared to polystyrene and polydivinylbenzene. The bactericidal and antibacterial adhesion properties of the coating materials were studied by a contact germicidal test and antibacterial adhesion test. The polymer had a strong inhibitory effect on Staphylococcus aureus. After immersion in room temperature water, the film maintained its strong inhibitory effect on S. aureus fluorescence intensity and had high fluorescence stability.","PeriodicalId":7372,"journal":{"name":"Advances in Polymer Technology","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2022-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44349405","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}
This paper focuses on the effect of degree of polymerization (N), density ( σ ), and pattern size ( x ) on the interaction force between a periodically patterned Poly(N-isopropylacrylamide) (PNIPAM) brush and protein. The hydrophobic interaction, the Van der Waals attractive force, and the steric repulsive force were expressed in terms of N , σ , and x . The osmotic constant (k1) and the entropic constant (k2) were determined from the fit of the steric repulsive force to an experimentally obtained force distance curve. The osmotic constant was 0.105, and the entropic constant was 0.255. Using these constants, the steric repulsive force was plotted as a function of the separation distance(s) between the substrate and the protein. The forces were determined at a separation distance equal to 0.3 nm, where L0 is the equilibrium thickness of the PNIPAM brush. At this separation distance, the value of the steric repulsive force was much higher than the value of the sum of the hydrophobic interaction and the Van der Waals attractive force for large degree of polymerization ( N > 100 ) and density ( σ > 0.2 chains/nm2). However, the repulsive force was comparable to the sum of the hydrophobic interaction and the Van der Waals attractive force for a small degree of polymerization ( N < 100 ) and density ( σ = 0.2 ). Furthermore, the steric repulsive force was plotted as a function of pattern size x . The plot indicated that the steric repulsive force becomes nearly zero for all degrees of polymerization and density when the value of the initiator structure size was less than 200 nm. In addition to the steric repulsive force, the lateral extension of the chains in the periodically patterned PNIPAM brush was calculated by scaling low and compared with the experimental data taken from previously published literatures. The polymer brush structure was modelled as if the immediate bare substrate is so wide that even a stretched polymer segment cannot reach to the next polymer brush structure. In such models, the value of the lateral extension was equal to the thickness of the homogenous brush. It was independent of the pattern size. However, when the polymer brush structure was modelled as if there is another polymer brush structure at a distance half of the size of the period, the lateral extension was found to be dependent on the size of the initiator structure size due to chain bridging. This was witnessed by the patterning of polymer brushes using the interferometric patterning of PNIPAM brushes and an atomic force microscopy imaging of the polymer brush structures both in air and in water. The polymer brush structure resolution in water was much lower than the resolution in air, which indicates the lateral extension of the polymer chains in water. For such kind of periodic polymer brush structures, the gap between them was calculated, and it was found dependent on the degree of polymer
{"title":"Investigation of the Effect of Molecular Weight, Density, and Initiator Structure Size on the Repulsive Force between a PNIPAM Polymer Brush and Protein","authors":"G. Tizazu","doi":"10.1155/2022/9741080","DOIUrl":"https://doi.org/10.1155/2022/9741080","url":null,"abstract":"This paper focuses on the effect of degree of polymerization (N), density (\u0000 \u0000 σ\u0000 \u0000 ), and pattern size (\u0000 \u0000 x\u0000 \u0000 ) on the interaction force between a periodically patterned Poly(N-isopropylacrylamide) (PNIPAM) brush and protein. The hydrophobic interaction, the Van der Waals attractive force, and the steric repulsive force were expressed in terms of \u0000 \u0000 N\u0000 \u0000 , \u0000 \u0000 σ\u0000 \u0000 , and \u0000 \u0000 x\u0000 \u0000 . The osmotic constant (k1) and the entropic constant (k2) were determined from the fit of the steric repulsive force to an experimentally obtained force distance curve. The osmotic constant was 0.105, and the entropic constant was 0.255. Using these constants, the steric repulsive force was plotted as a function of the separation distance(s) between the substrate and the protein. The forces were determined at a separation distance equal to 0.3 nm, where L0 is the equilibrium thickness of the PNIPAM brush. At this separation distance, the value of the steric repulsive force was much higher than the value of the sum of the hydrophobic interaction and the Van der Waals attractive force for large degree of polymerization (\u0000 \u0000 N\u0000 >\u0000 100\u0000 \u0000 ) and density (\u0000 \u0000 σ\u0000 >\u0000 0.2\u0000 \u0000 chains/nm2). However, the repulsive force was comparable to the sum of the hydrophobic interaction and the Van der Waals attractive force for a small degree of polymerization (\u0000 \u0000 N\u0000 <\u0000 100\u0000 \u0000 ) and density (\u0000 \u0000 σ\u0000 =\u0000 0.2\u0000 \u0000 ). Furthermore, the steric repulsive force was plotted as a function of pattern size \u0000 \u0000 x\u0000 \u0000 . The plot indicated that the steric repulsive force becomes nearly zero for all degrees of polymerization and density when the value of the initiator structure size was less than 200 nm. In addition to the steric repulsive force, the lateral extension of the chains in the periodically patterned PNIPAM brush was calculated by scaling low and compared with the experimental data taken from previously published literatures. The polymer brush structure was modelled as if the immediate bare substrate is so wide that even a stretched polymer segment cannot reach to the next polymer brush structure. In such models, the value of the lateral extension was equal to the thickness of the homogenous brush. It was independent of the pattern size. However, when the polymer brush structure was modelled as if there is another polymer brush structure at a distance half of the size of the period, the lateral extension was found to be dependent on the size of the initiator structure size due to chain bridging. This was witnessed by the patterning of polymer brushes using the interferometric patterning of PNIPAM brushes and an atomic force microscopy imaging of the polymer brush structures both in air and in water. The polymer brush structure resolution in water was much lower than the resolution in air, which indicates the lateral extension of the polymer chains in water. For such kind of periodic polymer brush structures, the gap between them was calculated, and it was found dependent on the degree of polymer","PeriodicalId":7372,"journal":{"name":"Advances in Polymer Technology","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2022-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41810188","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}
By introducing low-entanglement UHMWPE, the mechanical properties of polyolefins are improved to varying degrees. For polypropylene, the lack of interaction between UHMWPE and polypropylene results in an unsatisfactory reinforcement effect, and the disentangled state makes it easier for the particles to form defects driven by a chain explosion. In contrast, regarding polyethylene and elastomer containing ethylene segments, low-entanglement UHMWPE plays a better role in reinforcement. A series of measurements including scanning electron microscopy (SEM), rheological measurements, differential scanning calorimetry (DSC), and mechanical measurement were used to investigate the mechanisms for the different enhancement effects. It originates from interdiffusion and entanglement forming of polyethylene segments across the interface, endowing the material with different aggregated and defect structures. For instance, EPDM possesses a higher optimal dosage of UHMWPE particles reflected in good interfacial interdiffusion with UHMWPE particles, leading to significant optimized mechanical performance.
{"title":"Metallocene Polyolefins Reinforced by Low-Entanglement UHMWPE through Interfacial Entanglements","authors":"Xinlei Tang, Jinheng Xing, X. Yan, Chunlin Ye, Letian Zhang, Yu Zhang, Baoqiang Shu, Jingshan Mu, Wei Li, Jingdai Wang, Yongrong Yang","doi":"10.1155/2022/9344096","DOIUrl":"https://doi.org/10.1155/2022/9344096","url":null,"abstract":"By introducing low-entanglement UHMWPE, the mechanical properties of polyolefins are improved to varying degrees. For polypropylene, the lack of interaction between UHMWPE and polypropylene results in an unsatisfactory reinforcement effect, and the disentangled state makes it easier for the particles to form defects driven by a chain explosion. In contrast, regarding polyethylene and elastomer containing ethylene segments, low-entanglement UHMWPE plays a better role in reinforcement. A series of measurements including scanning electron microscopy (SEM), rheological measurements, differential scanning calorimetry (DSC), and mechanical measurement were used to investigate the mechanisms for the different enhancement effects. It originates from interdiffusion and entanglement forming of polyethylene segments across the interface, endowing the material with different aggregated and defect structures. For instance, EPDM possesses a higher optimal dosage of UHMWPE particles reflected in good interfacial interdiffusion with UHMWPE particles, leading to significant optimized mechanical performance.","PeriodicalId":7372,"journal":{"name":"Advances in Polymer Technology","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2022-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45672443","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}
Huiyue Liu, Gaiping Du, Yafeng Du, Dezhan Li, Jiangbo Chen
The effects of prepolymerization, temperature, and hydrogen concentration on propylene bulk polymerization with a commercial Ziegler-Natta catalyst were investigated, and the apparent polymerization rate constants were estimated by varying reaction temperatures, hydrogen partial pressures, and polymerization methods. It was shown that prepolymerization has different effects on the polymerization rate and isotacticity of the polymer; without prepolymerization, the polymerization rate and isotacticity reach their maximum at 70°C and 80°C, respectively, whereas the polymerization rate and isotacticity with prepolymerization increase with the polymerization temperature in the range of 50-80°C. Moderate prepolymerization time reduced the fine fraction while increasing polymerization rate and isotacticity. Appropriate prepolymerization technique can increase mass transfer performance and fragmentation, which is a promising way to improve polymerization rate, isotacticity index, and fine fraction. Otherwise, insufficient prepolymerization or excessive prepolymerization causes prepolymer particle fragmentation.
{"title":"Effects of Prepolymerization, Temperature, and Hydrogen Concentration on Kinetics of Propylene Bulk Polymerization Using a Commercial Ziegler-Natta Catalyst","authors":"Huiyue Liu, Gaiping Du, Yafeng Du, Dezhan Li, Jiangbo Chen","doi":"10.1155/2022/9980759","DOIUrl":"https://doi.org/10.1155/2022/9980759","url":null,"abstract":"The effects of prepolymerization, temperature, and hydrogen concentration on propylene bulk polymerization with a commercial Ziegler-Natta catalyst were investigated, and the apparent polymerization rate constants were estimated by varying reaction temperatures, hydrogen partial pressures, and polymerization methods. It was shown that prepolymerization has different effects on the polymerization rate and isotacticity of the polymer; without prepolymerization, the polymerization rate and isotacticity reach their maximum at 70°C and 80°C, respectively, whereas the polymerization rate and isotacticity with prepolymerization increase with the polymerization temperature in the range of 50-80°C. Moderate prepolymerization time reduced the fine fraction while increasing polymerization rate and isotacticity. Appropriate prepolymerization technique can increase mass transfer performance and fragmentation, which is a promising way to improve polymerization rate, isotacticity index, and fine fraction. Otherwise, insufficient prepolymerization or excessive prepolymerization causes prepolymer particle fragmentation.","PeriodicalId":7372,"journal":{"name":"Advances in Polymer Technology","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2022-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44235485","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, graphene oxide (GO) was employed as nanoscale reinforcement for the development of high-performance carbon fiber reinforced plastic (CFRP) composites. Initially, epoxy resin was modified by incorporating GO with different weight proportion from 0.05 to 0.6 wt.%. Then the unidirectional CFRP composites were prepared with the modified epoxy resin by winding and compression molding technique. The optimized GO-CFRP composites with GO content of 0.1 wt.% present tensile strength of 2756 MPa and monofilament interfacial shear strength of 29.06 MPa, respectively, which are 14.4% and 12.5% higher than the corresponding values of the pristine CFRP composites. To intuitively observe the fracture process of the CFRP composites, the digital image correlation system was employed. It is verified that the moderate addition of GO can improve the stress concentration of the CFRP composites during the deformation process. In addition, the reinforcing mechanism is investigated by analyzing the fracture surface of the modified epoxy resin and the CFRP composites. The results indicate that GO can make the cracks deflect or bifurcate along with the epoxy resin which closes to graphene, resulting in synergistically improved mechanical and interfacial properties of the GO-modified CFRP composites.
{"title":"Synergistically Improving Mechanical and Interfacial Properties of Epoxy Resin and CFRP Composites by Introducing Graphene Oxide","authors":"Lijuan Cao, Jieying Zhi, Yu Yang, Liye Yuan, Yingjun Song, Xiaoxuan Lu, Chunxiang Lu","doi":"10.1155/2022/8309259","DOIUrl":"https://doi.org/10.1155/2022/8309259","url":null,"abstract":"In this study, graphene oxide (GO) was employed as nanoscale reinforcement for the development of high-performance carbon fiber reinforced plastic (CFRP) composites. Initially, epoxy resin was modified by incorporating GO with different weight proportion from 0.05 to 0.6 wt.%. Then the unidirectional CFRP composites were prepared with the modified epoxy resin by winding and compression molding technique. The optimized GO-CFRP composites with GO content of 0.1 wt.% present tensile strength of 2756 MPa and monofilament interfacial shear strength of 29.06 MPa, respectively, which are 14.4% and 12.5% higher than the corresponding values of the pristine CFRP composites. To intuitively observe the fracture process of the CFRP composites, the digital image correlation system was employed. It is verified that the moderate addition of GO can improve the stress concentration of the CFRP composites during the deformation process. In addition, the reinforcing mechanism is investigated by analyzing the fracture surface of the modified epoxy resin and the CFRP composites. The results indicate that GO can make the cracks deflect or bifurcate along with the epoxy resin which closes to graphene, resulting in synergistically improved mechanical and interfacial properties of the GO-modified CFRP composites.","PeriodicalId":7372,"journal":{"name":"Advances in Polymer Technology","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2022-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42840865","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}
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