Macromolecular Reaction Engineering最新文献_第9页

New Insights on the Kinetics of Persulfate-Initiated Itaconic Acid Free-Radical Polymerization 过硫酸盐引发衣康酸自由基聚合动力学的新认识

IF 1.5 4区工程技术

Macromolecular Reaction Engineering Pub Date : 2023-04-24 DOI: 10.1002/mren.202300022

Jorge Herrera-Ordonez

{"title":"New Insights on the Kinetics of Persulfate-Initiated Itaconic Acid Free-Radical Polymerization","authors":"Jorge Herrera-Ordonez","doi":"10.1002/mren.202300022","DOIUrl":"10.1002/mren.202300022","url":null,"abstract":"A mathematical model is proposed that couples the decomposition kinetics of persulfate (S2O82−) and the free radical polymerization kinetics of itaconic acid (IA); the results are compared with experimental data reported in the literature. It is found that the former is highly affected by the acidification of the aqueous medium which is caused by the equilibrium dissociation of IA but mainly by HSO4− produced by side reactions of the S2O82− decomposition. This qualitatively explains the dependence of d[S2O82−]/dt with [IA] and the initial concentration of persulfate ([S2O82−]0), reported in the literature. According to the model results, temperature overshoots are very likely to occur in the experiments so there is doubt whether the reaction order >1 with respect to [IA] that is sometimes reported in the literature for the rate of polymerization (Rp) is an artifact related to an imprecise temperature (T) control or is due to a more complex mechanism. Due to the higher activation energy of the persulfate decomposition compared to the propagation reaction, small variations of T can lead to significant variations of d[S2O82−]/dt but to an almost imperceptible effect on Rp. Recommendations for future experimental work and refinement of the kinetic model are provided.","PeriodicalId":18052,"journal":{"name":"Macromolecular Reaction Engineering","volume":"17 5","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mren.202300022","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45192327","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Macromol. React. Eng. 2/2023 Macromol。反应工程师2/2023

IF 1.5 4区工程技术

Macromolecular Reaction Engineering Pub Date : 2023-04-17 DOI: 10.1002/mren.202370003

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Masthead: Macromol. React. Eng. 2/2023 刊头：Macromol。反应工程师2/2023

IF 1.5 4区工程技术

Macromolecular Reaction Engineering Pub Date : 2023-04-17 DOI: 10.1002/mren.202370004

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Mechanical Properties and Blocking Resistance of Films Cast from Core–Shell Latex Particles 核壳乳胶颗粒铸造薄膜的机械性能和抗堵塞性能

IF 1.5 4区工程技术

Macromolecular Reaction Engineering Pub Date : 2023-04-15 DOI: 10.1002/mren.202300021

Adrián Perez, Emily Kynaston, Christopher Lindsay, Nicholas Ballard

{"title":"Mechanical Properties and Blocking Resistance of Films Cast from Core–Shell Latex Particles","authors":"Adrián Perez, Emily Kynaston, Christopher Lindsay, Nicholas Ballard","doi":"10.1002/mren.202300021","DOIUrl":"10.1002/mren.202300021","url":null,"abstract":"The mechanical properties and blocking resistance of films cast from latex particles can be improved by addition of a reinforcing polymer of high modulus that acts as a “hard” phase. This work demonstrates that blocking resistance, a key performance parameter for use in coatings, of such films can be understood in terms of the relative contribution of the “hard” and “soft” components to the rheological properties of the material. In order to do so, representative latexes that contain a semicrystalline core of poly(stearyl acrylate) as a reinforcing phase and a shell of amorphous poly(styrene-co-butyl acrylate) are synthesized. By varying the composition of the amorphous phase (glass transition temperature, molar mass) and the relative amorphous/semicrystalline fraction, it is demonstrated that the improvement in blocking resistance is strongly correlated with the increase in the modulus of the material but is also affected by the dynamics of polymer diffusion of chains in the soft phase. This work allows to establish design rules for polymer and colloidal structures that can be targeted to maximize blocking resistance.","PeriodicalId":18052,"journal":{"name":"Macromolecular Reaction Engineering","volume":"17 5","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47403818","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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Use of Chicken Litter for In Situ Polymerization of Poly(Butylene Succinate) (PBS) Based Polymer Composites 用鸡粪原位聚合聚丁二酸丁二烯(PBS)基聚合物复合材料

IF 1.5 4区工程技术

Macromolecular Reaction Engineering Pub Date : 2023-04-15 DOI: 10.1002/mren.202200069

Carla Oliveira Nascimento, Vinícius De Melo Benites, Elaine Christine de Magalhães Cabral-Albuquerque, José Carlos Pinto, Rosana Lopes Fialho

{"title":"Use of Chicken Litter for In Situ Polymerization of Poly(Butylene Succinate) (PBS) Based Polymer Composites","authors":"Carla Oliveira Nascimento, Vinícius De Melo Benites, Elaine Christine de Magalhães Cabral-Albuquerque, José Carlos Pinto, Rosana Lopes Fialho","doi":"10.1002/mren.202200069","DOIUrl":"10.1002/mren.202200069","url":null,"abstract":"In the recent years, the growing amounts and incorrect disposal of solid wastes have created serious negative environmental impacts, including land and water pollution. Chicken litter (CL) is a type of solid waste which is generated during chicken production, the appropriate final destination of which is still subject to technical discussion. Because CL is composed mostly of fibers, proteins, carbohydrates, and different minerals, the use of this material as a filler for the manufacture of polymer materials has been suggested. The main objective of the present work is the manufacture of polymer composites in situ polymerization using CL as a filler and succinic acid and 1,4-butanediol as monomers, considering that the fiber content in CL is ≈20 wt%. The obtained poly(butylene succinate) (PBS) composites are characterized by Fourier transformed infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), gel permeation chromatography (GPC), nuclear magnetic resonance (NMR), scanning electron microscopy (SEM), degradability in distilled water, and compression analyses. The results show that the addition of CL to the mixture do not affect the course of the polycondensation reaction significantly. Furthermore, compression tests show that the compressive strength of test pieces increases with the CL content.","PeriodicalId":18052,"journal":{"name":"Macromolecular Reaction Engineering","volume":"17 4","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46716533","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}

引用次数: 0

Polyethylene Slurries: Swelling and Solubility 聚乙烯浆料:溶胀和溶解度

IF 1.5 4区工程技术

Macromolecular Reaction Engineering Pub Date : 2023-04-05 DOI: 10.1002/mren.202300020

Amel Ben Mrad, Nida Sheibat-Othman, Ana Paula Alves Amorim, Roberta Lopes do Rosario, Timothy F. L. McKenna

{"title":"Polyethylene Slurries: Swelling and Solubility","authors":"Amel Ben Mrad, Nida Sheibat-Othman, Ana Paula Alves Amorim, Roberta Lopes do Rosario, Timothy F. L. McKenna","doi":"10.1002/mren.202300020","DOIUrl":"10.1002/mren.202300020","url":null,"abstract":"The solubility of different alkanes in polyethylene (PE) of different densities, as well as the solubility of the polymers in the alkanes, and the degree of swelling of the powders are studied as a function of temperature. It is found that the solubility of linear low-density polyethylene (LLDPE) is as much as 6 times greater than that of high-density polyethylene (HDPE) at the same temperature, and that LLDPE swells at least 50% more than HDPE the same diluent at the same temperature. The breakthrough curves also show that lighter alkanes swell the PE more at a given temperature than heavier ones. Also, the breakthrough points (the temperature at which the swelling versus temperature curves change slope) occur at lower temperatures for PE of lower density. Gel formation is observed for medium and low density polyethylenes in pentane and hexane. This quantitative information will be useful in developing process models for different industrial polymerization processes, as particle swelling can have a significant impact on slurry viscosity and the flow stability and solids loading of commercial reactors.","PeriodicalId":18052,"journal":{"name":"Macromolecular Reaction Engineering","volume":"17 3","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44694171","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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Modeling the Formation of Rigid Polyurethane Foams Using Hydrofluorolefin as Expanding Agent 以氢氟烯烃为膨胀剂的硬质聚氨酯泡沫形成模型

IF 1.5 4区工程技术

Macromolecular Reaction Engineering Pub Date : 2023-04-04 DOI: 10.1002/mren.202300010

Beatriz N. Cassens, Reinaldo Giudici

{"title":"Modeling the Formation of Rigid Polyurethane Foams Using Hydrofluorolefin as Expanding Agent","authors":"Beatriz N. Cassens, Reinaldo Giudici","doi":"10.1002/mren.202300010","DOIUrl":"10.1002/mren.202300010","url":null,"abstract":"Polyurethanes are probably the most versatile among polymers of greater industrial use due to the possibility of being produced in a wide range of density, hardness, and mechanical properties and through different conversion processes. Its synthesis involves a great variety of raw materials and proportions between them. A mathematical model that describes the polyurethane foam formation can be very useful for the development of formulations and in the definition of the processing conditions, avoiding great consumption of time and errors in the development and experiments. The present work studies this process using industrial formulation. The kinetic parameters of the reaction between polyol with isocyanate are determined calorimetrically using the adiabatic temperature rise method, obtaining the values of activation energy 22.2 kJ mol−1 and heat of reaction 91.8 kJ mol−1. Data liquid–vapor equilibrium of the hydrofluorolefin blowing agent in a polyol mixture are obtained and treated with Flory–Huggins model with good agreement with experimental data (deviation of 1.6%). The mathematical model is satisfactory to describe the expanding process in a pilot scale, under different conditions.","PeriodicalId":18052,"journal":{"name":"Macromolecular Reaction Engineering","volume":"17 4","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49246679","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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Alkylaluminum/Urea Hybrid Cocatalysts and Their Use in Iron-Catalyzed Oligomerization of Ethylene 烷基铝/尿素杂化助催化剂及其在铁催化乙烯齐聚中的应用

IF 1.5 4区工程技术

Macromolecular Reaction Engineering Pub Date : 2023-03-28 DOI: 10.1002/mren.202300013

Ying Zhang, Jian Ye, Yinzhi Jiang, Shuqin Jiang, Wei Xiao, Dongchu Wei

{"title":"Alkylaluminum/Urea Hybrid Cocatalysts and Their Use in Iron-Catalyzed Oligomerization of Ethylene","authors":"Ying Zhang, Jian Ye, Yinzhi Jiang, Shuqin Jiang, Wei Xiao, Dongchu Wei","doi":"10.1002/mren.202300013","DOIUrl":"10.1002/mren.202300013","url":null,"abstract":"The bis(imino)pyridyl iron-based ethylene oligomerization catalysts have the advantages of mild reaction conditions, high activity and high selectivity to linear α-olefins. However, barriers, such as high polymer content in the product mixture and large methylaluminoxane (MAO) dosage, are still limitations for the development of these systems at the industrial scale. In this study, new cocatalysts are prepared by the reaction of alkylaluminums with urea and its derivatives, and successfully used to activate iron-based catalysts. It is found that the type and molar ratio of alkylaluminum and urea have significant influence on the performance of the cocatalysts. The activity of the preferred triisobutylaluminum/urea activated systems reaches more than 3.0 × 108 g (mol-Fe)−1 h−1, and the polymer content can be controlled to be less than 2 wt.%. Notably, the catalytic system exhibits good high temperature stability, the activity can still reach 1.0 × 108 g (mol-Fe)−1 h−1 even at 120 °C. Further 1H NMR studies show that alkylaluminum can react with the NH moieties of urea, forming complex alkylaluminum clusters, even aluminoxane-like structures. This study offers a promising family of cocatalysts, making it possible to simultaneously improve their performance and reduce their cost.","PeriodicalId":18052,"journal":{"name":"Macromolecular Reaction Engineering","volume":"17 3","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46844419","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}

引用次数: 0

Temperature-Optimized Synthesis of SiO2-Reinforced N-(Alkyl)Acrylamide-Based Semi-IPN Hybrid Gels Functionalized with Methacrylic Acid Units 甲基丙烯酸单元功能化SiO2增强N（烷基）丙烯酰胺基半互穿网络杂化凝胶的温度优化合成

IF 1.5 4区工程技术

Macromolecular Reaction Engineering Pub Date : 2023-03-23 DOI: 10.1002/mren.202300006

Birgül Kalkan, Merve Mocan, Nermin Orakdogen

{"title":"Temperature-Optimized Synthesis of SiO2-Reinforced N-(Alkyl)Acrylamide-Based Semi-IPN Hybrid Gels Functionalized with Methacrylic Acid Units","authors":"Birgül Kalkan, Merve Mocan, Nermin Orakdogen","doi":"10.1002/mren.202300006","DOIUrl":"10.1002/mren.202300006","url":null,"abstract":"In order to obtain a pH and temperature sensitive hybrids with a controlled structure, synthesis of N-(alkyl)acrylamide-based semi-interpenetrating polymer network (semi-IPN) reinforced with silica (SiO2) nanoparticles and functionalized with methacrylic acid units is carried out by optimizing the polymerization temperature. The study aims to understand the effect of polymerization temperature on the physical properties of semi-IPN hybrids. Changing preparation temperature between −30 and 23 °C leads to significant differences in physico-mechanical results, swelling tendency and adsorption ability, while silica nanoparticles strengthen hybrid walls, preventing their collapse during deswelling and providing rapid response. The hybrids prepared at higher temperatures are found to swell more and faster in water, while the lowest swelling is observed those prepared at 5 °C. The incorporation of SiO2 particles into copolymer structure via physical crosslinking with network chains enhances the elasticity. The effect of polymerization temperature on adsorption is investigated using methylene blue as a model dye. Increasing polymerization temperature increases the adsorption rate and shortens time to reach the equilibrium point, and adsorption efficiency increases when polymerization temperature is lowered. The results show that semi-IPN hybrids loaded with silica nanoparticles can be used as alternative and potential adsorbents in the treatment of industrial wastes.","PeriodicalId":18052,"journal":{"name":"Macromolecular Reaction Engineering","volume":"17 3","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49450263","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}

引用次数: 0

Encapsulated Colorimetric Indicators used as Additives During the Polymerization of Smart Polyethylene 智能聚乙烯聚合过程中用作添加剂的包封比色指示剂

IF 1.5 4区工程技术

Macromolecular Reaction Engineering Pub Date : 2023-03-22 DOI: 10.1002/mren.202200077

Cesar A. Heck, João Henrique Z. dos Santos

{"title":"Encapsulated Colorimetric Indicators used as Additives During the Polymerization of Smart Polyethylene","authors":"Cesar A. Heck, João Henrique Z. dos Santos","doi":"10.1002/mren.202200077","DOIUrl":"10.1002/mren.202200077","url":null,"abstract":"A number of colorimetric pH indicators (phenolphthalein, bromocresol green, 4-nitrophenol, phenol red, and bromothymol blue) are encapsulated within silica particles via an acid-catalyzed sol–gel process. The fabricated indicator is added during ethylene polymerization with a metallocene (Cp2ZrCl2) catalyst. Introduction of the indicator into the silica matrix affects the surface area, probably by partially blocking some of the pores. The encapsulated pH indicator reduces the catalytic activity by up to 17%, whereas adding a solution of the indicator reduced the catalytic activity by up to 34%. The crystallinities of the samples containing the silica-encapsulated pH indicators are lower than those of the samples to which the pH indicator is added in solution form. The prepared encapsulated colorimetric pH indicators are analyzed by diffuse reflectance UV-vis spectroscopy. The measured color values are distributed according to the CIE Lab lightness psychometric color space. Addition of the indicator in solution form (free) to the ethylene polymerization reaction does not result in indicator activity in acidic or alkaline media. The pH indicators incorporated into the polyethylene show color changes when exposed to acidic and alkaline media. Samples to which the unencapsulated pH indicators (free) are added exhibit lower catalytic activities and higher crystallinities than the samples containing the encapsulated pH.","PeriodicalId":18052,"journal":{"name":"Macromolecular Reaction Engineering","volume":"17 3","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47277490","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}

引用次数: 0