Pub Date : 2023-12-26DOI: 10.1177/0021955x231224765
J. Ruamcharoen, Chor Wayakron Phetphaisit, Purintorn Chanlert, Sameela Cheming, P. Ruamcharoen
Novel fillers from sago starch and esterified sago starch were employed as natural fillers for rigid polyurethane foams (RPUFs). Sago starch was esterified by maleic anhydride, resulting in the presence of ester groups on the starch structure. Filled RPUFs were prepared with 0.5-7.0 wt% of starch fillers in the polyol component. The influence of filler type and content on the cell morphology and properties of the RPUFs was analyzed. The results revealed that the esterified sago starch showed better compatibility with polyurethane matrix than the sago starch, which in turn impacted the cellular morphology and physico-mechanical properties of the resulting RPUFs. The density and compressive strength of the RPUFs filled with esterified sago starch were higher than those filled with unmodified sago starch, while their water absorption, and volume shrinkage were lower. The findings also suggested that the compressive strength and density of filled RPUFs increased with starch filler content up to the optimal point and then decreased. This was due to the impact of filler content on cell size, with smaller cell size at low filler content leading to increased strength and density, whereas larger cell size and more open cells at higher filler content reducing strength and density. The best properties were obtained with 1.0 wt% of unmodified sago starch and 0.5 wt% of esterified sago starch in the polyol component.
{"title":"Sago starch and esterified sago starch as eco-friendly fillers for rigid polyurethane foams","authors":"J. Ruamcharoen, Chor Wayakron Phetphaisit, Purintorn Chanlert, Sameela Cheming, P. Ruamcharoen","doi":"10.1177/0021955x231224765","DOIUrl":"https://doi.org/10.1177/0021955x231224765","url":null,"abstract":"Novel fillers from sago starch and esterified sago starch were employed as natural fillers for rigid polyurethane foams (RPUFs). Sago starch was esterified by maleic anhydride, resulting in the presence of ester groups on the starch structure. Filled RPUFs were prepared with 0.5-7.0 wt% of starch fillers in the polyol component. The influence of filler type and content on the cell morphology and properties of the RPUFs was analyzed. The results revealed that the esterified sago starch showed better compatibility with polyurethane matrix than the sago starch, which in turn impacted the cellular morphology and physico-mechanical properties of the resulting RPUFs. The density and compressive strength of the RPUFs filled with esterified sago starch were higher than those filled with unmodified sago starch, while their water absorption, and volume shrinkage were lower. The findings also suggested that the compressive strength and density of filled RPUFs increased with starch filler content up to the optimal point and then decreased. This was due to the impact of filler content on cell size, with smaller cell size at low filler content leading to increased strength and density, whereas larger cell size and more open cells at higher filler content reducing strength and density. The best properties were obtained with 1.0 wt% of unmodified sago starch and 0.5 wt% of esterified sago starch in the polyol component.","PeriodicalId":15236,"journal":{"name":"Journal of Cellular Plastics","volume":"109 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2023-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139154820","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}
Pub Date : 2023-12-26DOI: 10.1177/0021955x231224775
Özgün Ceren Akbay, B. Özdemir, Erkan Bahçe, E. Emir, Mine Uslu Uysal
In the present paper, the torsion and compression behaviors of lattice structures were studied. The PLA (Polylactic Acid) materials were used in assembly and produced by additive manufacturing method. The structure and lattice behaviors were investigated by Digital Image Correlation (DIC) system during experimental study. Models created using three different unit cell model as Trunch Octa Dense, Trunch Octa Light, Body Diagonals With Nodes and two different, 70 mm and 140 mm, total length size. The influence of the unit cell model, cell size on the strength of the structure were studied by compression and torsion experiments. The maximum compressive stress and maximum torsion were obtained and their deformations were presented. The highest maximum torque was determined in Body Diagonals With Nodes cell model and 140 mm due to the fact that the cell model structure compatible with torsion. The highest compressive stress was determined in Trunch Octa Light cell model and 140 mm cell length.
{"title":"Mechanical characterization of lattice structure produced by additive manufacturing under torsion and compression","authors":"Özgün Ceren Akbay, B. Özdemir, Erkan Bahçe, E. Emir, Mine Uslu Uysal","doi":"10.1177/0021955x231224775","DOIUrl":"https://doi.org/10.1177/0021955x231224775","url":null,"abstract":"In the present paper, the torsion and compression behaviors of lattice structures were studied. The PLA (Polylactic Acid) materials were used in assembly and produced by additive manufacturing method. The structure and lattice behaviors were investigated by Digital Image Correlation (DIC) system during experimental study. Models created using three different unit cell model as Trunch Octa Dense, Trunch Octa Light, Body Diagonals With Nodes and two different, 70 mm and 140 mm, total length size. The influence of the unit cell model, cell size on the strength of the structure were studied by compression and torsion experiments. The maximum compressive stress and maximum torsion were obtained and their deformations were presented. The highest maximum torque was determined in Body Diagonals With Nodes cell model and 140 mm due to the fact that the cell model structure compatible with torsion. The highest compressive stress was determined in Trunch Octa Light cell model and 140 mm cell length.","PeriodicalId":15236,"journal":{"name":"Journal of Cellular Plastics","volume":"2 29","pages":""},"PeriodicalIF":2.5,"publicationDate":"2023-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139156449","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}
Pub Date : 2023-11-01DOI: 10.1177/0021955X231215773
M. Le Saux, Jean-Baptiste Le Bail, Justin Becker, Célia Caër, Pierre Charrier, V. Le Saux, Laurent Maheo, Yann Marco
This paper presents protocols developed to quantitatively characterize the cellular microstructure of microcellular polyurethane foams, from scanning electron microscopy (2D) and X-ray micro-computed tomography (2D and 3D) data. The objectives are to provide, for both techniques: (i) a detailed description of the analysis steps based on open source Python algorithms; (ii) a method for automatic, robust and objective detection of the cells to limit user’s biases; (iii) a statistical description of fraction, size, shape and spatial distribution of cells. The study considers 12 samples with densities ranging from about 400 to 600 kg m−3 and pore sizes from a few micrometers to several hundred micrometers. In addition, the database obtained is used to investigate the reliability of 2D measurements to describe the cellular microstructure statistics.
{"title":"Statistical characterization of microcellular polyurethane foams microstructure based on 2D and 3D image analysis","authors":"M. Le Saux, Jean-Baptiste Le Bail, Justin Becker, Célia Caër, Pierre Charrier, V. Le Saux, Laurent Maheo, Yann Marco","doi":"10.1177/0021955X231215773","DOIUrl":"https://doi.org/10.1177/0021955X231215773","url":null,"abstract":"This paper presents protocols developed to quantitatively characterize the cellular microstructure of microcellular polyurethane foams, from scanning electron microscopy (2D) and X-ray micro-computed tomography (2D and 3D) data. The objectives are to provide, for both techniques: (i) a detailed description of the analysis steps based on open source Python algorithms; (ii) a method for automatic, robust and objective detection of the cells to limit user’s biases; (iii) a statistical description of fraction, size, shape and spatial distribution of cells. The study considers 12 samples with densities ranging from about 400 to 600 kg m−3 and pore sizes from a few micrometers to several hundred micrometers. In addition, the database obtained is used to investigate the reliability of 2D measurements to describe the cellular microstructure statistics.","PeriodicalId":15236,"journal":{"name":"Journal of Cellular Plastics","volume":"4 1","pages":"395 - 417"},"PeriodicalIF":2.5,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139299015","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}
Pub Date : 2023-11-01DOI: 10.1177/0021955X231215753
Apurv Gaidhani, Lauren Tribe, Paul Charpentier
Polystyrene (PS) composite foams are an intriguing class of materials that are well established for thermal insulation in construction and lightweight recyclable components in automotives. Research has shown the remarkable properties of these foams in terms of thermal and sound insulation and fire retardancy that can be enhanced by incorporating carbon fillers such as graphite, graphene, and biochar. Several methods have been examined by researchers to mix carbon with the polystyrene matrix and prepare PS carbon composite foams, which can broadly be categorized into suspension polymerization, solution mixing and melt blending. These methodologies along with foaming techniques for the expansion of PS using various blowing agents are reviewed. We also review the most relevant research studies in the field of PS carbon composite foams for insulation (thermal and sound) and fire retardancy. Due to its high infrared radiation absorption capacity and hetero nucleating action, expandable graphite and graphene can lead to excellent thermal and sound insulation along with fire retardancy in a PS foam, thus resulting in significant energy savings in a building. Biochar, due to its inherent low thermal conductivity and nucleating action, modifies the foam morphology, leading to enhanced heat and sound absorption and thus is a low-cost renewable carbon alternative that promotes the circular economy.
{"title":"Polystyrene carbon composite foam with enhanced insulation and fire retardancy for a sustainable future: Critical review","authors":"Apurv Gaidhani, Lauren Tribe, Paul Charpentier","doi":"10.1177/0021955X231215753","DOIUrl":"https://doi.org/10.1177/0021955X231215753","url":null,"abstract":"Polystyrene (PS) composite foams are an intriguing class of materials that are well established for thermal insulation in construction and lightweight recyclable components in automotives. Research has shown the remarkable properties of these foams in terms of thermal and sound insulation and fire retardancy that can be enhanced by incorporating carbon fillers such as graphite, graphene, and biochar. Several methods have been examined by researchers to mix carbon with the polystyrene matrix and prepare PS carbon composite foams, which can broadly be categorized into suspension polymerization, solution mixing and melt blending. These methodologies along with foaming techniques for the expansion of PS using various blowing agents are reviewed. We also review the most relevant research studies in the field of PS carbon composite foams for insulation (thermal and sound) and fire retardancy. Due to its high infrared radiation absorption capacity and hetero nucleating action, expandable graphite and graphene can lead to excellent thermal and sound insulation along with fire retardancy in a PS foam, thus resulting in significant energy savings in a building. Biochar, due to its inherent low thermal conductivity and nucleating action, modifies the foam morphology, leading to enhanced heat and sound absorption and thus is a low-cost renewable carbon alternative that promotes the circular economy.","PeriodicalId":15236,"journal":{"name":"Journal of Cellular Plastics","volume":"24 1","pages":"419 - 453"},"PeriodicalIF":2.5,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139291199","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}
Pub Date : 2023-11-01DOI: 10.1177/0021955X231215762
Hanyu Zhu, Enrique Velasquez Morquecho, Wei Li
Poly(ether-ether-ketone) (PEEK) is a high strength and high temperature-resistant plastic with good potential for medical use. The addition of hydroxyapatite (HA) can improve the mechanical performance and biocompatibility of PEEK. However, little study has been done on solid-state foaming of PEEK or PEEK-based composites due to the semicrystalline nature and high processing temperature requirement. In this study, the solid-state foaming behavior of PEEK/HA composite is studied using supercritical C O 2 . A quenching process is applied to reduce the crystallinity and improve the gas saturation behavior. The mechanical properties of foamed PEEK/HA composite are characterized. The results show that quenching substantially improved the foamability of PEEK/HA composite. Foamed PEEK/HA regained crystallinity and exhibit a compressive strength comparable to human trabecular bone.
聚醚醚酮（PEEK）是一种高强度、耐高温的塑料，具有良好的医疗用途潜力。添加羟基磷灰石（HA）可以改善 PEEK 的机械性能和生物相容性。然而，由于 PEEK 或基于 PEEK 的复合材料的半结晶性和较高的加工温度要求，有关其固态发泡的研究很少。本研究使用超临界 C O 2 研究了 PEEK/HA 复合材料的固态发泡行为。淬火工艺可降低结晶度并改善气体饱和行为。对发泡 PEEK/HA 复合材料的机械性能进行了表征。结果表明，淬火大大改善了 PEEK/HA 复合材料的发泡性。发泡后的 PEEK/HA 恢复了结晶性，并表现出与人体骨小梁相当的抗压强度。
{"title":"Solid-state foaming of poly(ether-ether-ketone)/hydroxyapatite composites","authors":"Hanyu Zhu, Enrique Velasquez Morquecho, Wei Li","doi":"10.1177/0021955X231215762","DOIUrl":"https://doi.org/10.1177/0021955X231215762","url":null,"abstract":"Poly(ether-ether-ketone) (PEEK) is a high strength and high temperature-resistant plastic with good potential for medical use. The addition of hydroxyapatite (HA) can improve the mechanical performance and biocompatibility of PEEK. However, little study has been done on solid-state foaming of PEEK or PEEK-based composites due to the semicrystalline nature and high processing temperature requirement. In this study, the solid-state foaming behavior of PEEK/HA composite is studied using supercritical C O 2 . A quenching process is applied to reduce the crystallinity and improve the gas saturation behavior. The mechanical properties of foamed PEEK/HA composite are characterized. The results show that quenching substantially improved the foamability of PEEK/HA composite. Foamed PEEK/HA regained crystallinity and exhibit a compressive strength comparable to human trabecular bone.","PeriodicalId":15236,"journal":{"name":"Journal of Cellular Plastics","volume":"253 1","pages":"379 - 393"},"PeriodicalIF":2.5,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139296068","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}
Pub Date : 2023-06-21DOI: 10.1177/0021955x221144705
Muzhen He, Shengfei Hu
The quite narrow PP foaming temperature window is the main challenge for continuous extrusion foaming of polypropylene (PP) using supercritical CO2. In this study, high impact polystyrene (HIPS) is added to PP to widen the polypropylene foaming temperature range by reducing the temperature sensitivity of the melt strength of the blend. The behavior of crystalline, dynamic rheology, and extensional rheological of PP/HIPS blends are analyzed. The results show that the crystallinity and crystallization temperature of PP/HIPS blends decreased significantly, the temperature dependence of the blends’ extensional viscosity and melt strength became weaker, and the activation energy of extensional viscosity and melt strength activation energy decreased, while the elastic modulus and viscosity and the system relaxation time increased. It means that the addition of HIPS reduces the crystallinity of PP, improves the cell morphology and to a certain extent overcomes the problem of a sharp decrease in PP melt strength with increasing temperature. The addition of HIPS extends the foaming temperature range of the PP material from 4 K to a maximum of 12 K. Furthermore, we simply estimated the temperature window for extruded foams using the Arrhenius equation. The estimated values have the same trend as the experimental results and are analyzed.
{"title":"A strategy for extending the processing temperature for polypropylene in foam extrusion and its theoretical validation","authors":"Muzhen He, Shengfei Hu","doi":"10.1177/0021955x221144705","DOIUrl":"https://doi.org/10.1177/0021955x221144705","url":null,"abstract":"The quite narrow PP foaming temperature window is the main challenge for continuous extrusion foaming of polypropylene (PP) using supercritical CO2. In this study, high impact polystyrene (HIPS) is added to PP to widen the polypropylene foaming temperature range by reducing the temperature sensitivity of the melt strength of the blend. The behavior of crystalline, dynamic rheology, and extensional rheological of PP/HIPS blends are analyzed. The results show that the crystallinity and crystallization temperature of PP/HIPS blends decreased significantly, the temperature dependence of the blends’ extensional viscosity and melt strength became weaker, and the activation energy of extensional viscosity and melt strength activation energy decreased, while the elastic modulus and viscosity and the system relaxation time increased. It means that the addition of HIPS reduces the crystallinity of PP, improves the cell morphology and to a certain extent overcomes the problem of a sharp decrease in PP melt strength with increasing temperature. The addition of HIPS extends the foaming temperature range of the PP material from 4 K to a maximum of 12 K. Furthermore, we simply estimated the temperature window for extruded foams using the Arrhenius equation. The estimated values have the same trend as the experimental results and are analyzed.","PeriodicalId":15236,"journal":{"name":"Journal of Cellular Plastics","volume":"47 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2023-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84371317","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 foaming of PP has encountered challenges because of its low melt strength and semi-crystalline characteristics. Introducing long chain branching (LCB) onto the PP backbone and the addition of particles as cell nucleating agent are the commonly used methods to improve the cell structure of PP foams. In this paper, clay-supported sodium benzoate (NaB-OMMT) was prepared from Na-montmorillonite (Na-MMT) via the partial ion exchange reaction with surfactant and subsequent reaction with benzoic acid. The as prepared NaB-OMMTs were then applied to prepare LCBPP/NaB-OMMT nanocomposites and their foams. The dispersion state of clay, crystallization behaviors and rheological properties of the nanocomposites, as well as the cell structure and compression properties of the foams were investigated. The results show that clay layers are mostly exfoliated in the nanocomposites with low NaB-OMMT content, while intercalated layers dominant with the content reaches 2% or higher. The melting temperature of the nanocomposites decreases and the crystallinity increases, while the spherulite size decreases compared to LCBPP. The melt viscosity and elasticity of nanocomposites increase significantly when the content of NaB-OMMT reaches 2% or higher. LCBPP/NaB-OMMT nanocomposites foams exhibit higher cell density, smaller cell size and its standard deviation. Therein, the foam with 1% of NaB-OMMT shows the maximum cell density and the minimum cell size. It is concluded that the cell structure of the foam is highly dependent on the content, dispersion state and structure of the cell nucleating agent. When NaB is supported on well dispersed and exfoliated clay layers, the cell nucleation efficiency is significantly enhanced. The compression properties of the foams depend on their cell structures and exhibit the similar variation trend with the latter with the content of NaB-OMMT increasing.
{"title":"Preparation of clay-supported sodium benzoate and its effect on the rheology, crystallization and foaming of long chain branched polypropylene","authors":"Jing Cao, Jingwen Zou, Siying Zheng, Na Wen, Weijie Xu, Yuying Zheng","doi":"10.1177/0021955x231162187","DOIUrl":"https://doi.org/10.1177/0021955x231162187","url":null,"abstract":"The foaming of PP has encountered challenges because of its low melt strength and semi-crystalline characteristics. Introducing long chain branching (LCB) onto the PP backbone and the addition of particles as cell nucleating agent are the commonly used methods to improve the cell structure of PP foams. In this paper, clay-supported sodium benzoate (NaB-OMMT) was prepared from Na-montmorillonite (Na-MMT) via the partial ion exchange reaction with surfactant and subsequent reaction with benzoic acid. The as prepared NaB-OMMTs were then applied to prepare LCBPP/NaB-OMMT nanocomposites and their foams. The dispersion state of clay, crystallization behaviors and rheological properties of the nanocomposites, as well as the cell structure and compression properties of the foams were investigated. The results show that clay layers are mostly exfoliated in the nanocomposites with low NaB-OMMT content, while intercalated layers dominant with the content reaches 2% or higher. The melting temperature of the nanocomposites decreases and the crystallinity increases, while the spherulite size decreases compared to LCBPP. The melt viscosity and elasticity of nanocomposites increase significantly when the content of NaB-OMMT reaches 2% or higher. LCBPP/NaB-OMMT nanocomposites foams exhibit higher cell density, smaller cell size and its standard deviation. Therein, the foam with 1% of NaB-OMMT shows the maximum cell density and the minimum cell size. It is concluded that the cell structure of the foam is highly dependent on the content, dispersion state and structure of the cell nucleating agent. When NaB is supported on well dispersed and exfoliated clay layers, the cell nucleation efficiency is significantly enhanced. The compression properties of the foams depend on their cell structures and exhibit the similar variation trend with the latter with the content of NaB-OMMT increasing.","PeriodicalId":15236,"journal":{"name":"Journal of Cellular Plastics","volume":"8 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2023-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89147943","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}
Pub Date : 2023-05-24DOI: 10.1177/0021955x231177811
Reza Ghanemi, Seyed Rasoul Mousavi, Sirwan Qewami, Ali Sharifi, As’ad Zandi, Jamshid Mohammadi-Roshandeh, H. Khonakdar, Farkhondeh Hemmati
Semi-conductive foams based on low-density polyethylene/ethylene-vinyl acetate copolymer (LDPE/EVA) blends in the presence of carbon nanotubes (CNTs) were prepared using a twin-screw extrusion process. The effects of CNTs content and localization state in the binary mixture on the physical and structural properties of LDPE/EVA/CNT foams were investigated. The results confirmed that the void fraction, cell density, bubble size and cell size distribution of foams are optimal against CNT loading. The lightest LDPE/EVA/CNT foam was obtained by the CNT localization in the LDPE matrix. This foam containing 2.5 phr of CNT had smaller cells and more uniform cell size comparing to the pure blend foam. The cell density of this foam was 1.598 × 106 cells/cm3, which is much larger than that for the blend foam, 8.64 × 105 cells/cm3. However, the CNT localization state in the dispersed EVA domains resulted in lower void fractions and cell densities comparing with the LDPE/EVA blend foam. The findings clarify the profound impact of the nanofiller localization state on the foam properties of the binary polymeric systems. Light semiconductive LDPE/EVA foams with small cells, uniform cell size and high cell densities were achieved by localizing and dispersing the CNT nanoparticles in the LDPE matrix phase.
{"title":"Extrusion foaming of multiphasic polyethylene/ethylene-vinyl acetate copolymer/carbon nanotube mixtures: Tailoring foam properties by selective localization of nanoparticles","authors":"Reza Ghanemi, Seyed Rasoul Mousavi, Sirwan Qewami, Ali Sharifi, As’ad Zandi, Jamshid Mohammadi-Roshandeh, H. Khonakdar, Farkhondeh Hemmati","doi":"10.1177/0021955x231177811","DOIUrl":"https://doi.org/10.1177/0021955x231177811","url":null,"abstract":"Semi-conductive foams based on low-density polyethylene/ethylene-vinyl acetate copolymer (LDPE/EVA) blends in the presence of carbon nanotubes (CNTs) were prepared using a twin-screw extrusion process. The effects of CNTs content and localization state in the binary mixture on the physical and structural properties of LDPE/EVA/CNT foams were investigated. The results confirmed that the void fraction, cell density, bubble size and cell size distribution of foams are optimal against CNT loading. The lightest LDPE/EVA/CNT foam was obtained by the CNT localization in the LDPE matrix. This foam containing 2.5 phr of CNT had smaller cells and more uniform cell size comparing to the pure blend foam. The cell density of this foam was 1.598 × 106 cells/cm3, which is much larger than that for the blend foam, 8.64 × 105 cells/cm3. However, the CNT localization state in the dispersed EVA domains resulted in lower void fractions and cell densities comparing with the LDPE/EVA blend foam. The findings clarify the profound impact of the nanofiller localization state on the foam properties of the binary polymeric systems. Light semiconductive LDPE/EVA foams with small cells, uniform cell size and high cell densities were achieved by localizing and dispersing the CNT nanoparticles in the LDPE matrix phase.","PeriodicalId":15236,"journal":{"name":"Journal of Cellular Plastics","volume":"107 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2023-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76836690","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}
Pub Date : 2023-05-24DOI: 10.1177/0021955x231177805
Zhaojian Li, Jianqiao Liu, Xingyi Xie
Recently developed CO2 adducts of alkylated polyethylenimines (PEIs) can replace traditional, ozone-depleting, and/or global warming halogen-containing blowing agents of polyurethanes (PUs). Meanwhile, water is the most common chemical blowing agent that is cheap and also environment neutral. Herein, the co-blowing performances of the two types of blowing agents were investigated. For the polyether polyol or castor oil derived polyol foaming systems, which were blended just before foaming, the consequent co-blown foams surprisingly did not possess lower densities than the control foams blown solely by water, showing an antagonistic effect in blowing performance. The relatively large particles (e.g. tens of micrometers) of the hydrophilic PEI-CO2 blowing agents absorbed water from the foaming mixtures, preventing the trapped water from chemically blowing PUs. After the foams were set, the absorbed water gradually diffused out to react with the residual isocyanate groups, which no longer contributed to PU foaming. Differently, after aging the castor oil derived polyol foaming mixtures (without water and isocyanate components that were added before PU foaming), the dispersed PEI-CO2 particles decreased in size down to nanoscale (about 20–180 nm). These nanoparticles were small enough for out-diffusion of the absorbed water, which generated foaming CO2 in time. The densities of the resultant foams could be lowered to the theoretical values. The additive effect with water could enhance the application freedom of the climate-friendly alkylated PEI-CO2 blowing agents.
{"title":"Polyurethane foams co-blown by water and alkylated polyethylenimine-CO2 adducts: An additive or antagonistic effect?","authors":"Zhaojian Li, Jianqiao Liu, Xingyi Xie","doi":"10.1177/0021955x231177805","DOIUrl":"https://doi.org/10.1177/0021955x231177805","url":null,"abstract":"Recently developed CO2 adducts of alkylated polyethylenimines (PEIs) can replace traditional, ozone-depleting, and/or global warming halogen-containing blowing agents of polyurethanes (PUs). Meanwhile, water is the most common chemical blowing agent that is cheap and also environment neutral. Herein, the co-blowing performances of the two types of blowing agents were investigated. For the polyether polyol or castor oil derived polyol foaming systems, which were blended just before foaming, the consequent co-blown foams surprisingly did not possess lower densities than the control foams blown solely by water, showing an antagonistic effect in blowing performance. The relatively large particles (e.g. tens of micrometers) of the hydrophilic PEI-CO2 blowing agents absorbed water from the foaming mixtures, preventing the trapped water from chemically blowing PUs. After the foams were set, the absorbed water gradually diffused out to react with the residual isocyanate groups, which no longer contributed to PU foaming. Differently, after aging the castor oil derived polyol foaming mixtures (without water and isocyanate components that were added before PU foaming), the dispersed PEI-CO2 particles decreased in size down to nanoscale (about 20–180 nm). These nanoparticles were small enough for out-diffusion of the absorbed water, which generated foaming CO2 in time. The densities of the resultant foams could be lowered to the theoretical values. The additive effect with water could enhance the application freedom of the climate-friendly alkylated PEI-CO2 blowing agents.","PeriodicalId":15236,"journal":{"name":"Journal of Cellular Plastics","volume":"54 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2023-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76662721","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}
Pub Date : 2023-05-16DOI: 10.1177/0021955x231174362
Alejandro E. Rodríguez-Sánchez, H. Plascencia-Mora
Expanded polystyrene foams are widely used materials for various applications in engineering, including their use for protective designs. For this type of application, in engineering analysis and design, it is required to know the mechanical response to compression of this type of material, since energy parameters that support the analysis of the effectiveness of a design are derived from it. One of these parameters is strain hysteresis, through which it is possible to know how capable a material is of absorbing energy. The modeling and prediction of this parameter is a challenge from the analysis point of view. This contribution presents a method based on feed-forward artificial neural network models that address a modeling approach to derive this parameter from the mechanical response of expanded polystyrene foam. From this, models are constructed that can predict the response of such material to various density and loading rate conditions. The best of a total of 30 neural network models, which are capable of deriving energy parameters such as hysteresis, is chosen. The results show that this approach is valid for the deformation energy analysis of expanded polystyrene foams since results consistent with the material phenomenology and errors of less than 3% with respect to experimental data are obtained.
{"title":"Modeling hysteresis in expanded polystyrene foams under compressive loads using feed-forward neural networks","authors":"Alejandro E. Rodríguez-Sánchez, H. Plascencia-Mora","doi":"10.1177/0021955x231174362","DOIUrl":"https://doi.org/10.1177/0021955x231174362","url":null,"abstract":"Expanded polystyrene foams are widely used materials for various applications in engineering, including their use for protective designs. For this type of application, in engineering analysis and design, it is required to know the mechanical response to compression of this type of material, since energy parameters that support the analysis of the effectiveness of a design are derived from it. One of these parameters is strain hysteresis, through which it is possible to know how capable a material is of absorbing energy. The modeling and prediction of this parameter is a challenge from the analysis point of view. This contribution presents a method based on feed-forward artificial neural network models that address a modeling approach to derive this parameter from the mechanical response of expanded polystyrene foam. From this, models are constructed that can predict the response of such material to various density and loading rate conditions. The best of a total of 30 neural network models, which are capable of deriving energy parameters such as hysteresis, is chosen. The results show that this approach is valid for the deformation energy analysis of expanded polystyrene foams since results consistent with the material phenomenology and errors of less than 3% with respect to experimental data are obtained.","PeriodicalId":15236,"journal":{"name":"Journal of Cellular Plastics","volume":"7 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2023-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78467214","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：