Pub Date : 2021-09-01DOI: 10.1177/02624893211043324
N. B. Ali, M. Khlif, D. Hammami, C. Bradai
There is a growing need for 3D printing of polymer structures in a cost-effective way and green. This study presents an experimental approach to investigate structural parameters effects on mechanical properties of polylactic acid (PLA) hollow-sphere structures manufactured with fused deposition modeling (FDM). The mechanical behavior characteristics of square_hexagonal stacking, closed_open porosity and parallel_perpendicular compression direction compared to the direction of manufacture under quasi-static uniaxial compression are examined using Taguchi method. The S/N ratio analysis and the Analysis of Variance (ANOVA) were used to find the optimal parameters that improve the mechanical properties (Young modulus, yield strength) and to provide a significant ranking of the different parameters analyzed in this paper. It was found that the optimum level and significance of each process parameter vary for “hexagonal cells,” “open porosity” and “parallel direction.” The optimal values of the results give a Young modulus E of 90.12 MPa and a yield strength σ y of 3 MPa. Furthermore, the experimental results further reveal that the porous structure with the loading direction that is parallel to the direction of manufacture, has a higher strength and a progressive collapse of the cells to those with a perpendicular direction.
{"title":"Optimization of structural parameters on hollow spherical cells manufactured by Fused Deposition Modeling (FDM) using Taguchi method","authors":"N. B. Ali, M. Khlif, D. Hammami, C. Bradai","doi":"10.1177/02624893211043324","DOIUrl":"https://doi.org/10.1177/02624893211043324","url":null,"abstract":"There is a growing need for 3D printing of polymer structures in a cost-effective way and green. This study presents an experimental approach to investigate structural parameters effects on mechanical properties of polylactic acid (PLA) hollow-sphere structures manufactured with fused deposition modeling (FDM). The mechanical behavior characteristics of square_hexagonal stacking, closed_open porosity and parallel_perpendicular compression direction compared to the direction of manufacture under quasi-static uniaxial compression are examined using Taguchi method. The S/N ratio analysis and the Analysis of Variance (ANOVA) were used to find the optimal parameters that improve the mechanical properties (Young modulus, yield strength) and to provide a significant ranking of the different parameters analyzed in this paper. It was found that the optimum level and significance of each process parameter vary for “hexagonal cells,” “open porosity” and “parallel direction.” The optimal values of the results give a Young modulus E of 90.12 MPa and a yield strength σ y of 3 MPa. Furthermore, the experimental results further reveal that the porous structure with the loading direction that is parallel to the direction of manufacture, has a higher strength and a progressive collapse of the cells to those with a perpendicular direction.","PeriodicalId":9816,"journal":{"name":"Cellular Polymers","volume":"41 1","pages":"3 - 20"},"PeriodicalIF":1.6,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44865241","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-08-24DOI: 10.1177/02624893211040938
G. Radhakrishna, Rupesh Dugad, A. Gandhi
In this article, the development of microcellular structure foams has developed by integrating the two successful and existing technologies, namely CO2 gas batch foaming and Fused Deposition Modeling (FDM) 3D printing technique. It is a novel approach to manufacture complex design porous products for customized applications. The eventual cell morphologies of the extruded 3D printing filament depends on the process parameters pertaining to both microcellular foaming and 3D printing processes. Further, morphological study has been conducted to evaluate the cell morphologies of the 3D printing filament developed through customized FDM setup. During this process, the significance of various process parameters including saturation pressure, saturation time, desorption time, feed rate and extrusion temperature were thoroughly studied. To pursue this study base material used was acrylonitrile butadiene styrene (ABS). The 3D printed filaments consisted of cells with an average cell size in the range of 2.3–276 µm and the average cell density in the range of 4.7 × 104 to 4.3 × 109 cells/cm3. Finally, it has found that by controlling the process parameters different cell morphologies can be developed as per the end application.
{"title":"Morphological evaluation of microcellular foamed composites developed through gas batch foaming integrating Fused Deposition Modeling (FDM) 3D printing technique","authors":"G. Radhakrishna, Rupesh Dugad, A. Gandhi","doi":"10.1177/02624893211040938","DOIUrl":"https://doi.org/10.1177/02624893211040938","url":null,"abstract":"In this article, the development of microcellular structure foams has developed by integrating the two successful and existing technologies, namely CO2 gas batch foaming and Fused Deposition Modeling (FDM) 3D printing technique. It is a novel approach to manufacture complex design porous products for customized applications. The eventual cell morphologies of the extruded 3D printing filament depends on the process parameters pertaining to both microcellular foaming and 3D printing processes. Further, morphological study has been conducted to evaluate the cell morphologies of the 3D printing filament developed through customized FDM setup. During this process, the significance of various process parameters including saturation pressure, saturation time, desorption time, feed rate and extrusion temperature were thoroughly studied. To pursue this study base material used was acrylonitrile butadiene styrene (ABS). The 3D printed filaments consisted of cells with an average cell size in the range of 2.3–276 µm and the average cell density in the range of 4.7 × 104 to 4.3 × 109 cells/cm3. Finally, it has found that by controlling the process parameters different cell morphologies can be developed as per the end application.","PeriodicalId":9816,"journal":{"name":"Cellular Polymers","volume":"40 1","pages":"244 - 266"},"PeriodicalIF":1.6,"publicationDate":"2021-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47959853","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-08-24DOI: 10.1177/02624893211041674
Anna Hössinger-Kalteis, J. Maurer, M. Reiter, M. Jerabek, Z. Major
Nowadays, there are several methods to obtain simulation models for foams which consider important microstructural features. This research study presents a method to obtain low density foam models directly from computed tomography (CT) data. Finite element meshes are created from CT measurement results of a polypropylene extrusion foam with two different densities. Sensitivity studies with regard to the tension behaviour are performed with the microstructural models. The study shows that the tension behaviour highly depends on the examined area of the foam because the microstructure and density vary through the foam. Furthermore, the simulation results are validated with experimental results. The validation shows that the tension behaviour of the investigated foams characterised by the simulation approach is in good agreement with the experimentally observed behaviour and that specific microstructural characteristics (e.g. anisotropic cell shapes) are captured in the model.
{"title":"Development and investigation of the applicability of microstructural models for polymeric low density foams directly obtained from computed tomography data","authors":"Anna Hössinger-Kalteis, J. Maurer, M. Reiter, M. Jerabek, Z. Major","doi":"10.1177/02624893211041674","DOIUrl":"https://doi.org/10.1177/02624893211041674","url":null,"abstract":"Nowadays, there are several methods to obtain simulation models for foams which consider important microstructural features. This research study presents a method to obtain low density foam models directly from computed tomography (CT) data. Finite element meshes are created from CT measurement results of a polypropylene extrusion foam with two different densities. Sensitivity studies with regard to the tension behaviour are performed with the microstructural models. The study shows that the tension behaviour highly depends on the examined area of the foam because the microstructure and density vary through the foam. Furthermore, the simulation results are validated with experimental results. The validation shows that the tension behaviour of the investigated foams characterised by the simulation approach is in good agreement with the experimentally observed behaviour and that specific microstructural characteristics (e.g. anisotropic cell shapes) are captured in the model.","PeriodicalId":9816,"journal":{"name":"Cellular Polymers","volume":"40 1","pages":"267 - 280"},"PeriodicalIF":1.6,"publicationDate":"2021-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48644477","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-08-20DOI: 10.1177/02624893211040949
M. Rostami, T. Azdast, R. Hasanzadeh, M. Moradian
Foaming a polymer not only turns it into a lightweight material but also gives some special properties to it. However, the most important issue is controlling the foaming process to achieve a desirable structure with high cell density and low relative density. In the present study, the extrusion foaming process of polyethylene was studied through stepwise amendments. An innovative extrusion system was designed and implemented to produce extrusion foams under different material and process conditions using N2 as blowing agent. In the first step, the final cooling condition was investigated. The air-cooling condition led to a higher cell density/lower cell size compared to the water-cooling condition although a higher relative density was obtained. In the second step, the effects of the addition of talc and the synergetic effect of talc/nanoclay at different contents were investigated in detail. The hybrid of talc/nanoclay had a noticeably improving effect on the cellular structure. In the third step, the effects of processing parameters including the die temperature and screw speed were studied on the foam properties. Finally, up to 49.4% decrease in the relative density of samples was observed, also cell densities up to 2.5 × 104 cell/cm3 and cell sizes as small as 280 µm were achieved.
{"title":"A study on fabrication of nanocomposite polyethylene foam through extrusion foaming procedure","authors":"M. Rostami, T. Azdast, R. Hasanzadeh, M. Moradian","doi":"10.1177/02624893211040949","DOIUrl":"https://doi.org/10.1177/02624893211040949","url":null,"abstract":"Foaming a polymer not only turns it into a lightweight material but also gives some special properties to it. However, the most important issue is controlling the foaming process to achieve a desirable structure with high cell density and low relative density. In the present study, the extrusion foaming process of polyethylene was studied through stepwise amendments. An innovative extrusion system was designed and implemented to produce extrusion foams under different material and process conditions using N2 as blowing agent. In the first step, the final cooling condition was investigated. The air-cooling condition led to a higher cell density/lower cell size compared to the water-cooling condition although a higher relative density was obtained. In the second step, the effects of the addition of talc and the synergetic effect of talc/nanoclay at different contents were investigated in detail. The hybrid of talc/nanoclay had a noticeably improving effect on the cellular structure. In the third step, the effects of processing parameters including the die temperature and screw speed were studied on the foam properties. Finally, up to 49.4% decrease in the relative density of samples was observed, also cell densities up to 2.5 × 104 cell/cm3 and cell sizes as small as 280 µm were achieved.","PeriodicalId":9816,"journal":{"name":"Cellular Polymers","volume":"40 1","pages":"231 - 243"},"PeriodicalIF":1.6,"publicationDate":"2021-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47333762","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-05-28DOI: 10.1177/02624893211017271
C. Patel, Nikhil R Dhore, Amit A. Barot, Raju V. S. N. Kothapalli
Aiming towards the liquefaction of paddy straw was accumulation as well as providing a technically viable route leading to preservation of the natural resources and environment, the paddy straw was chemically liquefied. Paddy straw were liquefied into bio-based polyol in the presence of castor oil and blend of castor and karanja oil as depolymerizing agent and P-Toluene sulfonic acid as catalyst. Liquefied product was characterized by chemical as well as analytical techniques. The agricultural waste base paddy straw was eventually converted into polymeric precursor (polyol) monomer with nearly 80 to 95% yield by employing 2% catalyst concentration and at optimized temperature of 180°C. Synthesized polyol can be utilized further in formulating high quality rigid polyurethane foams. The foams were characterized in terms of their physical, mechanical, thermal and morphological properties. All foams exhibit good compressive strengths and thermal stability. Thermal conductivity of foams varied between 0.012 and 0.023 Kcal/mh°C, with the lowest being of foam from liquefied (LP), making it suitable for utilization as an insulation material.
{"title":"An efficient and environment friendly bio-based polyols through liquefaction: Liquefaction temperature and catalyst concentration optimization and utilized for rigid polyurethane foams","authors":"C. Patel, Nikhil R Dhore, Amit A. Barot, Raju V. S. N. Kothapalli","doi":"10.1177/02624893211017271","DOIUrl":"https://doi.org/10.1177/02624893211017271","url":null,"abstract":"Aiming towards the liquefaction of paddy straw was accumulation as well as providing a technically viable route leading to preservation of the natural resources and environment, the paddy straw was chemically liquefied. Paddy straw were liquefied into bio-based polyol in the presence of castor oil and blend of castor and karanja oil as depolymerizing agent and P-Toluene sulfonic acid as catalyst. Liquefied product was characterized by chemical as well as analytical techniques. The agricultural waste base paddy straw was eventually converted into polymeric precursor (polyol) monomer with nearly 80 to 95% yield by employing 2% catalyst concentration and at optimized temperature of 180°C. Synthesized polyol can be utilized further in formulating high quality rigid polyurethane foams. The foams were characterized in terms of their physical, mechanical, thermal and morphological properties. All foams exhibit good compressive strengths and thermal stability. Thermal conductivity of foams varied between 0.012 and 0.023 Kcal/mh°C, with the lowest being of foam from liquefied (LP), making it suitable for utilization as an insulation material.","PeriodicalId":9816,"journal":{"name":"Cellular Polymers","volume":"40 1","pages":"212 - 227"},"PeriodicalIF":1.6,"publicationDate":"2021-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1177/02624893211017271","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42008508","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-05-25DOI: 10.1177/02624893211018825
Y. Dou, D. Rodrigue
In this work, polypropylene (PP) was foamed via rotational molding using a chemical blowing agent (CBA) based on azodicarbonamide over a range of concentration (0 to 0.5% wt.). The samples were then analyzed in terms of morphological, thermal and mechanical properties. The morphological analysis showed a continuous increase in the average cell size and cell density with increasing CBA content. Increasing the CBA content also led to lower foam density and thermal conductivity. Similarly, all the mechanical properties (tension, flexion and impact) were found to decrease with increasing CBA content. Finally, the efficiency of the rotomolding process was assessed by producing neat PP samples via compression molding. The results showed negligible differences between the rotomolded and compression molded properties at low deformation and rate of deformation indicating that optimal rotomolding conditions were selected.
{"title":"Morphological, thermal and mechanical properties of polypropylene foams via rotational molding","authors":"Y. Dou, D. Rodrigue","doi":"10.1177/02624893211018825","DOIUrl":"https://doi.org/10.1177/02624893211018825","url":null,"abstract":"In this work, polypropylene (PP) was foamed via rotational molding using a chemical blowing agent (CBA) based on azodicarbonamide over a range of concentration (0 to 0.5% wt.). The samples were then analyzed in terms of morphological, thermal and mechanical properties. The morphological analysis showed a continuous increase in the average cell size and cell density with increasing CBA content. Increasing the CBA content also led to lower foam density and thermal conductivity. Similarly, all the mechanical properties (tension, flexion and impact) were found to decrease with increasing CBA content. Finally, the efficiency of the rotomolding process was assessed by producing neat PP samples via compression molding. The results showed negligible differences between the rotomolded and compression molded properties at low deformation and rate of deformation indicating that optimal rotomolding conditions were selected.","PeriodicalId":9816,"journal":{"name":"Cellular Polymers","volume":"40 1","pages":"198 - 211"},"PeriodicalIF":1.6,"publicationDate":"2021-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1177/02624893211018825","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45598673","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Melamine-formaldehyde (MF)rigid foams with high closed cell content were prepared via oven heating process, using MF prepolymer prepared from melamine and paraformaldehyde as a matrix, cyclohexane as the foaming agent, dimethyl silicon oil as the foam stabilizers, hydrochloric acid as the catalyst. The effect of MF prepolymer viscosity, foaming temperature, amount of catalyst on morphology, closed cell content, apparent density, water absorption and compressive strength of MF rigid foams were systematically studied. The optimized foaming conditions are as follows: the viscosity of MF prepolymer ranges from 35 Pa·s to 45 Pa·s, the foaming temperature is 125°C and the content of the catalyst is 0.65 wt%. The as-prepared MF foams showed the best comprehensive performance with closed cell content of 83.5%, apparent density of 62 kg·m−3, water absorption of 12.0%, compressive strength of 292kPa, thermal conductivity of 0.033 W m−1 K−1 and limiting oxygen index (LOI) of 36%. Compared to conventional organic foams, MF rigid foams possess low water absorption, excellent thermal insulation and flame retardancy due to high closed cell content, and can be expected to be used as thermal insulation material for building exterior walls.
以三聚氰胺和多聚甲醛制备的三聚氰胺预聚物为基体，环己烷为发泡剂，二甲基硅油为泡沫稳定剂，盐酸为催化剂，采用烘箱加热法制备了高闭孔含量的三聚氰胺甲醛（MF）硬质泡沫。系统研究了MF预聚物粘度、发泡温度、催化剂用量对MF硬质泡沫的形态、闭孔含量、表观密度、吸水率和抗压强度的影响。优化的发泡条件为：MF预聚物的粘度在35Pa·s至45Pa·s之间，发泡温度为125°C，催化剂含量为0.65wt%。所制备的MF泡沫具有最佳的综合性能，闭孔含量为83.5%，表观密度为62 kg·m−3，吸水率为12.0%，抗压强度为292kPa，导热系数为0.033 W m−1 K−1，极限氧指数为36%。与传统的有机泡沫相比，MF硬质泡沫由于闭孔含量高，具有低吸水性、优异的隔热性和阻燃性，有望用作建筑外墙的隔热材料。
{"title":"Preparation and performance of melamine-formaldehyde rigid foams with high closed cell content","authors":"Chunhui Li, Haihong Ma, Cong Song, Zhengfa Zhou, Weibing Xu, Qiusheng Song, F. Ren","doi":"10.1177/02624893211017130","DOIUrl":"https://doi.org/10.1177/02624893211017130","url":null,"abstract":"Melamine-formaldehyde (MF)rigid foams with high closed cell content were prepared via oven heating process, using MF prepolymer prepared from melamine and paraformaldehyde as a matrix, cyclohexane as the foaming agent, dimethyl silicon oil as the foam stabilizers, hydrochloric acid as the catalyst. The effect of MF prepolymer viscosity, foaming temperature, amount of catalyst on morphology, closed cell content, apparent density, water absorption and compressive strength of MF rigid foams were systematically studied. The optimized foaming conditions are as follows: the viscosity of MF prepolymer ranges from 35 Pa·s to 45 Pa·s, the foaming temperature is 125°C and the content of the catalyst is 0.65 wt%. The as-prepared MF foams showed the best comprehensive performance with closed cell content of 83.5%, apparent density of 62 kg·m−3, water absorption of 12.0%, compressive strength of 292kPa, thermal conductivity of 0.033 W m−1 K−1 and limiting oxygen index (LOI) of 36%. Compared to conventional organic foams, MF rigid foams possess low water absorption, excellent thermal insulation and flame retardancy due to high closed cell content, and can be expected to be used as thermal insulation material for building exterior walls.","PeriodicalId":9816,"journal":{"name":"Cellular Polymers","volume":"40 1","pages":"183 - 197"},"PeriodicalIF":1.6,"publicationDate":"2021-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1177/02624893211017130","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49442641","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-05-13DOI: 10.1177/02624893211017284
Fukai Yang, Miao Xie, Zhang Yudi, Xinyu Xu
We report flexible polyurethane foams (PUFs) containing –OH functionalized multi-walled carbon nanotubes (MWCNTs) with different diameters (10–20 nm, 20–30 nm, >50 nm) from 0.1–0.6 wt% (per 100 resins of polyol by weight) prepared via in situ polymerization. After synthesis, the morphology of the MWCNT/PUF composites was observed through scanning electron microscopy (SEM) based on MWCNT amount. The MWCNTs acted as nucleating agents and increased the matrix viscosity. The pore size of the composites decreased and the number of pores increased with increasing MWCNT concentration. Dynamic mechanical analysis (DMA) showed that the storage modulus of the composites increased, the loss modulus decreased, and the Tg gradually decreased with increasing MWCNT content. The incorporation of MWCNTs induced remarkable thermal stabilization of the matrix. The increase in the degradation temperature from 294°C to 304°C resulted in a 50% weight loss. The mechanical properties of the MWCNT/PUF materials increased with increasing MWCNT proportion because of the excellent compatibility and strong interface interaction between the MWCNT and flexible PUF.
{"title":"Effect of multi-walled carbon nanotubes with different diameters on morphology and thermal and mechanical properties of flexible polyurethane foams","authors":"Fukai Yang, Miao Xie, Zhang Yudi, Xinyu Xu","doi":"10.1177/02624893211017284","DOIUrl":"https://doi.org/10.1177/02624893211017284","url":null,"abstract":"We report flexible polyurethane foams (PUFs) containing –OH functionalized multi-walled carbon nanotubes (MWCNTs) with different diameters (10–20 nm, 20–30 nm, >50 nm) from 0.1–0.6 wt% (per 100 resins of polyol by weight) prepared via in situ polymerization. After synthesis, the morphology of the MWCNT/PUF composites was observed through scanning electron microscopy (SEM) based on MWCNT amount. The MWCNTs acted as nucleating agents and increased the matrix viscosity. The pore size of the composites decreased and the number of pores increased with increasing MWCNT concentration. Dynamic mechanical analysis (DMA) showed that the storage modulus of the composites increased, the loss modulus decreased, and the Tg gradually decreased with increasing MWCNT content. The incorporation of MWCNTs induced remarkable thermal stabilization of the matrix. The increase in the degradation temperature from 294°C to 304°C resulted in a 50% weight loss. The mechanical properties of the MWCNT/PUF materials increased with increasing MWCNT proportion because of the excellent compatibility and strong interface interaction between the MWCNT and flexible PUF.","PeriodicalId":9816,"journal":{"name":"Cellular Polymers","volume":"40 1","pages":"165 - 179"},"PeriodicalIF":1.6,"publicationDate":"2021-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1177/02624893211017284","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44908253","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-04-05DOI: 10.1177/02624893211006879
Youming Chen, R. Das, Hui Wang, M. Battley
In this study, the microstructure of a SAN foam was imaged using a micro-CT scanner. Through image processing and analysis, variations in density, cell wall thickness and cell size in the foam were quantitatively explored. It is found that cells in the foam are not elongated in the thickness (or rise) direction of foam sheets, but rather equiaxed. Cell walls in the foam are significantly straight. Density, cell size and cell wall thickness all vary along the thickness direction of foam sheets. The low density in the vicinity of one face of foam sheets leads to low compressive stiffness and strength, resulting in the strain localization observed in our previous compressive tests. For M80, large open cells on the top face of foam sheets are likely to buckle in compressive tests, therefore being another potential contributor to the strain localization as well. The average cell wall thickness measured from 2D slice images is around 1.4 times that measured from 3D images, and the average cell size measured from 2D slice images is about 13.8% smaller than that measured from 3D images. The dispersions of cell wall thickness measured from 2D slice images are 1.16–1.20 times those measured from 3D images. The dispersions of cell size measured from 2D slice images are 1.12–1.36 times those measured from 3D images.
{"title":"Characterization of microstructures of SAN foam core using micro-computed tomography","authors":"Youming Chen, R. Das, Hui Wang, M. Battley","doi":"10.1177/02624893211006879","DOIUrl":"https://doi.org/10.1177/02624893211006879","url":null,"abstract":"In this study, the microstructure of a SAN foam was imaged using a micro-CT scanner. Through image processing and analysis, variations in density, cell wall thickness and cell size in the foam were quantitatively explored. It is found that cells in the foam are not elongated in the thickness (or rise) direction of foam sheets, but rather equiaxed. Cell walls in the foam are significantly straight. Density, cell size and cell wall thickness all vary along the thickness direction of foam sheets. The low density in the vicinity of one face of foam sheets leads to low compressive stiffness and strength, resulting in the strain localization observed in our previous compressive tests. For M80, large open cells on the top face of foam sheets are likely to buckle in compressive tests, therefore being another potential contributor to the strain localization as well. The average cell wall thickness measured from 2D slice images is around 1.4 times that measured from 3D images, and the average cell size measured from 2D slice images is about 13.8% smaller than that measured from 3D images. The dispersions of cell wall thickness measured from 2D slice images are 1.16–1.20 times those measured from 3D images. The dispersions of cell size measured from 2D slice images are 1.12–1.36 times those measured from 3D images.","PeriodicalId":9816,"journal":{"name":"Cellular Polymers","volume":"40 1","pages":"143 - 164"},"PeriodicalIF":1.6,"publicationDate":"2021-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1177/02624893211006879","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42885065","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-03-01DOI: 10.1177/0262489321989005
Rujuta Dhoke, A. Ojha, A. Chaudhary, R. Vijayakumar
Biopolyols were obtained from liquefaction of sugarcane bagasse and rice husk. Acid and hydroxyl numbers were determined for estimating the polyol value of the liquid products. These prepared biopolyols were mixed with the commercial polyol for the preparation of polyurethane foam (PU). To study the effects of biopolyol on properties of PU foam, various ratios of biopolyol to commercial polyol were used. It was observed that the density and foaming time of the PU foam increases with the increase in biopolyol content. The calculated Isocyanate index showed that sugarcane bagasse polyol can be used to make flexible foam and that rice husk can be used to make rigid foam. Foaming times and full rise times increased with increase in the biopolyol content. The Fourier-transform infrared spectroscopy (FTIR) spectra of prepared foams showed the characteristic peaks related to PU foam. The morphological studies were carried out using scanning electron microscopy (SEM). Thermal conductivity tests proved that the synthesized PU foams can be used as insulating materials. Further, PU foams were also prepared with the incorporation of carbon nanotubes (CNTs) in the polyol. The densities, thermal conductivities and SEM analysis of PU foams with and without carbon nanotubes were compared.
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