Pub Date : 2020-06-10DOI: 10.1177/0262489320929300
Z. Razzaz, A. Mohebbi, D. Rodrigue
The production of foamed hollow fiber membranes (HFMs) is presented based on polymer blends using various concentrations of linear low-density polyethylene (LLDPE) and low-density polyethylene (LPDE) combined with azodicarbonamide (chemical blowing agent) to prepare samples via twin-screw extrusion. In particular, the blowing agent concentration as well as the stretching speed were found to be the most important parameters to achieve a good cellular structure for membrane application. From the samples obtained, a complete set of morphological, thermal, and gas transport characterization was performed. The results show that LLDPE/LDPE blends compared to neat LLDPE lead to higher cell density at high stretching speed, which is appropriate for membranes having higher gas permeability and selectivity due to lower cell wall thickness. The results also show that the developed cellular structure has high potential for the continuous production of HFMs for different gas separation, especially for hydrogen recovery.
{"title":"Gas transport properties of cellular hollow fiber membranes based on LLDPE/LDPE blends","authors":"Z. Razzaz, A. Mohebbi, D. Rodrigue","doi":"10.1177/0262489320929300","DOIUrl":"https://doi.org/10.1177/0262489320929300","url":null,"abstract":"The production of foamed hollow fiber membranes (HFMs) is presented based on polymer blends using various concentrations of linear low-density polyethylene (LLDPE) and low-density polyethylene (LPDE) combined with azodicarbonamide (chemical blowing agent) to prepare samples via twin-screw extrusion. In particular, the blowing agent concentration as well as the stretching speed were found to be the most important parameters to achieve a good cellular structure for membrane application. From the samples obtained, a complete set of morphological, thermal, and gas transport characterization was performed. The results show that LLDPE/LDPE blends compared to neat LLDPE lead to higher cell density at high stretching speed, which is appropriate for membranes having higher gas permeability and selectivity due to lower cell wall thickness. The results also show that the developed cellular structure has high potential for the continuous production of HFMs for different gas separation, especially for hydrogen recovery.","PeriodicalId":9816,"journal":{"name":"Cellular Polymers","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2020-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1177/0262489320929300","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43631947","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 : 2020-06-05DOI: 10.1177/0262489320930328
Jinwei Chen, Ling Yang, Dahua Chen, Qunshan Mai, Meigui Wang, Lixuan Wu, Ping Kong
Microcellular polylactic acid (PLA) foams with various cell size and cell morphologies were prepared using supercritical carbon dioxide (sc-CO2) solid-state foaming to investigate the relationship between the cell structure and mechanical properties. Constrained foaming was used and a wide range of cell structures with a constant porosity of ∼75% by tuning saturation pressure (8–24 MPa) was developed. Experiments varying the saturation pressure while holding other variables’ constant show that the mean cell size and the mean cell wall thickness decreased, while the cell density and the open porosity increased with increase of pressure. Tensile modulus of PLA foams decreased with increasing the saturation pressure, but the specific tensile modulus of PLA foams was still 15–80% higher than that of solid PLA. Tensile strength and elongation at break first increased with increasing saturation pressure up to 16 MPa and then decreased with further increasing saturation pressure (20 MPa and 24 MPa) at which opened-cell structure produced. Compressive modulus, compressive strength, and compressive yield stress also followed the same variation trend. The results indicated that not only cell size plays an important role in properties of PLA foams but also cell morphology can influence these properties significantly.
{"title":"Cell structure and mechanical properties of microcellular PLA foams prepared via autoclave constrained foaming","authors":"Jinwei Chen, Ling Yang, Dahua Chen, Qunshan Mai, Meigui Wang, Lixuan Wu, Ping Kong","doi":"10.1177/0262489320930328","DOIUrl":"https://doi.org/10.1177/0262489320930328","url":null,"abstract":"Microcellular polylactic acid (PLA) foams with various cell size and cell morphologies were prepared using supercritical carbon dioxide (sc-CO2) solid-state foaming to investigate the relationship between the cell structure and mechanical properties. Constrained foaming was used and a wide range of cell structures with a constant porosity of ∼75% by tuning saturation pressure (8–24 MPa) was developed. Experiments varying the saturation pressure while holding other variables’ constant show that the mean cell size and the mean cell wall thickness decreased, while the cell density and the open porosity increased with increase of pressure. Tensile modulus of PLA foams decreased with increasing the saturation pressure, but the specific tensile modulus of PLA foams was still 15–80% higher than that of solid PLA. Tensile strength and elongation at break first increased with increasing saturation pressure up to 16 MPa and then decreased with further increasing saturation pressure (20 MPa and 24 MPa) at which opened-cell structure produced. Compressive modulus, compressive strength, and compressive yield stress also followed the same variation trend. The results indicated that not only cell size plays an important role in properties of PLA foams but also cell morphology can influence these properties significantly.","PeriodicalId":9816,"journal":{"name":"Cellular Polymers","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2020-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1177/0262489320930328","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49474206","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 : 2020-06-04DOI: 10.1177/0262489320929232
Chunhui Li, Haihong Ma, Zhengfa Zhou, Weibing Xu, F. Ren, Xinyu Yang
Toughing melamine-formaldehyde (MF) rigid closed-cell foams were prepared by using ethylene glycol (EG) and carbon fiber (CF) as composite toughening agents. The pulverization rate, compressive strength, bending strength, cellular structure, closed-cell ratio, water absorption ratio, thermal conductivity, thermal stability, limiting oxygen index (LOI), and char yield were characterized to study the morphology, mechanical, thermal, and fire-retardant properties of as-prepared toughing MF rigid foams. The pulverization rate result showed that introduction of composite modifier can obviously improve the toughness of MF rigid foams. The cellular structure, closed-cell ratio, and water absorption results showed that the addition of EG/CF can increase the closed-cell ratio and control the cell size of MF rigid foams. The compressive strength and bending strength results showed that the incorporation of composite modifier of MF rigid foams dramatically improved the mechanical properties. The LOI, char yield, and thermal stability results showed that the toughing MF rigid foams remained more intact char skeleton with flame-retardant effect, thus reducing the fire hazards. The as-prepared toughing MF rigid foams showed the best comprehensive performance with pulverization rate of 5.21%, compressive strength of 355.3 kPa, bending strength of 0.44 MPa, closed-cell ratio of 79.1%, water absorption of 9%, thermal conductivity of 0.031 W m−1 K−1, and LOI of 39.6%. Compared with unmodified MF rigid foams, toughing rigid closed-cell MF foams possess excellent pulverization rate, compressive strength, bending strength, cellular structure, thermal insulation, and flame retardancy.
以乙二醇(EG)和碳纤维(CF)为复合增韧剂，制备了三聚氰胺-甲醛(MF)刚性闭孔泡沫塑料。通过表征制粒率、抗压强度、抗弯强度、孔结构、闭孔比、吸水率、导热系数、热稳定性、极限氧指数(LOI)和炭产率，研究了制备的增韧MF刚性泡沫的形貌、力学性能、热性能和阻燃性能。粉碎率试验结果表明，复合改性剂的加入能明显提高MF刚性泡沫的韧性。细胞结构、闭孔率和吸水率结果表明，EG/CF的加入可以提高MF刚性泡沫的闭孔率，控制孔的大小。抗压强度和弯曲强度结果表明，复合改性剂的掺入显著改善了MF刚性泡沫的力学性能。LOI、炭产率和热稳定性结果表明，增韧MF刚性泡沫保持了更完整的炭骨架，具有阻燃作用，从而降低了火灾危险。制备的增韧MF刚性泡沫粉化率为5.21%，抗压强度为355.3 kPa，抗弯强度为0.44 MPa，闭孔率为79.1%，吸水率为9%，导热系数为0.031 W m−1 K−1,LOI为39.6%，综合性能最佳。与未改性的MF刚性泡沫相比，增韧MF闭孔刚性泡沫具有优异的粉碎率、抗压强度、抗弯强度、孔状结构、保温性能和阻燃性能。
{"title":"Preparation and properties of melamine-formaldehyde rigid closed-cell foam toughened by ethylene glycol/carbon fiber","authors":"Chunhui Li, Haihong Ma, Zhengfa Zhou, Weibing Xu, F. Ren, Xinyu Yang","doi":"10.1177/0262489320929232","DOIUrl":"https://doi.org/10.1177/0262489320929232","url":null,"abstract":"Toughing melamine-formaldehyde (MF) rigid closed-cell foams were prepared by using ethylene glycol (EG) and carbon fiber (CF) as composite toughening agents. The pulverization rate, compressive strength, bending strength, cellular structure, closed-cell ratio, water absorption ratio, thermal conductivity, thermal stability, limiting oxygen index (LOI), and char yield were characterized to study the morphology, mechanical, thermal, and fire-retardant properties of as-prepared toughing MF rigid foams. The pulverization rate result showed that introduction of composite modifier can obviously improve the toughness of MF rigid foams. The cellular structure, closed-cell ratio, and water absorption results showed that the addition of EG/CF can increase the closed-cell ratio and control the cell size of MF rigid foams. The compressive strength and bending strength results showed that the incorporation of composite modifier of MF rigid foams dramatically improved the mechanical properties. The LOI, char yield, and thermal stability results showed that the toughing MF rigid foams remained more intact char skeleton with flame-retardant effect, thus reducing the fire hazards. The as-prepared toughing MF rigid foams showed the best comprehensive performance with pulverization rate of 5.21%, compressive strength of 355.3 kPa, bending strength of 0.44 MPa, closed-cell ratio of 79.1%, water absorption of 9%, thermal conductivity of 0.031 W m−1 K−1, and LOI of 39.6%. Compared with unmodified MF rigid foams, toughing rigid closed-cell MF foams possess excellent pulverization rate, compressive strength, bending strength, cellular structure, thermal insulation, and flame retardancy.","PeriodicalId":9816,"journal":{"name":"Cellular Polymers","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2020-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1177/0262489320929232","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44801488","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 : 2020-05-01DOI: 10.1177/0262489319890076
Tianzheng Wen, Fei Guo, Yijie Huang, S. Zhu, X. Jia
We established a method for calculating and analyzing the static leakage rate based on a porous media model for foamed silicone rubber materials. The mechanical properties of the foamed silicone rubber material under macroscopic compression were described by the Ogden third (foam) model in the finite-element hyperelastic model. It solved the problem of difficult convergence of large compressible and volume compressible cell materials. The size and distribution of the cells on the surface of the foamed material were obtained by a white-light interferometer and mathematical fitting. The boundary conditions for solving the porous medium model were obtained by the coupling of the macroscopic contact pressure and the microscopic cell contact pressure. For the unique cell structure and contact state of the surface of the foamed material, the flow state of the fluid at the sealing interface was described by a porous medium model, and the leak rate was obtained. In addition, this article analyzed the effect of different compression and the relative pressure of the sealing end face on the leakage.
{"title":"Analysis of static sealing rules of foamed silicone rubber based on a porous media model","authors":"Tianzheng Wen, Fei Guo, Yijie Huang, S. Zhu, X. Jia","doi":"10.1177/0262489319890076","DOIUrl":"https://doi.org/10.1177/0262489319890076","url":null,"abstract":"We established a method for calculating and analyzing the static leakage rate based on a porous media model for foamed silicone rubber materials. The mechanical properties of the foamed silicone rubber material under macroscopic compression were described by the Ogden third (foam) model in the finite-element hyperelastic model. It solved the problem of difficult convergence of large compressible and volume compressible cell materials. The size and distribution of the cells on the surface of the foamed material were obtained by a white-light interferometer and mathematical fitting. The boundary conditions for solving the porous medium model were obtained by the coupling of the macroscopic contact pressure and the microscopic cell contact pressure. For the unique cell structure and contact state of the surface of the foamed material, the flow state of the fluid at the sealing interface was described by a porous medium model, and the leak rate was obtained. In addition, this article analyzed the effect of different compression and the relative pressure of the sealing end face on the leakage.","PeriodicalId":9816,"journal":{"name":"Cellular Polymers","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2020-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1177/0262489319890076","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46359606","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 : 2020-04-23DOI: 10.1177/0262489320920070
J. Werner, Lukas Vetter, Sebastian Hertle, M. Wolf, D. Drummer
In recent years, foams have experienced a major economic uprise, not least due to their lightweight construction potential. In this article, a new process variation is presented, which enables the generation of foamed structures in rotational molding by the utilization of vacuum. The novel method is based on entrapped air in the melt as an intrinsic physical blowing agent. By applying negative pressure in the cooling or solidification phase, the air bubbles expand. The crystallization freezes the existing conditions and thus forms the foamed structure. The investigations presented consider influences by different pressures as well as the temperature at which the vacuum is applied. The results with polyethylene show that by varying the pressure as well as the application temperature of the vacuum, components with different densities and cell characteristics result. The resulting foamed components excel by an improved stiffness per unit weight ratio.
{"title":"Air inclusions in the polymer melt functioning as intrinsic physical blowing agents for the generation of foams in rotational molding","authors":"J. Werner, Lukas Vetter, Sebastian Hertle, M. Wolf, D. Drummer","doi":"10.1177/0262489320920070","DOIUrl":"https://doi.org/10.1177/0262489320920070","url":null,"abstract":"In recent years, foams have experienced a major economic uprise, not least due to their lightweight construction potential. In this article, a new process variation is presented, which enables the generation of foamed structures in rotational molding by the utilization of vacuum. The novel method is based on entrapped air in the melt as an intrinsic physical blowing agent. By applying negative pressure in the cooling or solidification phase, the air bubbles expand. The crystallization freezes the existing conditions and thus forms the foamed structure. The investigations presented consider influences by different pressures as well as the temperature at which the vacuum is applied. The results with polyethylene show that by varying the pressure as well as the application temperature of the vacuum, components with different densities and cell characteristics result. The resulting foamed components excel by an improved stiffness per unit weight ratio.","PeriodicalId":9816,"journal":{"name":"Cellular Polymers","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2020-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1177/0262489320920070","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48016026","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 : 2020-04-22DOI: 10.1177/0262489320919952
Can Jiang, Shuo Han, Shihong Chen, Hongfu Zhou, Xiangdong Wang
The microcellular foaming of chain-extended polyethylene terephthalate (CPET) by crystallization induction method was reported in this article. The crystallization behaviors of various polyethylene terephthalate (PET) samples which were affected by the combined effect of pyromellitic dianhydride, Surlyn, and CO2 were investigated. After Surlyn was added to CPET, the crystal nucleation of various CPET samples was improved, and numerous but small spherulites were generated. Two kinds of CPET samples with the content of 0 phr and 1 phr Surlyn were foamed at various temperature by batch foaming method. Changing the saturation temperature could adjust the appearance of high-temperature melting crystals which would affect the final cellular structures in various CPET foams. With the decrease of saturation temperature, the cell size decreased while cell density increased. At the saturation temperature of 265°C and 250°C, the cell density of CPET foam with Surlyn was one magnitude larger than CPET foam without Surlyn. At the saturation temperature of 247°C, the microcellular PET foams with the cell density of 109 cells cm−3 and the cell size less than 10 µm had been developed successfully.
{"title":"Crystallization-induced microcellular foaming behaviors of chain-extended polyethylene terephthalate","authors":"Can Jiang, Shuo Han, Shihong Chen, Hongfu Zhou, Xiangdong Wang","doi":"10.1177/0262489320919952","DOIUrl":"https://doi.org/10.1177/0262489320919952","url":null,"abstract":"The microcellular foaming of chain-extended polyethylene terephthalate (CPET) by crystallization induction method was reported in this article. The crystallization behaviors of various polyethylene terephthalate (PET) samples which were affected by the combined effect of pyromellitic dianhydride, Surlyn, and CO2 were investigated. After Surlyn was added to CPET, the crystal nucleation of various CPET samples was improved, and numerous but small spherulites were generated. Two kinds of CPET samples with the content of 0 phr and 1 phr Surlyn were foamed at various temperature by batch foaming method. Changing the saturation temperature could adjust the appearance of high-temperature melting crystals which would affect the final cellular structures in various CPET foams. With the decrease of saturation temperature, the cell size decreased while cell density increased. At the saturation temperature of 265°C and 250°C, the cell density of CPET foam with Surlyn was one magnitude larger than CPET foam without Surlyn. At the saturation temperature of 247°C, the microcellular PET foams with the cell density of 109 cells cm−3 and the cell size less than 10 µm had been developed successfully.","PeriodicalId":9816,"journal":{"name":"Cellular Polymers","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2020-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1177/0262489320919952","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48395636","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 : 2020-03-30DOI: 10.1177/0262489320912357
Fatemeh Farhanmoghaddam, A. Javadi
In this article, poly (lactic acid) (PLA) was foamed via batch foaming using supercritical nitrogen as a physical blowing agent by two methods, conventional foaming process (CFP) and low-temperature foaming process (LTFP). The fabrication processes, cell morphologies, thermal properties, crystallization behavior, and electrical resistance of resulted foams were studied to investigate the effect of foaming on these properties of PLA. It was found that the foams resulted from CFP method have micrometric cell sizes, while LTFP method led to nanometric cell structure and high cell density. Also scanning electron microscopy showed that the PLA foams have a heterogeneous cellular structure. The results showed that the foaming process increased the melting point and degree of crystallinity of PLA, which led to decrease in the electrical resistance of samples.
{"title":"Fabrication of poly (lactic acid) foams using supercritical nitrogen","authors":"Fatemeh Farhanmoghaddam, A. Javadi","doi":"10.1177/0262489320912357","DOIUrl":"https://doi.org/10.1177/0262489320912357","url":null,"abstract":"In this article, poly (lactic acid) (PLA) was foamed via batch foaming using supercritical nitrogen as a physical blowing agent by two methods, conventional foaming process (CFP) and low-temperature foaming process (LTFP). The fabrication processes, cell morphologies, thermal properties, crystallization behavior, and electrical resistance of resulted foams were studied to investigate the effect of foaming on these properties of PLA. It was found that the foams resulted from CFP method have micrometric cell sizes, while LTFP method led to nanometric cell structure and high cell density. Also scanning electron microscopy showed that the PLA foams have a heterogeneous cellular structure. The results showed that the foaming process increased the melting point and degree of crystallinity of PLA, which led to decrease in the electrical resistance of samples.","PeriodicalId":9816,"journal":{"name":"Cellular Polymers","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2020-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1177/0262489320912357","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46085619","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 : 2020-03-19DOI: 10.1177/0262489320912521
Wei Liu, Xunxian Zhu, Hongxiang Gao, Xiangdong Su, Xian Wu
Improving foamability of poly (lactic acid) (PLA) resin is a key issue for its critical foaming applications with high-performance and ultralow density. However, owing to the rheological nature of linear PLA chain structure with relatively low molecular weight, the overall foamability of PLA resin cannot meet the processing requirements of foaming purpose. Here, we describe a simple and versatile technique to prepare high foamability PLA resin by inducing chain extender through grafting octa(epoxycyclohexyl) polyhedral oligomeric silsesquioxanes (POSS) on carbon nanotubes (CNT). After the orderly assemble of the two nanoparticles, an obvious increase in melt elasticity of PLA is observed. The enhanced melt elasticity of PLA had a significant effect on controlling subsequent foaming behavior. Thus, a homogeneous and finer cellular morphology of PLA rigid foam was obtained with a proper content of CNT-POSS. Eventually, the expansion ratio of chain-extended PLA foam was 13 times higher than that of unmodified PLA foam. The proposed design methodology will potentially pave a way for designing and preparing high-performance PLA rigid foam products.
{"title":"Preparation and characterization of PLA foam chain extended through grafting octa(epoxycyclohexyl) POSS onto carbon nanotubes","authors":"Wei Liu, Xunxian Zhu, Hongxiang Gao, Xiangdong Su, Xian Wu","doi":"10.1177/0262489320912521","DOIUrl":"https://doi.org/10.1177/0262489320912521","url":null,"abstract":"Improving foamability of poly (lactic acid) (PLA) resin is a key issue for its critical foaming applications with high-performance and ultralow density. However, owing to the rheological nature of linear PLA chain structure with relatively low molecular weight, the overall foamability of PLA resin cannot meet the processing requirements of foaming purpose. Here, we describe a simple and versatile technique to prepare high foamability PLA resin by inducing chain extender through grafting octa(epoxycyclohexyl) polyhedral oligomeric silsesquioxanes (POSS) on carbon nanotubes (CNT). After the orderly assemble of the two nanoparticles, an obvious increase in melt elasticity of PLA is observed. The enhanced melt elasticity of PLA had a significant effect on controlling subsequent foaming behavior. Thus, a homogeneous and finer cellular morphology of PLA rigid foam was obtained with a proper content of CNT-POSS. Eventually, the expansion ratio of chain-extended PLA foam was 13 times higher than that of unmodified PLA foam. The proposed design methodology will potentially pave a way for designing and preparing high-performance PLA rigid foam products.","PeriodicalId":9816,"journal":{"name":"Cellular Polymers","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2020-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1177/0262489320912521","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43366590","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 : 2020-03-01DOI: 10.1177/0262489319890201
S. Kudori, H. Ismail
The effects of filler loading and size of kenaf fibre on the mechanical properties of kenaf fibre-filled natural rubber latex foam (NRLF) have been studied. The NRLF was prepared by using the Dunlop method. The kenaf fibre was sieved to 97, 144 and 200 µm particle sizes and incorporated into the rubber vulcanizates at 0, 1, 3, 5 and 7 part per hundred rubber fibre contents. Increasing kenaf fibre loading in NRLF resulted in the reduction of tensile strength, elongation at break and recovery percentage but increased in modulus at 100% (M100), compression strength, compression set, hardness and foam density. At the same kenaf fibre loading, smaller size of kenaf fibre-filled NRLF showed higher tensile properties, compression strength, compression set and hardness. Scanning electron microscope demonstrated that as kenaf fibre loading and size increased, a larger pore size of NRLF was formed and this led to tensile strength, M100, compression strength and hardness.
{"title":"The effects of filler contents and particle sizes on properties of green kenaf-filled natural rubber latex foam","authors":"S. Kudori, H. Ismail","doi":"10.1177/0262489319890201","DOIUrl":"https://doi.org/10.1177/0262489319890201","url":null,"abstract":"The effects of filler loading and size of kenaf fibre on the mechanical properties of kenaf fibre-filled natural rubber latex foam (NRLF) have been studied. The NRLF was prepared by using the Dunlop method. The kenaf fibre was sieved to 97, 144 and 200 µm particle sizes and incorporated into the rubber vulcanizates at 0, 1, 3, 5 and 7 part per hundred rubber fibre contents. Increasing kenaf fibre loading in NRLF resulted in the reduction of tensile strength, elongation at break and recovery percentage but increased in modulus at 100% (M100), compression strength, compression set, hardness and foam density. At the same kenaf fibre loading, smaller size of kenaf fibre-filled NRLF showed higher tensile properties, compression strength, compression set and hardness. Scanning electron microscope demonstrated that as kenaf fibre loading and size increased, a larger pore size of NRLF was formed and this led to tensile strength, M100, compression strength and hardness.","PeriodicalId":9816,"journal":{"name":"Cellular Polymers","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2020-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1177/0262489319890201","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42263837","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}
Supercritical fluids have been widely used to prepare various polymer nanocomposite foams due to their high-efficiency, rich-resource, and environment-friendly characteristics. In this work, we prepared polystyrene (PS) nanocomposites with different contents of hybrid fillers of nanoclay and nano-calcium carbonate (nano-CaCO3) and then were foamed by batch foaming method using supercritical carbon dioxide as a physical blowing agent. The effect of hybrid nanofillers components and foaming temperature and pressure on the foaming properties and cellular structure of PS nanocomposite foams was systematically investigated. Dynamic rheology results indicated that the complex viscosity and storage modulus were enhanced with the addition of hybrid fillers. Scanning electron microscopic images show that all samples foamed uniformly macrocells under the given conditions. More importantly, the hybrid fillers of nano-CaCO3 and nanoclay exhibit a significant synergistic effect in improving PS foaming properties, which can be ascribed to the different roles of the two fillers during cell nucleation and cell growth. For instance, the PS/0.22/0.88 nanocomposite foamed under the conditions of 20 MPa and 130°C has shown the finest cell structure (higher cell density of 1.91 × 1010 and smaller cell diameter of 2.28 µm) due to the coeffect of the hybrid nanofillers. Finally, the synergistic mechanism of these two nanofillers on PS foaming behavior was discussed.
{"title":"Synergetic effect of nanoclay and nano-CaCO3 hybrid filler systems on the foaming properties and cellular structure of polystyrene nanocomposite foams using supercritical CO2","authors":"Xinghan Lian, Wenjie Mou, Tairong Kuang, Xianhu Liu, Shuidong Zhang, Fangfang Li, Tongxun Liu, Xiangfang Peng","doi":"10.1177/0262489319900948","DOIUrl":"https://doi.org/10.1177/0262489319900948","url":null,"abstract":"Supercritical fluids have been widely used to prepare various polymer nanocomposite foams due to their high-efficiency, rich-resource, and environment-friendly characteristics. In this work, we prepared polystyrene (PS) nanocomposites with different contents of hybrid fillers of nanoclay and nano-calcium carbonate (nano-CaCO3) and then were foamed by batch foaming method using supercritical carbon dioxide as a physical blowing agent. The effect of hybrid nanofillers components and foaming temperature and pressure on the foaming properties and cellular structure of PS nanocomposite foams was systematically investigated. Dynamic rheology results indicated that the complex viscosity and storage modulus were enhanced with the addition of hybrid fillers. Scanning electron microscopic images show that all samples foamed uniformly macrocells under the given conditions. More importantly, the hybrid fillers of nano-CaCO3 and nanoclay exhibit a significant synergistic effect in improving PS foaming properties, which can be ascribed to the different roles of the two fillers during cell nucleation and cell growth. For instance, the PS/0.22/0.88 nanocomposite foamed under the conditions of 20 MPa and 130°C has shown the finest cell structure (higher cell density of 1.91 × 1010 and smaller cell diameter of 2.28 µm) due to the coeffect of the hybrid nanofillers. Finally, the synergistic mechanism of these two nanofillers on PS foaming behavior was discussed.","PeriodicalId":9816,"journal":{"name":"Cellular Polymers","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2020-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1177/0262489319900948","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47098875","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}
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