Xiaohua Gu^1,*, Shiwei Lyu¹, Siwen Liu²

Journal of Renewable Materials, Vol.9, No.11, pp. 1913-1926, 2021, DOI:10.32604/jrm.2021.015400 - 04 June 2021

Abstract A bi-component alcoholysis agent containing propylene glycol (PG) and ethanolamine (ETA) was used to catalyst the degradation of the waste polyurethane rigid foam. The oligomer polyols obtained through degradation were used as raw materials to produce recycled polyurethane rigid foam composites with lignin as reinforcing filler. The effect of alcoholysis mass ratio on degradation was investigated by analyzing the viscosity, hydroxyl content and chemical structure of the degradation products. The effect of lignin addition on the properties of regenerated polyurethane rigid foam were investigated by analyzing water absorption rate, compressive strength, porosity, thermal stability, thermal More >

Christian Brütting¹, Julia Dreier², Christian Bonten², Volker Altstädt¹, Holger Ruckdäschel^1,*

Journal of Renewable Materials, Vol.9, No.11, pp. 1859-1868, 2021, DOI:10.32604/jrm.2021.016244 - 04 June 2021

Abstract Polylactide (PLA) bead foams show a high potential regarding their applicability in packaging or consumer products. Concerning the comparable properties of PLA to Polystyrene (PS) and the good CO₂ footprint it represents a potential alternative to petroleum-based polymer foams. However, foaming of PLA is challenging, due to its low melt strength, therefore chemical modifiers are often used. Concerning the bead foam technology regarding PLA, the available literature is limited so far. Within this study, the bead foaming behavior of neat and modified amorphous PLA was investigated. The material was modified by talc and an epoxy-based chain More >

Mohammad Javad Jafari¹, Mohsen Niknam Sharak², Ali Khavanin³, Touraj Ebadzadeh⁴, Mahmood Fazlali⁵, Rohollah Fallah Madvari^6,*

Sound & Vibration, Vol.55, No.2, pp. 117-130, 2021, DOI:10.32604/sv.2021.09729 - 21 April 2021

Abstract Fabricating of metal foams with desired morphological parameters including pore size, porosity and pore opening is possible now using sintering technology. Thus, if it is possible to determine the morphology of metal foam to absorb sound at a given frequency, and then fabricate it through sintering, it is expected to have optimized metal foams for the best sound absorption. Theoretical sound absorption models such as Lu model describe the relationship between morphological parameters and the sound absorption coefficient. In this study, the Lu model was used to optimize the morphological parameters of Aluminum metal foam… More >

Xiaohua Gu, Hongxiang Luo^*, Shiwei Lv, Peng Chen

Journal of Renewable Materials, Vol.9, No.7, pp. 1253-1266, 2021, DOI:10.32604/jrm.2021.014876 - 18 March 2021

Abstract Dramatically increasing waste polyurethane rigid foam (WPRF) draws the attention of the world. A mixture of ethylene glycol (EG) and diethylene glycol (DEG) is used as glycolysis agents. WPRF was subjected to alcoholysis using different catalysts which are titanium ethylene glycol and potassium hydroxide to obtain recycled polyol, respectively. The effect of a different catalyst on the viscosity and hydroxyl value of recycled polyol is discussed. The regenerated polyurethane (RPU) is performed using the recycled polyol. Infrared spectrum, compressive strength, apparent density, water absorption, scanning electron microscope, and thermogravimetric analysis are carried out to investigate… More >

Yun Zhao, Shi Yan^*, Jiale Jia

CMES-Computer Modeling in Engineering & Sciences, Vol.126, No.3, pp. 1251-1274, 2021, DOI:10.32604/cmes.2021.013478 - 19 February 2021

Abstract In this study, the pyramidal lattice stitched foam sandwich composite materials were manufactured by integrating top and bottom panels with pyramidal lattice core to overcome the weak interface between the core and the skins of the sandwich structure. The influence of the reinforcing core rods on the mechanical properties including compressive, shear, and three-point bending performances of the foam sandwich composite materials were revealed through theoretical analysis and comparative experiments. The theoretical predictions were consistent with the experimental results. Compressive test, shear test and three-point bending test were performed. The experimental results show that the… More >

Yang Liu¹, Jianjun Xie^1,*, Peng Hao¹, Ying Shi¹, Yonggen Xu^2,3, Xiaoqing Ding^2,3

Journal of Renewable Materials, Vol.9, No.2, pp. 237-253, 2021, DOI:10.32604/jrm.2021.012228 - 15 December 2020

Abstract Foam glass is a new green material to make use of waste glass and is popular for its energy-saving and light weight features. The problems in the current study of foam glass is that its properties require improvement to match the growing demands of application specific standards. Properties of foam glass is related to its porous structure, which is affected by various factors. The influence of raw material component, foaming agents and sintering system on the porous structure and properties of foamed glass is studied. Density decreases with the decrease of quartz and barite content.… More >

Fangzhou Wang^a,* , Gennifer A. Riley^b, Munonyedi Egbo^c, Melanie M. Derby^b, Gisuk Hwang^c, Xianglin Li^a,†

Frontiers in Heat and Mass Transfer, Vol.15, pp. 1-8, 2020, DOI:10.5098/hmt.15.1

Abstract This study conducts pore-scale simulations and experiments to estimate the permeability of two different types of porous materials: metal foams and sintered copper particles with porosities of approximately 0.9 and 0.4, respectively. The integration of micro X-ray computed tomography with pore-scale computational fluid dynamics simulations develops a unique tool to capture the pore-scale geometry of porous media and accurately predict non-isotropic permeability of porous media. The pore-scale simulation not only results in improved prediction accuracy but also has the capability to capture non-isotropic properties of heterogeneous materials, which is a huge challenge for empirical correlations,… More >

Jinxing Li^1,#, Jingjing Liao^1,#, Jun Zhang¹, Xiaojian Zhou^1,2,*, Hisham Essawy³, Guanben Du^1,2

Journal of Renewable Materials, Vol.8, No.12, pp. 1607-1616, 2020, DOI:10.32604/jrm.2020.013976 - 12 November 2020

Abstract In this study, pre-concentrated bark, furfuryl alcohol and other biomass raw materials were used to prepare foaming materials by high-speed mechanical stirring without using a foaming agent. We investigated the effect of the postadded water amount on the properties of foaming materials. In particular, we determined basic physical properties of these materials, including the limiting oxygen index (LOI), porosity, thermal conductivity, thermogravimetric analysis, pore size distribution, and microstructure. The results of scanning electron microscopy (SEM) indicated that the pore size distribution was uniform and the pore size increased with increasing water volume. Thermogravimetric analysis (TG/… More >

Ilze Beverte^1,*, Vairis Shtrauss¹, Aldis Kalpinsh¹, Uldis Lomanovskis¹, Ugis Cabulis², Irina Sevastyanova², Sergejs Gaidukovs³

Journal of Renewable Materials, Vol.8, No.9, pp. 1151-1170, 2020, DOI:10.32604/jrm.2020.010215 - 03 August 2020

Abstract Early investigations of dielectric permittivity of rigid polyurethane foams at low frequencies were made on petrochemical-origin foams, mainly by means of parallel plate capacitors. In the present investigation biopolyol was synthesized from Latvia-grown rapeseeds’ oil by the transesterification method with triethanolamine, in an environmentally friendly process, without emission of harmful substances, at temperatures 175°C ± 5°C. Rigid, closed-cell rapeseed oil polyol polyurethane biofoams and petrochemical foams were made ensuring content of the renewable rapeseed oil polyol in ready foams 27 wt.%–29 wt.%. Dielectric permittivity of the polyurethane foams and the underlying monolithic petrochemical-origin polyurethane and… More >

Ajay Veludurthi¹, Venkateshwarlu Bolleddu^2,*

Energy Engineering, Vol.117, No.4, pp. 237-248, 2020, DOI:10.32604/EE.2020.011304 - 31 July 2020

Abstract Mechanical characteristics of small wind turbine blades of National Advisory Committee for Aeronautics (NACA) 63-415 series with different Univinyl (UV) foam alignments have been evaluated experimentally using Universal Testing Machine and numerically using Finite Element Analysis (FEA) software ANSYS. The wind turbine blade models considered are selected from the NACA 63415 series to give a power output of 1 kW. The blades in this study are made like a sandwich beam structure. The outermost portion of the blade is made of glass fiber reinforced plastics with epoxy resin as composite and Uni-vinyl foam alignments are… More >