Dzun Noraini Jimat^*, Sharifah Shahira Syed Putra, Parveen Jamal, Wan Mohd Fazli Wan Nawawi, Mohammed Saedi Jami

Journal of Renewable Materials, Vol.8, No.7, pp. 739-757, 2020, DOI:10.32604/jrm.2020.010357 - 01 June 2020

Abstract Increasing usage of foams in various industry sectors had causing serious disposal problems once it reaches the end of its life-cycle. Herein, PVA-MFC foam was prepared by freeze-drying using polyvinyl alcohol (PVA) and microfibrillated cellulose (MFC) as a reinforced material from sugarcane bagasse (SCB). In this study, the PVA-MFC foam was chemically silylated with Y-methacryloxypropyltrimethoxysilane (MPS) and tetraethoxysilane (TEOS). The wetting ability and mechanical strength of the silylated _2,20PVA-MFC foam was greatly enhanced compared with unmodified _2,20PVA-MFC foam. The silane chemicals (MPS and TEOS) had been confirmed grafted on _2,20PVA-MFC foam due to the presence of Si-C… More >

Fei Song^1,2, Puyou Jia^1,*, Caiying Bo¹, Xiaoli Ren¹, Lihong Hu¹, Yonghong Zhou^1,*

Journal of Renewable Materials, Vol.8, No.5, pp. 535-547, 2020, DOI:10.32604/jrm.2020.09304 - 29 April 2020

Abstract In this study, we prepared a series of tung oil phenolic foams (TPF) by a one-pot method. The FT-IR and 1 H NMR spectra confirm the successful FriedelCrafts grafting of phenol to the long-chain alkyl group in tung oil. Modified TPFs exhibit enhanced mechanical properties, including compressive and flexural strengths of up to 0.278 ± 0.036 MPa and 0.450 ± 0.017 MPa, respectively, which represent increases of 68.75% and 86.72% over those of pure phenolic foam (PF). SEM spectra reveal the TPF microstructure to have uniform hexagonal cell morphology, narrower cell size distribution, and smaller More >

Rui Hou¹, Zhihuang Zhang¹, Guangzhao Zhang¹, Donglin Tang^1,2,3,*

Journal of Renewable Materials, Vol.8, No.4, pp. 397-403, 2020, DOI:10.32604/jrm.2020.08912 - 24 April 2020

Abstract It has been proved that introducing isocyanurate into polymer chains could improve the flame retardancy of polymers. We describe in this work the synthesis and the thermal property study of three thermoplastic polyisocyanurates, which are polyisocyanuratoamide (PICA-6), polyisocyanurato(ester amide) (PICEA-6) and polyisocyanurato(urea ester) (PICUE-6). These polymers show similar and improved thermal stability with the existence of isocyanurate rings. PICA-6 is more crystalizable than the rest two and the melting temperature is found to be around 240°C but it still crystalizes slowly. For PICEA-6 and PICUE-6, only glass transition can be observed on the DSC traces. More >

Nadezhda Petkova^1,*, Radka Arabadzhieva¹, Dragomir Vassilev², Gergana Gencheva¹, Yulian Tumbarski³, Tsveteslava Ignatova-Ivanova⁴, Sevginar Ibryamova⁴, Mina Todorova¹, Milena Koleva², Panteley Denev¹

Journal of Renewable Materials, Vol.8, No.4, pp. 365-381, 2020, DOI:10.32604/jrm.2020.09292 - 24 April 2020

Abstract Microwave-assisted irradiation was performed for esterification of chicory inulin with high degree of polymerization with acetic anhydride without a solvent only with a catalyst. The resulting esters were characterized by melting point, hydrophilic-lipophilic balance, thin-layer chromatography, ultraviolet spectroscopy, Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR) spectroscopy. Inulin acetate demonstrated a high degree of acetylation (2.5–3.0) and presented a white, water-insoluble substance with bitter taste. The FTIR and NMR spectra confirmed esterification and demonstrated the incorporation of hydrophobic residue to the water soluble inulin backbone. Swelling capacity, water holding, oil-holding capacities, the foamability,… More >

Ajay Veludurthi¹, Venkateshwarlu Bolleddu^2,*

Energy Engineering, Vol.117, No.2, pp. 49-61, 2020, DOI:10.32604/EE.2020.010666 - 23 April 2020

Abstract This work focused on modal and harmonic analysis of small wind turbine blades taken from the NACA 63415 series. The sandwich structure type composite blade is fabricated from GFRP and epoxy with Uni-vinyl hard foams of different alignments as stiffeners. In this work, the modal and harmonic analysis of different varieties of blades like solid, hallow and rectangular alignment blades is carried out by the finite element method using ANSYS 18.1 software. From Finite Element Analysis, the natural frequencies, amplitudes and mode shapes are obtained. Based on the working principle of wind turbine blades, the More >

Yongtong Li¹, Liang Gong^{1, *}, Hui Lu¹, Dexin Zhang¹, Bin Ding¹

CMES-Computer Modeling in Engineering & Sciences, Vol.123, No.2, pp. 895-912, 2020, DOI:10.32604/cmes.2020.09009 - 01 May 2020

Abstract In the present study, the thermal performance of metal foam heat sink was numerically investigated by adopting the local thermal non-equilibrium (LTNE) model and local thermal equilibrium (LTE) model. Temperature field distributions and temperature difference field distributions of solid and fluid phases were presented. Detailed thermal performance comparisons based on the LTE and LTNE models were evaluated by considering the effects of the relevant metal foam morphological and channel geometrical parameters. Results indicate that a distinct temperature difference exists between the solid and fluid phases when the LTNE effect is pronounced. The average Nusselt numbers… More >

Lionel Fabian Fourie¹, Lynndle Square^2,*

FDMP-Fluid Dynamics & Materials Processing, Vol.16, No.2, pp. 225-235, 2020, DOI:10.32604/fdmp.2020.08771 - 21 April 2020

Abstract A heat transfer study was conducted, in the framework of Computational Fluid Dynamics (CFD), on a Hot-Wire Chemical Vapour Deposition (HWCVD) reactor chamber to determine a safe deposition distance for atomic hydrogen produced by HWCVD. The objective of this study was to show the feasibility of using heat transfer simulations in determining a safe deposition distance for deposition of this kind. All CFD simulations were set-up and solved within the framework of the CFD packages of OpenFOAM namely; snappyHexMesh for mesh generation, buoyantSimpleFoam and rhoSimpleFoam as the solvers and paraView as the post-processing tool. Using More >

Yufeng Ma¹, Xuanang Gong¹, Puyou Jia^2,*

Journal of Renewable Materials, Vol.8, No.1, pp. 45-55, 2020, DOI:10.32604/jrm.2020.08621 - 01 January 2020

Abstract In order to improve the comprehensive performance of phenolic foam, 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) was grafted with itaconic acid (ITA) (DOPO-g-ITA) to modify microcrystalline cellulose (MCC). DOPO-g-ITA modified MCC (DIMMCC) was used to prepare composite phenolic foam (DCPF). The structures of DIMMCC were verified by Fourier transform infrared spectroscopy (FT-IR). The microstructure and crystalline property were characterized by scanning electron microscope (SEM) and X-ray diffraction (XRD) respectively. Compared with MCC, the crystallinity of DIMMCC was dramatically decreased, but the diffraction peak positions were unchanged. Thermal stability was decreased, and T_i decreased by 45.0°C. The residual carbon (600°C) More >

Roohalah Hajizadeh¹, Ali Khavanin^2,*, Mohammad Barmar³, Ahmad Jonidi Jafari⁴, Somayeh Farhang Dehghan⁵

Sound & Vibration, Vol.53, No.5, pp. 207-222, 2019, DOI:10.32604/sv.2019.06523

Abstract Polyurethane foam as the most well-known absorbent materials has a suitable absorption coefficient only within a limited frequency range. The aim of this study was to improve the sound absorption coefficient of flexible polyurethane (PU) foam within the range of various frequencies using clay nanoparticles, polyacrylonitrile nanofibers, and polyvinylidene fluoride nanofibers. The response surface method was used to determine the effect of addition of nanofi- bers of PAN and PVDF, addition of clay nanoparticles, absorbent thickness, and air gap on the sound absorption coefficient of flexible polyurethane foam (PU) across different frequency ranges. The absorption… More >

Zehui Ju¹, Qian He¹, Tianyi Zhan¹, Haiyang Zhang^1,*, Lin Sun¹, Lu Hong¹, Xinyi Shi², Xiaoning Lu^1,*

Journal of Renewable Materials, Vol.7, No.11, pp. 1077-1091, 2019, DOI:10.32604/jrm.2019.07525 - 14 July 2021

Abstract In this study, steam exploded peanut shell fibers (SE-PSFs) were utilized to fabricate with rigid polyurethane foam (RPUF) in order to improve sound absorption performance and hydrothermal weather resistance. Optimized method of SE treatment, RPUF preparation and flame retardant treatment were selected to prepare SE-PSF/RPUF composites in this experiment. Physical and mechanical properties including density, water absorption capacity, thickness swelling rate, compressive strength, thermal conductivity and average sound absorption coefficient of SE-PSF/RPUF were investigated and compared with the control (PRUF). The results showed that the density, water absorption capacity, thickness swelling rate and thermal conductivity More >