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

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, foam stability and emulsifying properties… 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

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) was increased by 22.34%.… More >

N. Elbers¹, C. K. Ranaweera¹, M. Ionescu², X. Wan², P. K. Kahol³, Ram K. Gupta^1,2*

Journal of Renewable Materials, Vol.5, Suppl.1, pp. 74-83, 2017, DOI:10.7569/JRM.2017.634137

Abstract The objective of this research is to prepare rigid polyurethane (PU) foams from α-phellandrene, a biobased compound. Two types of polyols were synthesized by reacting α-phellandrene with 2-mercaptoethanol and α-thioglycerol via thiol-ene chemistry route. The completion of the reaction was identified by using FTIR. PU foams from α-phellandrene polyols and commercial polyol were compared with regard to foam characteristics and properties. All the PU foams showed apparent density of 28–39 kg/m³ with closed-cell content above 90%. The highest glass transition temperature of 229 °C and compressive strength of 220 kPa were observed for the polyol synthesized by reacting α-phellandrene and… More >

C. K. Ranaweera¹, M. Ionescu², N. Bilic², X. Wan², P. K. Kahol³, Ram K. Gupta^1,2*

Journal of Renewable Materials, Vol.5, Suppl.1, pp. 1-12, 2017, DOI:10.7569/JRM.2017.634105

Abstract Biobased polyol was synthesized using 1-thioglycerol and limonene, an extract of orange peel, via thiol-ene chemistry as an alternative to petrochemical-based polyol for preparation of rigid polyurethane foams (RPFs). Fire-retardant polyurethane foams were prepared by addition of different amounts of dimethyl methyl phosphonate (DMMP) in the polyol. The effect of DMMP on the properties of RPFs was studied. All the biobased RPFs maintained a regular cell structure with uniform cell distribution and over 90% of closed cell. The RPFs showed excellent compressive strength of ~230 kPa without addition of DMMP. These RPFs almost retained their specific compressive strength even when… 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

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 showed an increasing trend with… More >

Xiaojian Zhou^1,2, Hui Wang¹, Jun Zhang², Zhifeng Zheng¹, Guanben Du^1,2,*

Journal of Renewable Materials, Vol.6, No.1, pp. 68-74, 2018, DOI:10.7569/JRM.2017.634150

Abstract Pineapple leaf nanofibers (PLNFs) extracted from pineapple leaf fiber were used for reinforcing biobased polyurethane foam (BPU). The dispersion performance of PLNF in the foaming mixture system, nanocomposite foaming behavior, cell morphology, cell size, density, compressive strength and dimensional stability were investigated. The viscosity of the mixtures increased with increasing the PLNF content. The addition of a tiny amount of PLNF did not influence the exothermic temperature of the foam system, but reduced the expansion and gel time of the nanocomposite foams. This reduced time was found to increase the production efficiency. Scanning electron microscopy (SEM) images showed that the… More >

Hanxing Zhu

The International Conference on Computational & Experimental Engineering and Sciences, Vol.17, No.4, pp. 131-132, 2011, DOI:10.3970/icces.2011.017.131

Abstract This paper aims to study the size-dependent elastic properties of micro- and nano-sized open-celled foams. To simplify the analysis, we use perfect regular body-centered cubic structure (i.e. BCC foam), which has cubic symmetry and only three independent elastic constants. Taking strut bending, twisting and axial compression/stretching as the deformation mechanisms, Zhu, Knott and Mills (JMPS, V45, pp. 319-343, 1997) have obtained closed form results of all the three independent elastic constants (i.e. the Young's modulus E11 , the shear modulus G12 and the Poisson ratio v12 ) as functions of the bending stiffness, the torsional stiffness and the compression/stretching stiffness… More >

N. Ohno¹, D. Okumura¹, A. Okada¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.8, No.2, pp. 73-80, 2008, DOI:10.3970/icces.2008.008.073

Abstract This paper describes buckling modes and stresses of elastic Kelvin open-cell foams subjected to uniaxial compressions. Cubic unit cells and cell aggregates in model foams are analyzed using a homogenization theory. The analysis is performed on the assumption that the struts in foams have a non-uniform distribution of cross-sectional areas as observed experimentally. By performing the analysis based on the uniformity of strut cross-sectional areas, it is shown that the non-uniformity of cross-sectional areas is an important factor for the buckling behavior of open-cell foams. More >

Yufeng Ma¹, Xuanang Gong¹, Bing Xie¹, Xiang Geng¹, Puyou Jia^2,*

Journal of Renewable Materials, Vol.7, No.10, pp. 1037-1046, 2019, DOI:10.32604/jrm.2019.07454

Abstract In order to improve the mechanical properties without reducing its flame retardancy of phenolic foams (PFs), 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) was introduced in the structure of cashew nut shell liquid (CNSL) to improve its flame retardant, and the product of DOPO grafting CNSL (DOPO-g-CNSL) was obtained to modify phenolic resin, and to prepare DOPO-g-CNSL modified PFs (DCMPFs). The structures of DOPO-g-CNSL were verified by Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance (1H-NMR). Compared with CNSL, thermal stability of DOPO-g-CNSL was decreased and Ti decreased by 3.53%, but the residual carbon (800°C) was increased by 35.05%. Compared with pure PF,… More >

Fei Song¹, Puyou Jia^1,*, Yanan Xiao², Caiying Bo¹, Lihong Hu¹, Yonghong Zhou^1,*

Journal of Renewable Materials, Vol.7, No.10, pp. 1011-1021, 2019, DOI:10.32604/jrm.2019.08044

Abstract Phenolic foams (PFs) as thermal insulation material with outstanding flame retardancy are required to match society’s ever expanding safety expectations; however, a trade off exists between flame retardancy and toughness. Here, for the first time, we synthesized a novel reactive phosphorus containing tung oil based derivative and used it to toughen PF, resulting in PFs with a combination of excellent mechanical properties and flame retardancy. Compared with pure PF, the modified PFs exhibit enhanced mechanical properties, with specific compressive and flexural strengths as high as 5.67 MPa and 12.46 MPa, which represent increases of 90.67% and 178.7% over those of… More >