CANSU ULKER TURAN^1,*, YUKSEL GUVENILIR¹

Journal of Polymer Materials, Vol.38, No.3-4, pp. 271-280, 2021, DOI:10.32381/JPM.2021.38.3-4.8

Abstract Rice husk ash is a side-product of rice production; thus, it is a cheap, abundant, and renewable material, and utilized as an enzyme carrier to immobilize Candida antarctica lipase B. In this study, Candida antarctica lipase B immobilized onto rice husk ashes was used to catalyze ring opening polymerization of 16-membered lactone, ω-pentadecalactone. In order to determine the best polymerization conditions for highest molar mass polymer, reactions were proceeded at various temperatures and time periods. The best reaction conditions were obtained as 80°C and 6 hours (M_n = 34255 g mol^-1). Molecular structure of this polymer sample was confirmed via… More >

Wu Jing^1,2,#, Ren Luo^3,#, Sha Ding², Ping Duan^3,4,5,6,7,*

Journal of Renewable Materials, Vol.10, No.7, pp. 1813-1828, 2022, DOI:10.32604/jrm.2022.018771

Abstract In this study, the workability and reaction mechanism of metakaolin (MK) based geopolymer blended with rice husk ash (RHA) and silica fume (SF) was investigated. The prepared samples were subjected to tests including compressive strength and fluidity tests. X-ray diffraction (XRD) and Scanning electron microscope (SEM) were employed to explore the phase composition and microstructure of geopolymers. The molecular bonding information of geopolymer was provided by Fourier transform infrared spectroscopy (FTIR). Meanwhile, the porosity of geopolymer was obtained by Mercury intrusion porosimeter (MIP) analysis. The high-activity RHA obtained after calcination at 600°C was used as a supplementary cementitious material to… More > Graphic Abstract

Naphol Yoobanpot^1,*, Prakasit Sokrai², Natt Makul²

Journal of Renewable Materials, Vol.9, No.11, pp. 2033-2049, 2021, DOI:10.32604/jrm.2021.015849

Abstract According to empirical evidence, high levels of energy and considerable amounts of natural resources are used in the production of concrete. Given the context, this study explores self-consolidating concrete (SCC) that includes rice husk ash (RHA) and metal furnace slag (MFS) as an alternative to cement and the natural aggregates in standard SCC mixes. In this study, mixture designs are investigated with 20 wt.% of RHA, 10–30 wt.% of MFS and water-to-powder material ratios of 0.30 and 0.40. Based on the findings regarding the fresh-state, hardened-state, and durability properties of the resulting SCC mixes, it is evident that the use… More >

V. Subrahmanian^1,*, M. Albert Noble Einstien²

Journal of Renewable Materials, Vol.7, No.2, pp. 171-192, 2019, DOI:10.32604/jrm.2019.00090

Abstract Nowadays an alternate source of filler from renewable and plant derivatives are being thought of in rubber industries due to their reliability, environmental and economic benefits. Rice Husk Ash (RHA) a byproduct of the rice milling industry is obtained on partial and as well as full combustion of the rice husks. This ash is a good source of silica, silicates and needle shaped carbon and hence can be used as filler for cements. In the present study, a detailed investigation was carried out to understand the RHA as reinforcing material using mechanical properties and fractography using SEM. The rubbers studied… More >

Yasemin Kaptan, M.Sc.^1,*, Yüksel Avcıbaşı-Güvenilir¹

Journal of Renewable Materials, Vol.6, No.6, pp. 619-629, 2018, DOI:10.32604/JRM.2018.00142

Abstract Surface-modified rice husk ash was used as an inorganic support material for immobilization of Candida antarctica lipase B. (3-aminopropyl) trimethoxysilane was used for surface modification. Immobilization of CALB was performed via both physical adsorption and cross-linking. PCL synthesis was carried out by using these immobilized enzymes, free enzyme and Novozyme 435®. Molecular weight distribution of polymer samples was obtained by gel permeation chromatography (GPC) and chain structures of the polymer samples were observed by hydrogen nuclear magnetic resonance (1H-NMR). The highest monomer conversion is generally obtained by using cross-linked enzyme, around 90%. PDI values for all polymer samples were approximately… More >

Cansu Ulker*, Yuksel Guvenilir

Journal of Renewable Materials, Vol.6, No.6, pp. 591-598, 2018, DOI:10.7569/JRM.2017.634189

Abstract As an alternative biodegradable aliphatic polyester, poly(w-pentadecalactone-co-ε-caprolactone) copolymer was synthesized via enzymatic ring-opening polymerization. A new biocatalyst, Candida antarctica lipase B, immobilized onto rice husk ash was used for catalysis. Reactions were carried out at various temperatures and periods for varied copolymer compositions in order to obtain the highest molecular weight copolymer. The best reaction parameters were found to be 80 °C and 6 hours and molecular weights increased proportionally with the amount of w-pentadecalactone (w-PDL). The molecular structure of copolymer with 75% weight ratio of w-PDL (Mn = 19720 g/mol) was characterized by proton and carbon nuclear magnetic resonance… More >

Nikolay Dishovsky^1*, Petrunka Malinova¹, Ivan Uzunov²

Journal of Renewable Materials, Vol.6, No.4, pp. 402-412, 2018, DOI:10.7569/JRM.2017.634171

Abstract Natural products from agricultural wastes are finding importance in the polymer industry due to their many advantages such as being lightweight, low cost and environmentally friendly. In the present study the potential of the two types of rice husk ash (RHA) prepared under different conditions as fillers in natural rubber-based elastomer composites was investigated. The fillers were prepared by rice husks incineration and characterized by means of X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), Brunauer-Emmett-Teller (BET) specific surface area, Hg-porosimetry and N2-adsorption. The evaluation involved determining the vulcanization characteristics of the compounds and their… More >