Cansu Ulker^*, Zeynep Gok, Yuksel Guvenilir

Journal of Renewable Materials, Vol.7, No.4, pp. 335-343, 2019, DOI:10.32604/jrm.2019.03819

Abstract Novozyme 435, which is the commercially available immobilized form of Candida antarctica lipase B, has been successfully conducted ring opening polymerization of lactones in organic solvents. In this paper, it was aimed to introduce an alternative biocatalyst for Novozyme 435. Candida antarctica lipase B immobilized onto rice husk ashes via physical adsorption (with a specific activity of 4.4 U/mg) was prepared in previous studies and used as a biocatalyst for poly(δ-valerolactone) synthesis in the present work. Polymerization reactions were proceeded at various reaction temperatures and periods via both two immobilized enzyme preparations. The resulting products More >

Marcia Cristina Branciforti^1,*, Caroline Faria Bellani², Carolina Lipparelli Morelli², Alice Ferrand³, Nadia Benkirane-Jessel³, Rosario Elida Suman Bretas²

Journal of Renewable Materials, Vol.7, No.3, pp. 269-277, 2019, DOI:10.32604/jrm.2019.01833

Abstract Although nanocomposites have recently attracted special interest in the tissue engineering area, due to their potential to reinforce scaffolds for hard tissues applications, a number of variables must be set prior to any clinical application. This manuscript addresses the evaluation of thermo-mechanical properties and of cell proliferation of cellulose nanocrystals (CNC), poly(butylene adipate-co-terephthalate) (PBAT), poly(ε-caprolactone) (PCL) films and their bionanocomposites with 2 wt% of CNC obtained by casting technique. Cellulose nanocrystals extracted from Balsa wood by acid hydrolysis were used as a reinforcing phase in PBAT and PCL matrix films. The films and pure CNC… More >

Ana Clara Lancarovici Alves, Rafael Grande, Antonio José Felix Carvalho^*

Journal of Renewable Materials, Vol.7, No.3, pp. 245-252, 2019, DOI:10.32604/jrm.2019.00833

Abstract The interest in thermoplastic starch (TPS) as a substitute material to replace conventional thermoplastics continues especially due its biodegradability, availability, low cost and because it is obtained from renewable sources. However, its poor mechanical properties and its high sensitivity to humidity have limited its use in several applications. Here, the copolymer poly (ethylene-co-vinyl alcohol) (EVOH), with two different ethylene contents, 27 and 44 mol% were blended with TPS by extrusion in order to overcome these limitations. The obtained blends were characterized by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), mechanical tensile testing, Scanning Electron Microscopy 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 More >

Fouad LAOUTID^1,*, Valeriia KARASEVA¹, Lucie COSTES^{1, 2}, Sylvain BROHEZ², Rosica MINCHEVA¹, Philippe DUBOIS¹

Journal of Renewable Materials, Vol.6, No.6, pp. 559-572, 2018, DOI:10.32604/JRM.2018.00004

Abstract In this study, tannic acid (TA) was investigated as flame retardant agent for PLA. Different strategies to modify its thermal degradation pathway have been explored in order to improve its charring effect. The first one consists in combining TA with organomodified montmorillonite (oMMT), and enables limiting the thermo-oxidative degradation of TA and promoting the formation of an effective char layer. Flame-retardant (FR) behavior of PLA-based composition has been found to be positively impacted by this combination since a reduction of the peak of Heat Release Rate (PHRR), more important than the value recorded when oMMT More >

Victor Gomes Lauriano Souza¹, Patrícia Freitas Rodrigues², Maria Paula Duarte¹, Ana Luísa Fernando^1*

Journal of Renewable Materials, Vol.6, No.5, pp. 548-558, 2018, DOI:10.7569/JRM.2018.634104

Abstract The aim of this work was to develop an active biopolymer based on chitosan by incorporating natural antioxidants. Five essential oils (ginger, rosemary, sage, tea tree and thyme) and six hydro-alcoholic extracts (from ginger, green and black tea, kenaf leaves, rosemary and sage plants) were tested. Migration assays were carried out to evaluate the films' activity, and total phenolic content and antioxidant activity were monitored in the simulant during storage. Interaction between natural compounds and polymeric matrix was evaluated by FTIR spectroscopy. The diffusion of the phenolic compounds was not detected in the films incorporated More >

Puneet Kumar^1,*, J. Srinivas²

CMC-Computers, Materials & Continua, Vol.54, No.1, pp. 1-20, 2018, DOI:10.3970/cmc.2018.054.001

Abstract Evolution of computational modeling and simulation has given more emphasis on the research activities related to carbon nanotube (CNT) reinforced polymer composites recently. This paper presents the composite cylinder assemblage (CCA) approach based on continuum mechanics for investigating the elastic properties of a polymer resin reinforced by multi-walled carbon nanotubes (MWCNTs). A three-phase cylindrical representative volume element (RVE) model is employed based on CCA technique to elucidate the effects of inter layers, chirality, interspacing, volume fraction of MWCNT, interphase properties and temperature conditions on the elastic modulus of the composite. The interface region between CNT More >

A. Subba Rao^a,* , V. Ramachandra Prasad^a , P. Rajendra^a , M. Sasikala^a , O. Anwar Beg^b

Frontiers in Heat and Mass Transfer, Vol.9, pp. 1-9, 2017, DOI:10.5098/hmt.9.2

Abstract In this article, we investigate the nonlinear steady state boundary layer flow and heat transfer of an incompressible Jeffery non-Newtonian fluid from a permeable horizontal isothermal cylinder. The transformed conservation equations are solved numerically subject to physically appropriate boundary conditions using a versatile, implicit, finite-difference technique. The numerical code is validated with previous studies. The influence of a number of emerging non-dimensional parameters, namely with Deborah number (De), surface suction parameter (S), Prandtl number (Pr), ratio of relaxation to retardation times (λ) and dimensionless tangential coordinate (ξ) on velocity and temperature evolution in the boundary… More >

Elizabeth PÉREZ-TEJADA^1,4*, Juan MORALES-CORONA³, Luis Ernesto GÓMEZ-QUIRÓZ², María Concepción GUTIERREZ-RUIZ², Roberto OLAYO³

BIOCELL, Vol.41, No.2-3, pp. 41-44, 2017, DOI:10.32604/biocell.2017.41.041

Abstract Low pressure plasma polymer films were synthesized using pyrrole and allylamine monomers and adding iodine was used (or not) for the reaction in both cases. They were polymerized on glass substrates under the same reaction conditions. Polymerization of allylamine was also studied at different operating powers. These thin polymer films were used as culture surfaces for HepG2 cells, a cell line derived from a human hepatoma. The proliferation, differentiation and two-dimensional propagation until obtaining monolayer of the cells was studied on the different synthetized films and correlations were established between the conditions of synthesis, the More >

Shegufta Shetranjiwalla, Shaojun Li, Laziz Bouzidi, Suresh S. Narine^*

Journal of Renewable Materials, Vol.5, No.5, pp. 333-344, 2017, DOI:10.7569/JRM.2017.634102

Abstract The impact of polymerization protocol on phase structure and properties of entirely lipid-derived thermoplastic poly(ester urethane)s (TPEU)s was investigated. The TPEUs were synthesized from 1,7-heptamethylene diisocyanate, polyester diols and 1,9-nonanediol (ND) as chain extender. A two-stage polymerization method was used to prepare two TPEUs; one in which ND was added in the first stage of polymerization as part of the prepolymer and another in the second stage after the prepolymer was formed. Two very different morphologies exhibiting different degrees of phase separation were obtained, driven by the sequence of addition of the chain extender. The More >