Advanced Search
Displaying 291-300 on page 30 of 308. Per Page  
  • Investigation of CNSL-Based Hybrid Sol in Conventional Polymeric Material
  • Abstract The performance properties of conventional polymeric material have been investigated by modifying it with cashew nut shell liquid (CNSL) derived hybrid precursor. The synthesis of hybrid material involved formation of maleic anhydride adduct of CNSL followed by silane modifi cation and subsequent hydrolysis and condensation with tetra ethyl orthosilicate. The developed hybrid material was characterized by a number of instrumental techniques like FT-IR, 1H-NMR and 13C-NMR, as reported in our earlier work. In the present work, we have investigated the effect of CNSL-based hybrid material on the performance properties of conventional alkyd-melamine formaldehyde-based stoving system. The synthesized material was used…
  • More
  •   Views:80       Downloads:59        Download PDF
  • Mineralization of Poly(lactic acid) (PLA), Poly(3-hydroxybutyrate-co-valerate) (PHBV) and PLA/PHBV Blend in Compost and Soil Environments
  • Abstract The present study investigates the mineralization of poly(lactic acid) (PLA) and poly(3-hydroxybutyrate-covalerate) (PHBV), and PLA/PHBV blend in compost and soil burial environments. The mineralization was assayed on the basis of carbon dioxide (CO2) release from the test materials incubated in compost and soil for a period of 200 days. The degradation was followed by means of fragmentation, thermogravimetric (TGA), FTIR spectroscopy and scanning electron microscopy (SEM) analyses. The results showed that PLA, PHBV and blend of PLA/PHBV achieved almost 90% biodegradation under composting conditions, while PHBV, PLA/PHBV blend and PLA respectively achieved only 35%, 32% and 4% biodegradation under soil…
  • More
  •   Views:115       Downloads:67        Download PDF
  • Poly(3-Hydroxybutyrate-co-3-Hydroxyvalerate)/ Purifi ed Cellulose Fiber Composites by Melt Blending: Characterization and Degradation in Composting Conditions
  • Abstract Novel biodegradable composites based on poly(3-hydroxybutirate-co-3-hydroxyvalerate) (PHBV) and different contents of purifi ed alpha-cellulose fi bers (3, 10, 25 and 45%) were prepared by melt blending and characterized. The composites were characterized by scanning electron microscopy (SEM), wide-angle X-ray scattering (WAXS) experiments, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamic mechanic analysis (DMA) and Shore D hardness measurements. Disintegrability under composting conditions was studied according to the ISO 20200 standard. Morphological results showed that high dispersion of the fi bers was achieved during mixing. Good adhesion on the fi ber-matrix interface was also detected by SEM. The addition of low…
  • More
  •   Views:90       Downloads:70        Download PDF
  • Effect of Epoxidized Jatropha Oil on the Cure, Thermal, Morphological and Viscoelastic Properties of Epoxy Resins
  • Abstract This article reports the effect of epoxidized jatropha oil (EJO) on the thermal, cure and viscoelastic properties of epoxy resins. Epoxidized jatropha oil with an oxirane value of 5.0 was prepared and epoxy formulations containing different concentrations of EJO were evaluated for cure, morphology, thermal and viscoelastic properties. The curing temperature of the formulations increased with increasing EJO content. The glass transition temperature of the cured films decreased from 56 °C for unmodified epoxy resin to 23 °C for the sample with 60 wt% EJO reactive diluent, suggesting good plasticizing action. The thermal decomposition was only marginally affected.
  • More
  •   Views:73       Downloads:73        Download PDF
  • Natural Fiber-Polypropylene Composites Made from Caranday Palm
  • Abstract Composites made from polypropylene (PP) and local South American fibers traditionally used in yarnderived craftsmanships, Caranday Palm, were studied regarding the effect of fiber addition, concentration and characteristics of the coupling agent (molecular weight and percentage of grafted maleic anhydride), as well as type of processing. A laboratory-scale intensive mixing followed by compression, and pilot plant twin extrusion followed by injection, were the two processes investigated. The use of the first one allowed the selection of processable formulations with high fiber concentration and a percentage of coupling agent below the surface fiber saturation. In fact, it was found that there…
  • More
  •   Views:71       Downloads:58        Download PDF
  • Mechanical and Thermal Properties of High-Density Rigid Polyurethane Foams from Renewable Resources
  • Abstract The most common sustainable solution for polyurethane (PU) materials is their production using renewable resources. Polyols derived from biomass and recycled polymers are the most promising way to do that. This study compares five different sustainable polyols as a possible raw material for production of highdensity rigid PU foams for automotive application. The goal of our study was to show that biobased polyols are a suitable replacement for polyols derived from petrochemical products. The influence of the chemical structure of polyols on the PU polymer matrix and foam properties was investigated. Two sources of PU raw material feedstock were studied:…
  • More
  •   Views:107       Downloads:135        Download PDF
  • Influence of Isocyanate Index on Selected Properties of Flexible Polyurethane Foams Modified with Various Bio-Components
  • Abstract In this article, the results of the foaming process analysis of fl exible polyurethane with different isocyanate indexes are presented. Two types of flexible polyurethane foams (FPURF) were obtained: (1) by using petrochemical components and a rapeseed-oil-based polyol (used in the amount of 20 wt%), (2) by using petrochemical components and cellulose as a natural fi ller in the amount of 3 php (per hundred parts of polyol). The characteristic parameters of the foaming process, such as the foam’s growth velocity, the core temperature and dielectric polarization, were measured using a Foamat device. Moreover, the following properties of flexible polyurethane…
  • More
  •   Views:112       Downloads:146        Download PDF
  • Synthesis, Structure and Properties of Poly(ester-Urethane- Urea)s Synthesized Using Biobased Diamine
  • Abstract Modern polymer science and technology is focused on the development of partial or fully green polymers. This focus is related to green chemistry trends, which propose using natural and renewable resources as monomers in the synthesis of polymers. In this study, biobased diamine was used as a chain extender of ester-urethane prepolymer. Obtained poly(ester-urethane-urea) contains 16 wt% of biobased diamine. There is mention of an amine curing agent that is an amine derivative of dimerized fatty acids (obtained from vegetable oils). Application of two chain extenders, i.e., 1,4-butanediol and biobased diamine (applied separately or in mixture), with different molecular weights…
  • More
  •   Views:97       Downloads:94        Download PDF
  • Biodegradation Pretreatment of Wood of E. grandis, E. dunnii, and E. benthamii to Work in Biorefi nery Processes
  • Abstract Nowadays, there is a great interest in using lignocellulosic materials as substrate for the production of biorefi nery products. Eucalypti are good options to use as crops to obtain different kinds of biofuels and derivatives, since their plantations show high adaptation potential to soil and weather conditions in Uruguay. The basic process steps involved in the obtainment of biorefi nery materials are: pretreatment, hydrolysis, fermentation and products separation. As delignifi cation is an important process to obtain biorefi nery products, in this context the evaluation of the biological (BT) and hydrothermal (TT) pretreatment of different species of Eucaliptus was studied.…
  • More
  •   Views:95       Downloads:64        Download PDF
  • Improved Permeability Properties for Bacterial Cellulose/ Montmorillonite Hybrid Bionanocomposite Membranes by In-Situ Assembling
  • Abstract Bacterial cellulose/montmorillonite (BCMMT) hybrid bionanocomposite membranes were prepared by in-situ assembling or one-step biosynthesis process. The presence of MMT in BC membranes was confi rmed by thermogravimetric analysis and quantifi ed by mass spectrometry, resulting in bionanocomposites with MMT contents between 7–13 wt%. The incorporation of MMT during BC biosynthesis modifi ed BC morphology and led to lower porosity, even though higher water holding capacity was achieved. Bionanocomposites showed improved thermal stability and water vapor and oxygen gas barrier properties up to 70 and 80% with respect to neat BC membranes. This improvement was related to the tortuous path of…
  • More
  •   Views:122       Downloads:92        Download PDF
Displaying 291-300 on page 30 of 308. Per Page