Search results for "Polyol"

Renewable polyol obtained by microwave-assisted alcoholysis of epoxidized soybean oil: Preparation, thermal properties and relaxation process

2019

[EN] The soybean oil polyol (SOP) use as feedstock in the polyurethane industry has been recently emphasized due to its excellent resistance to hydrolysis, which is also applicable in coatings and thermal insulation. In this article, the SOP was obtained by a very fast microwave-assisted alcoholysis of epoxidized soybean oil (ESO). The preparation method, thermal properties, and relaxation process were evaluated. High yields as opening and consumption epoxy group and selectivity of 99.8 mol%, 985 mol%, and 71.2 mol% were obtained. Through titrations, nuclear magnetic resonance and gel permeation chromatography were identified parameters as 0.32 mg KOH.g(-1) acid number, 190 mg KOH.g(-1) hyd…

The fluxional behaviour of η6(bicyclo[6.2.0]deca-2,4,6-triene) hexacarbonyl diruthenium (Ru-Ru) by 1H and 13C NMR techniques

1977

Abstract The variable temperature 1 H NMR spectra of [Ru 2 (CO) 6 η 6 -C 10 H 12 )] (C 10 H 12 = bicyclo [6.2.0]-deca-2,4,6-triene) shows that this molecule undergoes the fluxional behaviour previously reported for [M 2 (CO) 6 (η 6 -polyolefin)] complexes (M = Fe, Ru) which have in the solid an asymmetric skew-type structure. The use of 13 C NMR techniques, employed for the first time for a diruthenium complex of the above type, allows a comparison of the mechanism of the fluxional process with that of the diiron analog. Although the observed line shape changes of the carbonyl resonances in the two complexes are somewhat different the process are basically the same. In the case of the dirut…

Degradation and stabilization of the polyolefins and of the filled-polyolefins

2009

Synthesis and catalytic properties for olefin polymerization of new vanadium complexes containing silsesquioxane ligands with different denticity

2017

Resistance of Conifer Needle Polyolefin Composites (CNPCs) Against Biodecomposition Caused by Fungi

2017

This study describes the resistance of composites filled with conifer needles to biodecomposition processes caused by a single strain of Aspergillus niger as well as by a consortium of microorganisms present in the compost substrates (forest or spent mushroom composts). The impact of various types of conifer needles on the growth of A. niger was studied to determine whether the filler can show the fungistatic effect. The changes in chemical composition of the composites surfaces were examined using attenuated total reflectance Fourier transform infrared spectroscopy (FTIR/ATR). The results showed that the fungistatic effects of conifer needles polyolefin composites (CNPCs) were associated w…

Convenient Access to α‐Amino‐ω‐Hydroxyl Heterobifunctional PEG and PPO via a Sacrificial Hexahydro‐Triazine Star Strategy

2019

The anionic ring opening polymerizations of ethylene oxide (EO) and propylene oxide (PO) are performed by using 1,3,5-triethanol hexahydro-1,3,5-triazine (TrAz) as a "sacrificial" trifunctional initiator. Well-defined three-arm star polymers are obtained with a narrow molecular weight distribution (M w /M n < 1.1). Molecular weights range from 3-15 kg mol-1 . Since these star polymers possess an acid-labile hexahydro-triazine core, acidic hydrolysis leads to cleavage of the arms. This gives access to well-defined α-amino-ω-hydroxyl heterobifunctional poly(ethylene glycol) (PEG) and poly(propylene oxide) (PPO) in the molecular weight range of 1-5 kg mol-1 and low dispersity M w /M n < 1.1. T…

Copolymerization of ethylene with norbornene or 1-octene using supported ionic liquid systems

2016

Copolymerization of ethylene with norbornene (E/NB) and ethylene with 1-octene (E/Oct) is performed using supported ionic liquid (SIL) systems, in which metallocene (Cp2VCl2) or post-metallocene [VCl2(salenCl2)] vanadium catalysts are immobilized in pyridinium chloroaluminate ionic liquid supported on silica. The studied SIL catalysts show higher activities as well as stability than their non-supported analogues. In addition, higher activities and better comonomer incorporation are observed for norbornene (above 30 mol%). The comonomer incorporation has considerable influence on copolymer molecular weight (M w), melting temperature, crystallinity degree, and microstructure of the copolymers…

Reactive melt blending of functionalized-MW/CNTs with polyolefin

2012

Adding nanotube adding into a polymeric matrix leads to the formulation of nanocomposites with enhanced macroscopical performances, and, moreover, the use of functionalized MW-CNTs leads to the nanocomposite formulation with even better properties. Furthermore, the reactive melt blending can be considered as a powerful processing method, i.e. reasonably simple and ecologically friendly, in order to formulate polymer based nanocomposite with good performance. In this work, the reactive melt blending between an ethylene-acrylic acid co-polymer, bis-oxazoline and functionalized MW-CNTs was performed and the rheological properties of the formulated systems were investigated.

The consequences of physical post-treatments (microwave and electron-beam) on food/packaging interactions: A physicochemical and toxicological approa…

2016

IF 4.052; The safety of microwave and electron-beam treatments has been demonstrated, in regards to the formation of reaction products that could endanger human health. An integrated approach was used combining the potential toxicity of all the substances likely to migrate to their chemical characterizations. This approach was applied to polypropylene (PP) films prepared with a selection of additives. Components were identified by liquid and gas chromatography using a mass selective detector system. Their potential toxicity was assessed using three in vitro short-term bioassays and their migrations were carried out using a standards-based approach. After the electron-beam treatment some add…

Jauni viedie materiāli no multifāzu polimēru kompozīcijām, to fizikāli-mehānisko, deformatīvo un struktūras īpašību izmaiņas jonizējošā starojuma un …

2014

Promocijas darbā pētītas poliolefīnu – multifāzu kompozīcijas ar elastomēriem un šķērssaistīšanās promotoriem. Izvērtēta radiācijķīmiskās modificēšanas un lielas indukcijas magnētiskā lauka (B = 1,0-1,7 T) ietekme uz pētīto kompozītsistēmu stiprības-deformācijas, struktūras īpašībām, kā arī novērtēta magnētiskā lauka un jonizējošā starojuma mijiedarbības ietekme uz poliolefīnu makromolekulu šķērssaistīšanās efektivitāti. Iegūtas jaunas teorētiskas un praktiskas atziņas par radiācijķīmiski modificētu poliolefīnu multifāzu kompozīciju ekspluatācijas īpašībām, kas ļāva radīt jaunus uz polipropilēna bāzētus termonosēdmateriālus.