Search results for "EPO"

Study of the Curing Process of DGEBA Epoxy Resin Through Structural Investigation

2015

In this work, a multi-scale approach with different analytical methods is applied to study the curing process and the structural properties of a diglycidyl ether of bisphenol A (DGEBA) epoxy resin. This monomer, thermally cured using 4,4′-diaminodiphenilsulfone (DDS) as hardener, is analyzed after 10, 45, 90, and 120 min of reaction time at 180 °C to obtain information on samples with different cross-linking densities. Samples are also characterized after extraction in acetone in order to obtain structural information on the insoluble parts. For this purpose, differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA), solid-state nuclear magnetic resonance (ss-NMR),…

Design and synthesis of biobased epoxy thermosets from biorenewable resources

2017

International audience; Biobased diepoxy synthons derived from isoeugenol, eugenol or resorcinol (DGE-isoEu, DGE-Eu and DGER, respectively) have been used as epoxy monomers in replacement of the diglycidyl ether of bisphenol A (DGEBA). Their curing with six different biobased anhydride hardeners leads to fully biobased epoxy thermosets. These materials exhibit interesting thermal and mechanical properties comparable to those obtained with conventional petrosourced DGEBA-based epoxy resins cured in similar conditions. In particular, a high Tg in the range of 90–130 °C and instantaneous moduli higher than 4.3 GPa have been recorded. These good performances are very encouraging, making these n…

Evaluation of Ligno Boost™ softwood kraft lignin epoxidation as an approach for its application in cured epoxy resins

2018

Abstract In this study, modification of LignoBoost™ softwood kraft lignin with epichlorhydrin in water-organic solvents media was realized. Lignin-based epoxy resins were obtained by two ways: acetone extraction of glycidylated lignin or glycidylation of the acetone soluble lignin fraction. The effect of glycidylation regimes on the yields of acetone soluble fractions, their functional composition and physical-chemical characteristics was investigated using wet chemistry methods, FTIR spectroscopy, size exclusion chromatography (SEC) and differential scanning calorimetry (DSC). The positive effect of the biphasic phase transfer catalytic system – KOH/quaternary ammonium salt – on glycidylat…

Dielectric spectroscopy of novel thiol-ene/epoxy thermosets obtained from allyl-modified hyperbranched poly (ethyleneimine) and diglycidylether of bi…

2019

[EN] Dielectric Thermal Analysis (DETA) of a series of new thermoset obtained by click chemistry was performed. The new thermosets were obtained by a dual-curing process consisting in a first photochemical thiol-ene, followed by a thermal thiol-epoxy starting from an allyl-terminated hyperbranched poly(ethyleneimine) (HBPEI) and different proportions of diglycidylether of bisphenol A (DGEBA) and the corresponding stoichiometric proportions of pentaerythritol tetrakis (3-mercaptopropionate, PETMP). The dielectric behaviour was obtained experimentally supressing the conductive effects. Two sub-Tg intramolecular non-cooperative gamma and beta relaxations and an intermolecular cooperative alpha…

Bisphosphonate related osteonecrosis of the jaws in Italy: an observational report of 24 cases

2018

Localized charge storage in nanocrystal memories: Feasibility of a multi-bit cell

2004

We have realized Si nanocrystal memory cells in which the Si dots have been deposited by chemical vapor deposition (CVD) on the tunnel oxide and then covered by a CVD control oxide. In this paper we report a study on the potential of this type of cells for multi-bit storage. In particular, the possibilities offered by these devices from the point of view of program/erase mechanisms, endurance, and charge retention are shown and discussed.

Protocol for Low-level laser therapy in traumatic ulcer after troncular anesthesia: Case report in pediatric dentistry

2020

The aim of this study was to report a protocol of use for low-level laser therapy (LLLT) in traumatic ulcer in the lower lip after inferior alveolar nerve block anesthesia (IANBA). A 3-year-old patient, male, undergoing treatment of carious lesions was submitted to an indirect pulp capping in tooth 74 under IANBA. The procedure was completed without intercurrences, but on next day, the child presented extensive traumatic ulcer in the left lower lip, with complaint of pain. Two sequential applications with LLLT were applied in punctual mode under pressure around the lesion. After 1 week, the mother reported significant improvement. After 30 days, the lesion was fully healed. In conclusion, L…

Role of NO-synthases and cyclooxygenases in the hyperreactivity of male rabbit carotid artery to testosterone under experimental diabetes.

2009

Abstract Cardiovascular disease is the major cause of morbidity and mortality in diabetic patients, which in turn is also associated with low levels of serum testosterone. The working hypothesis was that diabetes might modify the mechanisms involved in the vascular actions of testosterone in isolated rabbit carotid arteries. Testosterone (10 −8 –3 × 10 −4  M) induced a concentration-dependent relaxation of precontracted carotid arteries, which was higher in diabetic than in control rabbits. In control rabbits neither endothelium removal nor the nitric oxide synthase (NOS) inhibitor N G -nitro- l -arginine ( l -NOArg, 10 −5  M) modified the relaxant action of testosterone, and the cyclooxyge…

Glycated albumin as a glycaemic marker in patients with advanced chronic kidney disease and anaemia: a preliminary report.

2019

BACKGROUND: The association between glycated albumin (GA) and glycaemic status has not been fully described in patients with advanced chronic kidney disease (CKD) in relation to anaemia. The aim of this study was to evaluate the relationship between GA and fasting plasma glucose (FPG) and HbA1c in patients with advanced CKD and to evaluate the influence of anaemia in such relationship. MATERIALS AND METHODS: Patients with CKD stage 4 or 5 were included in the study. eGFR was calculated by the CKD-EPI creatinine equation. Plasma GA was measured by an enzymatic method. RESULTS: Eighty-one patients were included in the study, 46 (57%) were males; the mean age was 67 ± 14 years. HbA1c was corre…

Ventricular remodelling in rabbits with sustained high-fat diet.

2013

Aim Excess weight gain and obesity are one of the most serious health problems in the western societies. These conditions enhance risk of cardiac disease and have been linked with increased prevalence for cardiac arrhythmias and sudden death. Our goal was to study the ventricular remodelling occurring in rabbits fed with high-fat diet (HFD) and its potential arrhythmogenic mechanisms. Methods We used 15 NZW rabbits that were randomly assigned to a control (n = 7) or HFD group (n = 8) for 18 weeks. In vivo studies included blood glucose, electrocardiographic, and echocardiographic measurements. Optical mapping was performed in Langendorff-perfused isolated hearts. Results Body weight (3.69 ±…