Search results for "swelling"
showing 10 items of 192 documents
Cyclic moisture sorption and its effects on the thermomechanical properties of epoxy and epoxy/MWCNT nanocomposite
2019
The aim of this work was to reveal the moisture absorption&ndash
Grafting of Maleic Anhydride onto Isotactic Polypropylene in the Presence of Supercritical Carbon Dioxide as a Solvent and Swelling Fluid
2004
Grafting of maleic anhydride (MA) onto isotactic polypropylene (iPP) was carried out by thermal decomposition of dicumylperoxide (DCP) using supercritical carbon dioxide (scCO2) as a solvent and swelling fluid. Provided that the initial concentration of anhydride dissolved in scCO2 is higher than 1% w/w, the grafting occurs without significant molecular weight modification of the polymer, and with a proper selection of the operative conditions, a grafting level higher than 0.5% w/w with respect to the polymer mass was obtained. The amount of grafted MA was determined by FT-IR spectroscopy and polymer degradation was monitored by dynamic mechanical tests in the melt state. The effect of MA a…
On the hydro-mechanical behaviour of a lime-treated embankment during wetting and drying cycles
2018
Abstract The paper presents some experimental results obtained on samples extracted from a full-scale embankment obtained by compacting a lime-treated clayey soil. A comprehensive test programme was carried out in order to highlight the improvement of mechanical behaviour induced by lime treatment as well as to assess the durability of the improved material, which may be affected by severe seasonal wetting and drying cycles. Direct shear tests, triaxial compression tests, swelling potential measurement and oedometric tests were performed on samples cured in controlled environmental conditions for at least 18 months. Wetting and drying cycles were applied in a very wide range of suction valu…
Effect of relative humidity on carvacrol release and permeation properties of chitosan based films and coating
2014
International audience; The influence of water vapour conditions on mass transport and barrier properties of chitosan based films and coatings were studied in relation to surface and structural properties. Water contact angles, material swelling, polymer degradation temperature, barrier properties (PO2, PCO2, WVP) and aroma diffusion coefficients were determined. The solvent nature and the presence of carvacrol influenced the surface and structural properties and then the barrier performance of activated chitosan films. Increasing RH from 0% to 100% led to a significant increase in material swelling. The plasticization effect of water was more pronounced at high humid environment, while at …
Modellvorstellungen und Versuche zur Spannungsrißkorrosion in hochpolymeren Stoffen
1963
Die Vorgange wahrend der Spannungsriskorrossion sind bei Metallen und bei Kunststoffen aus langen Kettenmolekulen wesentlich verschieden. Die innere Beweglichkeit der Kettenmolekule erlaubt es, vor allem in Gegenwart von Quellmitteln oder bei erhohter Temperatur innere Spannungen abzubauen und unter geeigneten Bedingungen Schwachstellen auszuheilen und damit die Neigung zur Risbildung erheblich zu vermindern. Es werden Modellvorstellungen besprochen, welche die drei Hauptwirkungen eines Netzmittels erklaren, namlich die Erhohung der Kerbspannung durch den von der Oberflachendiffusion in Mikrospalten herruhrenden momentanen Quelldruck, die Zeit erfordernde Schwachstellendiffusion, verbunden …
Surface, mechanical and barrier properties of bio-based composite films based on chitosan and whey protein
2014
Mono-component and composite bilayer and blend films composed of chitosan and whey protein were made. Colour, microstructure, water contact angles, swelling, water vapour sorption, barrier properties (oxygen, water vapour), water vapour diffusion coefficients and mechanical properties were determined. The influence of water vapour on barrier properties was studied in relation to the surface and structural properties. Mono-component and bilayer films were transparent with a homogeneous surface. Contrarily, blend films were translucent. Bilayer films had significantly lower water vapour permeability in comparison to mono-component and blend films. In all bilayer films, the air side (chitosan)…
Hydration and water holding properties of cross-linked lignite humic acids
2014
Abstract Lignite and lignite humic acids, which are used as soil amendments sometimes, are supposed to improve soil properties such as water holding capacity. The structure of those materials is composed of various organic molecules stabilized mostly by weak interactions. Therefore, excess of water causes only partial swelling, but most of the physical structure is destabilized. This accelerates the desiccation and hampers their application as natural hydrogel-like substances. In order to stabilize the structure of lignite humic acids and improve the water holding capacity, we applied formaldehyde cross-linking procedure based on covalent coupling of aromatic humic acids moieties. By combin…
The effect of cigarette smoking on the severity of pain, swelling and trismus after the surgical extraction of impacted mandibular third molar.
2012
Objective: The study objective was to investigate the effect of cigarette smoking on the severity of pain, swelling and trismus on male after the surgical removal of impacted lower third molar. Material and Methods: This prospective comparative study was conducted for 150 male in two groups of patients, smokers and non-smokers. Each group consisted of 75 patients; smoking patient were the ones who smoke more than twenty cigarettes per day for more than one year of continuous smoking. Postoperative pain was evaluated using a visual analog scale (VAS) and the degree of swelling was evaluated through facial reference points’ variation. The presence of trismus was analyzed through measurement o…
Corticosteroids use in controlling pain, swelling and trismus after lower third molar surgery use in controlling pain, swelling and trismus after low…
2011
Objectives: A study is made of corticosteroid use in controlling pain, swelling and trismus after lower third molar surgical removal. Material and methods: A Medline search and review was made of all randomized and controlled clinical trials on the effects of corticosteroids upon pain, swelling and trismus after lower third molar surgery. The review was limited to those studies published in the last 10 years. Of the 20 initially considered articles, 6 were finally excluded. Results: A total of 14 articles were included. In 5 of the studies, corticosteroid use resulted in statistically significant reductions in pain after third molar removal. In 7 of the 11 articles that analyzed the effect …
Effect of pre-operatory low-level laser therapy on pain, swelling, and trismus associated with third-molar surgery
2017
Background The extraction of impacted third molars is commonly associated to pain, edema, trismus, limited jaw opening and movements. The aim of this retrospective study is to verify if pre-surgical low-level laser therapy (LLLT) associated with the extraction of impacted lower third molars could add benefits to the postoperative symptoms respect LLLT performed only after surgery. Material and Methods Data from 45 patients subjected to a surgical extraction of lower third molars were pooled and divided into three groups. Patients that received only routine management were inserted in the control group. Group 1, were patients that received LLLT immediately after surgery and at 24 hours. In g…