Home  About us  Contact
 

Suitable Additives (suitable + additive)

Distribution by Scientific Domains
Polymers and Materials Science75%

Selected Abstracts

Effects of additives on oxidation characteristics of palm oil-based trimethylolpropane ester in hydraulics applications

EUROPEAN JOURNAL OF LIPID SCIENCE AND TECHNOLOGY, Issue 4 2009
Nor Halaliza Alias
Abstract Hydraulic fluids represent one of the most important groups of industrial lubricants. Increasing attention to environmental issues drives the lubricant industry to choose vegetable-based hydraulic fluids which are biodegradable as compared to mineral-based fluids. However, the lubricating properties of vegetable oil, such as poor oxidative stability and high pour point, have hindered their use. In this study, trimethylolpropane ester, which was derived from palm-based methyl ester, was used as the base hydraulic fluid. The purpose of the study was to determine the optimum formulation for palm oil-based synthetic lubricants by using suitable additives that can improve the oxidative stability and viscosity in accordance with the standard regulations for hydraulic fluid applications. The oxidative stability of the oil was evaluated by total acid number (TAN) and viscosity tests. In general, base oil without additive began to degrade after 200,h. The formulated oil, on the other hand, was quite stable even after 800,h of operation. The best formulation was obtained using 1.0% of either additive,A or additive,B. Both TAN and viscosity values were found to increase with increasing heating temperature. Meanwhile, the results have also shown that additive,A performs better than additive,B. After 800,h of exposure, the final TAN value for the formulated oil was only at 0.32 as compared to 4.88,mg KOH/g for the oil without additive. However, the kinematic viscosity of the oil at 40 and 100,°C was almost unchanged as compared to the oil without additive. [source]

Architecture of Supramolecular Soft Functional Materials: From Understanding to Micro-/Nanoscale Engineering

ADVANCED FUNCTIONAL MATERIALS, Issue 19 2010
Jing-Liang Li
Abstract This article gives an overview of the current progress of a class of supramolecular soft materials consisting of fiber networks and the trapped liquid. After discussing the up-to-date knowledge on the types of fiber networks and the correlation to the rheological properties, the gelation mechanism turns out to be one of the key subjects for this review. In this concern, the following two aspects will be focused upon: the single fiber network formation and the multi-domain fiber network formation of this type of material. Concerning the fiber network formation, taking place via nucleation, and the nucleation-mediated growth and branching mechanism, the theoretical basis of crystallographic mismatch nucleation that governs fiber branching and formation of three-dimensional fiber networks is presented. In connection to the multi-domain fiber network formation, which is governed by the primary nucleation and the subsequent formation of single fiber networks from nucleation centers, the control of the primary nucleation rate will be considered. Based on the understanding on the the gelation mechanism, the engineering strategies of soft functional materials of this type will be systematically discussed. These include the control of the nucleation and branching-controlled fiber network formation in terms of tuning the thermodynamic driving force of the gelling system and introducing suitable additives, as well as introducing ultrasound. Finally, a summary and the outlook of future research on the basis of the nucleation-growth-controlled fiber network formation are given. [source]

Architecture of Supramolecular Soft Functional Materials: From Understanding to Micro-/Nanoscale Engineering

ADVANCED FUNCTIONAL MATERIALS, Issue 19 2010
Jing-Liang Li
Abstract This article gives an overview of the current progress of a class of supramolecular soft materials consisting of fiber networks and the trapped liquid. After discussing the up-to-date knowledge on the types of fiber networks and the correlation to the rheological properties, the gelation mechanism turns out to be one of the key subjects for this review. In this concern, the following two aspects will be focused upon: the single fiber network formation and the multi-domain fiber network formation of this type of material. Concerning the fiber network formation, taking place via nucleation, and the nucleation-mediated growth and branching mechanism, the theoretical basis of crystallographic mismatch nucleation that governs fiber branching and formation of three-dimensional fiber networks is presented. In connection to the multi-domain fiber network formation, which is governed by the primary nucleation and the subsequent formation of single fiber networks from nucleation centers, the control of the primary nucleation rate will be considered. Based on the understanding on the the gelation mechanism, the engineering strategies of soft functional materials of this type will be systematically discussed. These include the control of the nucleation and branching-controlled fiber network formation in terms of tuning the thermodynamic driving force of the gelling system and introducing suitable additives, as well as introducing ultrasound. Finally, a summary and the outlook of future research on the basis of the nucleation-growth-controlled fiber network formation are given. [source]

Processability and Properties of Re-Graded, Photo-Oxidized Post-Consumer Greenhouse Films

MACROMOLECULAR MATERIALS & ENGINEERING, Issue 10 2005
Francesco Paolo La Mantia
Abstract Summary: The recycling of post-consumer plastics leads, in general, to secondary materials having properties worse than those of the reclaimed material and certainly worse than those of the same virgin polymer. This is because of the degradation undergone by the objects during their use and because of the thermo-mechanical degradation undergone during the reprocessing operations. The change of the molecular architecture is responsible for this worsening of properties. The use of stabilizing systems can slow the degradation during the melt processing but cannot give any improvement of the final properties of the material. In order to enhance the properties of the recycled plastics, some rebuilding of the molecular structure is necessary. The use of suitable additives can enlarge the molecular weight distribution or can create branching and cross-linking during the melt processing of the photo-oxidized PE. The processability in film blowing and the mechanical properties of these secondary materials are reported in this work. The rheological behavior, the filmability and most of the mechanical properties of the secondary PE with the rebuilt molecular structure are better than those of the post-consumer material and similar to those of the virgin polymer. TS in the machine and in the transverse direction for all the samples extruded at 50 rpm. [source]