Search results for "Solidification"

INFLUENCE OF PLASTICIZERS ( OR EXCESS FREE VOLUME ) ON SEMI-CRYSTALLINE POLYESTER BLEND SOLIDIFICATION UNDER PROCESSING CONDITIONS.

2011

SEGREGATION CONTROL AT DIRECTIONAL SOLIDIFICATION USING MAGNETIC FIELD AND ELECTRIC CURRENT

2015

International audience

Determination of impurity distributions in ingots of solar grade silicon by neutron activation analysis

2017

AbstractIn a series of crystallization experiments, the directional solidification of silicon was investigated as a low cost path for the production of silicon wafers for solar cells. Instrumental neutron activation analysis was employed to measure the influence of different crystallization parameters on the distribution of 3d-metal impurities of the produced ingots. A theoretical model describing the involved diffusion and segregation processes during the solidification and cooling of the ingots could be verified by the experimental results. By successive etching of the samples after the irradiation, it could be shown that a layer of at least 60 μm of the samples has to be removed to get r…

Structure and Morphology Control in Polymer Forming Through the Thermal History

2011

Two examples of the application of the Continuous Cooling Transformation (CCT) method for investigating polymer solidification under processing conditions are illustrated. One example concerns the solidification behaviour of syndiotactic polystyrene (sPS) from the melt, showing an anomalous trend of density versus cooling rate, exhibiting a minimum around 1 °C/s. Once phase composition is obtained from WAXD deconvolution, density can be closely predicted, its minimum depending on the competition among crystalline phases upon increasing cooling rate. Another example regards the formation of Poly-Left Lactic Acid (PLLA) foams via Thermally Induced Phase Separation (TIPS) by starting from ther…

Contamination Remediation with Soil Amendments by Immobilization of Heavy Metals

2015

Elektroniskā versija nesatur pielikumus

Polymer Solidification under Pressure and High Cooling Rates

2000

Abstract Polymer solidification under processing conditions is a complex phenomenon in which the kinetics of flow, high thermal gradients and high pressures determine the product morphology. The study of polymer structure formed under pressure has been mainly made using conventional techniques such as dilatometry and differential scanning calorimetry under isothermal conditions or non isothermal conditions but at cooling rates several orders of magnitude lower than those experienced in industrial processes. A new equipment has been recently developed and improved to study the crystallization of polypropylene when subjected to pressure and cooled rapidly. An experimental apparatus essentiall…

Solidification of Polypropylene Under Processing Conditions – Relevance of Cooling Rate, Pressure and Molecular Parameters

2012

Microstructure-process relationship and reactivity at the nanoscale : a molecular dynamics study of Ni, Ni-Al, and Ti-Al metallic systems

2023

The process-microstructure relationship is central in materials science because the microstructure will determine the properties of the materials developed by the processes. In our work, we focused on different metallurgical processes by adopting a description at the atomic scale. This approach allows us to detect the elementary mechanisms that are at the origin of the observed microstructures without having to postulate macroscopic mechanisms or estimate the associated parameters. In this respect, molecular dynamics simulations provide a tool for "in-situ" observation of metallic systems as long as an atomic interaction potential is available. The originality of our approach consists in mo…

The solidification behavior of a PBT/PET blend over a wide range of cooling rate

2009

In recent years, much attention has been paid to the development of high-performance polyester blends, among which blends of polybutylene terephtha- late/polyethylene terephthalate (PBT/PET) are expected to exhibit remarkable prop- erties as far as their crystallization behavior is concerned. Through trial and error, appropriate commercial compositions have been chosen which could not be otherwise explained by a suitable interpretation of the mechanisms determining their solidifica- tion behavior. The solidification behavior of a 60/40 w/w PBT/PET blend was studied in a wide range of cooling conditions, according to a continuous cooling transforma- tion (CCT) procedure developed previously,…

Structure development in poly(ethylene terephthalate) quenched from the melt at high cooling rates: X-ray scattering and microhardness study

2000

The structure and microhardness of poly(ethylene terephthalate) (PET) cooled from the melt, using a wide range of cooling rates, was studied. PET thin films rapidly cooled from the melt (cooling rates larger than 5°C/s) show a continuous variation of structure and properties depending on cooling rate. Results highlight differences in the micro-mechanical properties of the glass suggesting the occurrence of amorphous structures with different degrees of internal chain ordering. The comparative X-ray scattering study of two glassy PET samples (7500 and 17°C/s) reveals the occurrence of frozen-in electron density states giving rise to an excess of scattering for the amorphous sample solidified…