Continue reading »]]> What is Rheology?
Rheology is the study of how a material deforms during and after a force is applied. Rheology directly affects product handling and flow characteristics. Some common measurements used to describe rheology are viscosity, thixotropic index, dispense rate, and sag resistance.
Why is Rheology Important?
Controlling rheological properties is essential for polymeric processing and application.
• Mixing – Rheology effects ease of mixing whether by hand, with a premeasured package, or with a static mix tube.
• Dispensing – Rheology dictates how a material is applied whether by spatula, spray, pump, syringe, cartridge, screen/stencil printing, or pouring. It is influenced by how rapidly viscosity changes once mixed due to the mixture’s chemistry.
• Settling – Rheology affects the degree and rate at which fillers settle. Also important is filler type, particle size, shape, and size distribution. This is especially important for coatings and heavily filled encapsulants.
• Flow Control – Rheology affects the way a material flows. High flow allows easy entry into intricate spaces versus a low flow which prevents flow into critical areas. Flow control is very important during initial application and during the curing process as well.
What Affects Rheology?
• Resin – resin type and molecular weight affects viscosity and surface wetting.
• Formulation – additives and fillers (type, shape, size, size distribution, and surface smoothness).
• Temperature – with epoxies every 1°C change can cause up to a 5-10% change in viscosity.
• Shear – the duration and amount of any force applied to the material. Shear rate measures a constant force.

To the layperson, rheology is
• Mayonnaise does not flow even under stress for a long time; honey always flows
• Silly Putty bounces (is elastic) but also flows (is viscous)
• Dilute flour-water solutions are easy to work with but doughs can be quite temperamental
• Corn starch and water can display strange behavior – poke it slowly and it deforms easily around your finger; punch it rapidly and your fist bounces off of the surface
To the scientist, engineer, or technician, rheology is
• Yield stresses
• Viscoelastic effects
• Memory effects
• Shear thickening and shear thinning

Rheological Classifications
There are two types of fluids: Newtonian and Non-Newtonian.
Newtonian Fluids
These are truly viscous “ideal liquids”, which means as the shear rate changes the viscosity remains constant (water, oils, solvents). Hence if you double the strain rate you will double the stress required.
Non-Newtonian Fluids
These fluids are affected by shear and are divided into Power Law Fluids (Pseudoplastic or Dilatant) and Time Dependent Fluids (Rheopectic or Thixotropic). Most polymers are pseudoplastic and thixotropic.
• Pseudoplastic: As shear increases, viscosity decreases. No matter how long a pseudoplastic material is sheared at a given shear rate, the viscosity will remain the same. Many polymeric systems are pseudoplastic, perhaps the most classic example is mayonnaise.
• Dilatant: These are the opposite of pseudoplastic that is, as shear increases the viscosity increases. Some highly filled materials are dilatant.
• Rheopectic : Viscosity increases as a function of time. Examples would be a mixed epoxy increasing in viscosity as curing takes place or a solvent based adhesive or coating where the viscosity increases as the solvent evaporates.
• Thixotropic: Viscosity decreases over time when using a constant shear rate. As shear rate decreases the material will gradually recover the original internal structure before shear, this can take seconds or days to fully recover. Many times, when a material sits, it will “structure”, this will give a “false” high viscosity reading if the material is not premixed.

Measuring Rheological Properties
Viscosity
A measure of the internal resistance of friction when a material moves against itself. Viscosity can be effected by the resin chemical structure, or the type and amount of filler added. The lowest viscosity materials are unfilled, short chained compounds.
The internal resistance or viscosity is typically measured using a rotating spindle instrument such as a Brookfield viscometer. The amount of force needed to turn the spindle (torque) at a selected speed (RPM) is measured. A simple calculation converts this “internal resistance” to viscosity. There are different surface area spindles used to measure different viscosity ranges.
The higher the torque value, the higher the viscosity. The force is measured as Pascal seconds, Poise or Newton seconds per meter2. One milliPascal second (mPas.) equals one centipoise (cP) or 1×10-4 Newton seconds per meter2. ASTM D 2393 is an example of a common viscosity test procedure used in North America.
Rotational spindle viscometers and cone and plate viscometers are used for most adhesives, encapsulants , inks, and some coatings. The Zahn Cup, Ford Cup, DuPont Parlin, and ISO Cup are some of the methods commonly used for coatings. Their general principal is to measure the time it takes a given volume to gravity feed through a given orifice.
Viscosity Profiles: A viscosity value is usually just one reading taken at a specific shear and temperature. The most descriptive method is the viscosity profile. Cone and plate viscometers can provide continuous, precise measurements over a wide range of shear rates and temperatures.
Viscosity profiles can also be very useful for knowing how viscosity changes during cure. This can be essential in some applications with tightly toleranced flow properties.
Thixotropic Index
A more accurate term would actually be “Pseudoplastic Index”, however, thixotropic index or shear thinning index (STI) have become accepted terms. It gives an indication as to how stiff and non-sag a material will be. A common measurement runs viscosity at two different shear rates such as 1 RPM and 10 RPM. The value recorded at the higher RPM is divided into the value at the lower RPM to obtain the index. Generally materials have thixotropic index values between 1 (high flow) and 5 (low flow or non-sag).
Dispense Rate
A test that usually specifies the orifice size, dispensing pressure and dispensing temperature. Then one either measures the amount of material dispensed in a particular time or the time to dispense a particular amount. Press Flow (often for cartridges), orifice flow, and syringe dispense rate are common dispense rate tests.
Sag Resistance
A special rheological measure for highly thixotropic products. Sag resistance is a measure of the resistance to flow with no shear on the material. Generally a bead of material is applied to a flat surface and the final flow or spread is measured and recorded. The surface angle, temperature, and time are specified by the particular test method.

Source: www.emersoncuming.com and Michigan Tech Chemical Engineering

Continue reading »]]>  Viscosity is a measure of the resistance of fluid to an applied stress. In everyday terms it is like the “thickness” of a fluid or gas. For example, water has a low viscosity so it appears “thin”. In comparison, honey has a higher viscosity, so it appears “thick”. Viscosity essentially describes a liquids internal resistance to flow and may be thought of as a measure of its internal friction.

Continue reading »]]> Summer School
‘’Structured materials : elaboration, rheology and applications”
28th August 2011 – 3rd September 2011

PROGRAM

Sunday, August 28 : arrival Bucharest

Friday, 2 september: excursion

 Saturday, 3 september : departure to Bucharest and France

Continue reading »]]> French Romanian Summer School
Bucharest – Iasi, 28 August – 03 September 2011
“Structured Materials : Elaboration, Rheology and Applications”

organized by Romanian Society of Rheology (SRR) and University Paris Diderot, Sorbonne Paris Cité

Topics
The school will discuss recent research on multi-scale structured materials from the elaboration to the study of properties. In an interdisciplinary approach, this school will address the rapidly growing field interest in structured materials both experimentally and theoretically.

Romania

Bucuresti

Iasi

The program will consist of plenary conferences, oral presentations discussions and visits of laboratories in order to favor exchanges between participants. Social program will be also included.

 Invited speakers

• Corneliu Balan, Politehnica University Bucharest
• René Muller, University of Strasbourg
• Eugen Gheorghiu, Director of International Center of Biodynamics, Bucharest
• Bogdan C. Simionescu, Director of Institute of Macromolecular Chemistry “Petru Poni”, Iasi
• Alain Ponton, University Paris Diderot, Sorbonne Paris Cité
• Constanta Ibanescu, “Gheorghe Asachi” Technical University, Iasi

Contact Persons:

Prof. Diana Brooboana (PU Bucharest): diana.broboana@upb.ro (Phone:+40.744.353135)

Prof. Corneliu Balan (PU Bucharest): corneliu.balan@upb.ro (Phone: +40.744.910420)

Dr. Alain Ponton (University Paris Diderot): alain.ponton@univ-paris-diderot.fr

The school is sponsored by S.C. ROFAROM (Paar-Physica Romanian Representative) and DANTEC Representative Office in Romania.

Continue reading »]]> You can download the full program of the conference if you click HERE.

Dynamics of Complex Fluids Conference

“Petru Poni” Institute of Macromolecular Chemistry
Iasi, ROMANIA
May 5-7, 2011

Organized by:
ROMANIAN SOCIETY OF RHEOLOGY
http://reologie.ro
European Social Fund – “CRISTOFOR I. SIMIONESCU” Postdoctoral Fellowship Programme (POSDRU/89/1.5/S/55216), Sectoral Operational Programme Human Resources Development 2007–2013
http://www.postdoc-icmpp.ro/index.html
“PETRU PONI” Institute of Macromolecular Chemistry
http://www.icmpp.ro/
ROMANIAN CHEMICAL SOCIETY
http://www.schr.org.ro

CONFERENCE SCHEDULE

Thursday, 5 May 2011

8.00 – 9.00 Registration

9.00 – 9.30 Opening Ceremony

9.30 – 10.15 Plenary Conference

10.15 – 11.00 Plenary Conference

11.00 – 11.30 Coffee Break

11.30 – 13.00 Visit of “Petru Poni” Institute of Macromolecular Chemistry

13.00 – 14.00 Lunch

14.00 – 14.45 Plenary Conference

14.45 – 15.30 Plenary Conference

15.30 – 16.00 Coffee Break

16.00 – 17.20 Oral Presentations

17.20 – 18.50 Posters Session

19.00 Conference Dinner

Friday, 6 May 2011

9.00 – 9.45 Plenary Conference

9.45 – 10.30 Plenary Conference

10.30 – 11.00 Coffee Break

11.00 – 13.00 Oral Presentations

13.00 – 14.00 Lunch

14.00 – 18.00 Round Table

Saturday, 7 May 2011

9.00 – 10.00 Closing Remarks

10.00 – 18.00 Iasi Visit

Continue reading »]]> You can download the document if you click HERE.

European Social Fund – CRISTOFOR I. SIMIONESCU - Postdoctoral Fellowship Programme (POSDRU/89/1.5/S/55216), Sectoral Operational Programme Human Resources Development 2007–2013 http://www.postdoc-icmpp.ro/index.html

SRR – Romanian Society of Rheology

"Petru Poni" Institute of Macromolecular Chemistry, Iasi

SChR – Romanian Chemical Society

LOCATION: Petru Poni Institute of Macromolecular Chemistry, Iasi, Romania

CONFERENCE: Dynamics of Complex Fluids May 5-7, 2011 Iasi, Romania

All interested colleagues are invited to present and to discuss current results in the field of complex fluids (design and flow properties). Please submit your paper (title, authors, affiliation, a short abstract of maximum 400 words, with the specification of type of presentation) until February 28, 2011, to the conference office.

The conference is organised by „Cristofor I. Simionescu” Postdoctoral Fellowship Programme (POSDRU/89/1.5/S/55216), project co-financed by European Social Fund, Sectoral Operational Programme Human Resources Development 2007 – 2013, Priority axis 1, Major domain 1.5.
The conference Dynamics of Complex Fluids represents the 4^th event within the series of meetings organized by Romanian Society of Rheology . The aim of this conference is to get-together specialists interested in Flow and Design of Complex Fluids from Romania and abroad.
The profile of the Conference includes:
o Plenary Conferences (45 minutes)
o Lectures (20 minutes)
o Poster Communications
Conference Language is English.

Important deadlines:
Abstract submission deadline: February 28, 2011
Notification of acceptance: March 15, 2011
Full paper submission: April 10, 2011

Accomodation
Please book your accommodation using the appropriate hotel agencies or directly in hotels of Iasi.

Conference fee: 50 Euro/participant
The fee includes: Conference package, 2 Lunches, Conference Dinner, Coffee breaks.
The participants interested for one day excursion (7 May 2011) to Neamt Monasteries should mention on the Registration File and should support an extra-fee of 30 Euro.

Map of Iasi

Some pictures of Iasi:

This event also appears on Chemistry Conferences, All Conferences, Applied Rheology and Facebook.

Continue reading »]]> In a compilation of 4 short, educational videos called “Chemistry Matters“, 16 Nobel Laureates discuss new frontiers in their field and explore what life as a chemist entails. They also describe the beauty inherent in chemistry and recall the eureka moments when they discovered ‘a little of nature’s logic’. Designed for students aspiring to a career in chemistry, these videos also pay tribute to and celebrate the International Year of Chemistry 2011.

Enjoy!

Episode 1: Beyound the Textbook
Learn about chemistry’s many facets and why would one claim that chemistry is the ‘queen of all sciences’.

Episode 2: The Life of a Chemist
Explore how Nobel Laureates compare their own research to the adventures of Huckleberry Finn.

Episode 3: Beauty
From molecules to equations to experiments, learn how and why chemistry is beautiful.

Episode 4: Eureka!
Discover how groundbreaking discoveries are both thrilling and lonely.

Materials from Nobelprize.org

Continue reading »]]>

ICR 2012 Logo

August 05-10, 2012
ICR 2012 – XVIth International Congress on Rheology
Location: Joao Maia, Portugal
Contact: Prof. Joao Maia
(E-mail: joao.maia@case.edu; Tel: +1-216-368-6372;
Fax: +1-216-368-4202; Skype: jmaia.dep)

The website of the ICR 2012 – XVIth International Congress on Rheology is now available, with all the latest information on the technical and social programmes, deadlines, information on Lisbon, accomodation and travel, etc.

You are cordially invited to visit it and pre-register for free to receive all the website and conference updates by e-mail.

The Congress convenes every four years and brings together the world’s leading rheologists to present the latest advances and developments in this field. In addition, two short courses will be offered on the weekend before the Congress, August 3-4, 2012.

The Congress will have fifteen symposia covering all the aspects of Rheology and will take place in the Belém Cultural Center, a modern Conference and Arts Center located on the Lisbon riverfront next to several historical buildings and landmarks. We have prepared a Pre-registration facility so that you can receive first hand all the news on the conference and updates to the site, so that you can always be abreast of the latest developments.

Lisbon was founded by the Phoenicians, styled by the Moors and certainly enriched by the spice trade in the golden age of its overseas connections. It is one of Europe’s historic capitals, a blend of unusual character and charm and an amalgam of 800 years of cultural influences mingled with modern trends and life style creating spectacular contrasts. Spread across seven hills always opening a window towards the majestic Tagus river, Lisbon invites you.

In addition to the technical program, there will be an active social program not only during the conference but also before and after, so that this trip may also be an unforgettable family and social one.

TECHNICAL PROGRAM

Organizing Commitee
João Maia, Case Western Reserve University, Local Organizer
Crispulo Gallegos: University of Huelva, Technical Program Organizer
Igor Emri, University of Ljubljana, Technical Program Organizer

Scientific Comitee - consists in the International Delegates of the ICR member and associate societies (more information) and the Symposia Organizers.

Local Commitee
João Maia, Case Western Reserve University
Isabel Sousa, Agronomy College, Technical University of Lisbon
Anabela Raymundo, Piaget Institute
Maria Teresa Cidade, New University of Lisbon
Fátima Piteira, Dyrup Paints Lda
Cristiana Nunes, Piaget Institute
Bartolomeu Alvarenga, Beja Polytechnic Institute
Jose Maria Franco, University of Huelva
Catarina Leal, Lisbon Higher Institute of Engineering

The list of symposia and respective organizers is the following:
Non-Newtonian Fluid Mechanics: R. P. Chabra, Paulo Souza-Mendes
Constitutive and Computational Modeling: Mike Webster, Evelyne Van Ruymbeke
Advanced Experimental Methods: Malcolm Mackley, Manfred Wilhelm
Materials Processing: Jae Hyun, José Covas
Interfacial Rheology, Micro-rheology & Microfluidics: Gareth McKinley, Jan Vermant
Colloids and Suspensions: Dan Klingenberg, Norm Wagner
Emulsions and Foams: Peter Fischer, Pier Luca Maffettone
Biopolymers, Biofluids and Foods: Mats Stading, Rhodri Williams
Polymer Solutions, Melts and Blends: Hiroshi Watanabe, Chris Macosko
Associative Polymers, Surfactants and Liquid Crystals: Octavio Manero, Saad Khan
Solids and Granular Materials: Honbing Lu, Dietmar Drummer
Industrial Rheology: Jan Engmann, David Boger
Complex Flows: Philippe Coussot, Lionel Choplin
General Rheology: Antxon Santamaria, Alex Malkin
In addition, there will be three Special Symposia:
Professor Ken Walters Commemorative Symposium: David Binding
Non-Conventional Rate Effects in Materials: Igor Emri
Rheology of Bio-Pharmaceutical Systems: Crispulo Gallegos, Jai Pathak

Plenary Lectures:
Paula Moldenaers, Catholic University of Leuven, Belgium
Mosto Bousmina, Hassan II Academy of Science and Technology – INANOTECH, Morocco
Wolfgang Knauss, Caltech, USA
Philipe Tanguy, Total S.A., France

The most important deadlines to be:
Abstract submission: December 15, 2011
Notification of acceptance/refusal: February 15, 2012
Early bird registration: March 15, 2012
Regular registration and cut-off date for inclusion in the program and book of abstracts: April 15, 2012
NOTE: These deadlines are not final, so please stay updated.

www.youtube.com/watch?v=OEKykb5zfnE

Continue reading »]]> The International Year of Chemistry 2011 (IYC 2011) is a worldwide celebration of the achievements of chemistry and its contributions to the well-being of humankind. Under the unifying theme “Chemistry – our life, our future”, IYC 2011 will offer a range of interactive, entertaining, and educational activities for all ages. The Year of Chemistry is intended to reach across the globe, with opportunities for public participation at the local, regional, and national level.

The goals of IYC2011 are to increase the public appreciation of chemistry in meeting world needs, to encourage interest in chemistry among young people, and to generate enthusiasm for the creative future of chemistry. The year 2011 will coincide with the 100th anniversary of the Nobel Prize awarded to Madame Marie Curie – an opportunity to celebrate the contributions of women to science. The year will also be the 100th anniversary of the founding of the International Association of Chemical Societies, providing a chance to highlight the benefits of international scientific collaboration.
IYC 2011 events will emphasize that chemistry is a creative science essential for sustainability and improvements to our way of life. Activities, such as lectures, exhibits, and hands-on experiments, will explore how chemical research is critical for solving our most vexing global problems involving food, water, health, energy, transportation, and more.
In addition, the Year of Chemistry will help enhance international cooperation by serving as a focal point or information source for activities by national chemical societies, educational institutions, industry, governmental, and non-governmental organizations.
The IYC 2011 is an initiative of IUPAC, the International Union of Pure and Applied Chemistry, and of UNESCO, the United Nations Educational, Scientific, and Cultural Organization. It involves chemical societies, academies, and institutions worldwide, and relies on individual initiatives to organize local and regional activities.

Get Involved
You can participate, too, sharing what you plan to do for IYC 2011. You are able to submit and share an idea on the official website, and record the details of the activity that you plan to host in 2011. To be eligible, an IYC activity and event must address at least one of the year’s objectives, which are as follows:

• Increase the public appreciation and understanding of chemistry in meeting world needs
• Encourage the interest of young people in chemistry
• Generate enthusiasm for the creative future of chemistry
• Celebrate the role of women in chemistry or major historical events in chemistry, including the centenaries of Mme. Curie’s Nobel Prize and the founding of the International Association of Chemical Societies
Typical events or activities could be at the local, state, regional, or national level, and might include:
• Treating all levels of students, from preschool children to university students, to chemistry demonstrations at appropriate levels
• Organizing visits for members of the public to industrial sites, including manufacturers, chemical producers, or metal and petroleum refiners
• Publicizing the contributions that chemistry makes to the global economy by submitting articles to newspapers and magazines or developing television and radio programs
• Sponsoring poster exhibitions highlighting the usefulness and wonder of chemistry
• Organizing problem-solving projects through which students can use their knowledge of chemistry to develop solutions to local problems
• Publicizing the contributions that chemistry has made to improve lives, particularly recent developments in chemical research
• Holding career fairs at schools at which professionals show how they use chemistry in their jobs.
• Organizing hands-on activities and demonstrations to help participants gain an understanding of what it would be like to work in a chemistry-related field
• Interacting with government leaders to underscore the importance of a strong chemical enterprise

www.youtube.com/watch?v=IqGJ1URMJ-g

Visit the Ideas section to find out what people are thinking about, or browse the Activities section to see what people are actually planning.

2011 is Chemistry’s year, sharing its limelight with another international celebration – forests. The International Year of Chemistry (popularly abbreviated as IYC 2011) is an excellent window of opportunity for chemists, chemical educators, chemical scientists all over the globe. As the celebration involves sharing of ideas and later brainstorm them into understanding to a wider audience is already ongoing at various societies like the ACS, RSC and other related organisations.

IYC 2011 is a great opportunity to help the rest of the world understand the crucial role chemistry plays in meeting serious challenges. Topics are widely discussed with a thrust on Environment, Energy, Health and Materials. Being a follower of the every day events taking place in IYC , it definitely provides a focal point for the past successes and the future potential of chemistry- a central science.

The video shared below gives a clear message to a wider audience.

Also, you can watch a IYC2011 webinar HERE.

Continue reading »]]> ROMANIAN SOCIETY OF RHEOLOGY

European Social Fund – “CRISTOFOR I. SIMIONESCU” Postdoctoral Fellowship Programme (IDPOSDRU/89/1.5/S/55216), Sectoral Operational Programme Human Resources Development 2007–2013,

“Petru Poni“Institute of Macromolecular Chemistry

ROMANIAN SOCIETY OF CHEMISTRY

invite you to participate at Conference :

Dynamics of Complex Fluids

which will take place on 5-7 May 2011, at “Petru Poni” Institute of Macromolecular Chemistry, 41-A Ghigore Ghica Voda Alley, 700487 Iasi, Romania.

Contact: reologie@icmpp.ro

Organisers:

Contact by mail:
Dr. Simona Morariu
41-A, Grigore Ghica Voda Alley, 700487 Iasi, Room 119
Tel: ++40 232-241012 / 150
Fax: ++40 232-211299
E-mail: reologie@icmpp.ro

All interested colleagues are invited to present and to discuss current results in the field of complex fluids (design and flow properties). Please submit your paper (title, authors, affiliation, a short abstract of maximum 400 words, with the specification of type of presentation) until February 28, 2011 to the conference office.