【Deep Coating Society Coating Technology】Want to test the viscosity of materials? Don't miss these

viscosity

Viscosity is a physical quantity that measures the viscosity of a fluid, and is a measure of the internal friction generated between molecules when the liquid is moved by an external force
.

Why you need a viscosity test

The viscosity of the fluid is closely related to the processing, production and use of materials, so the measurement of viscosity is very important, especially in petroleum, chemical, light industry, coal, metallurgy, transportation and national defense, aerospace and other fields is of great significance
.

In some productions, the viscosity of the fluid needs to be as small as possible
.
For example, to transport crude oil from the oil field to ports, bases, and refineries thousands of miles away, if the viscosity of crude oil is large, the transportation will be difficult and require a large transportation power
.

In other scenarios, the viscosity of the fluid can also be used for production
.
For example, by adding lubricating oil with suitable viscosity between the rotating parts of the machine, the very large dry friction between solids can be turned into a small internal friction inside the liquid, so that the machine can run freely
.

Different types of viscosity tests

According to the viscosity characteristics, fluids can be divided into two basic types: Newtonian fluids and non-Newtonian fluids
.
A fluid whose shear stress at any point is linearly related to the rate of shear deformation is called a Newtonian fluid
.
Fluids that do not satisfy Newton's experimental law of viscosity, i.
e
.
, fluids whose shear stress and shear strain rate are not linear, are non-Newtonian.

According to the different composition of the fluid and different applications, different characterization methods can be used to reflect its viscosity, so that related materials
can be better used in life and production.
The following is an introduction to several viscosity tests:

01 Kinematic viscometer

Kinematic viscosity is the ratio
of the dynamic viscosity of the fluid to the density ρ of the fluid at the same temperature.

In the international system, the kinematic viscosity is s, that is, square meters per second (m2/s), and the actual determination is commonly expressed in centimeters (CST): 1CST=1mm2/s
.

Kinematic viscosity is widely used to determine liquid petroleum products
such as jet fuel oil, diesel, lubricating oil, etc.
We commonly use SYD-265C petroleum kinematic viscosity tester to determine the kinematic viscosity
of petroleum.

This instrument is suitable for determining the kinematic viscosity of liquid petroleum products (referring to Newtonian liquid) under a constant temperature condition according to the standard GB/T265 "Kinematic Viscosity Determination Method and Dynamic Viscosity
Calculation Method of Petroleum Products".

This instrument is equipped with glass capillary viscometers with different inner diameters, which can determine the kinematic viscosity
at different temperatures at room temperature ~ 100 °C.

02 Rotational Viscometer (Brinell Viscometer)

According to the definition of kinematic viscosity, there is also dynamic viscosity
in the fluid.
The resistance generated when two areas of each 1cm2 are taken in the fluid, 1cm apart, and the relative motion speed is 1cm/s is called dynamic viscosity
.
In the international system, the dynamic viscosity is mPa·s
.

Dynamic viscosity is formed under certain external force conditions, commonly used to determine the dynamic viscosity of fluids of the instrument is rotational viscometer, widely used to determine the viscosity
of grease, paint, plastic, food, medicine, cosmetics, glue and other fluids.

Rotary viscometers are further divided into rotary drum viscometers, cone plate viscometers and drop ball viscometers
.
At present, we are equipped with a rotary drum viscometer (rotational viscometer NDJ-8S), which is equipped with a temperature control device and different types of rotors, which can determine fluid products
with different temperatures and viscosities.

It is suitable for the standards "GB/T 15357-2014 Surfactant and Detergent Rotameter Provisions for Determination of Viscosity and Flow Properties of Liquid Products" and "GB/T 22314-2008 Determination of Viscosity of Plastic Epoxy Resin"
.

We can also use a cone plate viscometer (Brookfield) to determine the viscosity of fluids according to the standard "GB 9751.
1-2008 Determination of viscosity
by rotational viscometer for color paints and varnishes Part 1: Cone viscometer operating at high shear rate".

03 Tu-4 cup viscometer

The Tu-4 viscometer method is suitable for coating products with an outflow time of less than 150s, which is S
.
It is often used to measure the viscosity of low-viscosity coating products such as floor varnishes and wood coatings according to the standard "GB/T 1723-1993 Coating Viscosity
Determination".

04 Ou viscometer

Urkovian viscometer is widely used to determine the viscosity, polymerization degree, viscosity of different polymer materials and other test results
.
With the LAUDA PVS1/4 automatic Uwei viscometer, different polymer types can be tested
to the corresponding standard.
The main ones are as follows:

05 rheometer

Rheology is a window to observe the internal structure of polymer materials, through the response of molecular chains of different scales in polymer materials, such as plastics, rubber, resins, the molecular weight and molecular weight distribution of polymer materials can be characterized, and the quality inspection and quality control
of raw materials, intermediate products and final products can be carried out quickly, easily and effectively.

Rheometers are instruments
used to determine the rheological properties of polymer melts, polymer solutions, suspensions, emulsions, coatings, inks and foods.

Rheometers are mainly divided into rotational rheometers, capillary rheometers, torque rheometers and interfacial rheometers
.
At present, microspectroscopy can realize the determination of three rheometers: rotational rheometer, capillary rheometer and torque rheometer
。

Rotational rheometers can study the flow and deformation behavior
of samples ranging from low-viscosity fluids to high-strength solids.
It observes the response data of the sample to the applied load by applying forced steady-state rate load, steady-state stress load, dynamic sinusoidal periodic strain load or dynamic sinusoidal periodic stress load.
By measuring rheological data such as shear rate, shear stress, oscillation frequency, stress-strain amplitude, etc.
, the viscosity, storage modulus, loss modulus, Tan δ and other rheological parameters
of the sample were calculated.
Learn more about rotational rheometer testing services

Microspectral rotational rheometer parameters

• Temperature range: -150~600°C

• Shear rate range: 0.
001~1000s-1

•Equipped with: 25mm flat plate fixture, 25mm conical plate fixture (1°), tensile viscosity fixture, 8mm/25 mm throwable plate fixture

Oscillation frequency sweep measurement of thin film materials

High-pressure capillary rheometers are used to test the flow behavior
of thermoplastic materials and elastomers.
The change curve of shear viscosity of thermoplastics with shear rate, that is, the shear viscosity curve, is obtained mainly through testing, which provides important rheological performance indicators
for the research and development of new products.

Microspectroscopy's high-pressure capillary rheometer can achieve determination according to the standards "ISO 11443-2016" and "ASTM D3835-2016", the test temperature range covers room temperature ~ 400 °C, and the shear rate range is up to 70000s-1
.

Plastic particle viscosity as a function of shear rate (270°C).

Torque rheometers can be used to study the flow, plasticizing, thermal and shear stability of
polymer materials.

In the case of similar actual processing, the dynamic measurement method is used to determine the continuous, accurate and reliable rheological properties of the material, such as the mixing of multi-component materials, the cross-linking curing of thermosetting resin, the vulcanization of elastomers, the dynamic stability of the material and the influence of screw speed on the processing performance of the system, etc.
, as a small test test, the processing of simulated materials and the improvement
of formula and process can be quickly completed.

The torque curve of the polymer material with time at different speeds

Source: Microspectrum

Statement: This number is neutral to reprinting, sharing, statements, and opinions, the purpose is only for industry exchanges, and the copyright belongs to the original author
.
If copyright and intellectual property rights and other infringement issues are involved, please contact this backend to delete the content immediately
.

Gather the ordinary and build greatness together