Flow rate and viscosity testing - preferably in Hong Kong or China

[hkmensing]

Dear All,

Does anyone know whether there are labs in [green]Hong Kong[/green] or [green]China[/green], where I can do any of the following tests:

[blue]Melt Flow Index (MFI) - Melt Flow Rate (MFR): ASTM D 1238 (Procedure A), D3364, ISO 1133 (Procedure A)[/blue]
Scope: Melt Flow Rate measures the rate of extrusion of thermoplastics through an orifice at a prescribed temperature and load. It provides a means of measuring flow of a melted material which can be used to differentiate grades as with polyethylene, or determine the extent of degradation of the plastic as a result of moulding. Degraded materials would generally flow more as a result of reduced molecular weight, and could exhibit reduced physical properties. Typically, flow rates for a part and the resin it is moulded from are determined, then a percentage difference can be calculated. Alternatively, comparisons between "good" parts and "bad" parts may be of value.

[blue]Dilute Solution Viscosity of Polymers - Inherent Viscosity, Intrinsic Viscosity, Relative Viscosity: ASTM D2857/D 4603/D 2857[/blue]
Scope: Dilute Solution Viscosity is used as an indication of the molecular weight of polymers. The results of the test are expressed in Relative Viscosity, Inherent Viscosity, or Intrinsic Viscosity. It is used for polymers that dissolve completely without chemical reaction or degradation and can provide an excellent determination of lot-to-lot consistency or be used to compare moulded parts to original resin for determinations of degradation from moulding.

[red]Or does anyone have any idea on other types of tests to determine the quality of plastics? Also preferably in [green]Hong Kong[/green] or [green]China[/green].[/red]

Cheers,

GM

 

[patprimmer]

Any university or polytechnic, or technical college with a plastics or textiles technology department or courses in those subjects should be able to do these relatively basic tests

Regards
pat pprimmer@acay.com.au
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[benutella]

hi, hkmensing
^Q^
nice to meet you!
i am also making some research on viscoelastic property about glass fibre, now i have some questions about modeling using maxwell and kelvin element.
do you have any idear about it?
thank you very much!

 

[jmw]

You can measure MFI in process.

A web search under melt flow index (MFI) should find a number of on-line instruments.
A typical device is basically a short capillary tube through which a small sample flow of polymer is pumped at constant flow. The change in dynamic viscosity causes a change in pressure drop which is measured and scaled accordingly.

Some applications use process rotational viscometers (Couette type) as these will operate at high temperature and pressure, sufficient for many polymer applications.

When dissolving the polymer in solvent you can use either a process viscometer or a lab viscometer, e.g. a rotational type which operates at constant shear. Again, the measurement is of dynamic viscosity.

The ASTM standard for molecular weight (can't remember the number) actually correlates kinematic viscosity with molecular weight but density should not vary significantly, in many cases the dynamic viscosity is sufficient. In the lab you would expect to measure the density separately.

The new digital viscometers measure density and dynamic viscosity so you can get kinematic viscosity but i have never found an equation solution for molecular weight from viscosity (if anyone knows of an equation solution, please let me know) so it is back to the tables etc in ASTM. However, for a single product process, well documented, the relationship between dynamic viscosity at the measurement temperature with molecular weight can possibly be treated as linear within the process limits and to the limits of accuracy required for closed loop control if looking for process measurement.

A typical application of the digital viscometers is in end point spotting in batch and continuous production of methyl methacrylates, for example. The software is often capable of correcting for process temperature variation (using ASTM D341 equation as a model) but as I say, the final correction to molecular weight depends on tables.

JMW

http://www.viscoanalyser.com

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[hkmensing]

Hi All,

Someone informed me that there is a better test called: [red]Gel-permeation chromatography (GPC)[/red]. It's supposed to be quicker than the above mentioned. Anyone know of labs in Hong Kong and/or China which can do this test?
I know one University [blue](University of Hong Kong - Chemistry Department)[/blue] that can do it here, but would like more locations, if possible.

Cheers,

GM

 

[mrswax]

Hi to all,
I have to points here:

1) I am working on the rotational viscometer to measure dynamic viscosity through relation ship between shear rate and shear stress, if I want to calculate kinematic viscosity which value I should take for my calculation because I have many point lets say from 0-1000 s-1 shear rate is it correct if I take the first point as dyanamic viscosity?
2) could you please help me to find ASTM method for wax appearance temperature. I just found ASTM for transition temperature which is D4419-90.

if you have idea please let me know
many thanks