Using Ubbelohde viscometer one-point method to determine the intrinsic viscosity

Material: a triangular flask

Two 10ml pipettes

Ubbelohde viscometer (capillary 0.5mm)

A water bath (temperature control accuracy of ± 0.1 ℃)

A stopwatch

Rubber hose two sections

A syringe

Wash the ear ball one

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step:

1, the system solution: Take a certain amount of polymer, add 10mm solvent, make it completely dissolved, if necessary, heated.

2, constant temperature: installed device, stable temperature up and down changes 0.1 ℃.

3, plus the solution balance 5min: up and down into the capillary tube three times.

4, determination: measured three sets of data, so that the deviation but 0.2s.

5, Determination of solvent flow time.

data processing:

ηr = t / t0 (t is the solution flow time, t0 solvent time)

ηsp = ηr-1

[η] = [2 (ηsp-ηr)] / C (C is the concentration unit g / ml)

[η] = (ηSP / C) c = 0 = (ln ηr / C) c = 0 [η] = KMα

Remove the pipette has been pre-heated solution 10ml, into the viscometer, the same method, the installation of viscometer, the determination of the solution outflow time t. Then followed by adding 2.00,3.00,5.00,10.00 ml of distilled water.

Kent Yuan (Mr.) Hangzhou Zhongwang Technology Co., LTD. Skype: kenyuan9023   Wechat/WhatsApp:+86 15068109723E lei@zonwon.com  W www.zonwontech.com

Various viscosity measurement formula

Kinematic viscosity: V = K * (t-Δt)

Dynamic viscosity: η = K * (t - Δt) * ρ

Limit Viscosity --- ISO 1628/1 Schulz-Blaschke formula: [η] = I / (1 + K '· I · C)

Ultimate Viscosity --- Huggins Formula: [η] = [(1 + 4KHηsp) 1/2 -1] / 2KH · C

Ultimate Viscosity --- Kraemer Formula: [η] = [1 - (1 - 4β lnηr) 1/2] / 2 β · C

Solvent-Solomon-Ciuta equation: [η] = [2 (ηsp-lnηr)] 1/2 / C

Limiting viscosity number --- Malone Maron formula: [η] = (γlnηr + ηsp) / (1 + γ) · C

The ultimate viscosity --- Dong's formula [η] = (2lnηr + ηsp) / 3 · C.

Limit Viscosity --- Billmeyer formula: [η] = (3lnηr + ηsp) / 4 · C

Limiting viscosity - Martin Martin Log I = log [η] + K [η] · C.

Limit Viscosity --- Linear Extrapolation: Measure the viscosities and logarithm viscosities of more than three different concentrations of dilute polymer solutions for linear extrapolation to determine the limiting viscosity.

Relative viscosity: ηr = (t - Δt) / (t0 - Δt0)

Viscosity number: I = (ηr-1) / C

K value for polyvinyl chloride and polyvinyl alcohol according to the Fickentscher formula: K = 1000 {a - 1 + [1 + (2 / C + 2+ a) a] 1/2} / (150 + 300C)

Where: a = 1.5 logηr

The above limit viscosity number measurement, such as the input Mark -houwink formula K, α value can be calculated viscosity average molecular weight.

M = ([η] / K) 1 / α

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Kent Yuan (Mr.) Hangzhou Zhongwang Technology Co., LTD. Skype: kenyuan9023   Wechat/WhatsApp:+86 15068109723E lei@zonwon.com  W www.zonwontech.com

Influence of Test Temperature on Polyester Chips Viscosity

Influence of Test Temperature on Polyester Chips Viscosity

Abstract: Testing result indicates that polyester chips viscosity are very sensitive to the test temperature. So it requires to control the temperature precision range strictly . Therefore, an ideal constant temperature water bath is necessary to get the reliable result of the viscosity.

Polyester resin in the field of polymer occupy a leading position, it is not only high strength, good heat resistance, non-toxic, and good insulation. By different processing means, it can be made in the film, in the audio and video tapes, lighting film, food packaging, for high-strength composite film, and can be processed into different types of beverage bottles and electrical parts. Polyester chips are also important raw materials for the chemical fiber industry. Spinning polyester chips must maintain a high purity. So the inspection department to each batch of products to conduct a series of performance indicators to ensure the quality of the batch. The viscosity index indirectly represents the size of the molecular weight, which directly affects the quality of the finished polyester yarn, and the test temperature is particularly sensitive to the viscosity, so the required test temperature range must be strictly controlled.

Polyester chips are specified in the relevant standard method by dissolving one or two mixed solvents at a certain temperature to a certain concentration and then measuring the solvent at a specified test temperature by an Ubbelohde viscometer (having a defined capillary diameter) And the time the solution flows, converted into relative viscosity and intrinsic viscosity. ASTMD2857 specified test temperature accuracy of ± 0.01 ~ 0.02 ℃, ISO12228 specified test temperature accuracy of ± 0.05 ℃, China is the national standard in principle to the ISO closer to the set, also set to ± 0.05 ℃

Select the Taiwan polyester chips (contract, the intrinsic viscosity IV0.645 ± 0.015) set the temperature of the thermostat different temperature for the test to observe the changes in viscosity:

1. Test conditions

Solvent: mixed solvent, weight ratio of phenol: tetrachloroethane = 3: 2

Solution concentration: 0.5%

Test temperature: 25.00 ~ 25.08 ℃

2. Accuracy measurement at different temperatures

Table 1 Effect of temperature on the determination of PET slice adhesion

The same time as

Test temperature ° C Relative viscosity Viscosity

25.00  1.363  0.645

25.01  1.363  0.645

25.02  1.360  0.641

25.05  1.355  0.634

25.08  1.350  0.625

From the data of Table 1, the intrinsic viscosity value decreases with increasing temperature, the temperature rises by 0.01 ℃ Viscosity is not affected; the temperature rises 0.02 ℃, the intrinsic viscosity decreases 0.004; when the temperature rises to 0.05 ℃, the intrinsic viscosity decreases 0.011; To 0.08 ℃, the intrinsic viscosity dropped to 0.021, has been outside the scope of the contract. This shows that the temperature parameters directly affect the size of the viscosity, it is necessary to strictly control the temperature accuracy range, the determination of the results can be a reliable guarantee.

3. Need to pay attention to the problem

Determination of viscosity method is not complicated, but in order to ensure the correctness of the test results must be strictly to the various test links, try to avoid errors. This is mainly: ① weighing; ② solution preparation; ③ viscometer cleaning; ④ viscosity determination of the viscosity of the vertical degree; ⑤ visual line when the level of the situation; ⑥ timer press speed; ⑦ constant temperature water bath temperature The

Among them, the constant temperature water bath temperature control accuracy is determined by the thermostat, and the visual line of the error is also determined by the thermostat, especially those observation window for the arc when the marking line blurred, the greater the error. In addition, it is almost entirely determined by the quality of the inspectors. Therefore, the configuration of an ideal precision constant temperature water bath is a guarantee of an important device for viscosity determination.

The same time as

At present, the domestic production of the thermostat groove accuracy is rarely higher than ± 0.05 ℃, roughly, seems to meet some of the international standards and the implementation of the new national standard, but in fact, due to uneven temperature distribution throughout the tank, With the temperature control temperature fluctuations, the overall control accuracy is clearly inferior to 0.05 ℃, especially in the factory application, a number of viscometer placed in different locations, this phenomenon even more directly affect the test data, while , The thermostatic bath with the refrigeration system is far from being extended, and the viscosity test also brings a lot of trouble (generally, there is no cooling system of the thermostat, only when the room temperature is lower than the test temperature of 5 ℃, to ensure that the temperature control Precision).

What is the true 0.01 ° C temperature control accuracy?

The same time as after adjusting the temperature of the thermostat, from today to tomorrow, the temperature changes, not more than 0.01 ℃, and the temperature inside the thermostat tank temperature distribution is poor, not more than 0.01 ℃.

Kent Yuan (Mr.) Hangzhou Zhongwang Technology Co., LTD.

P  /Wahtsapp: +86 15068109723  E lei@zonwon.com

K, α value of Some Common Polymer

K, α value of Some Common Polymer 

Abstract:

Polymer, Polymerization Method, Molecular Weight Range, Solvent Temperature K Value, Polystyrene (PS) Solution Polymerization 3-1700 Toluene 25 ° C 1.7 0.69 1-11 Benzene 25 ° C 4.17 0.60 5.9-5.2 Benzene 20 ° C 1.23 0.72 330-Benzene 30 ° C 1.1 0.73 polymethylmethacrylate bulk polymerization 70-6300 benzene 25 ° C 0.468 0.77 (PMMA) 240-4500 benzene 25 ° C 0.38 0.70 emulsion polymerization 410-3400 acetone 25 ° C 0.96 0.69 410-3400 toluene 25 ° C 0.71 0.73 410-3400 Chloroform 25 ° C 0.34 0.83 styrene-butadiene rubber (SBR) emulsion polymerization 25-500 toluene 25 ° C 5.25 0.66 emulsion polymerization 50 ° C 26-1740 toluene 30 ° C 1.65 0.73 emulsion polymerization 5 ° C 55-1000 toluene 30 ° C 2.95 0.75 natural rubber (NR) 0

Polymer	Polymerization Method	Molecular Weight Range	Solvent	Temperature	K Value	α Value
Polystyrene (PS)	solution polymerization	3-1700	Toluene	25 ° C	1.7	0.69
		1-11	benzene	25 °C	4.17	0.60
		5.9-5.2	benzene	20 ° C	1.23	0.72
		330-	benzene	30 ° C	1.1	0.73
Poly (methyl methacrylate) （PMMA）	Polymerization	70-6300	Benzene	25 ° C	0.468	0.77
		240-4500	benzene	25 ° C	0.38	0.70
	Emulsion Polymerization	410-3400	Acetone	25 ° C	0.96	0.69
		410-3400	Toluene	25 ° C	0.71	0.73
		410-3400	Chloroform	25 ° C	0.34	0.83
Styrene-butadiene rubber (SBR)	emulsion polymerization	25-500	Toluene	25 ° C	5.25	0.66
	Emulsion Polymerization 50 ° C	26-1740	Toluene	30 ° C	1.65	0.73
	Emulsion Polymerization 5 ° C	55-1000	Toluene	30 ° C	2.95	0.75
Natural rubber (NR)		0.4-1500	Benzene	25 ° C	5.02	0.17
Butadiene rubber (BR)		20-1300	Toluene	25 ° C	2.15	0.65
		26-660	Butanone	30 ° C	4.8	0.55
Polyacrylonitrile (PAN)		48-270	Dimethylformamide	25 ° C	1.66	0.81
Polyester (PET)		3-370	Dimethylformamide	25 ° C	2.33	0.75
		12-28	Phosphorus Chlorobenzene	25 ° C	3.0	0.77
		5-25	phenol / tetrachloroethane	25 ° C	2.1	0.82
Polyvinyl alcohol (PVA)		11.6-195	Water	25 ° C	5.95	0.63
		44-1100	Water	50 ℃	5.9	0.67
		30-120	Water	30 ℃	6.6	0.64

Kent Yuan (Mr.) Hangzhou Zhongwang Technology Co., LTD.

P  /Wahtsapp: +86 15068109723  E lei@zonwon.com

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