Polyester Products Intrinsic Viscosity Measuring Method

Polyester Products Intrinsic Viscosity Measuring Method

Abstract: the measuring method of intrinsic viscosity of polyester products

1 Range

This standard applies to the determination of polymers, polyester chip and the intrinsic viscosity of the melt. Measuring range: 0.020-1.500dL/g

2 Methods introducing

The sample is dissolved in phenol and 1,2- Mixture of p-dichlorobenzene in the determination of flow time by Ubbelohde viscometer t And then ubbelohde viscometer and phenol 1,2- P-dichlorobenzene mixture flow time t0 , To calculate the viscosity of the sample η Rel = t/ t0. 。 Relative viscosity and relation between intrinsic viscosity can be determined by Billmeyer equation says:

η Attributes = 1/4x (ηrel -1) /c+ 3/4x (nη )/c

In the formula: C -Sample solution concentrations g/100mL;

η Properties-viscosity of the sample, dL/g ;

η Relative-relative viscosity of the sample.

3 Instrument

3.1 Viscosity measuring instrument: the ability to control temperature 25.00±0.05 ℃ 。

3.2 Ubeelohde viscometer, and viscometer holder.

3.3 Thermometer: 0-50 ℃ And 0.1 degree.

3.4 Magnetic heating stirrer.

3.5 Pipette: 25mL 。

3.6 Metal filters: 200 Mesh.

3.7 Flask: 50 mL 。

3.8 PTFE stir.

3.9 Glass funnel diameter 5cm 。

3.10 Beaker: 5000mL 。

4 Reagents and materials

4.1 Water: the GB 6682 - 92 Provides three levels of water demand.

4.2 Phenol.

4.3 1,2- P-dichlorobenzene.

4.4 Ethanol.

4.5 Hydrochloric acid solution: ( 1 + 1 )。

4.6 Acetone.

5 Test Procedure

5.1 Phenol -1,2- Preparation of solution of p-dichlorobenzene

5.1.1 Mixed phenols /1,2- P-dichlorobenzene: 510mL 1,2- P-dichlorobenzene , Join with 1kg Bottle of phenol ( Mixing ratio by weight 3:2) By mixing the solution density is1.151±0.001g/cm3(25 ℃ ) 。

5.1.2 Heat the mixture in the oven, the oven temperature 60 ℃ , The heating process ,shake continuously until fully mixed.

5.1.3 The solution through the filter into the brown liquid in bottles.

5.2 Measuring the blank solution viscometer.

5.2.1 Set the viscometer bath temperature 25.00±0.05 ℃ .

5.2.2 Add approximately to viscometer 17 mL Phenol /1,2- P-dichlorobenzene solution ( 5.1 ) To between two marked lines.

5.2.3 Viscometer placed in water bath 15-20 Minutes, measure the flow time five times of phenol /1,2- Dichlorobenzene. The deviation shall not exceed 0.1 Seconds.

5.2.4 Take the average of the five tests, as reference of each new preparation of phenol /1,2- Dichlorobenzene solution of flow time. Determination to the flow time should be in 80-120 seconds, too low too high are not allowed.

5.3 Preparation of the sample

5.3.1 Polyester moisture content should be less than 0.5% Wet slice. Using acetone to clean the surface water. Put the slice in 80 ℃ Oven drying 15-20 minutes to clean the residues  acetone . Make sure the residual moisture has very little effect on the relative viscosity.

5.3.2 If polyester high crystallinity, its crystal structure must be destroyed. The method is to slice into the right crusher, crushing sliced (about 150bar).

5.4 Test

5.4.1 Take 125-145mg Samples, accuracy to 0.0001g. Put the sample into 50 mL Erlenmeyer flask, then add 25 mL ( 28.75--28.80 g) Phenol /1,2- P-dichlorobenzene solution ( 5.1.1 ), Into the magnetic stirring bars, sealed.

5.4.2 Place the Erlenmeyer flask on a magnetic stirrer. heating, mixing, dissolving sample on 90-100 ℃ Temperature

5.4.3 Cool the sample after dissolution.

5.4.4 Pour the sample solution into the viscometer through 200 Mesh metal screen filter. 5.4.5 Put the viscometer into the constant temperature water bath for 20 minutes. Measure the viscosity three times to determine the sample flow time. The difference must not exceed 0.2 Seconds.

5.4.6 Calculate the average of three measurements “t” 。

5.5 Calculation

5.5.1 Determination of viscosity

η Rel = t (Sample average outflow of time, in seconds) / t0 (Phenol /1,2- Average outflow of dichlorobenzene solution time in seconds)

5.5.2 Related factors F

          The factors read out from the schedule F 。

5.5.3 Calculation of viscosity

         Related factors F Divided by the sample weight, and its value is the intrinsic viscosity.

η Properties = F/W

          :η Properties - Intrinsic viscosity of the sample, dL/g ;

F- Related factors ,mg·dL/g ;

W- Sample weight, mg 。

5.5.4 The same sample two parallel determination of the difference is not more than 0.008 dL/g , Take the arithmetic mean as the result, rounding off the results to the third decimal place.

5.6 Viscometer cleaning

5.6.1 When the operation is complete, pour waste liquid viscosity solution in bottle.

5.6.2 Viscometer shall be cleaned and placed in the beaker.

5.6.3 Adding ethanol to the viscometer , Ear suction ball washing times , Completely out of the residue.

5.6.4 Soaking in hydrochloric acid solution one day.

5.6.5 Wash the viscometer , Then wash with ethanol-run , On the shelf upside down to dry.

5.6.6 Viscometer in the case of first-time or more impurities, chromic mixture to clean.

6 Description

Dissolve normal pet chips or oil when heating temperature is not too high, not more than 100 ℃ This step takes about 15 Minutes.

Dry slices of dissolved before spinning, heating temperature can be increased to 130 - 140 ℃ 。

7 Attention

Phenol, 1,2- Dichlorobenzene with acetone poisonous, avoid inhalation and contact with skin, formulation and use of these chemicals, wear rubber gloves and goggles, all operations including waste treatment, should be completed in a fume hood. Waste in the waste bin regularly.

Published by Hangzhou Zhongwang Technology Co.,ltd