Viscosity Test Vinyl Chloride Polymer Dilute Solution- ASTM D 1243

Scope:

In this ASTM D 1243 standard test, a solution with a predetermined concentration is made by dissolving the resin in cyclohexanone. Measuring the solvent and polymer solution flow times yields information on the intrinsic viscosity. The relationship between viscosity and molecular structure can be seen in the correlation between vinyl chloride polymer diluted solution viscosity and the molecular size of the dissolvable polymer part.

Test Procedure:

The procedure for dissolving duplicate resin samples as described in ASTM D 1243 standard test method dissolution of Resin Samples: Duplicate resin samples weighing 0.260002 g each (with moisture content less than 0.1%) are placed into a 100-mL glass-stoppered volumetric flask. Alternatively, the resin (0.260002 g) can be weighed directly into a tared 100-mL volumetric flask with a glass cap. The flask is then filled with 50 to 70 mL of cyclohexanone to ensure thorough moistening of the resin and prevent lump formation. The mixture is heated at 85 ± 10°C until complete dissolution of the resin occurs, with periodic shaking to expedite the process. Heating times should ideally be kept under 12 hours to minimize degradation, and a new solution should be prepared if any gel-like particles are observed.

Cooling and Volume Adjustment: After dissolving the resin, the solution is cooled to the desired test temperature by submerging the flask in a 30°C bath for a minimum of 30 minutes. Once cooled, the solution is adjusted to a final volume of 100 mL, and the mixture is filtered using a fritted-glass filter.

The flow rates of both the prepared solution and the pure solvent (aged at 85 ± 10°C) are recorded in the viscometer at 30.0 ± 0.5°C. After placing the viscometer in a water bath, it is allowed to acclimate to the temperature for approximately 10 minutes. Any significant fluctuation exceeding 0.1% in the flow time of the solvent or solution during repeated runs using the same filling should be viewed with suspicion.

Test Specimen:

Vinyl Chloride Polymer Solution Viscosity Standard test procedure ASTM D 1243.

Data:

In this ASTM D 1243 Calculate the relative and inherent viscosity (viscosity

ratio and logarithmic viscosity number) as follows:

                                       = tt0

                                         inh =ln relC

where:

ηrel = relative viscosity (viscosity ratio),

t = efflux time of the solution,

to = pure solvent of the efflux time,

C = weight of sample used per 100 mL of solution,

ηinh = inherent viscosity (logarithmic viscosity number),

ln ηrel = Natural logarithm of relative viscosity (viscosity ratio) is written as ln rel.

Conclusion:

The standard method for determining the dilute solution viscosity in vinyl chloride polymers is described in ASTM D 1243’s conclusion, which also offers crucial instructions for a precise assessment of viscosity during polymer characterization.