ISO 1628-4:1999 download.Plastics — Determination of the viscosity of polymers in dilute solution using capillary viscometers — Part 4: Polycarbonate (PC) moulding and extrusion materials.
This part of ISO 1628 describes the conditions necessary for the determination of the viscosity number (also known as the reduced viscosity) and the relative viscosity of polycarbonates in dilute solution.
It can be used for pure polycarbonates and blends with other polymers, as well as mixtures of both, with or without tillers, as defined in ISO 7391-1.
2 Normative references
The following standards contain provisions which, through reference in this text, constitute provisions of this part of ISO 1628. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this part of ISO 1628 are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid International Standards.
ISO 1628-1:1998, Plastics — Determination of the viscosity of polymers in dilute solution using capillary viscometers — Part 1: General pnnciples.
ISO 3105:1994, Glass capillary kinematic viscometers — Specifications and operating instructions.
ISO 4793:1980, Laboratory sintered (fritted) filters — Porosity grading, classification and designation.
ISO 7391-1:1996, Plastics — Polycarbonate (PC) moulding and extrusion materials — Part 1: Designation system and basis for specifications.
ISO 7391-2:1996, Plastics — Polycarbonate (PC) moulding and extrusion materials — Part 2: Preparation of test specimens and determination of properties.
5.1 Viscometer:
a) Ubbelohde capillary viscometer, capillary size number OC. capillary diameter 0,36 mm, receiver flask 2 ml, as specified in ISO 3105.
b) Other viscometers listed in ISO 3105, provided that the same values are obtained as with the viscometer specified above.
c) When using automatic viscometers with suitable automatic timing devices (see below), identical results are obtained even if capillaries with a larger diameter (e.g. 0.58 mm) are used (cf. ISO 1628-1, table 1), which means that other capillaries can be used in conjunction with this type of apparatus.
In cases of doubt, a viscometer conforming to the requirements given in a) shall be used. The viscometer shall be calibrated by the method described in annex A.
5.2 Timing device, capable of being read to the nearest 0.1 s and accurate to within ± 0,1 % over a 15-minute period, except when using automatic viscometers with larger-diameter capillaries [see 5.1, item C)] when the timing device shall be capable of being read to the nearest 0.01 s and be accurate to within ± 0,1 % over a 15minute period.
5.3 Thermostatic bath, operated at 25 C.
Temperature fluctuations may not exceed ±0,1 °C.
5.4 Volumetric flasks, volume 100 ml at the temperature of calibration, fitted with a ground-glass or plastic stopper giving an airtight seal.
5.5 Analytical balance, accurate to 0,1 mg.
5.6 Drying oven, operated at 110 °C.
5.7 Petri dishes.
5.8 Slntered-glass filter crucible, porosity class P1,6 (see ISO 4793).
5.9 Sintered-alass filter crucible. Dorositv class P4 (see ISO 4793L
6.4.1 Non-reinforced samples containing little or no pigment/additive
Using the analytical balance (5.5). weigh, to the nearest 0,1 mg, 500 mg of the test material into a 100 ml volumetric flask (5.4). Add approximately 70 ml of dichloromethane (6.1) and place on the shaker (5.11) until completely dissolved. Make up to the mark with dichloromethane at the calibration temperature, and shake once more to homogenize the solution.
When testing materials containing small amounts of pigments and/or additives (see below), increase the mass of the sample in proportion to the amount of pigment or additive present so that the resulting concentration of pure polycarbonate is 5 gil.
NOTE 1 This correction is only necessary if the pigment and/or additive content is more than 1 %. Soluble dyes, pigments and/or additives at concentrations of less than 1 % will not affect the result of the determination.
NOTE 2 Higher concentrations of pigments/additives or very intense dyes (preventing optical measurements using photoelectric cells) affect the measurement so much that these components must be removed from the test solution with the help of a filter aId (5.10) or centrifuge (5.12). The instructions given in 6.4.2 are applicable to the treatment of the sample in such cases.
NOTE 3 When using an automatic viscometer with computerized control equipment [5.1 c)J, the amount of polymer weighed out can differ from the set value by up to 10 %, as long as the polymer concentration, which will also differ from the set value, is taken into account when calculating the result [see A.3c)J.
6.4.2 Glass-fibre-reinforced samples and/or samples with high pigment/additive contents
Weigh approximately 5 g of the material under test into a 100 ml volumetric flask (5.4). Add approximately 70 ml of dichioromethane and place on the shaker until completely dissolved. The sample can be crushed mechanically before this step to increase the speed of dissolution.
Allow the insoluble components (glass fibres, pigments, etc.) to settle out and filter the solution through a P4 filter crucible (5.9) into a Petn dish (5.7). Place the Petri dish in the drying oven (5.6) operated at 110 0C to evaporate off the dichioromethane. Leave the film which remains in the drying oven until it reaches constant mass (1 h to 10 h, depending on the thickness of the film). Prepare a solution from the dried film using the procedure described in
6.4.1.
where
v is the kinematic viscosity of the solution, in m2s-1
v0 is the kinematic viscosity of the solvent, in m2s1
r is the arithmetic mean of the flow times for the solution, in s:
‘o is the arithmetic mean at the flow times for the solvent, in s;
c is the concentration of the solution, in gml 1
i is the kinetic-energy correction fort, provided by the manufacturer of the capillary, in s;
is the kinetic-energy correction for ‘o provided by the manufacturer of the capillary, in s. NOTE This equation conforms to the relationship defined in ISO 1628-1, but addihonally takes the kinetic-energy correction into account. This correction is necessary in order to obtain accurate results with the capillaries specified.
Equation (12) given in Iso 1628-1:1998, which, using the symbol VN instead of I, reads
VN
toe
can be applied with sufficient accuracy if a viscometer with a comparatively thin capdlary is used since the kinetic- energy correction term constitutes less than 0,2 % of the efflux time.