RP 3000 Rapid Plastimeter for Polymers and Natural Rubber
The MonTech Rapid Plastimeter measures the plasticity or viscosity of polymers and unvulcanised rubbers. The test is simple, clean and quick. The instrument is typically used in conjunction with the MonTech ageing oven for plasticity testing to determine the Plasticity Retention Index (PRI) of raw natural rubbers.
The variable temperature range from 25°C to 200°C for easier to read with freely programmable conditioning and load times allow a convenient characterisation of the flow behavior of natural and synthetic rubbers at variable test conditions. For some applications this method offers a quick, low cost alternative to a Mooney Viscosity test.
The instrument is supplied in a complete set along with a table-top, mechanical volumetric specimen cutter for a reliable preparation of test specimens with a volume of 0.40 cm³ according to international standards. The instrument is supplied with 10 mm diameter top platen installed period. Alternative top platens of 7.3 and 14 mm diameter are supplied as accessories. The platens are easily interchangeable.
Plasticity Retention Index (PRI)
PRI is a measure of the resistance of raw natural rubber to oxidation. The oxidation effect is assessed by measuring the plasticity before ageing (P0) and after ageing for 30 mins in the MonTech ageing oven for Plasticity testing at 140°C (P30)
(PRI = (P30/P0)x100)
Working Principle
A modified parallel plate compression principle is used with automatically timed “conditioning” and “load” periods. A sample is compressed between two circular platens which are maintained at a temperature of typically 100°C.
The sample is conditioned for 15 seconds at a thickness of 1 mm. A compressive force of 100 N is then applied for 15 secs. The final thickness of the test piece expressed in units of 0.01 mm, is the plasticity number. Besides this procedure described by the standards, the MonTech RP 3000 can operate at fully variable temperature and conditioning / load times. During the loading period, the material flow and plasticity curve can be acquired by the optional MonPlast computer software.
Test Procedure
The sample is prepared using the mechanical, double-working specimen cutter and it is then enclosed between two pieces of tissue paper, as defined by international standards, before being placed between the platens. The tissue paper prevents the material sticking to the platens or sliding between them.
The automatic test sequence is started when the start lever on the instrument is rotated. Conditioning and loading periods are then automatically controlled. The reduction in thickness of the sample as well as the load that is applied to the sample is displayed digitally on the PC screen by the optional MonPlast software. After testing, all results are shown on the PC screen and automatically stored in the database for recalling them later or creating batch reports.
