ISO 16565:2013 pdf download.Rubber- Determination of 5-ethylidenenorbornene (ENB) or  dicyclopentadiene (DCPD) in ethylene-propylene-diene ( EPDM) terpolymers.
ISO 16565 specifies the methods to be used to determine the content of 5-ethylidenenorbornene (ENB) or dicyclopentadiene (DCPD) in ethylene-propylene-diene (EPDM) terpolymers in the 0,1 % to 10 % range.
ENB and DCPD are dienes introduced into ethylene-propylene rubbers to generate specific cure properties. Since high precision for diene content determination is important, a Fourier transform infrared spectroscopic (FT-IR) method is utilized.
NOTE The procedures for the mass fraction of ENB and the mass fraction of DCPD differ only in the location in the infrared (IR) of the peak being quantified.
2 Principle
A test specimen is moulded between two PTFE-coated aluminium or mylar sheets. The ENB content is determined from its infrared absorbance at 1 681 cm-1 to 1 690 cm-1 (a measure of the exocyclic double bond in ENB). The DCPD content is determined from its infrared absorbance at 1 605 cm-1 to 1 610 cm-1 (a measure of the monocyclic double bond in DCPD).
The second derivative of the absorbance is calculated and ratioed to an internal standard. For ENB, the resulting second-derivative peak near 1 690 cm-1 is related to the ENB mass fraction by calibrating the instrument with known EPDM standards. For DCPD, the resulting second-derivative peak near 1 610 cm1 is related to the DCPD mass fraction in the same way.
For oil-extended polymers, the oil shall be extracted before the diene content is determined.
3 Apparatus
3.1 Carver-type press, capable of compressing films at 150 °C and 10 MPa.
3.2 Mould.
3.2.1 The mould primarily used is made of a stainless-steel strip 400 urn thick with an opening, which gives a specimen of the appropriate size for the specimen-film holder described in 3.4 (2 cm by 2 cm). The mould shall have approximately the same dimensions as the press platens.
3.2.2 Alternatively, a thinner mould plate may be used. However, precision can be adversely affected at low diene levels. The precision of the method shall be determined when thinner films are utilized. For example, 127 urn-thick stainless-steel foil with a 15 mm by 35 mm opening may be used for the simultaneous determination of ethylene and diene.
3.3 PTFE-coated aluminium moulding sheets, type A, 36 um thick, or silicone release sheeting.
3.4 Specimen-film holders: films may be moulded, cut out and transferred to a film holder. Magnetic- film holders are ideal. Alternatively, a mould sized to fit in the spectrophotometer specimen compartment, with an appropriate-sized opening, may be used to support the film without removal after compressing. A standard salt plate support is used for liquid samples prepared between salt plates.
3.5 Infrared Fourier transform spectrophotometer. The instrument shall be capable of spectral resolution of 2 cm. A deuterated triglycine sulfate (DTGS) or, as an alternative, a mercury cadmium tellu ride (MCT) detector shall be used.
NOTE A specification for the evaluation of the analysis of infrared spectra is given in Reference.ISO 16565 pdf download.