ISO 248-2-2012 pdf free download

ISO 248-2-2012 pdf free download.Rubber, raw Determination of volatile- matter content
Part 2:Thermogravimetric methods using an automatic analyser with an infrared drying unit
Caoutchouc brut — Determination des matières volatiles — Partie 2. Méthodes thermogravimétriques utilisant un analyseur automatique avec une unite de séchage infrarouge.
7.1 General
Either method A (which uses a pre-defined drying time) or method B (In which drying ends when the mass loss rate has decreased to a pre-defined level) can be chosen, provided the automatic analyser used offers the choice. The end point (the pre-defined drying time for method A or the pre-defined mass loss rate for method B) shall be determined for each of the two methods for each type or grade of rubber to be analysed.
7.2 Determination of end points for method A and method B
7.2.1 First take a typical sample of the type or grade of rubber being analysed and determine its volatile- matter content in accordance with one of the methods described in ISO 248-1.
7.2.2 Then, for method A, take a test portion of between 2 g and 15 9 and weigh it to the nearest 1 mg. Operating the automatic analyser in accordance with the manufacturer’s instructions, set a drying temperature (preferably between 100 °C and 120 DC) and obtain a drying profile (X-axis: time in mm. V-axis: volatile matter lost, in %). From the drying profile (see Figure 1), determine the time at which the volatile-matter content determined by the automatic analyser is equal to that determined in 7.2.1. Take this drying time as the predefined drying time to be used in method A for this particular type or grade of rubber.
7.2.3 For method B, take a test portion of between 2 9 and 15 g and weigh it to the nearest 1 mg. Operating the automatic analyser in accordance with the manufacturer’s instructions, set a drying temperature (preferably between 100 DC and 120 °C) and obtain a drying profile (X-axis: time, V-axis: mass). From the drying profile (see Figure 2), determine the mass loss rate at the point on the profile where the volatile-matter content corresponds to that determined in 7.2.1 – Take this value of the mass loss rate as the end point for use in method B for this particular type or grade of rubber.ISO 248-2-2012 pdf free download.