GB/T 533-2008 in English

《GB/T 533-2008硫化橡胶或热塑性橡胶 密度的测定》由TC35（全国橡胶与橡胶制品标准化技术委员会）归口，TC35SC2（全国橡胶与橡胶制品标准化技术委员会通用试验方法分会）执行，主管部门为中国石油和化学工业联合会。
本标准代替ＧＢ／Ｔ５３３―１９９１《硫化橡胶密度的测定》。本标准规定了测定固体硫化橡胶或热塑性橡胶密度的两种方法。
本标准适用于控制混炼胶的质量和对生产已知体积橡胶制品所需胶料量的估算。
本标准不适用于橡胶相对密度的测量，橡胶相对密度是指在一定温度下一定体积橡胶的质量与等体积纯水的质量之比。本标准与ＧＢ／Ｔ５３３―１９９１相比较主要差异如下：
―――将本标准名称用《硫化橡胶或热塑性橡胶　密度的测定》代替《硫化橡胶密度的测定》。
―――增加了前言；
―――增加了警告和注意；
―――删除了“内部质量控制试验的试样质量不少于１ｇ”规定内容（１９９１版６．１，本版５．１）；
―――去掉了密度瓶容量的规定（１９９１版５．４，本版４．５）；
―――增加了“成型与试验时间间隔”，“试样的调节”，“试验温度”三章（１９９１版６．４，６．５，本版第６，７，８章）；
―――增加了“样品制备”的详细说明（１９９１版６．３，本版９．１）；
―――增加了方法Ａ 的“注１”到“注４”（本版９．２）；
―――增加了对细丝材料的要求（１９９１版７．１．３，本版９．２）；
―――增加了试验报告内容的要求（１９９１版第９章，本版第１２章）。

1 Scope

This Standard specifies two methods of test for the determination of the density of solid vulcanized and thermoplastic rubbers.
This Standard is applicable to the control of the quality of a rubber compound and in the calculation of the mass of rubber required to produce a given volume of material.
This Standard does not cover the determination of the relative density of rubber, which is the ratio of the mass of a given volume of rubber to the mass of an equal volume of pure water at a given temperature.

2 Terms and Definitions

For the purposes of this document, the following terms and definitions apply.
2.1
Density
Mass of unit volume of the rubber at a stated temperature. It is expressed in megagrams per cubic metre (mg/m3).

3 Principle

Two methods, A and B, are given in this Standard.
In method A, the mass of the test piece and the mass of water equal in volume to the volume of the test piece are determined using a balance equipped with a pan straddle. The apparent mass of the test piece when immersed in water is less than that in air by the mass of water displaced, the volume of water displaced being equal to that of the test piece.
Method B is intended to be used only when it is necessary to cut up the test piece into small pieces to eliminate air spaces, as in the case of narrow-bore tubing and electric-cable insulation. Measurements are made using a balance and a density bottle.
Note: For convenience, all gravity in this Standard are expressed in mass unit.