GB/T 39691-2020Plastics - Determination of refractive index (English PDF)

Foreword

This standard was drafted in accordance with the rules given in GB/T 1:1-2009:

This standard uses the redrafting method to modify and adopt ISO 489:1999 "Determination of Plastic Refractive Index":

Compared with ISO 489:1999, this standard has more structural adjustments: Appendix A lists the chapters of this standard and ISO 489:1999:

Article number comparison list:

The technical differences between this standard and ISO 489:1999 and the reasons are as follows:

--- Regarding normative reference documents, this standard has made adjustments with technical differences to adapt to my country's technical conditions and adjustments:

The situation is collectively reflected in Chapter 2 "Normative Reference Documents", and the specific adjustments are as follows:

* Replace ISO 291:2008 with GB/T 2918-2018 which is modified to adopt international standards:

This standard was proposed by the China Petroleum and Chemical Industry Federation:

This standard is under the jurisdiction of the National Plastics Standardization Technical Committee (SAC/TC15):

The main drafting units of this standard: China Blue Chenguang Chengdu Testing Technology Co:, Ltd:, Guangzhou Quality Supervision and Testing Research Institute, Anhui Huaiyuan Kanghua

Plastic Products Co:, Ltd:, Shenzhen Zhongan Testing Standard Technology Co:, Ltd:, Qingdao Product Quality Supervision and Inspection Institute, People's Republic of China

Qingdao Dagang Customs, Lianxing New Material Technology (Guangzhou) Co:, Ltd:

1 Scope

This standard specifies two test methods for determining the refractive index of plastics:

Method A: Refractometer method: The refractometer is used to measure the refractive index of molded parts, die-cast or extruded plates or films: Apply to each

Isotropic, transparent, translucent, colored or opaque materials are also suitable for anisotropic materials: When high precision test is required, it is recommended to use this

method: This method is not suitable for powder or granular samples:

Method B: Microscopic immersion method (using the Baker line phenomenon): This method can be used to determine the refractive index of powdery or granular transparent materials:

Generally speaking, monochromatic light should be used to avoid dispersion effects: This method is suitable for isotropic translucent materials and colored materials, but not

Transparent materials and anisotropic materials:

2 Normative references

The following documents are indispensable for the application of this document: For dated reference documents, only the dated version applies to this document.

Pieces: For undated references, the latest version (including all amendments) applies to this document:

GB/T 2918-2018 Standard environment for condition adjustment and testing of plastic specimens (ISO 291:2008, MOD)

3 Significance and use

3:1 The refractive index is a basic attribute that can be used to check the purity and composition of materials, and can be used to identify materials and design optical components: fold

The change of light rate with temperature can indicate the transition point of the material:

3:2 When method B is used cautiously by experienced operators, the precision of method B is roughly the same as that of method A (see section

Chapter 8):

4 Apparatus and materials

4:1 Method A

4:1:1 Abbe refractometer or any other refractometer that can give the same result, accurate to 0:001, and the measurement range of refractive index is from 1:300

To 1:700: Temperature control devices (4:1:3) shall be provided for the samples and prisms:

4:1:2 White light or sodium lamp as light source:

4:1:3 The temperature control of the water bath can keep the temperature of the main prism, sub-prism and sample at (23:0+/-0:5) degrees C: The circulating water should be distilled water:

4:1:4 Contact liquid:

Warning---In the process of handling, storage and disposal, contact with liquid may harm the environment: Should comply with national and local safety management and disposal

Regulations:

The refractive index of the contact liquid should be higher than the refractive index of the tested material, and the plastic material must not be softened, corroded or dissolved: Liquids listed in Table 1

It can be used for corresponding plastic materials, but other liquids that meet these requirements can also be used: