GB/T 45128-2025 Active National standards

GB/T 45128-2025 Plastics—Determination of water content

Publish Date: 2025-01-24 Implement Date: 2025-08-01 For services related to genuine standard inquiry, procurement, translation, and other related services in China, please Contact Us

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Basic Information

Standard Code: GB/T 45128-2025

Standard Type: National standards

Standard Status: Active

is_force_gb: no

CCS Name: Basic standards and general methods for synthetic resins and plastics

ICS Name: Plastic Composite

Publish Date: 2025-01-24

Implement Date: 2025-08-01

Pages: 36 pages

Scope

This document describes six methods for detecting the water content in plastic powders, granules, and products. Methods A, B, C, and E are suitable for all types of plastics, while Method D is applicable to polyamide (PA), polycarbonate (PC), polypropylene (PP), polyethylene (PE), epoxy resins, polyesters, polytetrafluoroethylene (PTFE), polyvinyl chloride (PVC), polylactic acid (PLA), and polyamide-imide (PAI). It is not suitable for samples that release NH3. **Method A (Anhydrous Methanol Extraction Method):** This method is suitable for determining the water content in all samples smaller than 4 mm × 4 mm × 3 mm and with a water content greater than or equal to 0.1%. The accuracy of the method is within 0.1%. It can also be used to determine the water content in powder prepolymers that are insoluble in methanol. **Method B1 (Tube Furnace Evaporation Method):** This method is suitable for determining the water content in all samples smaller than 4 mm × 4 mm × 3 mm and with a water content greater than or equal to 0.01%. **Method B2 (Sample Bottle Evaporation Method):** This method is suitable for determining the water content in all samples smaller than 4 mm × 4 mm × 3 mm and with a water content greater than or equal to 0.01%. **Method C (Pressure Measurement Method):** This method is suitable for determining the water content in all samples with a water content greater than or equal to 0.01%. It is not suitable for plastic samples containing volatile compounds (except water), as these compounds can significantly affect the pressure measurement at room temperature. When using Method C, regular checks should be conducted using methods such as gas chromatography to determine whether the samples (especially new types or brands) contain volatile compounds. **Method D (Phosphorus Pentoxide (P2O5) Electrochemical Method):** This method is suitable for determining the water content in all samples with a water content greater than or equal to 0.01%. Howeve