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ASTM D6980 Standard Test Method for Determination of Moisture in Plastics by Loss in Weight
Last updated February 13, 2026
ASTM D6980 Standard Test Method for Determination of Moisture in Plastics by Loss in Weight
ASTM D6980 provides a quantitative test procedure to determine moisture content in plastics using a loss-in-weight process. It is performed by heating a previously weighed plastic sample under fixed conditions and noting the weight lost due to moisture evaporation. This is of special interest to thermoplastic resins for which moisture contents play a vital role in influencing processing and finished product quality. The standard defines the drying temperature, time, and specimen handling methods to provide repeatable and accurate results. ASTM D6980 is extensively applied in quality assurance and material certification to ensure that raw plastic feedstocks are within acceptable moisture limits before molding or extrusion.
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ASTM D6980 Introduction
Moisture in plastics can cause adverse effects during processing and in the end performance of polymer products. Excessive moisture can lead to hydrolytic degradation upon melt processing, manifesting in inadequate mechanical properties, surface irregularities, or size instability. ASTM D6980 helps counter this by imparting a uniform technique to evaluate moisture content in virgin and compounded plastic materials. It employs the basis of mass loss through heating under specified conditions to measure the percentage of moisture present. The process is beneficial for sensitive materials towards chemical reactions or those that do not release moisture equally under vacuum or Karl Fischer titration procedures. The test is required in areas where plastics are in storage or transported under conditions of fluctuating humidity and must, therefore, be checked for moisture content just before use.
Get Certified ASTM D6980 Testing for Uncompromising Quality and Project Success
ASTM D6980 certification can be used to provide accurate moisture analysis that secures production efficiency and product performance. The tests are done under controlled conditions in laboratories with the help of calibrated balances and heating systems. Certification also shows that they adhered to accepted testing guidelines and enhances the credibility of suppliers in the competitive markets.
The specimen is heated in a forced-air oven at 105°C ± 3°C for a fixed duration, typically 3 hours.
Initial and Final Weighing
The sample is weighed before and immediately after drying using an analytical balance with 0.1 mg sensitivity.
Moisture Calculation
Moisture content is expressed as a percentage of weight loss relative to the initial weight of the specimen.
Scope of ASTM D6980
Determines plastic moisture levels.
Relates to pellets, powders, and molded specimens.
Assists in quality control when inspecting the raw materials.
Aids in the troubleshooting of processing flaws.
Appropriate for laboratory examination.
ASTM D6980 Equipment and Sample Preparation
Analytical Balance
A precision balance capable of measuring to 0.1 mg is used for weighing both pre- and post-dried specimens.
Aluminum Weighing Pans
Non-corrosive, lightweight pans are used to hold the sample during heating, ensuring no reaction with the material.
Specimen Preparation
Approximately 5 grams of plastic pellets or powder are spread evenly in the pan to allow uniform drying.
Use of ASTM D6980
Provides adequate drying before molding.
Prevents the occurrence of voids and bubbles in the final product.
Enhances dimensional stability.
Improves the mechanical consistency of the property.
Favors supplier qualification programmes.
Common Challenges and Troubleshooting in ASTM D6980
Balance calibration gives false values of moisture. Misaligned heating results in disproportional loss of weight. Laboratories are strictly temperature regulated, and equipments are regularly checked to ascertain its calibration. Ambient humidity contaminates samples, too, so the technicians handle them quickly and place them under dry conditions.
ASTM D6980 Aggregate Testing Technique Process and Data Collection
Technicians take preliminary mass measurements, heating temperature, heating time, and final mass data. They take the percentage of moisture as the difference between the weight and the weight of the original. Record keeping can be done accurately in order to be traceable and repeatable.
Analysis Results and Interpretation for ASTM D6980
The moisture content is determined by the difference between the pre-drying and the post-drying weights. The answer is given as a percentage with significant figures appropriate to the mass measured. An increase in moisture values will show poor drying or storage. Reduced moisture content improves processing. Material batches are approved or rejected depending on the result compared by engineers with the specifications of the materials. Data trends are consistent to help optimize processes and control production.
Problem and The Solution for ASTM D6980
Humidity in pastries leads to surface blemishes, a brittle nature, and low strength. ASTM D6980 is a good alternative that offers a measure of control of heating and weight with the help of analysis. Excess moisture is detected in the early stages of laboratories, and corrective drying procedures are suggested in order to avoid the losses during the manufacturing process.
Factors to Consider Us To Test For ASTM D6980
Speed
Quick tests will allow making decisions in time and reduce downtime.
Expert
Skilled technicians provide for correct measurement and sound interpretation.
Cost
Cost-effective moisture testing eliminates costly product failures and rework.