Raw material mass loss rate testing quantifies the percentage of mass a material loses when exposed to defined thermal, chemical, or mechanical conditions, offering critical insight into purity, moisture content, thermal stability, and durability. Accredited third-party laboratories routinely perform this testing to support incoming material inspection, supplier qualification, and product development across the polymer, metal, ceramic, and chemical industries. This article explains the technical principle, applicable standards, sample types, testing items, and practical applications of mass loss rate testing for raw materials.
Technical Overview
Mass loss rate (MLR) is a fundamental material characterization parameter defined as the percentage of mass a specimen loses relative to its initial mass after being subjected to a controlled test condition, such as heating, drying, ignition, chemical immersion, or mechanical abrasion. The result is typically expressed as:
Mass Loss Rate (%) = (m0 − m1) / m0 × 100, where m0 is the initial mass and m1 is the residual mass after testing.
For raw materials, mass loss rate serves as a sensitive indicator of volatile matter, moisture, degradation behavior, filler or ash content, and resistance to corrosion or wear. Excessive mass loss in incoming materials often signals contamination, incomplete curing, insufficient drying, or poor thermal stability, all of which can compromise downstream processing and final product quality. Testing is conducted in accordance with internationally recognized standards published by ISO, ASTM, EN, GB, JIS, and other standards organizations, ensuring results are traceable, repeatable, and acceptable for quality documentation.
Testing Samples
Polymer Raw Materials
Thermoplastic resins, engineering plastics, pellets, masterbatches, recycled polymers, and polymer powders are tested to determine moisture content, volatile matter, and thermal decomposition behavior before injection molding or extrusion.
Rubber and Elastomers
Natural rubber, synthetic rubber compounds, and elastomer feedstocks are evaluated for volatile matter and cure-related mass changes in accordance with ISO 248 and ASTM D297.
Metals and Alloys
Metal sheets, bars, wires, and machined coupons are assessed for corrosion-induced mass loss to estimate corrosion rates and validate protective treatments.
Ceramic, Mineral, and Carbon Materials
Ceramic powders, mineral fillers, glass fibers, graphite, coke, and carbon black are tested for loss on ignition and thermal mass loss to verify composition and purity.
Coatings, Adhesives, and Chemical Raw Materials
Liquid resins, adhesives, sealants, pigments, additives, and other chemical feedstocks are analyzed to quantify non-volatile content, solvent retention, and thermal stability.
Testing Items
- Moisture content and volatile matter content
- Loss on drying
- Loss on ignition (LOI) and ash residue
- Thermal decomposition mass loss and thermal stability index
- Mass loss rate during combustion (fire performance characterization)
- Corrosion mass loss rate and corrosion rate of metals
- Abrasion and wear mass loss
- Mass loss after thermal aging, UV aging, or humidity exposure
Testing Methods
Thermogravimetric Analysis (TGA)
TGA continuously records specimen mass while temperature is ramped at a controlled rate under nitrogen or air atmosphere. It provides mass loss curves, onset decomposition temperature, and residue content, and is performed per ISO 11358-1, ASTM E1131, and ASTM E2550. This is the preferred method for full decomposition profiling of polymers and carbon-based raw materials.
Oven Drying Method
Specimens are dried to constant mass in a ventilated or vacuum oven at a specified temperature, and the mass difference determines moisture or volatile content. This gravimetric approach is simple, economical, and widely used for incoming inspection of resins, powders, and chemical feedstocks.
Muffle Furnace Ignition Method
Loss on ignition is determined by heating the specimen in a muffle furnace at 550–950 °C depending on the material, with organic and combustible fractions volatilized to leave an inorganic residue. Applicable references include ASTM D7348 and ASTM D2584.
Corrosion Mass Loss Method
Metal coupons are exposed to corrosive media or salt spray, then cleaned of corrosion products following ASTM G1 and ISO 8407 procedures before re-weighing. Combined with ASTM G31 immersion protocols, the resulting mass loss data are converted into corrosion rates in mm/year.
Abrasion and Wear Testing
Rotating-drum or rotating-disc abrasion tests per ASTM G65, and Taber abrasion per ASTM D4060, measure mass loss after a defined number of cycles to quantify wear resistance of raw material formulations.
Fire Performance Mass Loss Rate
Cone calorimetry per ISO 5660-1 and ASTM E1354 measures the mass loss rate of a burning specimen in real time, providing essential fire-science data for material flammability evaluation.
Applications
- Incoming quality control and batch acceptance of purchased raw materials
- Supplier qualification, comparison, and periodic re-audit programs
- Verification of drying, curing, and processing parameters before production
- Material selection and benchmarking in research and development
- Failure analysis when mass loss defects are suspected in finished goods
- Compliance documentation for regulatory submissions and customer audits
- Support for recycled and reclaimed material validation programs
FAQ
How is mass loss rate calculated?
Mass loss rate equals the difference between the initial mass and the post-test mass, divided by the initial mass and multiplied by 100. A result of 0.5% means the specimen lost 0.5 grams per 100 grams of original material.
What is the difference between moisture content and total mass loss?
Moisture content measures only water removed at a low drying temperature, typically below 105 °C, whereas total mass loss under TGA or ignition conditions may include solvents, plasticizers, decomposition products, and combustible organic fractions.
How much sample is required?
TGA typically requires 5–20 mg per run, while oven drying and loss on ignition methods generally require 1–50 g depending on homogeneity. Accredited laboratories can advise on exact quantities for specific material classes.
Which standards apply to polymer raw materials?
Commonly applied standards include ISO 11358-1 and ASTM E1131 for thermogravimetry, ISO 248 for rubber volatile matter, ISO 15512 for water content in plastics, and ASTM E2550 for thermal stability assessment.
What is a typical turnaround time?
Simple gravimetric tests such as moisture and loss on ignition can often be completed within one to three working days, while corrosion immersion studies and aging programs require exposure durations specified by the relevant test protocol.