Moisture content plays a vital role in the polymer compounding process — if stored improperly, hygroscopic resins including PA, PC, and PET — retain moisture at the molecular level. The water isn’t superficial — it diffuses into the molecular structure, leading to serious complications during melting and extrusion.

The compounding process requires melting polymers at precise heat levels to incorporate additives effectively}. Even trace amounts of humidity in the feedstock — it transforms into gaseous water under process conditions. The vaporization induces internal porosity and micro-bubbles, manifesting as surface blemishes, poor shine, or inconsistent texture. These imperfections compromise aesthetics, and critically, they diminish mechanical performance, lowering fracture toughness and durability.

Water exposure leads to irreversible chemical reactions in certain polymers. In polyesters and polyamides, hydrolysis occurs, a reaction that severs polymer chains at the molecular level. The breakdown lowers the polymer’s molar mass, and critically affects processability and extrusion stability. The material loses ductility and toughness, making it prone to cracking and premature failure, a risk that can be catastrophic in load-bearing or safety-critical applications.

To prevent these issues, thorough drying prior to compounding is non-negotiable. Resins like nylon and PET require thermal treatment within this range, over several hours tailored to resin sensitivity and ambient moisture. State-of-the-art facilities use precision drying technologies, ensuring moisture levels fall below 0.02% by weight.

Even after drying, polymers can reabsorb moisture if left exposed. Therefore, strict handling and storage protocols are essential. This includes using sealed containers, moisture-barrier bags, or nitrogen-purged hoppers. Additionally, operators must continuously monitor ambient humidity in the compounding area, and processing must occur within strict time windows after drying.

Moisture management is a core pillar of successful compounding operations. Neglecting moisture control leads to expensive scrap, rework, تولید کننده گرانول بازیافتی and downtime. It can also trigger customer complaints, warranty claims, and brand damage. With comprehensive moisture management systems, trained personnel, and process controls, manufacturers can ensure consistent, high-quality output.