The level of moisture in polymers significantly influences compounding outcomes — when exposed to ambient humidity, many polymers—especially hygroscopic types like nylon, polycarbonate, and PET — retain moisture at the molecular level. This absorbed moisture doesn’t merely reside on the surface — it infiltrates the polymer matrix, resulting in processing anomalies under high heat.
During compounding, polymers are heated to high temperatures to enable melt flow and uniform blending with additives}. Even trace amounts of humidity in the feedstock — it transforms into gaseous water under process conditions. This steam generation creates bubbles, voids, or entrapped gas pockets, manifesting as surface blemishes, poor shine, or inconsistent texture. They reduce the part’s surface finish, and critically, تولید کننده کامپاند پلیمری they diminish mechanical performance, reducing tensile strength, elongation, and impact resistance.
Moisture doesn’t just cause physical issues—it triggers molecular breakdown. 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. Modern compounding systems frequently integrate desiccant dryers or hot-air drying units, ensuring moisture levels fall below 0.02% by weight.
Dried material is vulnerable to rehydration during handling. Controlled environments are mandatory post-drying. Operators must utilize airtight storage, dry-air purged feed systems, or vacuum-sealed bins. Additionally, operators must continuously monitor ambient humidity in the compounding area, and processing must occur within strict time windows after drying.
It is a fundamental parameter that dictates product quality and process reliability. Ignoring this factor results in inconsistent batches, rejected parts, and production delays. It can also trigger customer complaints, warranty claims, and brand damage. By implementing rigorous drying, sealed handling, and environmental monitoring, they achieve optimal compounding efficiency and product reliability.