The Critical Role of Moisture in Polymer Compounding > 자유게시판

Moisture content plays a vital role in the polymer compounding process — under uncontrolled environmental conditions, تولید کننده کامپاند پلیمری materials such as nylon, PET, and polycarbonate — retain moisture at the molecular level. It doesn’t just cling externally — it infiltrates the polymer matrix, causing disruptions in the melt phase.

The compounding process requires melting polymers at precise heat levels to incorporate additives effectively}. If moisture is present in the pellets — it transforms into gaseous water under process conditions. Gas formation leads to cavities within the molten polymer, resulting in visible surface flaws such as splay marks, dull finishes, or streaking. These imperfections compromise aesthetics, and significantly weaken structural integrity, lowering fracture toughness and durability.

Beyond physical defects, moisture can induce chemical degradation. For materials like PET and nylon, water initiates chain scission, a reaction that severs polymer chains at the molecular level. The breakdown lowers the polymer’s molar mass, which directly alters melt viscosity and flow behavior. The material loses ductility and toughness, making it prone to cracking and premature failure, potentially leading to field failures in high-performance parts.

Eliminating moisture before processing is a mandatory industry practice. Typical drying protocols range from 80 to 120 degrees Celsius, with time adjusted based on resin thickness and storage history. Advanced lines employ closed-loop desiccant dryers or thermal dehumidifiers, 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. Humidity levels in the processing zone require constant surveillance, and processing must occur within strict time windows after drying.

In essence, moisture content is not a peripheral concern in polymer compounding. Neglecting moisture control leads to expensive scrap, rework, and downtime. It risks long-term customer relationships and compliance standards. With comprehensive moisture management systems, trained personnel, and process controls, manufacturers can ensure consistent, high-quality output.