How to quickly determine the batch quality stability of recycled PP engineering plastics through testing methods?
Publish Time: 2024-12-16
At a time when recycled materials are booming, ensuring the quality stability of each batch of recycled PP engineering plastics is of great significance to downstream industries. Accurate and efficient testing methods are like "eagle eyes and golden eyes" and are the key to controlling quality.Melt flow rate (MFR) testing is the first to bear the brunt. With the help of a professional melt flow rate meter, the amount of recycled PP melt flowing out of a standard capillary is measured under specific temperature and pressure conditions. A stable MFR means that the material processing fluidity is constant. If the MFR fluctuates greatly between batches, problems such as uneven filling and product size deviation will occur during injection molding or extrusion molding. Frequent testing and the establishment of an MFR database can intuitively present the differences in fluidity of each batch and quickly identify anomalies.Infrared spectroscopy analysis focuses on molecular "fingerprints". The regeneration process is prone to introduce impurities or change the molecular chain structure. The infrared spectrometer can capture changes in the absorption peaks of different functional groups. Newly emerged impurity peaks may indicate the mixing of other polymers or chemical residues; the change in the intensity and position of characteristic peaks is related to the fine-tuning of PP crystallinity and branching degree, which in turn reflects the fluctuation of material performance, and thus quickly eliminates the hidden dangers of batch quality deviation caused by unstable molecular structure.Thermal analysis technology is also indispensable. Differential scanning calorimetry (DSC) determines the thermal transition temperature of materials. Parameters such as glass transition temperature, melting point and crystallization temperature are the yardsticks for measuring crystal morphology and thermal stability. If these temperature values drift between batches, the heat resistance and dimensional thermal stability of the products will be impacted. Regular DSC scanning is performed to check the consistency of thermal performance of each batch. In case of abnormal heating or cooling curves, the production process problems can be traced back immediately.Mechanical performance testing provides intuitive feedback. The universal material testing machine stretches, bends, and impacts the regenerated PP specimens to record the strength, modulus and toughness values. Stable batches should have extremely small deviations in various mechanical indicators. Once a batch is easily broken when stretched or easily shattered when impacted, data comparison can be used to accurately identify the root cause of quality decline, from uneven raw material mixing to fluctuations in processing technology, and everything can be seen at a glance, ensuring that every batch of recycled PP entering the market can withstand the test of rigorous industrial applications and consolidate the quality foundation of the industry.
