Process Monitoring of Polymers

Modern product management philosophies like "Total Quality Management" or "Zero Defect Operation" share the same aim: To produce highest quality as quickly as possible for the least possible expense. This is why in recent years, the need of on-line monitoring of chemical reactions and production flows became more and more important. The polymer and plastics industry needs fast, reliable, non-invasive and cost-effective analytical methods for process control.

FT-NIR spectroscopy has a distinct advantage compared to other technologies:

• It provides a real-time assessment of the process on a molecular basis. The recorded spectra relate directly to the composition of the material.
• With the use of fiber-coupled probe heads, the "eye" is brought straight into the area of interest without interference in the production process.
• The spectrometer itself can either be installed alongside the measurement point or further away in the analysis house.

Modern control software hands the data over to the process control system and if the product is running out of specification, it will be detected within seconds and corrective measures can be carried out. With the classical off-line analysis, several hours can pass before the sample is analyzed. During that time the production of material with unknown quality continues; the longer the analysis time, the more waste could be produced.

With direct insight into the molecular structure of the material, parameters like OH number, NCO content, acid value, or the content of free monomers can be determined. But also the analysis of physical properties is possible. A typical application is the simultaneous monitoring of density and Melt Flow Index of Polyethylene. These parameters are crucial for the processing of the material, like extruding or molding, making them the most frequently determined parameters in the quality control of polymers.

Bruker's process spectrometers are designed for the harsh industrial environment. The MATRIX-F incorporates advanced multiplexing options, allowing the monitoring of up to 6 positions with one spectrometer. The MATRIX-F and its peripherals are individually enclosed modules which can be built into 19" racks. A wide range of probe adaptations are available for analyzing liquids and emulsions as well as powders and pellets. Recent advances in the development of new high temperature and high pressure probes allow the adaptation into various processes.

Dedicated process control software which handles different protocols such as Modbus, Profibus, Industrial Ethernet or OPC is available for the constant monitoring and control of a variety of processes.

Another important application for FT-NIR spectroscopy is the quality control of the incoming raw materials. To produce high quality products, it is essential, that the delivered goods like additives, stabilizers, antioxidants or plasticizers meet the desired quality criteria. With the MPA (Multi Purpose Analyzer), Bruker also offers lab-based solutions for the QC laboratory or the warehouse.