Copolymer levels in polymer pellets – nondestructive determination in less than 30 seconds

Laboratory technician with DS2500 near-infrared spectroscopy analyzer
Metrohm is pleased to present a new application for the determination of copolymer levels in polyethylene (PE) and polyvinylacetate (PVA) pellets by near-infrared spectroscopy (NIRS). Without any sample preparation and in less than 30 seconds, NIRS determines the composition of the polymer blends investigated. 

Thermal polymers are typically supplied in the form of chips or pellets. Some of the very properties desired for the polymers such as strength, solvent resistance, acids, etc. make analysis of these materials a challenge. Typical methods of analysis require dissolution of the pellets, which can take from several hours to more than a day depending on the material.

NIRS is uniquely suited for quantitative analysis of polymers due to the inherent benefits of this method:
  • no sample preparation required
  • method is non-destructive
  • results in a matter of seconds
NIRS has been successfully used to analyze other copolymers such as ethylene/propylene, styrene/butadiene, and butylene/terephtalate. Polymer additives such as antioxidants, stabilizers, and slip agents are also being monitored by NIR in pelletized samples.