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Comonomer unit wt% Measurement(Copolymer or not?)

For the purpose of the Customs classification, the expression "copolymers" covers all polymers in which no single monomer unit contributes 95% or more by weight to the total polymer content.

Measurement of weight % of each comonomer unit

There are direct and indirect methods to measure a weight % of each comonomer unit. The general direct method applicable to most samples is one using a nuclear magnetic resonance equipment (NMR). One of the indirect methods is a calibration curve method using an infrared spectrophotometer. However, the standard samples are necessary to make the calibration curve and in most case, the weight % of the standard sample itself is measured by NMR.

[ How to measure the weight % of each comonomer unit: ]

NMR is used.

photo of NMR
Nuclear Magnetic Resonance equipment (NMR)

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