1. Department of Chemical Engineering, Ningbo University of Technology, Ningbo 315016, China 2. Department of Chemistry, Jiangxi Science and Technology Teacher’s College, Nanchang 330013, China
Abstract：Cross linked copolymer silicon oil-Co-lactide(Si-co-LA) was analyzed quantitatively by IR. Potassium sulfocyanate(KSCN) was chosen as an inside mark material, because it has only one strong absorption peak at 2 100 cm-1 and the peak was chosen as its quantitative peak. The peak at 1 750 cm-1 is the characteristic absorption of carbonyl and was chosen as the quantitative peak of lactide(LA). The ratio of the two absorbencies is I, and I=ALA/AKSCN. KSCN and LA were mixed according to a certain mass ratio C=MLA/MKSCN to prepare standard samples. The curve of C versus I is the quantitative work curve. The result of the experiment indicates that the work curve has good linearity in the range of 2/5＜MLA/MKSCN＜8/5. The formulas calculating the proportion of every component in the cross linked copolymer were established: MKSC/Mp=B，MLA/MKSCN=C, and (MLA/Mp)×100%=BC×100%. Cross Linked Copolymer is hard to be analyzed quantitatively, because of its no dissolving and no melting. A convenient method of determining the component of the cross linked copolymer or other copolymer has been provided.
Key words：Cross linked copolymer;IR-spectra;Quantitative analysis;Component of copolymer;Lactide
