Comprehensive Analysis Of Lube Oil Viscosity Index Improvers And Spectroscopic Characterization For Sequence Distribution Of Ethylene-Propylene Copolymer

Eleven kinds of lube oil viscosity index improvers were purified and analyzed comprehensively. FTIR, UV, TG were used to qualitative analysis, and confirmed that the samples can be classified into two kinds. One kind of the samples was random ethylene-propylene copolymer, and the other kind was the mixture of random ethylene-propylene copolymer and polystyrene; GPC, ¹H-NMR and ¹³C-NMR were used to quantitative analysis, and the main sequential structure, average molecular weight, molecular weight distribution and the link ratio of ethylene to propylene in each sample were obtained.In this paper, based on the analysis of ¹³C-¹H chemical shift correlation spectrum and ¹³C-NMR spectrum for ethylene-propylene copolymer, we proposed that some assignments for the ¹H-NMR spectrum of ethylene-propylene copolymer were different from those of predecessors, and discussed preliminarily the reason why some protons attached to the same carbon exhibit different resonances with markedly different chemical...