Preparation Of Polarity SBS Containing PEO Block

As a thermoplastic elastomer, Polystyrene-butadiene-styrene (SBS) has so many advantages and important applications in enormous fields. With the requirements of the properties of materials higher and higher, modified SBS gains a huge potential value. When introducing polar groups to SBS chain, the polarity of the polymer changed, providing SBS stronger adhesion and compatibility to polar materials. It’s application expanded after modified. This paper intends to achieve the goal of SBS modifying by introducing PEO block to SBS backbone.A model block polystyrene-ethylene oxide (PS-b-PEO) copolymer was prepared first with cyclohexane solvent, n-butyl lithium initiator, triisobutylaluminum additives by anion living polymerization method. Then the preliminary production was characterized by gel permeation chromatography (GPC), Fourier transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance spectroscopy (1H-NMR), differential scanning calorimeter (DSC) etc. These characterization made us known to the relationship between copolymer structure with the molecular weight. And then we monitored the reaction process online with an ultraviolet visible spectrophotometer (UV-Vis) to explore the reaction mechanism. At last, a series different molecular weight of SBS-PEO block copolymer were synthesized with known reaction condition. Besides, a copolymer with two ends of PEO segment was also prepared by dilithium initiator.According to the experimental results analysis, we obtained the following conclusions:the best molar ratio of triisobutylaluminum and n-butyl lithium for the reaction is between 12 and 14 at 50 ℃. The molecular weight of block copolymer containing PEO cannot be obtained by GPC alone but with’H-NMR to calculate. The molecular weight of PEO segment can be as high as 26000 g/mol, thus satisfying the requirements of industrial applications.