Study On The Effect Of Different Sequence Structure Polyester Polyols On The Properties Of Thermoplastic Polyurethane Elastomers

In order to study on the effects of polyester polyols on the performance of polyurethane elastomer, three different sequence structures polyester polyols, which named PAEB-R,PAEB-B and PAEB-A, were synthesized with adipic acid (AA), 1,4 - butanediol (BDO), ethylene glycol (EG). Three polyurethane solutions, which solid content is 30% and the viscosity is 100,000 mpa.s, were further synthesized with polyester polyols and 4,4-diphenylmethane diisocyanate (MDI) by adopting one-step method, and the corresponding polyurethane elastomer films were then prepared by open-coating.During the polyester polyol synthesis process, it is found that the consumption of synthsis time is shortest and the viscosity can be controlled at 1200±150mPa.s under 75℃when the appropriate alcohol/acid molar ratio is kept to be 1.18:1, 1.4:1 and 1.08:1 for polyester polyol PAEB-R, PAEB-B and PAEB-A respectively. Infrared spectroscopy (FTIR) analyses results showed that the characteristic functional group -OH,-COO- absorbance peaks of the polyester polyol did not occurr chemical shift by adopting different synthesis methods. Nuclear magnetic resonance (¹H NMR) analyses results showed that H of the polyester polyol did not also occurr chemical shift by adopting different synthesis methods. Both analyses of differential scanning calorimetry (DSC) and wide-angle X-ray Diffraction (WAXS) showed that the obtained polyester polyols have different molecular arrangement manner, polyester polyol PAEB-A regularity is better than polyester polyols PAEB-B and polyester polyols PAEB-R is no regularity.Infrared spectroscopy (FTIR) analyses results showed that the structures of three kinds of polyurethane PU-PAEB-R, PU-PAEB-B, PU-PAEB-A were confirmed to be terminated with -OH. The fact that the free isocyanate group is least in polyurethane PU-PAEB-A showed the more sequence structure polyester polyol PEAB-A and MDI is the most raction efficient. Infrared spectroscopy (FTIR), nuclear magnetic resonance (¹H NMR) structural analyses results further showed that the structure of polyurethanes of the different sequences soft-paragraphexist (?),(?) branched-chain structure. Scanning and transmission electron microscopy (SEM) and atomic force microscope (AFM) analyses results showed that polyurethanes of the different sequences soft-paragraph exist micro-phase separation, and in PU-PAEB-R, the hard segment is more uniform scattered in soft phase, and in PU-PAEB-A, the hard segment is scattered in the form of reunite in soft phase. It is concluded that the micro-phase separation degree of polyurethane PU-PAEB-A is below the level of micro-phase separation of PU-PAEB-R. The mechanical properties of polyurethane elastomer showed that the regularity of polyester polyols structure is higher, the 100% modulus of the polyurethane elastomer is higher, but the fractureelongation is lower.The power function between ester carbonyl characteristic group absorption peak intensity and polyester polyol hydroxyl value was explored by studing the law of ester carbonyl characteristic group absorption peak intensity (Y) and polyester polyol hydroxyl value (X), and the curve equation Y=22.76+5800.48X^-1 was established. So, a new method which is based on infrared spectrometry method was founded. This method can be applied to determine hydroxyl value in the synthesis process of polyester polyols, and plays a monitoring role in the reaction degree as well as the quality of products.A water-dispersible polyester polyol, which is acid value<1mgKOH/g and hydroxyl value=37±3mgKOH/g, was synthesized with adipic acid (AA), ethylene glycol (EG), isophthalic acid -5-sodium (SIPM) by adopting one-step and two-step methods. It is found that the appropriate molar ratio of AA: EG: SIPM is 1:3:1 in one step and the appropriate molar ratio of AA: the product which is EG: SIPM=2:1 is 1:1.5 in the two-steps.