Preparation Of Oligo (carbonate-ether) Polyols And Their Applications In Synthesis Of Polyurethane

Double metal cyanide complexes?DMC?-catalyzed oligomerization of CO₂ and epoxide to prepare oligo?carbonate-ether?polyols provides an efficient approach to make full use of the greenhouse gas CO₂ with low energy consumption.The polyurethanes made from oligo?carbonate-ether?polyols combine excellent properties of both polyester polyurethanes and polyether polyurethanes,such as wear resistance,water resistance,and solvent resistance.In this thesis,we frist studied the structure and catalytic performances of DMC which were prepared by adding emulsifiers with different hydrophilic lipophilic balance values?HLB?.Then we investigated that DMC catalyzed oligomerization of propylene oxide?PO?and CO₂using bisphenols as chain transfer agent?CTA?.The last part is the study on the preparation of polyurethanes?PUs?using oligo?carbonate-ether?polyols and castor oil as mixed soft-segment.The main results were summarized as follows:1.Four kinds of DMC were prepared in/without the presence of emulsifiers with different HLB value,and the structure of DMC were characterized by Elementary Analysis,IR spectrum,X-ray diffraction and Scanning Electron Microscopy.The catalytic activity of DMC was evaluated by copolymerization of CO₂ and PO,and the properties of resultant products were characterized.On the basis of results,DMC-1 was selected for the preparation of oligo?carbonate-ether?polyols.2.The preparation of oligo?carbonate-ether?polyols was studied.Firstly,the effect of chain transfer agent type on the oligomerization was investigated.Then,we systematically investigated the influences of the molar ratio of PO/BPA,reaction temperature,reaction pressure,the amount of catalyst,etc.on oligomerizations under bisphenol A?BPA?as chain transfer agent.The number average molecular weight?M_n?of obtained polyols can be controlled below 2400 g/mol and f _PPC can be up to 53%.The catalyst activity of DMC reached to 7.6 Kg/g DMC when the oligomerization was performed at 95 ^oC under 4.0 MPa with 20mg DMC for 6 h in 150 mL PO.Results suggested that the M_n of the polyols was in good linear relationship to the molar ratio of PO to BPA;lower temperature and higher CO₂pressure were beneficial for increasing f_PPC while reaction activity is decrased.Of interest,the PU prepared from BPA-based polyols as soft segment exhibited flame retardant property.3.PUs were prepared by using purchased oligo?carbonate-ether?polyols and castor oil as mixed soft segments.The results demonstrated that the tensile strength and thermal stability of the polyurethane increased gradually with increaseing amount of castor oil in the preparation of PU,however,elongation at break is decreased.The catalyst also play a essential role in the preparation of PU.PU prepared with Cat 1 in the absence of castor oil display better mechanical properties of polyurethane catalyzed than that under other catalysts.However,when using oligo?carbonate-ether?polyols and castor oil as mixed soft segment,Cat 2 was the best one among the catalysts employed.The tensile strength and elongation at break of PU prepared with the mixed oligo?carbonate-ether?polyols and castor oil as soft segment and MOCA as CTA can be improved concurrently with increaseing MOCA loading in a certain extent.