Preparation Of Polycarbonate Diols And (pcdl) Properties Of Polyurethane Elastomers

In this dissertation, a series of polycarbonate diols(PCDL) , catalyzed by efficient catalysts, were synthesized by carbonate interchange reaction. The properties of polyurethane elastomer made from PCDL flexibile segment were studied. The structure and properties of the materials were investigated in detail by FTIR, strain-stress machine, TG, DSC, et al. This dissertation mainly consists of three parts as follows:Polycarbonate diols(PCDL) were synthesized by carbonate interchange reaction of dimethyl carbonate with 1,4-butanediol in the catalysis of amines. The structure of PCDL was determined by FT-IR and 1H-NMR , it was confirmed that the chemical structures of product were consistent with that of pure polycarbonate diols. The process parameters affecting the characters of product, such as molar ratio of DMC/1,4-BDO, the dosage of catalyst, vacuum reaction time, were studied respectively. The experimental results showed that desired polycarbonate diols with excellent technical specifications were prepared by means of stage temperature under the conditions of molar ratio for n(DMC):n(1,4-BDO)=1.2～1.25, temperature of at 190℃and amines accounting for 0.5 weight percent of 1,4-BDO.Poly(1,6-hexanediol) carbonate diols (PCDL) were synthesized using 1,6-hexanediol (HDO) and diethyl carbonate(DEC) in the presence of Ti(OBu)4 as catalyst. The polymerization reaction was carried out in a two-stage process, including atmospheric pressure and vacuum process. All reaction conditions were investigated based on Ti(OBu)4. The experiment results showed that Ti(OBu)4 accounting for 0.05 weight percent of HDO exhibited the best catalytic effect. PCDL with expected number average molecular weight were prepared rapidly with raising the reaction temperature. It was available for controlling the molecular weight and polydispersity of PCDL to alter the vacuum time. The characters of PCDL were determined by FT-IR,1H-NMR,GPC and DSC. It was concluded that Ti(OBu)4 was evidenced to be an effective catalyst for transesterification. The possible reaction mechanism of Ti(OBu)4 was offered.A series of Polyurethane elastomers were prepared using soft segment,hard segment and chain-extender,including PCDL,PTMG,TDI,MDI,PPDI,BDO and DMTDA et al.The mechanical and thermal properties of polyurethane elastomers with different materials were studied. The experimental results show that PU elastomer made from PCDL exhibited better mechanical properties and heat resistance compared with polyether type elastomers.