聚酯–聚醚型聚氨酯的制备及性能

采用两步法制备聚酯–聚醚型热塑性聚氨酯(PUR-T),其中聚己内酯(PCL)和聚四氢呋喃(PTMG)作为软段,异佛尔酮二异氰酸酯(IPDI)作为硬段,二月桂酸二丁基锡作为催化剂制备预聚体,然后利用1,4-丁二醇(BDO)进行扩链.通过傅里叶变换红外光谱、差示扫描量热、X射线衍射和凝胶渗透色谱对PUR-T的结构进行表征,然后分别用万能试验机和热重(TG)分析仪对其力学性能和热稳定性进行表征.结果表明,以PTMG和PCL为软段的PUR-T成功合成,当PTMG与PCL的物质的量之比是2/3时,相比于分别以PTMG和PCL为软段合成的聚氨酯的拉伸强度和断裂伸长率均有非常明显的提高,可以分别达到19.06 MPa和1647%.但随着PTMG含量的增加,PUR-T的拉伸强度和断裂伸长率逐渐降低.此外,随着PTMG在PUR-T中含量的增多,PUR-T中PCL结晶性能逐渐降低,这是导致PUR-T力学性能降低的主要原因.同时通过TG分析,发现随着PTMG加入量的增多,PUR-T的热稳定性逐渐增强.

Preparation and Properties of Polyester-Polyether Polyurethane

Polyester-polyether polyurethanes (PUR-T) were prepared by two-step method,in which the prepolymer was synthesized by using polycaprolactone diol (PCL) and polytetrahydrofuran (PTMG) as soft segment,isophorone diisocyanate (IPDI) as hard segment,dibutyltin dilaurate as catalyst,and then 1,4-butanediol (BDO) was used to extend the polymer chain. The structure was characterized by FTIR, DSC, XRD and GPC,next the mechanical properties and thermal stability were tested by universal testing machine and TGA,respectively. The results demonstrate that polyester-polyether polyurethane,which used PCL and PTMG as soft segment,is synthesized successfully. Compared with polyurethanes that was synthesized by PCL and PTMG respectively,the stress and strain of polyester-polyether polyurethane increase obviously,which can reach to 19.06 MPa and 1 647%,respectively, when the amount of PTMG added is 2/3 (ratio of mass to mass) of PCL. However,with the increase of PTMG content,the stress and strain of PUR-T decrease gradually. With the increase of PTMG content in PUR-T,the crystal properties of PCL in PUR-T reduce gradually,which may be the main reason for the decrease of mechanical properties of PUR-T. Through TG analysis,it is found that with the increase of PTMG addition,the thermal stability of PUR-T is gradually improved.