HTPB引入方式对不饱和树脂改性效果的影响

Modification of unsaturated polyester resin by HTPB:effect of introducing method of the rubber

以高顺式端羟基液体顺丁橡胶(HTPB)为改性剂,分别采用共混-共固化法、共缩聚法制备了共混改性型不饱和聚酯[UPR+HTPB(blend)]、无规共缩聚改性型不饱和聚酯(UPR-HTPB)和嵌段共缩聚改性型不饱和聚酯(UPR-MAH-HTPB),系统地考察了三种改性不饱和聚酯固化样品的机械物理性能。结果表明,三种改性不饱和树脂的断裂伸长率、拉伸强度和冲击强度均优于未改性的不饱和树脂,固化收缩率大幅降低,且共缩聚改性树脂(UPR-HTPB和UPR-MAH-HTPB)的增韧效果和降收缩效果明显优于共混改性树脂。此外,UPRMAH-HTPB的拉伸模量也优于未改性的不饱和树脂,硬度和热变形温度则基本保持不变。冲击断面的形貌、交联密度和DMA分析表明,UPR+HTPB(blend)固化体系中存在着HTPB聚团的现象,而共缩聚改性树脂,尤其是嵌段型的UPR-MAH-HTPB,因HTPB嵌入到UPR的主链中,使HTPB微相分离,并更多地参与交联,在增韧的同时保持了树脂良好的刚性和强度。

By using the co-curing method and copolycondensation method,three kinds of modified unsaturated polyester resin(UPR)with high cis-1,4 hydroxyl-terminated polybutadiene(HTPB)were prepared,which were blends of UPR and HTPB[UPR+HTPB(blend)],random copolycondensate of UPR and HTPB(UPR-HTPB),and block copolycondensate of UPR and HTPB(UPR-MAH-HTPB).Mechanical and physical properties of their curing products were investigated.It has been found that the elongation at break,the tensile strength and the impact strength of the three modified UPR are superior to those of the pure UPR,and their curing shrinkage are significantly reduced.The toughening and strengthening effects of UPR-HTPB and UPR-MAH-HTPB are more obvious than UPR+HTPB(blend).In addition,it is found that the tensile modulus of UPR-MAH-HTPB is superior to that of pure UPR,and the hardness and thermal deformation temperature are almost unchanged.It is shown by analyses of the impact section morphology,the crosslinking density and the dynamic mechanics that agglomeration of HTPB rubber is existed in the curing system of UPR+HTPB(blend),while microphase separation occurs in the curing system of modified UPR by copolycondensation,especial by block copolycondensation in which the HTPB units are inserted into the main chain of modified UPR,and more HTPB units participate in the crosslinking network.The modified UPRs by copolycondensation maintain their good rigidity and strength while being toughened.