Abstract: Seven low molecular weight saturated polyesters were synthesized and their shrinkage-compensation effects were estimated.It has been found that aromatic saturated polyesters as low-shrinkage agents are more effective than aliphatic ones.Some sheet-molding compounds and hulkmolding compounds were prepared, and the volume and linear shrinkage of these products as well as mechanicaland thermal properties were determined.The properties of these modified low-shrinkage unsaturated polyesters are found excellent.

Key words: Unsaturated polyester, Low shrinkage, Shrinkage resistance polyester molding