Effect of Plasticizers on the Strength of a Plastic Motor Case

摘要

The report summarizes the effect of plasticizers on the strength of a glass-fiber-reinforced plastic motor case and, specifically, the effect on the burst strength of the motor case. Maximum average loss in burst strength occurred with dipropyl adipate and amounted to 79 psi out of an average burst of the blank of 2842 psi. Deterioration did not increase with longer intervals of storage. A direct correlation could be established between burst pressure and extension at break of a ring cut from an identical (same lot) motor case and treated with plasticizer. In addition, a direct correlation could be established between burst pressure and the reciprocal of the amount of sag of a coupon cut from an identical motor case. The effect on a motor case after two years storage in contact with a plasticizer is considered negligible. (Author)