Reference

Effect of irradiation on the aging of injection-molded polymethacrylates for medical purposes

Effect of irradiation on the aging of injection-molded polymethacrylates for medical purposes. Postrigan, M. V.; Tikhomirova, N. S.; Neverov, A. N.; Krivonosov, A. I.; Semenenko, E. I.; Polunin, V. A. (USSR). Plast. Massy, (7), 53-5 (Russian) 1977. CODEN: PLMSAI. DOCUMENT TYPE: Journal CA Section: 36 (Plastics Manufacture and Processing) Section cross-reference(s): 63 Samples of Dakril 4B [25852-37-3] and Dakril 2M [9011-87-4] irradiated at sterilizing dosages of 2.5 Mrad showed a change in their strength properties (yield point in elongation) during heat aging (60-90.degree.) which was described by a curve with a max. The presence of the max. was attributed to branching and crosslinking at active centers formed during irradn. A method of accelerated aging is described for predicting the service life of articles during long-term storage at 20.degree. and during use at 60-90.degree..

Mechanism of the thermal decomposition of copolymers of methacrylates with acrylates

Mechanism of the thermal decomposition of copolymers of methacrylates with acrylates. Kopylova, N. A.; Semchikov, Yu. D.; Ryubov, A. V.; Terman, L. M. (USSR). Tr. Khim. Khim. Tekhnol., (3), 56-7 (Russian) 1975. CODEN: TKKTAE. DOCUMENT TYPE: Journal CA Section: 35 (Synthetic High Polymers) New evidence for the validity of the radical chain mechanism proposed by Semchikov, et al. (1972) for the thermal decompn. of acrylate-methacrylate copolymers at .gtoreq.280.degree. was obtained in the study of the thermal decompn. of Bu acrylate-Me methacrylate copolymer (I) [25852-37-3] at 300.degree.. Kinetic curves for the decompn. of I indicated an autocatalytic nature for the reaction. This, along with the formation of appreciable amts. of Bu methacrylate in the decompn. products, supported the proposed mechanism involving sequential .beta.-degrdn. of macroradicals and cleavage of the allylic bonds formed.