Photochemistry of Ketone Polymers. III. Energy Transfer in Ethylene-Carbon Monoxide Polymers

Abstract

Studies have been made of electronic energy transfer to and from the excited states of carbonyl groups in ethylene-carbon monoxide copolymers in decahydronaphthalene solution and in the solid phase. The results were compared with those obtained using 6-undecanone as a model ketone. The partition of photochemical reaction between singlet and triplet precursors was examined by the use l-c/s,3-cA-cyclooctadiene as a triplet quencher. About 50 % of the photochemical reaction in the carbonyl copolymer originated from the triplet state as compared with 55% in the case of 6-undecanone. Studies of the quenching of naphthalene fluorescence by carbonyl groups were used to determine energy transfer rate constants, kq, and the probability of reaction during collision. These data were used to estimate the lifetimes of the ketone carbonyl triplet of 6-undecanone in solution O = 0.34 X 10-8 sec) and for the carbonyl copolymer in solution (r = 1.4 X 10-8 sec) and in the solid phase (r = 1.0 X 10~8 sec). The rate constant for exchange energy transfer, kq, is about one-third the value of kass calculated from the diffusion constants using the Smoluchowski equation, indicating that only about one collision in three is effective. The significance of these results on the feasibility of using energy transfer as a means of inhibiting photochemical degradation is considered.

Studies of energy transfer and molecular mobility in polymer photochemistry

“…In early studies we showed by measurements of the type II process in polyethylene-carbon monoxide that the triplet reactions could be quenched by cyclooctadiene at approximately collisional rates in dilute solution, and also in the solid phase. (10,11) In this case the limiting rate is the diffusion of the cyclooctadiene through the amorphous polyethylene matrix. Studies of the quenching of type II photolysis of poly(phenyl vinyl ketone) showed that substantially all the reaction arose from the excite<l triplet state and that the quantum yields and lifetimes were dependent upon sequence distribution in phenyl vinyl ketone-styrene copolymers.…”

Copolymerization of carbon monoxide and norbornene derivatives with ester groups by palladium catalyst

“…They reported that only oligocopolymerization of carbon monoxide (CO) with mer (molecular weight Å 350) was obtained from olefins because of several advantages offered by copolymerization of CO and norbornene after 3 the resultant copolymers. [1][2][3][4][5] First, carbon monoxdays. 7 Drent et al 9,10 was the first to use pallaide is inexpensive.…”

Miscible Blends of Polystyrene and Poly(ε-caprolactone) with Phenylacetylene-Carbon Monoxide Alternating Copolymer

“…For the simplest model, if the blends contained only two phases after PCL crystallization, viz., the PCL crystalline phase and the miscible amorphous phase, the composition of the miscible amorphous phase can be calculated once the PCL degree of crystallinity is known. (2) where w copolymer and WpcL are the initial weight fraction of copolymer and PCL, respectively. Figure 4 also displays the plot of Tg vs. the composition after adjusting for the PCL crystallization.…”

“…[1][2][3][4][5][6] In a prior study, Liaw et al have successfully synthesized an alternating copolymer of CO and phenylacetylene (PA) by palladium complex. 7 Poly(PA-alt-CO) is an amorphous material with a glass transition temperature (Tg) around l00°C.…”