Solid‐state photopolymerization of α,α′‐bis(4‐acetoxy‐3‐methoxybenzylidene)‐p‐benzenediacetonitrile

Abstract

One crystalline form of α,α′‐bis(4‐acetoxy‐3‐methoxybenzylidene)‐p‐benzenediacetonitrile is photopolymerized by a four‐center reaction to give a polymer containing alternating benzene and cyclobutane rings. The polymer is highly crystalline and insoluble in most solvents. Location of groups around the cyclobutane ring is deduced from the products obtained on thermal decomposition. Chain contained benzene rings are located in positions 1 and 3; aromatic groups alternate sides of the cyclobutane ring. Special characterization and quantum yield of the polymerization are reported, as well as polymer solution viscosity and alkaline depolymerization of the polymer.

Photopolymerization of diolefin crystals

“…39 In the case of AMBBA, the quantum yield was measured for overall polymerization of the monomer crystal in slurries. 18 The quantum yields (4>) are defined as the number of olefin double bonds consumed to form cyclobutane per absorbed quantum. Thus, the theoretical maximum value is equal to 2 for the stepwise photoreaction.…”

“…18 These two findings of a new type of crystalline-state photopolymerization prompted polymer chemists to study the generality of this type of polymerization. As a consequence, a large number of diolefin crystals have been found to photopolymerize to linear high molecular weight polymers.…”

The crystal and molecular structure of p-phenylenediacrylic acid diethyl ester

“…As an extension of solid-state photodimerization many compounds with two or more cinnamic acid moieties were synthesized in order to examine whether they are photopolymerizable. Only p-PDA derivatives give crystalline polymers; dicinnamates and dicinnamides containing alkylene units between two cinnamic moieties, and m-phenylenediacrylic acid derivatives produce amorphous oligomers Miura, Kitami & Nagakubo, 1968;Holm & Zienty, 1972). From the view of crystal design and/or crystal engineering (Schmidt, 1971), it is of great interest to examine why the rigid rod-like molecules such as p-PDA derivatives only favour this…”

Organic photochemistry. XVII. Polymerization of unsaturated compounds by photocycloaddition reactions

“…The substituted distyrylbenzene 181 polymerized on irradiation in the crystal state (eq 51). 100 The polymer hv, >375 nm (crystal state) dispersed in MeOH-H20 (1:1) Original assignment of configuration93 opposite to that reported later." '99 c [a]25D = +54°.…”