TENSILE PROPERTIES AND PARTIAL ALIGNMENT OF POLYACETYLENE, (CH)X, FILMS

In the reported experiments, tensile properties of both cis- and trans-polyacetylene, (CH)//x//, were investigated in order to determine the variables that influence the ultimate extension ratio (l/l//0) of polyacetylene films. It was found that when cis-films of polyacetylene were extended in an e inert (argon) atmosphere, ultimate extension ratios as high as 3. 3 were obtained and with subsequent isomerization at 160-200 degree C under stress, a final l/l//0 of about 4 was obtained. The extension ratio is extremely sensitive to exposure to oxygen and decreases markedly after periods as short as 1 min. It appears as though crosslinking may occur in the polymer when it is exposed to air and this produces brittleness in the specimen. When (CH)//x was isomerized from cis to trans, it became brittle, even in the absence of air.