Effect of the backbone composition of some polycarbosilanes on their structure and thermal properties

A series of newly synthesized poly(organocarbosilanes) with a variable cont ent of silicon and carbon atoms in the backbone were studied by X-ray diffr action, differential scanning calorimetry, and thermomechanical techniques. All the studied polymers represent partly crystalline high-molecular-mass compounds capable of forming simple liquid-crystalline structures. The samp les of uniaxially oriented poly(dimethylsiltrimethylene) with an ultrahigh molecular mass (M = 7.6 x 10(6)) exhibit the phenomenon of one-dimensional diffraction, which is evidence of a considerable fraction of unfolded polym er chains penetrating through the amorphous- crystalline matrix in the dire ction of sample orientation.