The temperature spectra of the dynamic mechanical properties of polydimethylsi-loxane-polymethyl phenylsiloxane block copolymers with different block length of polydimethylsiloxane and polyblend which has the same chemical composition as block copolymer
were determined over a temperature rang from -150°to 100℃ by using the vibrating reed method in audio frequencies. The influence of the block length
block copolymer and polyblend on the shape of the loss peaks are discussed.