Why does my hair get frizzy after i straighten it.?!?!?

ive bought about 5 straighteners and NONE seem to work.! is it the straightener itself or myhair.?!?!?! okay every straigtener i havee this is what i do; i wake up 4 school... straighten my hair for 1 1/2 hours ; make it STRAIGHT time to go to the busstop i walk out ; get to school and my hair is puffy frizzy and NOT STRAIGHT.! is there a way to prevent that? or does anyone know a straightener that axually works ; i heard chi; so i bought it and NO; i Heard a "herstyler" at the mall; bought it No.... Instyler; bought it no.,!!! i was thinking a keyoseky but does it workk.?!?!?!?!?