An online

non-destructive test system

based on small angle light scattering (SALS) measurements

was presented and applied to the phase-size investigation of polyethylene/polyamide 1010(PE/PAl010) immiscible blends along the extruder during twin-screw extrusion At the same time

some specimens were sampled online and analyzed by use of scanning electron microscopy (SEM)．From SALS analysis．the phase size was characterized by the correlation length α

average chord length Lscatt and average diameter of dispersed phase

Dscatt according to the Debye theory Because the correlation length αc is related to the average particle size and the volume fraction both

αc is only suitable for representing particle size among blends with the same composition．Average diameter of dispersed phase Dscatt is suitable for representing the size of dispersed phase for discrete systems．Average chord length Lscatt

however

could represent the phase size for discrete or co-continuous systems among blends with the same or different compositions From SEM analysis the average chord length LSEM and average diameter of dispersed phase DSEM were also calculated according to their definition．The results of SALS and SEM ale in good agreement

which show that SALS online system can be a powerful method to investigate the phase size during twin-screw extrusion Both SALS and SEM show that the dispersed particle size becomes progressively smaller Moag the screw length．For the ukimate morphology of PE/PA1010 blends with different components (PA1010≤50％

volume fraction)

the size of dispersed phases increases and the size of continuous phase decreases with the increase of the PA1010 component．At the composisions(PE/DA1010) of 60140 and 70/30

co-continuous phases occur．