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The thermal behavior

miscibility

crystallite conformation and thermal stability ofcrosslinked（CL-） PVA/PVP blends were studied by DSC and TG methods

respectively. DSCresults showed that in the blend

the crystallinity

T

m

and T

c

of PVA were obviously lower thanthose of pure PVA; the crystal growth changed from three dimensional to two dimensional andonly a single T

g

was detected. These facts demonstrated that this crystalline and amorphousblend have good miscibility. TG curves showed that providing the quantity of K

2

S

2

O

8

added ismore than 3 wt%

in the blends PVA will form a stable CL-network

whose thermal degradationtemperature was near to that of PVP. But crosslinking reaction will not take place for PVP. Theprocesses of thermal degradation of CL-blends are based on combining both the thermaldegradation of PVP and that of PVA crosslinked with corresponding quantity of K

2

S

2

O

8

CL-agent

respectively. The UV measurements showed that 75 wt% of PVP may be remained in CL-blend hydrogelscrosslinked by adding （3--5 wt% ）K

2

S

2

O

8

. This is mainly due to the stable CL-network formed and the good compatibility and properentanglement between the composites in the CL-blends.