A sample of polyvinyl acetate with Mn=1.48×106 (by GPC) was obtained by bulk photo-polymerization

and then it was conversed into poly(vinyl alcohol) with Mη=2.3×105

as HMWPVA thereafter.The specimens of ice strengthened by HMWPVA were prepared per following procedures:(1) the aqueous solutions of HMWPVA with predetermined concentrations were prepared and then degassed; (2) poured the above solutions in models and then put them in a -18℃ refrigerator for over 48 h.The tensile and compression testing was performed at -18℃.It showed that with addition of 3% (mass fraction) HMWPVA

the values of the tensile strength

elongation at break

compressive strength and compressive modulus of ice were 11.7

3.5

2.3 and 2.1 times of those of pure ice

respectively.It implied that there was a strong dependence of the tensile strength on the molecular weights of the PVA.Furthermore

the addition of HMWPVA increased the melting time

for example

the melting time of pure ice is about 5 min at 29℃

but the samples with 2%

3% and 4% HMWPVA are 25 min

60 min and 240 min

respectively.