Radiation curable phase change material solutions and shape stable thermoset phase change material gels formed therefrom

A radiation curable phase change solution comprising:

• a hydrophobic phase change material;
• (a) 1% wt/wt to 15% wt/wt of a polybutadiene based rubber polymer that is soluble in the hydrophobic phase change material and has (i) a pendant 1,2 vinyl content of at least 0.5% wt/wt thereof or (ii) a 1,4 cis content of at least 9.0% wt/wt;
• or (iii) a combination of 1,2 vinyl content plus a 1,4 cis content of at least 45% wt/wt;
• or
• (b) 1% wt/wt to 15% wt/wt of a polyisoprene based rubber polymer that is soluble in the hydrophobic phase change material and has (i) a combination of 1,2 Add plus 3,4 Add content of at least 0.5% wt/wt thereof or (ii) a combination of 1,4 cis content plus a 1,4 trans content of at least 40% wt/wt;
• and
• 0.01% wt/wt to 0.50% wt/wt of a photoinitiator soluble in the hydrophobic phase change material;
• wherein the hydrophobic phase change material is the balance thereof, and upon exposure to radiation the composition cures to form a thermoset gel.