Polyurethane foaming system, heat-recoverable polyurethane foam and preparation method thereof

The invention belongs to the field of polyurethane foam, and relates to a polyurethane foaming system, heat-recoverable polyurethane foam and a preparation method of the heat-recoverable polyurethane foam. The polyurethane foaming system comprises: an isocyanate reactive component having an average functionality of 1.7-2.4, the isocyanate reactive component comprising a polyol having a molecular weight of higher than 500 g/mol; one or more catalysts selected from the group consisting of amine-based catalysts and organometallic compound-based catalysts; a siloxane based surfactant; water; optionally, a chain extender having a functionality of 2 and/or a cross-linking agent having a functionality of 3 or more; and optionally an additive; and an isocyanate component having an average functionality of 1.9-2.4, which contains a polyisocyanate and/or isocyanate group-terminated prepolymer prepared by reacting a polyisocyanate with a compound containing two or more hydroxyl groups, the ratio of the weight of the tri