The document summarizes research on modifying an epoxy resin with a hyperbranched polymer to simultaneously improve its cryogenic tensile strength, ductility, and impact strength. Key findings include: - Adding 10% by weight of the hyperbranched polymer Boltorn H30 to the epoxy resin led to the maximum improvements in tensile strength, failure strain, and impact strength at cryogenic temperatures of 77K. - At 77K, the hyperbranched polymer reduces the effect of residual stresses caused by thermal shrinkage, increasing strength and ductility. - Scanning electron microscopy images showed the fracture surfaces of the modified epoxy exhibited a "protonema" structure that explains its