In various embodiments, the present invention provides well-defined biodegradable poly(lactone-b-propylene fumarate) diblock and triblock polymers formed using a novel one-pot, scalable ring-opening block-order copolymerization (ROBOCOP) technique that utilizes magnesium 2,6-di-tert-butyl-4-methylphenoxide (Mg(BHT)2(THF)2) to "switch" from the ROP of cyclic esters to the ROCOP of maleic anhydride(MAn) and propylene oxide (PO) to produce PPF based block copolymers for application in additive manufacturing and patient specific regenerative medicine. These block copolymers are fully resorbable and can be photochemically crosslinked in a number of applications, including 3D printing. By adding the lactone block to the PPF polymer, the viscosity of the resulting block copolymer at working temperatures can be precisely controlled and the quantity of the reactive diluent in printable resins can be reduced or eliminated.