A method for forming a polyurethane formulation, comprising: preparing a reaction mixture that includes: a polyether polyol formed from epoxypropane or 1,2-epoxybutane; and an alkylene oxide selected from the group consisting of epoxypropane, 1,2-epoxybutane and a combination thereof; adding a Lewis acid catalyst to the reaction mixture, the Lewis acid catalyst having the general formula M(R 5 ) 1 (R 6 ) 1 (R 7 ) 1 (R 8 ) a , where M is boron, aluminum, indium, bismuth or erbium, a is 0 or 1, R 5 and R 6 are each independently select from the group consisting of a fluoro-substituted phenyl or a methyl group, R 7 is selected from the group consisting of a fluoro-substituted phenyl, a methyl group, a functional group and a functional polymer group, and when a is 1 R 8 is selected from the group consisting of a functional group or functional polymer group; adding an additional amount of epoxypropane or 1,2-epoxybutane to the reaction mixture including the Lewis acid catalyst to form a polyol composition including a polyether-acetal polyol functionalized with at least one acetal functional group, where the polyol composition has an average hydroxyl functionality from 2 to 8 and a hydroxyl equivalent weight from 150 to 4000, where the portion of the polyether-acetal polyol that is functionalized with the at least one acetal functional group is 1 percent to 40 percent of a total weight of the polyether-acetal polyol, where the polyether-acetal polyol has a primary hydroxyl group content of at least 55 percent; and combining the polyol composition with a polyisocyanate to form a polyurethane formulation, where the polyurethane formulation has an isocyanate index in a range from 70 to 500. preparing a reaction mixture that includes: a polyether polyol formed from epoxypropane or 1,2-epoxybutane; and an alkylene oxide selected from the group consisting of epoxypropane, 1,2-epoxybutane and a combination thereof; a polyether polyol formed from epoxypropane or 1,2-epoxybutane; and an alkylene oxide selected from the group consisting of epoxypropane, 1,2-epoxybutane and a combination thereof; adding a Lewis acid catalyst to the reaction mixture, the Lewis acid catalyst having the general formula M(R 5 ) 1 (R 6 ) 1 (R 7 ) 1 (R 8 ) a , where M is boron, aluminum, indium, bismuth or erbium, a is 0 or 1, R 5 and R 6 are each independently select from the group consisting of a fluoro-substituted phenyl or a methyl group, R 7 is selected from the group consisting of a fluoro-substituted phenyl, a methyl group, a functional group and a functional polymer group, and when a is 1 R 8 is selected from the group consisting of a functional group or functional polymer group; adding an additional amount of epoxypropane or 1,2-epoxybutane to the reaction mixture including the Lewis acid catalyst to form a polyol composition including a polyether-acetal polyol functionalized with at least one acetal functional group, where the polyol composition has an average hydroxyl functionality from 2 to 8 and a hydroxyl equivalent weight from 150 to 4000, where the portion of the polyether-acetal polyol that is functionalized with the at least one acetal functional group is 1 percent to 40 percent of a total weight of the polyether-acetal polyol, where the polyether-acetal polyol has a primary hydroxyl group content of at least 55 percent; and combining the polyol composition with a polyisocyanate to form a polyurethane formulation, where the polyurethane formulation has an isocyanate index in a range from 70 to 500. <EOS>