The reaction of this substance with sulfuric acid “levels off” at a point called the LODP. Acidic hydrolysis of this substance can convert it to nanocrystal form, whose applications include molecular scaffolds and aerogels. A form of this substance substituted with carboxy·methyl groups can be used as a thickener or cation exchange resin. Dissolving copper hydroxide in ammonia makes a reagent for dissolving this substance. (*) Acetate esters of this substance form semipermeable membranes for protein filtration. Either PVDF or a nitro derivative of this polymer (10[1]-5[1])forms the membrane in a western blot. This polymer is dissolved, then spun into fibers, to make rayon. Before PET, photographic film was made from, for 10 points, what biopolymer made of beta-1,4 linkages between glucose monomers? ■END■ (10[1]0[1])