Study On The Preparation And Performance Of The Blended Product Of Sodium Alginate And Water-soluble Polymer

Sodium alginate（SA）is a kind of natural water soluble polysaccharide polymer,which is refined from marine algae.It has the characteristics of environmental protection,biodegradability,good biocompatibility,ect.Waterborne polyurethane（WPU）and polyvinyl alcohol（PVA）have excellent mechanical properties and environmental friendliness.They are hot topics for the synthesis of water-soluble polymers in recent years.The blending of sodium alginate and natural water-soluble polymer can not only combine the advantages of them,but also make up for the shortcomings of some polymer materials.CA/WPU membranes were prepared by blending sodium alginate with waterborne polyurethane,while SA/PVA fibers were prepared by blending sodium alginate with polyvinyl alcohol.The properties of the product were characterized by LOI、TG、FTIR、SEM and rheological property tests.The results show that:（1）The limit oxygen index of pure polyurethane membranes is 17.6,and the addition of sodium alginate can improve the flame retardancy of the pure waterborne polyurethane membrane.With the content of sodium alginate increasing,the oxygen index of CA/WPU membrane increases and the value can reach up to 39.5.Its flame retardancy mechanism presents a clear flame retardant mechanism of metal ions.We can analyse the residue after the combustion of the membrane are calcium oxide and calcium carbonate through XRD and thermal stability analysis.With the content of sodium alginate increasing,the quality of the residue increased.The residue can be used as a barrier or insulation surface to isolate oxygen and slow down the diffusion of combustible gases.With the addition of sodium alginate,the tensile strength of CA/WPU membranes decreased and then increased,while the elongation at break decreased.When the mass fraction of sodium alginate is 50%,the tensile strength of the blend film is the lowest.（2）The initial viscosity of SA/PVA solution increased significantly with the addition of PVA.,and the initial viscosity of the blend solution with boric acid increases more obvious.The blend solution did not change the rheological properties and still had good spinning properties,showing"shear thinning".The blend fiber has obvious fiber morphology.Compared with pure calcium alginate fiber,the hygroscopic property and water absorption property of the blend fiber increase with the content of polyvinyl alcohol increasing,but the hydrophilic property of the blend fiber adding boric acid decreases with increasing of polyvinyl alcohol.When the drafting ratio is 2.0,the strength of the blend fiber can reach 2.08 cN dtex^-1.