Preparation And Performance Of Natural Polymer Super Absorbent Resin And Its Modified Waterborne Polyurethane

Super absorbent resin （SAR）, also called super absorbent polymers commonly, is akind of new functional polymer materials which can absorb water of several times oreven hundreds times of its own volume. It’s mechanism of absorption and retention inbrief is the swelling equilibrium process of a polymer which with three-dimensionalreticular structure. Traditional water absorption and retention materials, based on SAR,are provided with high speed of absorption, excellent retention and well thermostability,and in some certain conditions them can be reused recycle. The SAR have shown thepotential in agriculture, gardening, reclamation of desert areas, oil exploitation andconstruction industry. Beyond those use above, the SAR have found applications inpharmaceutical dosage and personal care products. However, the complex ProductionProcess and high costs and poor mechanical property of SAR limit its developmentpartly.Waterborne polyurethane （WPU）, use water instead of organic as solvent, not onlypreserved the excellent performance of polyurethane such as high intensity, acid andalkali resistant, but also has the advantages of non-toxic, environmental protection,nonflammable and energy conservation. WPU have been used in many industrialapplications where high intensity, environmental, and high pH resistant are theperformance requirements, such as coating, adhesive and processing industry accessoryingredient. Most of the WPU are relatively hydrophilic and low solid content and do notqualify in water resistence applications.In order to integration advantages of SAR and WPU, we can combine themtogether to promote properties.This thesis mainly contents: the preparation of natural polymer SAR and itsmodified WPU. Synthesis process, water absorption performance and salt resistanceproperties have been discussed. Natural polymer SAR based on microwave initiation polymerization were preparedby sodium alginate （SA）, starch （ST）, acrylic acid （AA） system; and xanthan gum （XG）,acrylamide （AA）, acrylic acid （AA） system. The results of the best ratio of monomer areas follow. The best ratio of SA（SAR） is m_AA/m_ST=6, SA content is5%, neutralization ofAA is70%. The best ratio of XG（SAR） is m_AA/m_AM=5, XG content is3%, neutralizationof AA is70%. Study on water absorption shows that, both of these tow types of SARhave well salt resistance properties, and their water absorbency are decline following theincrease of ion concentration.SA and XG composite films were prepared by blending method. Mechanicalproperties test shows that the tensile strength of SA composite films increase with the Rvalue （n-NCO/n-OH） or ω_WPUincreasing; the elongation of SA composite films decline withR value or ω_WPUincreasing. The maximum value of tensile strength is9.40MPa, presentto R=1.25, ω_WPU=90%; and the maximum value of elongation is437.3%, appeared atR=0.95, ω_WPU=10%. The result of water absorption test shows that water absorbency ofSA composite films decrease with the R value or ω_WPUincreasing. The maximum valueof absorbency of SA composite films is180.58%, appeared at R=0.95, ω_WPU=10%,5.5h.Mechanical properties test shows that the tensile strength of XG composite films increasewith the R value increasing; and decrease with ω_WPUincreasing. The maximum value oftensile strength is9.82MPa, present to R=1.25, ω_WPU=10%. The elongation of XGcomposite films decline with R value increasing, and increase with ω_WPUincreasing. Themaximum value of elongation is28.02%, appeared at R=0.95, ω_WPU=90%. The result ofwater absorption test shows that water absorbency of XG composite films decrease withthe R value or ω_WPUincreasing. The maximum value of absorbency of XG compositefilms is1342.35%, appeared at R=0.95, ω_WPU=10%,52h.