磷-硼杂化预聚物嵌段水性聚氨酯纸张施胶剂的制备和性能

以甲苯二异氰酸酯（TDI）、聚乙二醇（PEG）为单体，二羟甲基丙酸（DMPA）和磷-硼杂化预聚物PBHP为扩链剂，通过逐步加聚制备不同组分的含磷、硼元素的阻燃水性聚氨酯（FRWPU）。FRWPU与聚磷酸铵（APP）、季戊四醇（PER）、三聚氰胺（MEL）膨胀阻燃体系复配制备阻燃纸张施胶剂。采用红外光谱（FTIR）、核磁共振波谱（NMR）、热重分析（TGA）、扫描电镜（SEM）、接触角测定、X射线光电子能谱（XPS）和垂直燃烧测试对FRWPU分散体、FRWPU薄膜、未施胶纸样和施胶纸样进行了表征。研究表明，随着PBHP加入量的提高，薄膜的疏水性增强，FRWPU40的接触角为85.4°，较FRWPU0提高了35.3%；同时，薄膜的最大热分解速率下降，800℃的残留质量从0上升到7.80%；施胶纸样的最大热分解速率下降，残留质量提高，平均炭化长度减小。当PBHP含量为50%时，残炭量为27.84%，较FPU0/IFR提高了30.6%；平均炭化长度为5.9cm，较FPU0/IFR降低了30%。SEM结果表明，施胶纸样燃烧后表面生成更加致密的炭层，阻燃性能提高。

Preparation and properties of waterborne polyurethane paper sizing agents with phosphorus-boron hybrid prepolymer blocks

Using toluene diisocyanate (TDI) and polyethylene glycol (PEG) as monomers, dimethylpropionic acid (DMPA) and phosphorus-boron hybrid prepolymer PBHP as chain extender, FRWPU containing different phosphorus and boron elements was prepared by step polymerization. The paper sizing agent was prepared with ammonium polyphosphate (APP), pentaerythritol (PER) and melamine (MEL) expansion flame retardant system. FRWPU dispersion, FRWPU films, uncoated and coated paper samples were characterized by infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (NMR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), contact angle determination, X-ray photoelectron spectroscopy (XPS) and vertical combustion test. The results showed that with the increase of PBHP content, the hydrophobicity of the films increased, and the contact angle of FRWPU40 was 85.4°, which was 35.3% higher than that of FRWPU0. At the same time, the maximum thermal decomposition rate of the films decreased, and the residual mass at 800℃ increased from 0 to 7.80%. The maximum thermal decomposition rate of the coated paper samples decreased, the residual quality increased and the average carbonization length decreased. When the PBHP content was 50%, the carbon residue was 27.84%, which was 30.6% higher than FPU0/IFR. The average carbonization length was 5.9cm, 30% lower than that of FPU0/IFR. SEM results indicated that more dense carbon layer was formed on the surface of the coated paper after combustion, and the flame retardant performance was improved.