臺灣產繖形科新變種植物：大屯當歸

Angelica pubescens var. tatunensis (Apiaceae), a new variety from Taiwan

本文發表臺灣特產之繖形科當歸屬新變種植物：大屯當歸（Angelica pubescens var. tatunensis）。大屯當歸目前僅發現於臺灣北部大屯山地區，過去常被錯誤鑑定為野當歸（Angelica dahurica var. formosana），但其紫色花藥、小苞片稀缺、葉片被毛、三級脈隆起、羽軸不具翼及果實油脂腺數量較多等特徵與野當歸明顯相異；大屯當歸與毛當歸（Angelica pubescens var. pubescens）整體形態較相似但仍有部分差異，大屯當歸的葉柄近光滑，子房被毛，花瓣較毛當歸大，在此將大屯當歸處理為毛當歸之一新變種。

This study explored the use of renewable materials to replace petroleum resources by incorporating inorganic nanoparticles into bio-based waterborne polyurethane (WPU) nanocomposite films and improving their properties. These films were prepared via an environmentally friendly prepolymerization method using castor oil and polytetramethylene ether glycol (PTMG) as the bio-based polyol, and isophorone diisocyanate (IPDI) as the isocyanate. The bio-based polyols were castor oil and PTMG, while the isocyanate was IPDI, with an NCO/OH molar ratio set at 1.4. Zinc oxide nanoparticles (ZnONPs) were synthesized through a simple chemical precipitation process, which was optimized to a reaction time of 30 minutes. The synthesized ZnONPs exhibited an average particle size of 75.5 nm and a polydispersity index (PDI) of 0.3, indicating a narrow size distribution. X-ray diffraction confirmed that the ZnONPs possessed a hexagonal Wurtzite structure. Incorporating ZnONPs at concentrations of 0, 500, and 1000 ppm increased the Young's modulus of the WPU film from 195.8 MPa to 273.6 MPa, demonstrating increased stiffness. The water absorption of the films decreased significantly from 101.3% to 0.8%, and the weight retention improved from 41.8% to 86.8% with the addition of 1000 ppm ZnONPs. These results demonstrate that the incorporation of ZnONPs into WPU films enhances both their mechanical strength and water resistance, effectively leveraging the advantages of inorganic materials in the nanocomposite.