添加硫酸鉀之甲基／羥丙基甲基纖維素水膠之化學、 熱及保水性質

Chemical, thermal and moisture retention properties of methylcellulose and hydroxypropyl methylcellulose-based hydrogels blended with potassium sulfate

水膠（Hydrogel）可改善土壤保水性質及提高農用化學品之效率，水膠可吸收並保留大量水分或水溶液，其原料為石油基或天然材料親水性高分子，其可使用物理或／和化學交聯方式製備，目前使用環境友善性之再生性資源開發於植物保水劑為研究發展趨勢，本研究以纖維素衍生物之甲基纖維素（Methylcellulose, MC）與羥丙基甲基纖維素（Hydroxypropyl methylcellulose,HPMC）為原料，並添加硫酸鉀（Potassium sulfate,K2SO4）製備纖維素水膠。使用傅立葉轉換紅外線光譜儀（Fourier transform infrared spectroscopy,FT-IR）與熱重分析儀（Thermogravimetric analyzer,TGA）對MC與HPMC水膠進行化學結構與熱性質分析，並觀察乾膠膨潤形態與水膠保水力。由實驗結果得知，經溶解後再乾燥的MC及HPMC原料與原MC及HPMC之化學結構無差異；於形態觀察中發現添加硫酸鉀之MC水膠與市售土壤改良劑（Commercial soil conditioner,CS）形態相似；由保水力結果證明纖維素基質水膠之保水性高於市售植物保水劑。

Hydrogels has been shown to improve water retention capability and increase the efficiency of agricultural chemicals. Hydrogels can absorb and retain significant amount of water or other aqueous solutions. Hydrogels are prepared from petroleum-based or natural hydrophilic polymers thorough physical and/or chemical crosslinking methods. Nowadays, environmentally friendly natural materials have been developed to replace petroleum-based materials. Natural, environmentally and sustainable cellulose and their derivative can be used to prepare hydrogels. In this study, the temperature-responsive hydrogels were prepared by blending methyl cellulose (MC) or hydroxypropylmethyl cellulose (HPMC) with potassium sulfate (K2SO4) to modify the hydrophobic interaction and influence the gelation at room temperature. Fourier transform infrared spectroscopy (FT-IR) and thermogravimetric analyzer (TGA) were used to assess the appearance and moisture retention capability of the hydrogels. The results showed that MC and HPMC raw materials and hydrogels have the same chemical and thermal characteristics. The appearance of the K2SO4 blended MC and HPMC hydrogels were similar to commercial soil conditioner (CS). Our results demonstrated that cellulose derivatived hydrogels have higher moisture retention capability than the CS hydrogel.