การเตรียมวัสดุดูดซับน้ำโดยการกราฟต์ฟางข้าวด้วยกรดอะคริลิกโดยการฉายรังสีแกมมา / อนุรัตน์ โพธิ์หล้า = Preparation of water absorbing material from grafting of acrylic acid onto rice straw by gamma irradiation / Anurat Polar
Water absorbing material from grafting of acrylic acid onto rice straw (rice straw-g-acrylic) was prepared by gamma irradiation. Major parameters studied were monomer concentration, rice straw content and total dose. The optimum condition for graft copolymerization reaction of acrylic acid onto rice straw was 10 % acrylic acid solution with 10 % rice straw (w/w) and 10 kGy of radiation. Under this condition, the swelling of rice straw-g-acrylic was 8069 %, the degree of grafting of rice straw-g-acrylic was 43.46 %, and the equilibrium water absorbency was 540 minutes. Properties of graft copolymer were analyzed using Fourier transform infrared (FTIR) spectroscopy technique.
Fertilizer loading and release characteristics were studied. An experiment was done to allow the water absorbing material to absorb urea fertilizer by dipping the material in 10 % aqueous urea solution. The material exhibited outstanding urea loading of 796 %. The release of urea was determined by immersing samples in distilled water with slow agitation, and then pipetting out at desired intervals. The concentration of urea was determined by UV-Vis spectrophotometer at 440 nm. It was found that the release amount increased with time until it reached a maximum value and became constant. The 89.00 % release of urea was found at 12 hours.
The degradation of water absorbing material in soil was studied. The material exhibited exceptional durability with more than 2 months without complete degradation.
