Synthesis of Trifunctional Poly(propylene glycol) with Acetal Linkages and Properties of Chemically Recyclable Crosslinked Polyurethanes Prepared Therefrom

The synthesis and characterization of chemically recyclable crosslin.ked polyurethanes were studied in this work. Acetal units were introduced into polypropylene glycol having three hydroxyl terminal groups (PPG) by the reaction of the hydroxy groups of PPG with 4-acetoxybutyl vinyl ether followed by conversion of the acetate groups into hydroxy groups. Crosslinked polyurethanes were prepared by the reaction of the acetal-containing polyols (PPG-acetal-OH) with tolylene diisocyanates (TDI) at 120 °C under vacuum. The obtained polyurethanes formed elastomeric films and exhibited good mechanical properties. The treatment of the polyurethane films with aqueous acid at room temperature caused smooth hydrolysis of their acetal units to give PPG as a degradation product

Time series analysis of the chemical and oceanographic parameters of the seawater around coral reef ecosystems, Okinawa, Japan

琉球大学21世紀プログラム「サンゴ礁島嶼系の生物多様性の総合解析」平成17年度成果発表会（平成18年3月6日開催）　会場：琉球大学大学会館3