การเตรียมและสมบัติของพอลิยูรีเทนอิลาสโตเมอร์ซ่อมแชมตัวเองผ่านการผันกลับได้ ของพันธะไดซัลไฟด์

Abstract

Preparation and properties of polyurethane elastomers containing disulfide bonds in the main chain were investigated. 4,4'-methylene bis(cyclohexyl isocyanate) (HMDI) was used as initial isocyanate substance. The parameters including, (1) the influence of polytetrahydrofuran (polyTHF):1,4-butanediol(BDO) (THF:BDO) molar ratio, (2) the influence of 1,4-butanediol and hydroxyethyl disulfide (HEDS) (BDO:HEDS) molar ratio, (3) the influence of chain extender types (ie., BDO; HEDS and 3,3- dihydroxydiphenyl disulfide, DPS) and (4) the influence of polyol types (i.e., polytetrahydrofuran, polyTHF; polyethylene glycol, PEG; and hydroxyl terminated natural rubber, HTNR), on polyurethane properties were studied. The chemical structure of polyurethane was confirmed by Fourier transform infrared spectrometer (FT-IR) and Raman spectra analysis (FT-Raman). In addition, the mechanical, dynamic mechanical, thermal properties and self-healing efficiency of polyurethanes were evaluated. The results showed that molar ratio of polyTHF:BDO at 1:1 provided the highest tensile strength. Self-healing polyurethanes were successfully prepared by using HEDS and DPS as chain extender via the chain exchange reaction of disulfide bonds and shape memory effect. 90.64% self-healing efficiency of the polyurethane was obtained by using HMDI:polyTHF:BDO:DPS molar ratio of 2.05:1:0.5: 0.5 after healing at 65°C for 4 h.