Viscoelastic Behavior and Interfacial Thermodynamics of Poly(vinyl alcohol-g-sodium styrenesulfonate)[PVA-g-SSS] Hydrogels

• Main Authors: Mei-Chiung Chen, 陳美瓊
• Other Authors: David Shiaw-Guang Hu
• Format: Others
• Language: zh-TW
• Published: 1999
• Online Access: http://ndltd.ncl.edu.tw/handle/36896105666856754218

碩士 === 國立臺灣科技大學 === 纖維及高分子工程研究所 === 87 === Abstract (Part I) PVA[Poly(vinyl-aclohol)] was grafting-copolymerized with SSS(sodium styrenesulfonate) and ammonium cerium(IV) sulfate at 60℃. The SSS content of various copolymers were analyzed with UV-VIS spectroscopy. The water content in hydrogels increases with SSS grafting. The tensile measurements result in the elastic modulus of gels at various temperatures, which yields the crosslink density of hydrogels and Flory-Huggins interaction parameters (χ). Theχparameters decreases with temperature and grafting ratio, and the enthalpic component(χh) decreases with temperatures. The entropic component(χS) decreases with temperature and grafting ratio. The partial molar energy of mixing of water phase decreases with temperatures and grafting ratio. The slip-link model indicates that number of slip-link(or physical entanglement) decreases with temperature and grafting ratio. It is concluded that higher temperature and grafting ratio causes the higher water content, and signifcant disentanglement due to water swelling. The gels are ideal elastomer when the number of slip-link equate zero. It is found that the temperatures at which PVA-g-SSS gels are ideal elastomer decrease with grafting ratio. The swelling ratio of hydrogels increases with the ratio of SSS grafting and crosslink of density due to hydroxyl reactions. Abstract (Part II) An investigation on the influence of ionic contents on interfacial energy was caried out. PVA[Poly(vinyl-aclohol)] grafting-copolymerized with SSS(sodium styrenesulfonate) and ammonium cerium(IV) sulfate at 60℃, as well as PET[poly(ethylene terephalate)] mixture with PETSS(sulphonate sodium-containing PET) were used. The sodium contents of PETSS were analyzed with atomic absorption spectroscopy. The water content of hydrogels and polymer blends increases with ionic sontent. The contact angle of air and n-octane on hydrogels and polymer blends in water at 25℃ were measured. which yield the surface energy of samples(γsv), the dispersion component of surface energy(γdsv), the polar component of surface energy (γpsv) and the water-polymer interfacial energy (γsw). The result imply that the surface energy and the water-polymer interfacial interaction energy (Isw) increases with water content, as well as the water-polymer interfacial energy decreases with water content. Also, the water-gels interfacial energy is corr with Flory-Huggins interactions of polymer-water with fluctuations theory of interface.