【摘要】 海藻酸钠(SA)是一种优良的可降解生物质成膜材料,为了改善SA薄膜亲水性强、薄膜硬脆的缺点,采用两步法,在碱性条件下将环氧封端聚氨酯接枝到SA上,制备了一种改性SA薄膜。傅里叶红外光谱(FT-IR)和凝胶渗透色谱(GPC)分析结果证明了该接枝反应的发生,X射线衍射(XRD)分析结果表明聚氨酯的引入使SA分子的晶型结构发生改变。扫描电镜(SEM)分析结果表明,聚氨酯的引入破坏了SA的分子间作用力。热重(TG)分析结果表明,聚氨酯的引入提高了SA在低温区的热稳定性,降低了其在高温区的热稳定性。水接触角、水蒸汽透过率和力学性能分析表明,当改性剂聚氨酯的加入量从0%到50%变化时,薄膜的水接触角从55.0°提高到77.1°,水蒸汽透过率从2450.28g/(m2·24h)下降到1078.74g/(m2·24h),薄膜的拉伸强度从82.44MPa下降到12.51MPa,断裂伸长率从6.87%增大到41.82%。当改性剂的加入量为50%～60%时,改性SA的接枝率可达18.01%。更多还原

【Abstract】 Sodium alginate(SA)is an excellent biodegradable biomass film-forming material.In order to reduce the disadvantages of sodium alginate film,such as the strong hydrophilicity,hard and brittle film.A modified sodium alginate film was prepared by grafting epoxy terminated polyurethane on sodium alginate under alkaline condition.Fourier transform infrared spectroscopy(FT-IR)and gel permeation chromatography(GPC)confirmed the occurrence of grafting reaction.XRD showed that the introduction of polyurethane caused a change in the crystal structure of sodium alginate.The microstructure of modified film was characterized by scanning electron microscopy(SEM).Thermal gravimetric analysis showed that the introduction of polyurethane improved the thermal stability of sodium alginate in the low temperature region,and reduced its thermal stability at high temperature.The analysis of water contact angle,water vapor transmission rate and mechanical properties showed that when the addition amount of modifying agent polyurethane was changed from 0%to 50%,agent polyurethane was changed from 0% to 50%,the water contact angle of the film increased from 55.0°to 77.1°,Water vapor transmission agent polyurethane was changed from 0%to 50%,the water contact angle of film increased from 55.0°to 77.1°.Water vapor transmission rate decreased from 2450.28 g·m-2·24 h-1 to 1078.74 g·m-2·24 h-1,the tensile strength of film decreased from 82.44 MPa to12.51 MPa.And the elongation at break increased from 6.87%to 41.82%.When the modifier was added in an amount of 50%～60%,the grafting rate of modified sodium alginate can reach 18.01%.更多还原