發(fā)布時間：2018-07-29 18:43

【摘要】：天然乳膠是一種經生物合成的、可再生的自然資源。因其優(yōu)異的彈性和成膜性,被廣泛地應用于醫(yī)用彈性薄膜制品領域。但是純天然乳膠薄膜的拉伸強度不高、耐溶劑性和致密性較差等缺陷在一定程度上限制了天然乳膠的應用發(fā)展。本文利用硅溶膠、陽離子聚電解質改性硅溶膠以及大豆蛋白／二氧化硅雜化溶膠分別對天然乳膠進行改性,獲得一系列結構可控的有機-無機復合材料,所得膜材料的機械性能、耐溶劑性和致密性均得到不同程度的改善。 本課題以正硅酸乙酯(TEOS)作為前驅體,在其水解縮聚生成硅溶膠的不同階段共混改性天然乳膠。研究結果表明共混膠乳中原位生成的納米Si02能夠有效地提高薄膜的力學性能,同時薄膜的親水性和耐紫外老化性能也得到了提高,但仍存在Si02向薄膜表面遷移的問題,影響了原位補強的效果。進一步用陽離子聚電解質對硅溶膠中的SiO2膠粒進行包覆改性后,帶正電性的Si02膠粒能與帶負電的天然乳膠粒子形成一種以乳膠粒子為核、SiO2膠粒為殼的核殼結構,這種緊密的核殼結構能夠提高膜材料中有機無機兩相之間的交聯(lián)程度,進而提高薄膜的力學性能和耐溶劑性,同時解決了Si02向膜表面遷移的問題。 大豆蛋白具備良好的成膜性和界面結合能力,能夠與乳膠表面的非膠物質結合,并且大豆蛋白中的極性基團容易和其他官能團構成物理或化學交聯(lián)點。本文通過TEOS在大豆蛋白溶液中的水解縮聚反應,制備出一種大豆蛋白／二氧化硅雜化溶膠,用于改性天然乳膠。研究表明這種雜化溶膠能夠填補乳膠粒子間的空隙,改性薄膜在力學性能大幅提高的同時,薄膜表面的致密性和耐溶劑性也均得到明顯改善。
[Abstract]:Natural latex is a biologically synthesized, renewable natural resource. Because of its excellent elasticity and film forming, it is widely used in the field of medical elastic film products. However, the tensile strength of pure natural latex film is not high, and the poor solvent resistance and compactness limit the application of natural latex to some extent. In this paper, a series of organic-inorganic composites with controllable structure were obtained by using silica sol, cationic polyelectrolyte modified silica sol and soybean protein / silica hybrid sol respectively. The mechanical properties, solvent resistance and densification of the films were improved to some extent. In this paper, tetraethyl orthosilicate (TEOS) was used as the precursor, and the natural emulsion was blended in different stages of hydrolysis and condensation to produce silica sol. The results show that the in-situ nanosized Si02 can effectively improve the mechanical properties of the films, and the hydrophilicity and UV aging resistance of the films are also improved, but there is still the problem of Si02 migration to the surface of the films. The effect of in-situ reinforcement is affected. After further modification of SiO2 particles in silica sol with cationic polyelectrolyte, the positively charged Si02 particles can form a core-shell structure with latex particles as core SiO2 particles and negative charged natural latex particles. The close core-shell structure can improve the cross-linking degree between organic and inorganic phases in the membrane materials, and then improve the mechanical properties and solvent resistance of the films. At the same time, the problem of Si02 migration to the surface of the membrane can be solved. Soybean protein has good film-forming and interfacial binding ability, and can bind to non-colloidal substance on the surface of emulsion, and the polar group in soybean protein can easily form physical or chemical crosslinking point with other functional groups. In this paper, a soybean protein / silica hybrid sol was prepared by hydrolysis and condensation of TEOS in soybean protein solution, which was used to modify natural latex. The results show that the hybrid sol can fill the gap between latex particles and the surface densification and solvent resistance of the modified films are improved significantly while the mechanical properties of the modified films are greatly improved.
【學位授予單位】：華東理工大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TB383.2

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