共查询到19条相似文献,搜索用时 62 毫秒
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温度及pH敏感性聚乙烯醇/羧甲基壳聚糖水凝胶的制备与性能研究 总被引:2,自引:0,他引:2
以聚乙烯醇(PVA)和羧甲基壳聚糖(CMCh)为原料,采用60Co-γ射线辐照交联制备聚乙烯醇/羧甲基壳聚糖(PVA/CMCh)水凝胶;研究了PVA与CMCh的配比、温度、pH及离子强度等对PVA/CMCh水凝胶溶胀率的影响。结果表明适当配比的PVA/CMCh水凝胶具有一定的温度、pH及离子敏感性。该水凝胶在5~20°C时具有较高的溶胀率,温度在20°C以上溶胀率较低,并且有一定的可逆性;水凝胶在pH较低(pH<4.0)和较高(pH>6.0)时溶胀率均较大,而当pH为4.0~6.0时溶胀率较小,显示出一定的pH敏感性。 相似文献
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采用逐步聚合凝胶法完成对含有端烯基聚氨酯(UAA)预聚物与N-异丙基丙烯酰胺(NIPA)共聚,得到具有温度和pH双重敏感性的聚氨酯水凝胶。通过对该凝胶最大溶胀形貌观察,在不同温度及pH环境中对溶胀性能的探讨,发现该凝胶空间结构、溶胀性等方面适合作药物缓释。选用模拟药物茶碱,在模拟人体消化系统,即不同pH条件下对其缓释,7 h基本释放完,茶碱浓度相对稳定。因此,该材料在介入诊疗方面有极大的应用潜力,是一种有着巨大应用前景的生物医用材料。 相似文献
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在5种不同温度下聚合交联,制备了一系列温度和pH双重敏感性聚(N-异丙基丙烯酰胺-co-衣康酸)水凝胶。实验发现,15、25℃得到的凝胶是透明的,45、55℃得到的凝胶是白色不透明的,而在相转变温度附近(35℃)得到的凝胶则是半透明的。FTIR测定表明,它们具有相似的化学组成和结构。SEM观察证实,它们具有不同的表面形态。测定了不同温度和pH下达到平衡时水凝胶的溶胀比,考察了水凝胶在水和强酸性溶液中的去溶胀动力学。结果表明,与15℃或25℃制备的水凝胶相比,45℃和55℃制备的水凝胶的性能有显著提高:(1)溶胀比大为增加。15℃或25℃制备的水凝胶在25℃时溶胀比分别为65.3和68.1,而45℃和55℃制备的水凝胶此时溶胀比分别高达105.7和110.1;(2)45℃和55℃制备的水凝胶在极端环境下对温度的变化仍具有较快的响应速率。例如在温度为60℃,pH=1.67的强酸条件下,45℃和55℃制备的水凝胶在60 min内皆可失去95%的水,而15℃或25℃制备的水凝胶在120 min内只能失去42%左右的水。 相似文献
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敏感性水凝胶制备研究 总被引:1,自引:1,他引:1
本文研究了用溶液聚合及辐照聚合两种方法制备敏感性水凝胶,发现聚合温度、赶氧充分性、引发剂浓度是聚合成功的关键因素。并对两种方法对其凝胶敏感性的影响进行了比较。 相似文献
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阻燃PTT共聚酯的制备及性能研究 总被引:1,自引:0,他引:1
采用直接酯化-缩聚工艺,在酯化后加入磷系阻燃剂2-羧乙基苯基次膦酸(CEPPA)与1,3-丙二醇(PDO)的酯化溶液(CEPPA-PDO),制得阻燃聚对苯二甲酸丙二醇共聚酯(FR-PTT)。通过FT-IR、DSC、TG、SEM以及垂直燃烧法对FR-PTT的结构及性能进行表征。结果表明:阻燃剂CEPPA可能是以共聚的方式接入到大分子链中,并且随着磷含量的增加,FR-PTT的Tc上升,而Tm呈下降趋势,同时FR-PTT在高温处理后成炭性良好,阻燃级别达到FV-0级。 相似文献
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以丙烯酸全氟辛基乙酯为主要单体,采用乳液聚合法制备了含氟丙烯酸酯共聚物,通过红外光谱和激光粒度分析对共聚物进行了表征,测试了共聚物乳液的稳定性,研究了单体含量和交联剂对共聚物性能的影响,测定了共聚物于皮革表面的防水、防油性能,并对共聚物乳液处理的皮革表面进行了SEM分析。结果表明,含氟丙烯酸酯共聚物乳液防水等级9级,防油等级6级,具有良好的低表面性能。 相似文献
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含氟丙烯酸酯共聚物的制备及性能 总被引:2,自引:0,他引:2
自制含氟丙烯酸酯单体与其他丙烯酸酯分别以溶液聚合和乳液聚合制得含氟丙烯酸酯溶液共聚物(Ⅰ)和乳液共聚物(Ⅱ),并与不含氟的丙烯酸酯共聚物(Ⅲ)性能进行了对比:Ⅰ在水中浸泡96h后涂膜完好,Ⅲ剥离;Ⅱ在水中浸泡24h后吸水率为12 01%~13 65%,Ⅲ为24 87%;Ⅰ、Ⅱ分别在丙酮和w(NaOH)=5%的水溶液中浸泡24h,涂膜基本完好,Ⅲ则剥离、破裂或溶解;w(氟单体)=5%时以KH-570改性Ⅰ并按上述方法测试性能,涂膜完好,硬度由HB提高到H;Ⅰ与水的平均接触角为62 1°~68 4°,Ⅱ为53 9°~61 0°,Ⅲ为29 1°~30 5°,KH-570改性Ⅰ后为63 4°~67 3°。上述结果表明:含氟共聚物涂膜的耐水性、耐碱性、耐溶剂性和自洁性均优于不含氟的共聚物,且含氟单体与KH-570具有良好的协同作用。 相似文献
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概述了pH、温度敏智能水凝胶的种类及其作用机理,重点论述其在水处理、分离萃取、药物缓释等领域中的应用,指出了此类智能水凝胶目前存在的问题、解决办法及未来的发展方向。 相似文献
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Summary Polymer-clay hydrogel composite was prepared on the basis of polyacrylamide (PAAm) gel containing the clay mineral sepiolite.
The properties of swelling and dye adsorption of poly(acrylamide-sepiolite) (AAm/Sep) composite hydrogel were investigated.
The parameters of swelling and diffusion in water and dye solutions were calculated for the AAm and AAm/Sep hydrogels. It
was found that the equilibrium swelling degree of obtained composite higher than that of AAm gel. Spectroscopic analysis of
composite and composite-dye systems was done with FT-IR method. Adsorption of monovalent cationic dyes such as Basic Blue
12 (BB-12) Basic Blue 9 (BB-9), and Basic Violet 1 (BV-1), was studied on the composite. In the adsorption experiments, S
(Sigmoidal) type for composite gel adsorption isotherms in the Giles classification system was found. Adsorption studies indicated that
the amounts of adsorbed dyes on the AAm/Sep composite hydrogel were increased with following order; BB-12 > BB-9 > BV-1. The
composite hydrogel may be considered as good candidate for environmental application to retain more water and dyes. 相似文献
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Benbo Zhao Mingda Zhao Liming Li Shixiong Sun Heping Yu Yuan Cheng Yuedi Yang Yujiang Fan Yong Sun 《International journal of molecular sciences》2022,23(17)
Natural polymer hydrogels have good mechanical properties and biocompatibility. This study designed hydroxyapatite-enhanced photo-oxidized double-crosslinked hydrogels. Hyaluronic acid (HA) and gelatin (Gel) were modified with methacrylate anhydride. The catechin group was further introduced into the HA chain inspired by the adhesion chemistry of marine mussels. Hence, the double-crosslinked hydrogel (HG) was formed by the photo-crosslinking of double bonds and the oxidative-crosslinking of catechins. Moreover, hydroxyapatite was introduced into HG to form hydroxyapatite-enhanced hydrogels (HGH). The results indicate that, with an increase in crosslinking network density, the stiffness of hydrogels became higher; these hydrogels have more of a compact pore structure, their anti-degradation property is improved, and swelling property is reduced. The introduction of hydroxyapatite greatly improved the mechanical properties of hydrogels, but there is no change in the stability and crosslinking network structure of hydrogels. These inorganic phase-enhanced hydrogels were expected to be applied to tissue engineering scaffolds. 相似文献