PVA-蚕丝复合水凝胶的制备与性能评价

选用高分子聚乙烯醇（PVA）和脱胶后的蚕丝为原料,采用反复冷冻-融化法制备PVA-蚕丝复合水凝胶.在去离子水溶液中浸泡,并通过称重法研究复合水凝胶的溶胀特性以及蚕丝的含量对其溶胀性能的影响.采用平头圆柱压头测定复合水凝胶的压缩弹性模量并依据国标GB1685-82测量复合水凝胶的应力松弛特性.用S-3000N型扫描电镜表征PVA-蚕丝复合水凝胶的微观结构.结果表明：在去离子水中,复合水凝胶的溶胀趋势基本一致,而且溶胀比均随着蚕丝含量的增高而降低;PVA-蚕丝复合水凝胶的弹性模量和应力松弛速率均随着蚕丝添加量的增高而增高;丝胶与聚乙烯醇有良好的结合性,蚕丝的加入使PVA基体结构的方向性增强.     

PVA/壳聚糖/淀粉水凝胶的制备和性能

采用反复冷冻-解冻法制备了一系列的PVA/壳聚糖/淀粉水凝胶.测试了共混膜的力学性能、脱水率和溶胀度.结果表明:壳聚糖含量为2.7%的水凝胶具有最大的断裂延伸率,拉伸强度也较高.淀粉和壳聚糖的加入,改变了复合水凝胶的脱水率和溶胀度.     

壳聚糖/聚乙烯醇复合水凝胶的溶胀与力学性能

研究了酒精脱水和自然干燥对用作抗菌人工皮肤的CS/PVA复合水凝胶的脱水率和二次溶胀度的影响.结果表明,酒精脱水速率高于自然干燥脱水速率;酒精脱水后的CS含量为2%的CS/PVA复合水凝胶在37℃的二次溶胀度不亚于其自然干燥的二次溶胀度;壳聚糖的加入对CS/PVA复合水凝胶的抗拉强度影响不大,断裂延伸率则有明显提高.     

海藻酸钠/氧化石墨烯复合水凝胶的制备与性能

为了研究氧化石墨烯（GO）对海藻酸钠（SA）凝胶性能的影响,以Ca2+与Fe3+作为交联剂,在SA水凝胶自组装过程中加入GO水溶液,一步法得到了海藻酸钠/氧化石墨烯（SA/GO）复合水凝胶。通过扫描电子显微镜与X射线衍射表征了所得凝胶的结构与微观形貌,测试了不同凝胶样品的平衡溶胀性能和力学性能。研究结果表明,Fe3+交联得到的凝胶结构相比Ca2+交联得到的凝胶更加紧凑,平衡溶胀性能降低较多;随着GO的加入,复合水凝胶的力学性能提升,平衡溶胀性能降低,这表明SA/GO复合水凝胶的性能可以通过选择合适的交联剂与GO用量进行调控。关键词:海藻酸钠;氧化石墨烯;复合水凝胶     

聚丙烯酸／细菌纤维素复合凝胶的制备与性能

通过在聚丙烯酸（PAA）聚合过程中添加细菌纤维素（BC）,制备PAA／BC复合凝胶,并研究无机填料蒙脱土（MMT）、硅藻土对PAA／BC复合凝胶的影响．结果表明：PAA／BC复合凝胶与PAA凝胶相比,吸水性能及保水性能均有一定程度的提高,BC用量为0．4％N,该复合凝胶的吸水及保水性能综合最佳．添加MMT、硅藻土的PAA／BC复合凝胶的吸水及保水性能均有提高,同样用量的MMT对凝胶的吸水性能提高更明显,而硅藻土对凝胶的保水性能提高更明显．SEM的微观结构分析验证了上述结果．     

PAA/GO/Fe~(3+)水凝胶的制备及自修复性能研究

为了制备高自修复效率水凝胶,本文以丙烯酸(AA)为单体,过硫酸铵((NH4)2S2O8)为引发剂,Fe~(3+)为离子交联剂,制备了具有自修复性能的双物理交联网络PAA/GO/Fe~(3+)水凝胶。采用红外光谱仪、电子万能试验机等对凝胶进行了表征和测试,分析了GO含量、Fe~(3+)浓度对凝胶的拉伸性能、溶胀性能以及自修复性能的影响。实验结果表明:当Fe~(3+)摩尔分数x为0.5%,GO质量分数w为0.4%时,水凝胶的综合力学性能最好,拉伸强度为0.28MPa,断裂伸长率为760%;吸水倍率为70倍,自修复效率达到了62%。     

PAA/CS/GO水凝胶的制备及其吸附性能

为了克服壳聚糖在酸性条件下不稳定的缺点，提高氧化石墨烯的分散性能，提升壳聚糖/氧化石墨烯体系对亚甲基蓝的吸附性能，利用自由基聚合和热交联法将丙烯酸（AA）引入壳聚糖（CS）/氧化石墨烯（GO）体系，制备了聚丙烯酸（PAA）/CS/GO水凝胶，并采用电子扫描电镜和傅里叶变换红外光谱对水凝胶的表面结构及化学成分进行了表征，探究了丙烯酸用量、pH值、吸附时间、染料浓度和温度对水凝胶吸附亚甲基蓝容量的影响。结果表明：PAA/CS/GO水凝胶内部成功引入了大量羧酸基团，内部充满孔洞结构并具有稳定性和极佳的吸水溶胀性能；吸附实验表明，丙烯酸剂量为12 mL时制备的PAA/CS/GO水凝胶在温度为333 K时对亚甲基蓝（MB）具有最佳吸附效果，吸附量达到了771.5 mg/g；同时该水凝胶对亚甲基蓝的吸附过程遵循拟二阶动力学模型和Freundlich等温吸附模型。吸附机理研究发现，静电作用力、氢键、共轭作用和孔隙结构是高吸附性能的主要影响作用力。     

聚吡咯/石墨烯复合水凝胶的制备与性能

先通过软模板法制备具有纳米管状结构的聚吡咯（PPy）,再以此PPy与氧化石墨烯（GO）为前驱物,通过水热法制备具有三维结构的聚吡咯/石墨烯（PG）复合水凝胶。研究了PPy用量对复合水凝胶的影响。利用扫描电子显微镜对其形貌进行表征,用循环伏安法和恒电流充放电法对复合凝胶的电化学性能进行了研究。结果表明,当m（PPy）∶m（GO）在1.5∶1到2.5∶1之间时,可以形成完整的PG复合水凝胶,复合水凝胶可承受自身重量约1 000倍的压力。PG复合水凝胶具有良好的电化学性能,当恒电流充放电测试的电流密度增加到20 A/g时,复合水凝胶的比电容仍然大于400 F/g。这些结果表明PG复合水凝胶在超级电容器领域有着较好的应用前景。     

PVA/PAA/Fe~(3+)超分子水凝胶的制备及其性能

为提高水凝胶的力学性能并扩展其应用,采用生物相容性良好的聚乙烯醇(PVA)、聚丙烯酸(PAA)为基质材料,以氢键和配位键为物理交联点,制备具有高力学性能的PVA/PAA/Fe~(3+)水凝胶;通过调节溶液中盐酸浓度、Fe~(3+)浓度和水凝胶浸泡时间研究其对水凝胶力学性能的影响,通过溶液的pH值探讨水凝胶的稳定性,通过循环加载-卸载实验评估水凝胶的自恢复性能。研究结果表明:红外光谱表征水凝胶网络结构氢键及配位键已形成;当溶液盐酸浓度为0.2 mol/L、Fe~(3+)浓度为0.09 mol/L、浸泡时间为20 h时,水凝胶力学强度最优,其拉伸强度为12.69 MPa,韧性为41.64 MJ/m~3;将水凝胶做一次循环加载-卸载实验之后,静置240min,其应力、应变恢复率分别达到90%、87.8%。     

疏水缔合水凝胶对CH4的储气性能研究

以丙烯酰胺（AM）为亲水单体,与两种单体（丙烯酸十八酯C18、两性单体二甲基乙酰胺DMAC）、三种表面活性剂（十二烷基硫酸钠SDS、四丁基溴化铵TBAB、十六烷基三甲基溴化铵CTAB）采用自由基溶液聚合法制备得到5种疏水缔合水凝胶,并测量了5种水凝胶对CH4的储气性能及吸水性能。结果表明,两种表面活性剂（TBAB、CTAB）的添加,对水凝胶的储气性能有明显的影响,其中,水凝胶HC⁃SDS/TBAB对CH4的储气性能最好;两种表面活性剂的添加,对水凝胶的溶胀率也存在明显的影响,添加有两种表面活性剂的水凝胶溶胀性能明显低于单一添加SDS的水凝胶溶胀性能。     

Effect of Microfibrillated Cellulose Loading on Physical Properties of Starch/Polyvinyl Alcohol Composite Films

The starch/polyvinyl alcohol (PVA)/ microfibrillated cellulose (MFC) composite films were prepared using solution casting method after adding MFC into starch/PVA blend matrix.The effects of MFC content on the mechanical properties of starch/PVA composite films were investigated.As MFC content increases,the elongation at break and tensile strength increase firstly and then decrease.When the content of MFC is 2wt%,the tensile strength is 26.6 MPa and reaches the maximum.Through Fourier transform infrared (FTIR),scanning electron microscopy (SEM),X-ray diffraction (XRD) and thermogravimetric analysis (TGA),good dispersion of MFC in starch/PVA matrix at the loading of 2wt%,lower crystallinity of the starch/PVA/MFC films in comparison with starch/PVA blend and the effect of glass transition temperature increasing with MFC content from 0.5wt% to 4wt% can be found observed.And,incorporating MFC does not change the composition and crystal structure of the starch/PVA composite films.Thus,the reinforcing mechanism for the improvement of mechanical properties is attributed to the homogeneous dispersion of MFC with large aspect ratio,good compatibility and interfacial interactions between starch/PVA blend matrix and MFC.     

原位复合纳米羟基磷灰石／聚乙烯醇水凝胶的制备及性能研究

原位合成方法制备了n—HA／PVA复合水凝胶．通过调节聚乙烯醇、纳米羟基磷灰石和水的含量，制备了不同配比的复合水凝胶．用燃烧实验、TEM、IR和XRD等对材料的组成和结构进行了表征，并测定了水凝胶的力学性质．结果表明，PVA高分子空间三维结构对羟基磷灰石晶体的原位水热生长有一定影响，复合水凝胶中n-HA与PVA有一定键合，两相分布均匀，羟基磷灰石的含量对复合水凝胶的力学强度有很大影响．     

Thermal aging behavior of high performance poly(vinyl alcohol) hydrogel

The thermal aging behavior of poly(vinyl alcohol) (PVA) hydrogel was studied at four different temperatures of 40 ℃, 50 ℃, 60 ℃ and 70 ℃ in one year. The samples of PVA hydrogel were closely covered by plastic film. The changes of their chemical structures and physical properties during aging were measured through different measurable techniques including tensile testing, gel permeation chromatography (GPC), viscosity analysis, and Fourier transform infrared (FTIR) spectrum. The results showed that the molecular weight of PVA in hydrogel changed little with time and temperature. FTIR spectra of PVA in all the samples were similar to those of the original samples. The tensile strength of PVA hydrogel didn’t change until the 330th days.     

Research on the friction and wear mechanism of Poly(vinyl alcohol)/hydroxylapatite composite hydrogel

Poly(vinyl alcohol)/Hydroxylapatite (PVA/HA) composite hydrogel was prepared with poly(vinyl alcohol) and hydroxylapatite as raw materials, using the method of repeated freezing and thawing. The morphologies of PVA/HA composite hydrogel were observed by means of high-accuracy 3D profiler and scanning electron microscope (SEM). The compressive elastic modulus and the stress relaxation characteristics of PVA/HA composite hydrogel were measured using the flat-head cylinder indenter. The friction and wear tests between PVA/HA composite hydrogel and bovine knee articular cartilage were performed on the micro-tribometer. The worn morphologies of PVA/HA composite hydrogel were observed with environmental scanning electron microscope (ESEM). The results showed that PVA/HA composite hydrogel has the cross-link network microstructure which is similar to that of the natural bovine knee articular cartilages. With the increase of freezing-thawing cycles and the HA content, the degree of cross-link and the crystallization of PVA/HA composite hydrogel both increase, the elastic modulus increases evidently, the rate of stress relaxation is improved and the value of balance stress decreases. The friction coefficient decreases with the increase of the freezing-thawing cycles and the HA content. The more the freezing-thawing cycles are, the earlier the friction coefficient reaches the stable balance value. The friction deformation depth between PVA/HA composite hydrogel and bovine knee articular cartilage is inversely proportional to freezing-thawing cycles and the HA content. The main wear mechanisms of PVA/HA composite hydrogel are plastic flowing and adhesive flaking. The wear severity degree decreases with the increase of freezing-thawing cycles and the HA content. Supported by Key Program of the National Natural Science Foundation of China (Grant No. 50535050), Program for New Century Excellent Talents in University (Grant No. NCET-06-0479) and Natural Science Foundation of Jiangsu Province (Grant No. BK2005403)     

电子束辐射制备pH敏感性聚乙烯醇水凝胶

应用电子束辐射交联技术制备了聚乙烯醇接枝丙烯酸(PVA-g-AAc)水凝胶。研究了pH值、AAc单体用量和辐照剂量等因素对PVA-g-AAc水凝胶溶胀率的影响。实验结果表明,在1 697cm-1处,PVA-g-AAc水凝胶的红外光谱图上出现强烈的羰基的C O特征峰,表明AAc成功接枝到PVA分子上;PVA-g-AAc水凝胶的溶胀率随PVA/AAc/H2O中AAc的质量分数和浸泡时间增加而增大;在pH=9.2时,PVA-g-AAc水凝胶具有显著的pH敏感性;辐射剂量为15kGy时,由PVA/AAc/H2O(1/1/20,质量比)混合溶液制备的PVA-g-AAc水凝胶具有较高的溶胀率;辐射剂量为5kGy时,由PVA/AAc/H2O(1/5/20,质量比)混合溶液制备的PVA-g-AAc水凝胶具有较高的溶胀率。     

pH/温度双重敏感高分子水凝胶的合成及性能

选用具有优良pH敏感的丙烯酸(AAc)及温敏性的N-异丙基丙烯酰胺(NIPA)为基本原料,制备了pH/温度双重敏感水凝胶,系统研究了丙烯酸系水凝胶的基本物理性能(密度、平均分子量、交联密度、平衡态水含量、固定电荷密度等),表征了水凝胶在不同离子强度下的溶胀、退溶胀性能,并对其响应机理进行了探讨,同时对水凝胶的机械性能进行测试。结果表明:pH/温度双重敏感水凝胶的溶胀情况受pH值和温度2个因素控制,在同一温度下,pH值越高,溶胀率越高;在同一pH值下,温度越高,溶胀率越低。     

Fabrication and Characterization of One Interpenetrating Network Hydrogel Based on Sodium Alginate and Polyvinyl Alcohol

One interpenetrating network hydrogel based on sodium alginate(SA) and polyvinyl alcohol(PVA) was synthesized by combining the raw materials of PVA and SA with the double physical crosslinking methods of freezing thawing and Ca~(2+) crosslinking. The PVA-SA composite hydrogel have been characterized by scanning electron microscopy for surface morphology, infrared spectroscopy for investigating the chemical interactions between PVA and SA, X-ray diffraction for studying the PVA-SA composite structure property and thermal gravimetric for understanding the PVA-SA composite thermal stability. The swelling behavior and the degradation rate of the PVA-SA composite hydrogel were studied in simulated gastrointestinal fluid. Using bovine serum albumin(BSA) and salicylic acid as the model drugs, the release behavior of the PVASA composite hydrogel on macromolecular protein drugs and small molecule drug were evaluated. The results showed that the water absorption and degradation ability of the PVA-SA composite hydrogel was much better compared to the pure SA hydrogel or pure PVA hydrogel. The hydrogel exhibited remarkable pH sensitivity and the network was stable in the simulated intestinal fluid for more than 24 h. With the advantages such as mild preparation conditions, simple method, less reagent and none severe reaction, the PVA-SA composite hydrogel is expected to be a new prosperous facile sustained drug delivery carrier.