聚乙二醇改性纳米纤维素/聚乙烯醇复合水凝胶的制备及性能

通过酸碱处理和机械研磨结合的方法制备纳米纤维素(CNFs),并利用冻融循环法分别制备了聚乙烯醇(PVA)和纳米纤维素/聚乙烯醇(CNFs/PVA)复合水凝胶,以及聚乙二醇(PEG)改性PVA和CNFs/PVA复合水凝胶。考察不同配方下复合水凝胶的微观形貌变化,并对复合水凝胶的溶胀性能、压缩强度及热稳定性能进行研究。结果表明,CNFs与PEG对PVA水凝胶的微观形貌均有改善作用,加入PEG后形成的PEG/PVA凝胶产生明显的三维网络结构。当PEG与CNFs同时加入到PVA凝胶后形成的CNFs-PEG/PVA凝胶具有均匀的互穿孔洞结构,此时复合水凝胶的孔隙率最高((67.5±4.3)%),溶胀度最好(980%),且压缩强度较PVA水凝胶也有所提升。PEG对复合凝胶的热稳定性无影响,而加入CNFs后,CNFs-PEG/PVA复合凝胶的初始热分解温度从235℃上升至300℃,显著提高了PVA凝胶的热稳定性。     

PVA／HA复合水凝胶的结构和摩擦学性能

将聚乙烯醇(PVA)和纳米羟基磷灰石(HA)按一定比例共混,采用反复冷冻-融化法制备出PVA/HA复合水凝胶.观察了PVA/HA复合水凝胶的微观结构和晶态结构,并在小牛血清稀释液润滑条件下进行了PVA/HA复合水凝胶与牛膝关节软骨的摩擦磨损试验.结果表明:随着冷冻-融化循环数的增加,PVA/HA复合水凝胶结构中氢键的作用增强,缠结结构链上的交联点增多,复合水凝胶的结晶度也随之提高,微孔结构趋于完整,因而使其压缩刚度增大;PVA/HA复合水凝胶与牛膝关节软骨的摩擦系数、接触变形和磨损量都随着冷冻-融化循环数的增加而显著减小,使复合水凝胶的减摩性和耐磨性提高.     

细菌纤维素/聚谷氨酸复合水凝胶的辐照制备及性能

采用Co~(60)-γ射线辐照交联法制备细菌纤维素/聚谷氨酸(BC/PGA)复合水凝胶。采用红外光谱和扫描电子显微镜等对复合水凝胶的结构进行表征,研究了BC引入对复合水凝胶的凝胶分数、热失重、溶胀性能、压缩性能和流变性能的影响,并利用CCK-8法对复合水凝胶进行了细胞毒性评价。研究结果表明,辐照作用下BC纳米纤维和PGA形成双交联复合凝胶网络,BC可有效增加复合水凝胶的压缩强度、储能模量(G')和凝胶分数,降低复合水凝胶的平衡溶胀度。50kGy辐照剂量下,相对于纯PGA水凝胶,复合水凝胶压缩强度增大5倍,G'增大10倍。同时复合水凝胶无细胞毒性,可安全应用于生物医学领域。     

细菌纤维素/聚乙烯醇双网络复合水凝胶的制备与性能研究

利用冷冻-解冻法制备了细菌纤维素（BC）/聚乙烯醇（PVA）双网络复合水凝胶,研究不同BC含量及循环周期对BC/PVA复合水凝胶力学性能和溶胀特性的影响,结果表明,随着BC含量的增多,复合水凝胶的含水率、平衡溶胀比、拉伸强度和压缩强度与普通的PVA水凝胶相比均有一定程度的提高;综合考虑,当BC含量为4%时,各项性能均达到最佳值;随着循环次数的增多,水凝胶内部的物理交联点增多,导致水凝胶的含水率下降,拉伸强度和压缩强度则有明显的上升趋势。SEM观察的结果与之前的分析是一致的。     

高强度耐低温纳米纤维素/聚乙烯醇导电复合水凝胶制备及其在柔性传感中的应用

纳米纤维素具有大长径比、较高的弹性模量与比表面积及丰富的表面官能团,是一种优良的纳米增强材料。首先以纳米纤维素(CNFs)为分散介质辅助分散MXene纳米片层,制备CNF-MXene纳米复合物,并通过FTIR与XPS分析CNFs与MXene的相互作用。以此复合物为增强填料,聚乙烯醇(PVA)为基底,制备CNF-MXene/PVA复合水凝胶,进一步通过KOH溶液处理,提高复合水凝胶的力学性能,并赋予复合水凝胶优异的离子导电性。该复合水凝胶表现出优异的力学性能,其拉伸强度与断裂伸长率分别达到255.9 kPa与1098.2%,还具有高电导率(2.38 S/m)、一定的抗冻性能与灵敏的应变/压力响应性。基于该复合水凝胶组装的应变/压力柔性传感器,由于具有极低的检测极限质量(100 mg)与极快的响应时间(225 ms),可以监控脉搏跳动与喉咙发声微小震动引起的压力变化。因此,该复合水凝胶基柔性传感器非常有希望应用于未来新一代可穿戴电子、人机交互等领域。      

Ag/PVA复合水凝胶的制备及其性能的研究

通过沉淀法制备Ag/PVA复合水凝胶,对复合水凝胶的微观结构进行了表征,并对其力学性能和抗菌性能进行了研究.结果表明,银微粒可以通过沉淀法均匀分散在水溶性的PVA中,形成Ag/PVA复合水凝胶,并且这种复合水凝胶具有抗菌性能,并改善了PVA水凝胶的力学性能.     

聚对二氧环己酮/聚乙烯醇复合水凝胶的制备及性能

在聚乙烯醇(PVA)水凝胶的网络中引入完全生物降解的聚对二氧环己酮(PPDO),采用冻融法制备出生物降解周期可控的PPDO/PVA复合水凝胶。通过调整低分子量PPDO与高分子量PVA之间的比例,使PPDO柔性分子链与PVA分子链之间形成聚合物网络互穿结构,实现改善水凝胶力学性能和生物降解性能的目的。采用红外光谱、扫描电镜和万能试验机对水凝胶进行了结构表征和性能测试;并通过溶胀性能及失水性能测试、降解性能测试和抑菌性测试对水凝胶进行了研究。结果表明,PPDO/PVA复合水凝胶呈现出孔隙均匀的三维网络结构,拉伸强度和压缩强度与纯PVA水凝胶相比提高了1～3倍;在37℃的PBS缓冲溶液中降解,降解速率明显提升,35 d可以降解45%,且在伤口愈合的周期内保持优异的力学强度。平板细菌培养实验证明了复合水凝胶具有抑菌的特性。PPDO/PVA复合水凝胶在伤口敷料领域具有广泛的应用前景。     

木质纳米纤维素增强聚乙烯醇复合水凝胶的制备及性能研究

以自制含木质素纳米纤维素纤丝(LCNFs)为增强相，聚乙烯醇(PVA)为基体，通过一次冻融制备LCNFs/PVA复合水凝胶。研究LCNFs添加量对复合水凝胶微观结构及含水量、吸水溶胀率、抗压缩性能的影响，以及载药复合水凝胶的药物释放模型及抑菌效果。结果表明，复合水凝胶呈多孔网络结构；其含水量及溶胀率随LCNFs添加量的增加而降低，抗压缩性能LCNFs随添加量的增加而增加。载药水凝胶药物释放模型符合Korsmeyer-Peppas模型，药物释放率可达95%以上，且对测试细菌有良好的抑制作用，在伤口创面敷料等领域具有潜在的应用前景。     

羟基磷灰石纳米纤维增强甲基丙烯酸酐改性明胶复合水凝胶的制备及性能

采用溶剂热法制备了具有超高长径比的羟基磷灰石(HAP)纳米纤维,并将其与甲基丙烯酸酐改性明胶(GelMA)结合,利用紫外光交联制备了HAP纳米纤维/GelMA复合水凝胶。通过SEM、XRD、力学测试、溶胀测试、降解测试、细胞培养等对HAP纳米纤维/GelMA复合水凝胶进行结构表征和性能测试。SEM断面观察表明,HAP纳米纤维/GelMA水凝胶呈三维孔隙贯通的多孔结构。力学实验表明,HAP纳米纤维能有效增强水凝胶的弹性模量,且随着HAP纳米纤维添加量的增加,力学性能增强效果越明显。溶胀实验表明,当HAP纳米纤维质量分数为5.2wt%~14.2wt%时,HAP纳米纤维复合水凝胶的溶胀率变化不明显,当质量分数为18.2wt%时,溶胀率降低。降解实验表明,HAP纳米纤维的加入能有效保持水凝胶结构形态,使其更加稳定可控。细胞包裹培养实验表明,HAP纳米纤维/GelMA复合水凝胶能为细胞提供良好的三维生长环境,表现出优良的生物相容性。本实验制备的HAP纳米纤维/GelMA复合水凝胶在组织工程领域有着良好的应用前景。      

PVA/P(AA-AM)复合水凝胶的制备及性能

采用水溶液聚合方法合成了不同组成的丙烯酸-丙烯酰胺共聚物(P(AA-AM))。将聚乙烯醇(PVA)与所合成的P(AA-AM)共混,以戊二醛为交联剂,制备出了不同结构的PVA/P(AA-AM)复合水凝胶。采用扫描电镜观察了凝胶形貌,研究了复合水凝胶的结构与性能关系。结果表明,复合水凝胶溶胀性能与所用交联剂加量有关,复合水凝胶的溶胀度随着交联剂加量增加先增大后减小,在交联剂加量为0.5%时水凝胶溶胀度达到最大值。复合凝胶中的聚合物组成对溶胀度影响显著,随着P(AA-AM)含量提高,水凝胶的溶胀度逐渐增大。适当结构的复合水凝胶具有pH敏感性,敏感程度随着凝胶中P(AA-AM)含量的增加而增强。     

Preparation and in vitro characterization of BC/PVA hydrogel composite for its potential use as artificial cornea biomaterial

In order to investigate the potential use for bacterial cellulose (BC) as a novel artificial cornea replacement, BC/poly(vinyl alcohol) (BC/PVA) hydrogel composites were synthesized by freezing-thaw method. The BC/PVA composites were characterized by UV–Vis spectrophotometer (UV–Vis), X-ray diffraction (XRD), thermogravimetric (TG) analysis, mechanical property tests and scanning electron microscope (SEM) analyses. Our results showed that the resultant BC/PVA composites exhibited desirable properties as artificial cornea replacement biomaterial including high water content, high visible light transmittance and suitable UV absorbance, increased mechanical strength and appropriate thermal properties. Results of this work revealed that the BC/PVA composites exhibited some promising characteristics as artificial cornea composite material and may be improved further for its realistic applications.     

Property-based design: optimization and characterization of polyvinyl alcohol (PVA) hydrogel and PVA-matrix composite for artificial cornea

Each approach for artificial cornea design is toward the same goal: to develop a material that best mimics the important properties of natural cornea. Accordingly, the selection and optimization of corneal substitute should be based on their physicochemical properties. In this study, three types of polyvinyl alcohol (PVA) hydrogels with different polymerization degree (PVA1799, PVA2499 and PVA2699) were prepared by freeze-thawing techniques. After characterization in terms of transparency, water content, water contact angle, mechanical property, root-mean-square roughness and protein adsorption behavior, the optimized PVA2499 hydrogel with similar properties of natural cornea was selected as a matrix material for artificial cornea. Based on this, a biomimetic artificial cornea was fabricated with core-and-skirt structure: a transparent PVA hydrogel core, surrounding by a ringed PVA-matrix composite skirt that composed of graphite, Fe-doped nano hydroxyapatite (n-Fe-HA) and PVA hydrogel. Different ratio of graphite/n-Fe-HA can tune the skirt color from dark brown to light brown, which well simulates the iris color of Oriental eyes. Moreover, morphologic and mechanical examination showed that an integrated core-and-skirt artificial cornea was formed from an interpenetrating polymer network, no phase separation appeared on the interface between the core and the skirt.     

多孔PVA/CNFs复合水凝胶的制备与性能

目的研究聚乙二醇(PEG)的加入对复合凝胶微观结构、溶胀性能和热稳定性的影响,扩大复合凝胶在包装领域的应用。方法以PEG为致孔剂,纳米纤维素(CNFs)为增强相,利用物理交联法制备出多孔聚乙烯醇/纳米纤维素复合水凝胶。结果 PEG作为致孔剂时可制得网络互穿结构的多孔水凝胶,复合凝胶的溶胀度可达到1000,相比于纯PVA水凝胶有极大的提高,同时加入CNFs的聚乙烯醇凝胶与纯的聚乙烯醇凝胶相比具有更好的热稳定性。结论这种有着高溶胀性和良好热稳定性的多孔复合凝胶可用于包装产品的保鲜与物流防护。     

微波原位合成2D Ni-Fe MOF/硅藻土复合材料及其改性聚乙烯醇水凝胶不锈钢筛网油水分离性能

如何高效处理含油污水的问题,是如今世界科研人员共同关注的问题。聚乙烯醇(PVA)水凝胶作为高含水量及具有三维亲水网络的软材料在油水分离领域引起了广泛的关注。但是,和大多数具有超润湿性质的水凝胶一样,PVA水凝胶类油水分离材料不仅力学性能差,同时也存在化学稳定性差的问题。基于此,通过微波法制备了2D Ni-Fe金属-有机框架材料(MOF)-硅藻土(Dia)纳米材料及其PVA复合水凝胶。同时,不锈钢网经过浸泡2D Ni-Fe MOF-Dia/PVA水凝胶溶液得到2D Ni-Fe MOF-Dia/PVA水凝胶不锈钢筛网,表现出超亲水-水下超疏油性质。利用SEM、XPS分析2D Ni-Fe MOF-Dia及其复合水凝胶的化学组成和表面形貌。研究了2D Ni-Fe MOF-Dia/PVA复合水凝胶的力学性能及2D Ni-Fe MOF-Dia/PVA复合水凝胶不锈钢筛网的油水分离与乳液分离的分离效率及水通量,并对其耐盐性、耐酸耐碱性油水分离性能进行了测试。结果表明:2D Ni-Fe MOF-Dia/PVA复合水凝胶具有优异的力学性能,拉伸与压缩强度分别达到1.49 MPa及0.58 MPa,同时表现出超亲水-水下超疏油性质,2D Ni-Fe MOF-Dia/PVA不锈钢筛网的油水分离与乳液分离效率与通量分别可达99.2%和742.7 L·m?2·h?1。在酸性、碱性、盐性环境下均保持优异的分离效率与通量,并且在5次循环后,依旧保持稳定的分离效率与通量。      

Graphite/poly (vinyl alcohol) hydrogel composite as porous ringy skirt for artificial cornea

Graphite/poly (vinyl alcohol) (PVA) hydrogel composites, which were designed as the porous ringy skirt surrounding the transparent core of a novel artificial cornea, were prepared by using the freeze/thawing process and the particle-leaching technique. The properties of the composites, including the water content, the mechanical strength, the porous architecture and the interactions between the graphite and PVA, were investigated. The tissue responses to the composite and pure PVA hydrogel were studied by in vivo implantation in the dorsal muscles of mice. The results showed that chemical interactions were present between the graphite and PVA in the composite, which benefited the combination of the two phases and enhanced the uniform distribution of graphite particles in the PVA matrix. However, the present of graphites in the PVA hydrogels reduced the tensile strength, elongation at break and water content of the composite. Moreover, the porous graphite/PVA hydrogel composite had interconnective pore structure with high porosity and enough mechanical strength. According to the histological analysis of 1 week and 12 weeks post-implantation, the graphite/PVA hydrogel composites showed less inflammatory reactions than the PVA hydrogels at the 1 week post-implantation. Moreover, compared to pure PVA hydrogel, the graphite/PVA hydrogel composite exhibited enhanced migration and infiltration of cells, and more neovascularization and tissue ingrowth. These in vivo characteristics will be beneficial for the long-term biofixation of artificial cornea. Therefore, the porous graphite/PVA hydrogel composite has a potential to be used as novel artificial cornea skirt.     

聚乙烯醇/聚乙烯基吡咯烷酮复合水凝胶的结构与性能研究

用溶液共混法和冷冻解冻工艺制备聚乙烯醇(PVA)/聚乙烯基吡咯烷酮(PVP)二元复合水凝胶,通过红外、XRD、DSC、含水率与溶胀测试等对材料的结构与性能进行分析表征,并研究了材料的力学性能与细胞毒性.结果表明,PVP能与PVA通过化学键合形成分子级混合的PVA/PVP复合水凝胶.PVP含量可以影响PVA水凝胶的结构、结晶度、玻璃化转变温度、吸水率以及力学性能.该复合水凝胶具有高的吸水率和良好的细胞相容性,而且具有类似天然软骨的可渗透性.PVP/PVA复合水凝胶是一种有发展前景的人工软骨替代材料.     

MWCNTs增强聚乙二醇-聚乙烯醇复合水凝胶的制备及性能

利用冻融循环法制备了羧基化多壁碳纳米管(MWCNTs)/聚乙二醇(PEG)-聚乙烯醇(PVA)复合水凝胶。考察了不同质量配比下MWCNTs/PEG-PVA复合水凝胶的微观形貌变化,并研究了复合凝胶的溶胀性能、拉伸强度、热稳定及导电性能。结果表明,加入MWCNTs后MWCNTs/PEG-PVA复合凝胶仍具有多孔的三维网状结构但孔径尺寸变小。当MWCNTs与PVA的质量比大于1.0∶100时,MWCNTs/PEG-PVA复合凝胶的孔洞均匀性降低。随着MWCNTs量的增加,MWCNTs/PEG-PVA复合凝胶的溶胀度及拉伸强度均先升高后降低。当MWCNTs与PVA的质量比为1.0∶100时,MWCNTs/PEG-PVA复合凝胶的溶胀度达到最大(1450%),孔隙率最高(75.8%),拉伸强度及断裂伸长率达到最大值,分别为0.97 MPa和384.0%。MWCNTs的加入提高了MWCNTs/PEG-PVA复合凝胶的热稳定性,MWCNTs/PEG-PVA复合凝胶的初始热分解温度从235℃上升至260℃;随着MWCNTs量的增加,MWCNTs/PEG-PVA复合凝胶的电导率从1.10×10-6 S/cm升高至6.96×10-4 S/cm。