活性炭对聚丙烯酸水凝胶pH敏感性的影响

以丙烯酸(AA)为单体、活性炭(AC)为惰性致孔剂、N,N-亚甲基双丙烯酰胺为交联剂、过硫酸铵为引发剂,采用自由基溶液聚合法制备了聚丙烯酸(PAA)/AC复合水凝胶,并研究了AC的引入对PAA水凝胶pH敏感性的影响以及不同pH值的缓冲液中水凝胶的溶胀动力学。结果表明:AC的引入并未影响PAA水凝胶的化学组成和热稳定性,但增大了其孔隙尺寸;AC的引入提高了PAA水凝胶的pH敏感性;冻干的PAA/AC复合水凝胶比烘干的PAA/AC复合水凝胶达到溶胀平衡的速率更快、平衡溶胀比更大。     

可注射甘油磷酸钠-壳聚糖/海藻酸钠复合水凝胶的制备及性能研究

通过物理交联方法,将海藻酸钠(SA)与甘油磷酸钠-壳聚糖(GP-CS)复合制备可注射GP-CS/SA复合水凝胶,考察了物料比(GP-CS与SA的质量比)对复合水凝胶凝胶化时间、溶胶含量、微观形态、热稳定性、平衡溶胀等物理化学性能的影响。结果表明,复合水凝胶中SA比例越大,凝胶化时间越短,溶胶含量越少;扫描电镜和红外光谱分析表明,GP-CS与SA通过物理交联形成三维网络结构的水凝胶;热重分析表明,复合水凝胶与GP-CS水凝胶的热稳定性没有很显著差异;平衡溶胀实验表明,随着SA比例的增大,复合水凝胶的溶胀率和平衡溶胀率升高。GP-CS/SA复合水凝胶比单一的GP-CS水凝胶具有更高的机械强度、更好的吸水性和平衡溶胀性能。     

空心玻璃微珠对聚丙烯酸水凝胶溶胀性能的影响

为了研究空心玻璃微珠(HGM)的加入对合成聚丙烯酸(PAA)水凝胶的吸水溶胀性、耐盐性及pH敏感性的影响,以丙烯酸(AA)为单体、聚乙二醇为有机致孔剂、HGM为无机致孔剂、过硫酸铵为引发剂、N,N-亚甲基双丙烯酰胺为交联剂,通过自由基溶液聚合制备了5种不同HGM投料量的PAA水凝胶,并对其结构、热稳定性、表面形貌以及其在纯水、生理盐水和pH缓冲液中的溶胀行为进行了表征。结果表明,HGM的加入并不影响PAA水凝胶的化学组成和热稳定性,但有利于凝胶致孔;适量HGM的加入有助于大幅提高PAA水凝胶的吸水溶胀性、耐盐性和pH敏感性;当HGM的投料量为单体AA质量的10%时,PAA水凝胶的孔结构最丰富,其吸水平衡溶胀比可达345 g/g,吸盐水平衡溶胀比为47 g/g,pH敏感性在5种水凝胶中最佳。     

n-HA添加对聚磷酸钙水凝胶结构与性能的影响

采用共混法制备纳米羟基磷灰石/聚磷酸钙(n-HA/CPP)复合水凝胶,探究了n-HA的添加对CPP水凝胶的结构形貌、热稳定性、溶胀降解性能和力学性能的影响.结果 表明:通过控制n-HA的添加量可以改变CPP水凝胶的链长进而改变其性能,n-HA的加入提高了CPP水凝胶的热稳定性.随着n-HA添加量的增加,n-HA/CPP复合水凝胶的溶胀率和降解率均呈现先减小后增大再减小的趋势,溶胀后内部孔洞大小也呈现先减后增再减的变化规律.添加量为1wt％时,n-HA/CPP复合水凝胶的抗压强度达到最大值(5.06±0.60) MPa,与纯CPP水凝胶相比提高了22％.     

PAM/SA/CNFs复合水凝胶的制备与性能研究

通过溶液交联聚合法制备了聚丙烯酰胺(PAM)/海藻酸钠(SA)/纤维素纳米纤维(CNFs)半互穿网络结构复合水凝胶。研究了不同添加量的CNFs对SA/PAM/CNFs复合水凝胶的溶胀性能和力学性能的影响;并测定了该复合水凝胶对亚甲基蓝染料的吸附性能。结果表明:当CNFs添加量为0.1ω/%时,复合水凝胶对亚甲基蓝染料的吸附效果最好,且平衡溶胀度最大为9.47,复合水凝胶压缩应力达到114.64 kPa。     

纳米铜碳/海藻酸钠复合水凝胶的制备及性能

以吸附了硫酸铜的天然棉纤维为原料,高温热解制备纳米铜碳复合材料(NCCC),并利用原位释放法以二价钙离子为交联剂制备出纳米铜碳复合材料/海藻酸钠(NCCC/SA)复合水凝胶,来缓释抑藻材料NCCC。调节CaCO₃/SA的质量比,考察海藻酸钠水凝胶的力学性能、溶胀和降解性能来优选凝胶载体。调节NCCC/SA质量比,考察NCCC/SA复合水凝胶力学性能、溶胀和降解性能。NCCC/SA质量比越大,复合水凝胶的力学性能越差,但其溶胀和降解性能几乎没有影响。为了应对动态水环境的使用要求,最终选用CaCO₃/SA的质量比为18.18%的海藻酸钠水凝胶为载体,NCCC/SA质量比为2∶1来制备复合水凝胶,并模拟NCCC的缓释,为NCCC应用于抑藻的研究奠定了理论基础。     

聚丙烯酸/氧化石墨烯复合水凝胶制备及对亚甲基蓝吸附

以丙烯酸(AA)为原料,二丙烯酸酯(Pul DA)分散的氧化石墨烯(GO)纳米胶粒(GO-Pul DA)为增强剂,N,N'-亚甲基双丙烯酰胺(BIS)为交联剂,通过自由基共聚合制备了一系列结构均一的聚丙烯酸/氧化石墨烯复合水凝胶(PAA/GO-Pul DA)。考察了BIS质量浓度、GO质量浓度以及溶液pH值对复合水凝胶力学性能、吸水性和亚甲基蓝(MB)吸附量的影响。结果表明,当GO质量浓度从0.1 g/L增加至1.0 g/L时,复合水凝胶拉伸强度从5.0 k Pa增加至10.4 k Pa,断裂伸长率高于100%,当GO的质量浓度为0.3 g/L时,复合水凝胶的断裂伸长率最高为151%;复合水凝胶表现出pH敏感的高吸湿性,pH从3.0增加至6.8时,平衡溶胀比(SRe)变化可达386 g/g,pH=6.8时最大SRe高达490 g/g。当溶液pH值从3.0增加至11.0时,PAA/GO-Pul D对MB的平衡吸附量(qe)可增加1 400~1 500 mg/g,pH=11.0时最大的qe高达1 789 mg/g。复合水凝胶对MB的吸附行为符合准一级动力学模型。5次吸附-解吸附循环后,相对于首次吸附,PAA/GO-Pul D对MB的吸附能力仍保持高达60%,解吸附效率高于90%。     

辐射交联PVA/PVP/胶原复合水凝胶的制备及性能研究

采用辐射交联与冻融循环相结合的方法,将胶原引入聚乙烯醇(PVA)/聚乙烯基吡咯烷酮(PVP)水凝胶体系,制备具有较高生物活性的PVA/PVP/胶原复合水凝胶。通过含水率、溶胀性能、力学性能及微观结构研究胶原对复合水凝胶结构与性能的影响,并优选最佳体系进行体外细胞毒性实验(MTT法)。研究结果表明,复合水凝胶具有均匀分布的三维多孔结构,胶原的添加增大水凝胶网络空间结构,其初始含水率达92%,并在10 h内达到溶胀平衡,但力学性能降低。辐射交联与冻融循环相结合的方法有利于提高胶原水凝胶制备效率,胶原结构不改变,其体外细胞存活率从PVA/PVP水凝胶的77.3%提高到93.8%,细胞相容性提高。     

聚丙烯酸-丙烯酰胺复合水凝胶的制备及性能研究

将不同配比的丙烯酰胺(AM)、丙烯酸(AA)和细菌纤维素(BC)单体混合后进行共聚,制得了P(AA-co-AM)/BC复合水凝胶。测定了其吸水性能、保水性能、动态力学性能、热性能、微观结构以及对金属离子的吸附性能等。研究结果表明:当w(AM)=60%(相对于AA质量而言)、w(BC)=0.4%(相对于单体总质量而言)时,复合水凝胶的吸水性能、保水性能、溶胀性能相对最好,其动态力学性能和耐热性均得到改善;当w(AM)=70%、w(BC)=0.4%时,复合水凝胶对金属Cu2+的吸附性能更好;添加BC后复合水凝胶具有更多的微孔结构,孔隙排列密集、均匀。     

纳米复合多孔水凝胶薄膜的合成及其力学性能研究

采用物理交联的方法，以聚乙烯醇为成膜剂，加入纳米级有机硅酸镁锂，增强水凝胶膜的机械性能，又加入聚乙二醇作为成孔剂制造多孔结构，制备得到了纳米复合多孔水凝胶膜，对其结构及力学性能进行了表征，并研究了聚乙二醇的相对分子质量以及聚乙二醇浓度对纳米复合水凝胶膜的微观结构的影响；结果表明，在可见光的范围内，纳米复合多孔水凝胶膜的透明度可达99%;纳米复合水凝胶膜力学性能优异，杨氏模量可达6.77 MPa。采用纳米复合多孔水凝胶薄膜作为基底，结合特异性显色试剂制备成了比色传感器，为快速可穿戴式的检测提供了技术支持。     

The effect of antimicrobial peptide HX-12C on the properties of chitosan/polyacrylic acid hydrogel

Antimicrobial peptide (AMP) hydrogel is a novel biomaterial widely used in wound healing. However, there have been limited studies investigating the effect of AMP on hydrogel properties so far. Therefore, this study aimed to examine the influence of the AMP HX-12C on the chitosan/polyacrylic acid (CS/PAA) double-network (DN) hydrogel. The results showed that the mechanical properties of CS/PAA/HX-12C hydrogel are significantly improved compared with those of CS/PAA hydrogel. The maximum tensile stress increased from 41.0 to 258.5 KPa, and the compression stress required for 80% hydrogel deformation increased from 3.7 to 6.7 MPa. Furthermore, the thermal stability of CS/PAA/HX-12C showed a noticeable enhancement when compared with CS/PAA hydrogel. In addition, the CS/PAA/HX-12C hydrogel exhibited improved porosity and swelling performance. The addition of HX-12C significantly enhanced the antibacterial activity of the hydrogel against Escherichia coli and methicillin-resistant Staphylococcus aureus. Cytotoxicity test showed that the viability of L929 cell remained above 90% after treatment with CS/PAA/HX-12C hydrogel extract, indicating the good biocompatibility. In conclusion, AMP assuredly enhances the mechanical property, swelling performance and antimicrobial activity of hydrogel. The CS/PAA/HX-12C hydrogel shows potential for use as anti-infective medical material.     

水溶性Janus型POSS的设计合成及其对PAA/PAM水凝胶力学性能影响的研究

利用丙烯酰氧丙基多面体低聚倍半硅氧烷（Acrylo-POSS）和3-巯基-1-丙烷磺酸盐（MPS）之间的巯基点击反应，一步合成水溶性Janus型多面体低聚倍半硅氧烷（AS-POSS）。通过改变投料比可以调控AS-POSS的水溶性和双键与磺酸钠基团的物质的量比。将AS-POSS与丙烯酸（AA）和丙烯酰胺（AM）共聚制备了一系列不同AS-POSS含量的AS-POSS/PAA/PAM水凝胶，其中AS-POSS质量占单体总质量1%的1% AS-POSS/PAA/PAM水凝胶的平衡溶胀比达到512，断裂伸长率达到1074%，压缩强度为583 kPa，压缩应变为89%，屈服应变为330%，均大于对照组MBA/PAA/PAM水凝胶，表明AS-POSS的引入显著提高了水凝胶的溶胀度，明显增强了水凝胶的韧性、抗压缩性能和动态力学性能。AS-POSS/PAA/PAM水凝胶具有良好的导电性，离子电导率最高可达0.401 S/m。     

Synthesis,characterization, and enzymatic degradation of chitosan/PEG hydrogel films

Poly(ethyleneglycol) (PEG)/tartaric acid (TA)‐crosslinked chitosan hydrogel (CPT) films were prepared, and the formation of the PEG/TA‐crosslinked structure was confirmed by Fourier transformed infrared (FTIR), nuclear magnetic resonance (NMR), and scanning electron microscope (SEM) measurements. The thermal properties of the crosslinked films were also determined with thermogravimetric analysis (TGA) and differential scanning calorimeter (DSC) analysis. The swelling properties of the films were investigated at different temperature and pH values. It was found that the swelling ratio increased with the decrease of pH value of the surrounding buffer solutions, amount of PEG, and with the increase of temperature. Swelling behavior of the PEG/TA‐crosslinked chitosan hydrogel films depended on pH and reversible with the temperature. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

改性聚天冬氨酸复合水凝胶的制备及性能

以聚琥珀酰亚胺（PSI）、丙烯酸（AA）和丙烯酰胺（AM）为原料,KH550和KH570为联合交联剂,采用水溶液聚合法合成了聚天冬氨酸/聚（丙烯酸-丙烯酰胺）复合水凝胶［KPAsp/P（AA-AM）］;探讨了交联剂用量、原料配比对KPAsp/P（AA-AM）复合水凝胶溶胀性能的影响;采用FTIR和TG对水凝胶进行了表征。结果表明当v（KH550）∶v（KH570）=1∶1和n（PSI）∶n（AA）∶n（AM）=1∶3∶1时,所合成的复合水凝胶溶胀性能最佳,溶胀度达到395。通过吸水动力学研究表明,共聚链的引入改变了水凝胶的吸水行为。研究了复合水凝胶对阿莫西林的控释性能,结果表明,复合水凝胶的载药量可达29.98mg/g;在37℃、pH=1.8的NaCl溶液中,负载了阿莫西林的复合水凝胶在2h对药物的释放率达到57%,24h左右达到85%。     

Synthesis of poly(AA‐co‐AM) superabsorbent composites by reinforcement of halloysite nanotubes

A novel poly(acrylic acid‐co‐acrylamide)/halloysite nanotubes [PAA‐AM/HNTs] superabsorbent composite was synthesized by free radical polymerization with using HNTs as an inorganic additive. The composite was characterized by Fourier transform infrared spectroscopy, scanning electron microscope, and thermogravimetric analysis. The results revealed that HNTs and PAA‐AM were combined well together to form a porous structure with a pore size of about 10 μm, and HNTs were uniformly distributed in the composite. The thermal stability was improved by adding HNTs in the composite. The influences of contents of initiator and halloysite, neutralization degree of AA, and molar ratio of AM to AA on water absorbency were investigated. The water absorbency and the water retention capacity were improved after adding HNTs into PAA‐AM. The composite containing 10% HNTs had the highest water absorbency of 1276 g/g in distilled water. Moreover, PAA‐AM/HNTs composite also had a high swelling rate within 60 min and could maintain 78% initial swelling capability after five reswelled test. The substantial enhancement of swelling properties enables PAA‐AM/HNTs suitable for numerous practical applications. POLYM. COMPOS., 36:229–236, 2015. © 2014 Society of Plastics Engineers     

Swelling-induced surface instability of a hydrogen-bonded LBL film and its self-healing

Thin hydrogel films attached to a rigid substrate can only swell along the direction perpendicular to the substrate, which generates compressive stress within the gel. When the stress is sufficiently large, the free surface of the gel will locally buckle and fold against itself to form various wrinkling patterns. Here we show that hydrogen-bonded layer-by-layer (LBL) films of poly(vinyl pyrrolidone) (PVPON) and poly(acrylic acid) (PAA) also swell in ethanol/water mixtures. Like ordinary hydrogel films attached to a substrate, the LBL films also undergo mechanical instability when their swelling degree is large enough. By adjusting the composition and pH of the ethanol/water mixture, the swelling degree of the film can be adjusted, which further decides whether the mechanical instability occurs or not. Like ordinary hydrogel films, the surface wrinkling of the PVPON/PAA films occurs via a nucleation-growth process. Unlike ordinary hydrogels, the critical swelling degree for the onset of wrinkling for PVPON/PAA films increases with increasing film thickness. More importantly, the wrinkling patterns can be healed automatically, because the transient network of PVPON/PAA films allows for the relief of compressive stress via its rearrangement. The phenomenon observed here may provide a possible way to erase the undesired wrinkling patterns on constrained hydrogel films.     

高弹性自愈水凝胶(C3H5O)1CB[7]/PAA的制备及性能

用丙烯氧基七元瓜环（（C₃H₅O）₁CB[7]）替代传统的交联剂N,N-亚甲基双丙烯酰胺（BIS）制备了新型丙烯氧基七元瓜环/聚丙烯酸凝胶（（C₃H₅O）₁CB[7]/PAA gel）,该凝胶具有高弹性和自愈性。采用IR和¹H NMR技术对其结构进行表征,研究了该水凝胶的溶胀、力学性能,宏观观察了其自愈性能。结果表明：（C₃H₅O）₁CB[7]/PAA gel的网络形成作用力主要是多重氢键;在丙烯酸（AA）17.2%,水82.1%,（C₃H₅O）₁CB[7]0.33%,过硫酸钾（KPS）0.33%时该水凝胶具有良好的自愈性及力学性能,其最大伸长量为105.6 cm,为原长的86倍,弹性模量0.39 kPa,平衡溶胀率是600%。该水凝胶有望成为一种潜在的生物组织工程材料。     

Valorization of bio-calcium carbonate based Chamelea gallina shell waste fillers in shape memory polymer composites

In recent years, the focus has been on the use of calcium carbonate-based seashell wastes in the production of new thermoplastic and thermoset polymer materials, paving the way for their use as biofillers in polymeric composites. In this study, it is aimed to obtain a new polymeric composite material by doping Chamelea gallina shells, on polylactic acid (PLA)/polyethylene glycol (PEG) blend. Structural characterization of the obtained PLA/PEG blend/C. gallina composite films was performed with attenuated total reflection infrared spectroscopy (ATR-IR). When the thermal properties of composite materials were examined by thermogravimetric analysis (TGA), it was determined that the thermal stability of polymeric composites increased with the addition of C. gallina. SEM images showed that the polymer blend films, which appeared to have a porous structure, filled the pores with increasing C. gallina ratio. It was observed that the biodegradability of PLA/PEG blend composite films decreased with increasing C. gallina shells addition. However, C. gallina had a positive effect on the swelling and water absorption capacities of polymeric composites. The increase in tensile strength and elongation at break values of PLA/PEG blend/C. gallina composite films with increasing C. gallina means that the mechanical properties of the polymer are improved.     

Porous boron nitride nanofibers/PVA hydrogels with improved mechanical property and thermal stability

Polyvinyl alcohol (PVA) hydrogel is a promising material possessing good chemical stability, high water absorption, excellent biocompatibility and biological aging resistant. However, the poor mechanical performance of PVA hydrogel limits its applications. Here we report the utilization of one-dimensional (1D) BN nanofibers (BNNFs) as nanofillers into PVA matrix to prepare a novel kind of BNNFs/PVA composite hydrogel via a cyclic freezing and thawing method. For comparison, the composite hydrogels using spherical BN nanoparticles i.e. BN nanospheres (BNNSs) as fillers were also prepared. The mechanical properties, thermal stabilities and swelling behaviors of the composite hydrogels were investigated in detail. Our study indicates that the mechanical properties of the hydrogels can be improved by adding of BNNFs. After loading of BNNFs into PVA with content of 0.5?wt%, the compressive strength of the composite hydrogel increases by 252% compared with that of pure PVA hydrogel. The tensile performance of BNNFs/PVA composite hydrogels has also been improved. Impressive 87.8% increases in tensile strengths can be obtained with 1?wt% BNNFs added. In addition, with the increase of BNNFs content, the thermal stability and the swelling ratio of hydrogels are increased gradually. The swelling ratio of hydrogel increases by 56.3% with only 1?wt% BNNFs added. In comparison, the improvement effects of the BNNS fillers on the mechanical strengths and swelling ratios are much weaker. The enhanced effects of BNNFs can be ascribed to the strong hydrogen bond interaction between BNNFs and PVA. The high aspect ratios of the nanofibers should also be took into account.     

Synthesis of polyacrylate/poly(ethylene glycol) hydrogel and its absorption properties for heavy metal ions and dye

A novel polyacrylate/poly(ethylene glycol) (PAA/PEG) hydrogel was synthesized by a simple two‐step aqueous prepolymerization method. The deswelling properties were investigated in the case of changing the neutralization degrees of PAA, the pHs and the concentration of multivalent salt solutions. Methyl orange (MO) dye can be adsorbed and released using the swelling–deswelling property of the PAA/PEG hydrogel. The PAA/PEG hydrogel can adsorb MO of 29 mg/g at equilibrium and release about 80% in 30 min. Based on the deswelling property, the dyes in wastewater can be reclaimed and reused. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers