GO-P(AA-AM)吸水树脂的制备及其性能北大核心

以氧化石墨烯(GO)为改性剂,丙烯酸(AA)、丙烯酰胺(AM)为单体,N,N-亚甲基双丙烯酰胺(NMBA)为交联剂,偶氮二异丁咪唑啉盐酸盐(Va-044)为引发剂,采用水溶液聚合法制备了GO-聚(AA-AM)[P(AA-AM)]吸水树脂,并研究了GO对吸水树脂吸水性能的影响。结果表明,GO改性吸水树脂的最佳制备条件:中和度为80%,GO,NMBA,Va-044用量分别为AA质量的0.3%,0.7%,0.7%,m(AA)∶m(AM)为3∶1,得到的吸水树脂的吸水倍率为293.0 g/g。GO的加入明显改善了吸水树脂的溶胀速率、保水性能及重复使用性能。     

PAA/PEG复合水凝胶膜的制备及其性能

以丙烯酸(AA)为单体、聚乙二醇(PEG)为大分子模板、N,N-亚甲基双丙烯酰胺为交联剂、过硫酸铵为引发剂,通过自由基溶液聚合法原位聚合制备了聚丙烯酸(PAA)/PEG复合水凝胶膜,研究了PEG用量对复合水凝胶成膜性、热稳定性、溶胀性能和力学性能的影响。结果表明:成功制备了PAA/PEG复合水凝胶膜;适量PEG的引入有利于复合水凝胶成膜;PAA/PEG复合水凝胶膜的热稳定性良好;PEG的引入对水凝胶膜的吸水溶胀性能不利;适量PEG有利于提高凝胶的力学性能,复合水凝胶膜软而韧;PEG与AA质量比为0.4的PAA/PEG复合水凝胶的拉伸强度和断裂标称应变最大,分别为1.58 MPa,414%。     

CMC-P(AA-AM)水凝胶的制备及溶胀性能测定

以羧甲基纤维素钠(CMC)为原料、丙烯酸(AA)和丙烯酰胺(AM)为单体、偶氮二异丁咪唑啉盐酸盐(VA-044)为引发剂、N,N-亚甲基双丙烯酰胺(NMBA)为交联剂制备了CMC-P(AA-AM)水凝胶，研究了聚合条件对其溶胀性能的影响，通过单因素试验确定最佳聚合条件；利用傅里叶红外光谱、热失重对水凝胶结构进行表征；重点考察了水凝胶在不同盐、pH及表面活性剂溶液中的溶胀性能。结果表明，CMC、VA-044、NMBA、AM占AA的质量分数分别为9%、0.7%、0.7%、33.3%时，水凝胶溶胀倍率最大，为253.2 g/g。CMC-P(AA-AM)在不同盐溶液中的溶胀性能差距较大，对重金属离子更为敏感。水凝胶在pH 5～9范围内保持了较高的溶胀性能，表现出良好的pH响应性能。CMC-P(AA-AM)在阴离子表面活性剂溶液中溶胀性能优于非离子、阳离子溶液，在油酸钠中的吸水倍率为210.0 g/g。     

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。     

丙烯酸类共聚物超吸水树脂的合成研究

用丙烯酸（AA）和丙烯酰胺（AM）作原料,以氢氧化铝为交联剂,过硫酸盐为引发剂,通过溶液聚合法,合成了高吸水性树脂聚（丙烯酸-丙烯酰胺）（P（AA-AM））共聚物。讨论了其在蒸馏水和NaCl水溶液中的吸液性能,考察了单体配比、丙烯酸中和度、交联剂用量、反应温度、引发剂用量等条件对树脂吸水性能的影响。结果表明,最佳合成丁艺为：n（AM）：n（AA）为O．3-0．4,AA的中和度为70％,过硫酸钾和单体的质量比为0．2％-0．3％,氢氧化铝和单体的质量比为0．03％-0．05％,聚合温度为55-60℃。测得的吸水倍率为1050g／g。     

海藻酸钠复合吸水树脂的生物降解

以醚化海藻酸钠（ESA）、聚乙烯醇（PVA）、丙烯酰胺（AM）、丙烯酸(AA)为单体,N, N–亚甲基双丙烯酰胺为交联剂,过硫酸铵-亚硫酸氢钠为引发剂,采用水溶液法制备聚丙烯酸钠p(NaAA)吸水树脂和海藻酸钠/丙烯酸钠（SA/NaAA）、海藻酸钠/丙烯酸钠/聚乙烯醇（SA/NaAA/PVA）及海藻酸钠/丙烯酸钠/丙烯酰胺（SA/NaAA/AM）吸水性复合树脂。采用微生物处理方法对以上吸水材料进行了表观降解性能的初步研究。研究结果发现,环境混合霉菌降低了海藻酸钠复合吸水树脂的质量和力学性能,60d试片失重率依次为9.41%、20.65%和18.60%,试片的破坏形变百分率下降依次是23.5%、25.1% 和26.4%;单一细菌和真菌降解实验显示,菌群在含有AM和PVA的SA/AA/AM和SA/AA/PVA凝胶中呈现中度或深度生长状态,在SA/AA凝胶表面呈现轻度生长。     

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。     

P(AAm-co-AA)/Ag复合材料制备及表征

以N,N-亚甲基双丙烯酰胺(N,N-MBA)为交联剂,过硫酸钾(KPS)为引发剂,采用交联共聚方法合成了具有pH敏感性的半互穿网络丙烯酰胺-co-丙烯酸水凝胶P(AAm-co-AA),利用水凝胶网络结构作为纳米反应器,自组装制备了纳米复合水凝胶P(AAm-co-AA)/Ag。水凝胶的溶胀行为研究表明,AAm与AA的质量比影响P(AAm-co-AA)/Ag水凝胶平衡溶胀率。     

吸水膨胀型聚合物堵漏剂的合成与评价

本实验研制了一种吸水膨胀聚合物堵漏剂,该堵剂由丙烯酸（AA）、丙烯酰胺（AM）、膨润土、N,N-亚甲基双丙烯酰胺通过溶液自由基聚合法合成。并通过实验探讨了交联剂用量、引发剂用量等因素对此聚合物堵漏剂的性能的影响,获得了适宜的制备条件为：引发剂用量0.35%;AA/AM=3：1;单体浓度30%;膨润土加入量15%;交联剂用量0.06%;体系pH值7.0;反应温度50℃。再采用正交实验法对聚合物配方进行了优选。并将优选出的几组配方进行堵漏评价,实验结果表明,该吸水膨胀聚合物具有堵漏性能,且该聚合物具有吸液倍数大、耐盐性好、吸水后凝胶强度较好的等特点。     

丙烯酸-丙烯酰胺共聚物吸水树脂的制备

采用溶液聚合法,以丙烯酸(AA)和丙烯酰胺(AM)为单体,N,N’-亚甲双丙烯酰胺(NMBA)为交联剂,过硫酸铵为引发剂,制备了丙烯酸-丙烯酰胺共聚物吸水树脂,探讨了单体配比(mAA/mAM)、交联剂和引发剂用量对树脂吸水率的影响。结果表明:在65℃时,丙烯酸-丙烯酰胺共聚物吸水树脂的最佳制备条件为:丙烯酸和丙烯酰胺质量比为4:1,交联剂和引发剂用量分别为聚合单体(丙烯酸和丙烯酰胺)总质量的0.02%和0.4%。     

Ethanol organosolv lignin as a reactive filler for acrylamide‐based hydrogels

Hydrogels based on acrylamide (AM) and ethanol organosolv lignin (EOL) with high swelling and good mechanically elastic properties were synthesized in an alkaline solution. EOL was used as a reactive filler for the preparation of AM‐based hydrogels. The impact of EOL addition on the physicochemical properties of AM‐based hydrogels was investigated using Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy, and their mechanical properties were examined. The water swelling ratio of the prepared hydrogels increased with the increase of EOL content, and their maximum swelling ratio could reach up to 180. Mechanical measurements indicated that their tensile strength was highly dependent on the amount of EOL, and their elongation at break reached up to 1400%. The formation mechanism of EOL composite hydrogels was probably that most of AM was synthesized into the crosslinked poly(acrylic amide) network, and small quantities of AM was hydrolyzed to acrylic acid ions under alkaline condition. The chain transfer of free radicals from AM and/or AA to EOL molecules occurred in the polymerization process. With increasing EOL content in the hydrogels, an interpenetrating polymer network might be mainly formed by the hydrogen bonding between EOL and AA and/or AM molecules. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42638.     

新型改性高吸水树脂P(AA-AM)的合成及性能评价

以N,N’-亚甲基双丙烯酰胺为交联剂,过硫酸钾为引发剂,丙烯酸、丙烯酰胺为原料,合成出原位自交联高吸水树脂P(AA-AM)。通过正交实验得出最佳合成工艺为:n(丙烯酸)∶n(丙烯酰胺)=4.5∶1,单体浓度5%,中和度70%,交联剂0.12%,引发剂0.30%(以上均相对AM、AA总量而言);产物的最大吸液性能为:吸蒸馏水最大倍率QW=2 152.4 g/g,吸10%盐水最大倍率Q盐水=28.5 g/g;由于引入适量的AM,产物吸水率和吸盐率得到大幅度的提高,产物形态由最初的粘接颗粒变成分散颗粒。     

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。     

Preparation and characterization of microporous sodium poly(aspartic acid) nanofibrous hydrogel

A novel biodegradable sodium poly(aspartic acid) (PASP) hydrogel with microporous structure was manufactured using electrospun polysuccinimide (PSI) nanofibers. PSI is the intermediate of sodium PASP and could be electospun into nanofibers easily. Firstly, PSI nanofibers were prepared from PSI/N, N-dimethylformamide solution. Then the PSI nanofibrous mats were crosslinked and hydrolyzed to obtain biodegradable microporous sodium PASP nanofibrous hydrogels. The chemical structures, morphologies and pore sizes of PSI nanofibrous mats and microporous sodium PASP nanofibrous hydrogels were investigated. Moreover, the properties of PSI electrospinning solutions, and the swelling ratio and biodegradability of sodium PASP hydrogels were also examined. The results showed that the swelling ratio of microporous sodium PASP nanofibrous hydrogels achieved to 21.0–24.3 g/g and were obviously higher than that of the sodium PASP casting film, reporting a swelling ratio of only 4.6 g/g. When the microporous sodium PASP nanofibrous hydrogel was immersed in water, it exhibited quick absorption and morphological robustness. The microporous sodium PASP nanofibrous hydrogel showed 83 wt% weight loss after 7 days of trypsin catalyzed biodegradation, and the SEM analysis demonstrated the significant morphology change of the microporous sodium PASP nanofibrous hydrogel during the biodegradation.     

Hydroxyethyl cellulose hydrogel modified with tannic acid as methylene blue adsorbent

This work developed an effective way to improve the methylene blue (MB) adsorption performance of cellulose-based hydrogel by modified with tannic acid (TA). HEC-co-p(AA-AM)/TA hydrogel was synthesized by grafting of acrylic acid (AA) and acrylamide (AM) onto hydroxyethyl cellulose (HEC), followed by modified with TA. Fourier transform infrared spectroscopy manifested that AA and AM were successfully grafted onto the hydrogel, and TA was immobilized in the hydrogel. Field emission scanning electron microscope demonstrated that the hydrogel after TA modification had a homogeneous pore structure. Brunauer-Emmett-Teller (BET) surface areas, total pore volume, and average pore diameters of the hydrogel are 11.821 m² g⁻¹, 0.0641 cm³ g⁻¹, and 2.538 nm, respectively. The high swelling ratio (1179.2 g g⁻¹ in deionized water) was in favor of the MB adsorption. The results of the adsorption experiments illustrated that HEC-co-p(AA/AM) hydrogel had excellent MB adsorption performance. As the pH increases, the electrostatic attraction is enhanced, and the adsorption capacity is improved. The adsorption process was more fit with pseudo-second-order kinetics, and the maximum adsorption capacity (3438.27 mg g⁻¹) was determined by Langmuir model. Thermodynamic studies suggested that the adsorption process is spontaneous, exothermic, and entropy reduction. X-ray photoelectron spectroscopy analysis confirmed that MB molecules were reacted with the oxygen atoms in hydroxyl and carboxyl groups by ion-exchange. High reusability demonstrated that the hydrogel could be a potential candidate for removal cationic dye from industrial effluents.     

A facile route to obtain an acidic hydrogel containing lactate moieties

The idea to develop hydrophilic lactic acid-based polyelectrolyte was presented. A facile route was utilized to prepare smart hydrogels that contained lactate units and carboxylic groups. The hydrogels were obtained through the radical cross-linking reaction between an unsaturated lactate-contained macromonomer and acrylic acid (AA)/itaconic acid (IA) monomer pair. The structure and performances of the hydrogels were characterized with thermogravimetric analysis, dynamic thermal analysis, scanning electron microscopy, swelling tests and adsorption measurements. The equilibrium swelling ratios of the hydrogels in acidic (pH 3.6) and basic (pH 11.5) media reached 25.3 and 62.3 respectively. The pH-sensitive swelling behaviors of the hydrogel confirmed that the hydrogels contained carboxylic groups and they were hydrophilic. The metal ions including calcium, copper, lead and cerium ions were bound into the hydrogels, which also confirmed the existence of the carboxyl groups. Moreover, the swelling ratio and adsorption capacity of the gel prepared from monomer pair were significantly higher than those obtained in absence of IA, which suggested that the properties of the hydrogels could be controllable by simply adjusting the ratio of AA/IA. In addition, the weight loss percentage of the hydrogel was around 37% after two-week in vitro degradation, which indicated the hydrogel contained lactate units.     

聚丙烯酸树脂吸液性能的条件探讨

本实验采用溶液聚合法,以丙烯酸（AA）和丙烯酰胺（AM）为单体,氢氧化铝作为交联剂,过硫酸钾为引发剂合成高吸水性树脂,并探讨了单体丙烯酰胺与丙烯酸的配比率、丙烯酸的中和度、交联剂用量、聚合温度、引发剂对高吸水树脂吸液性能的影响.结果显示当丙烯酰胺和丙烯酸单体的配比率0.3～0.4,丙烯酸的中和度60 ％～70％,交联剂的用量约占单体0.03 ％～0.05％,引发剂用量约占单体的0.2％加.3％,聚合温度为55～60℃时,合成树脂的吸水倍率达最大,为995.35 g/g.     

柚皮粉接枝P(AA-AM)树脂的制备及其尿素吸放性能

采用水溶液聚合法,以农林废弃物柚皮粉(PP)为原料,与丙烯酸(AA)、丙烯酰胺(AM)接枝共聚,制备了低成本高吸水树脂(PP-SA),并探讨了其形成机理。利用FTIR和TG对PP-SA的结构及热稳定性进行了表征,结果表明:PP与AA、AM之间发生了接枝共聚反应;PP-SA升温至700℃失重率仅约为60%,而纯聚丙烯酸-聚丙烯酰胺共聚物〔P(AA-AM)〕为79%。考察了PP-SA在不同质量浓度的尿素溶液中的吸液倍率、尿素负载量及尿素释放率,结果显示:PP-SA对6 g/L的尿素溶液有最大的吸收倍率(362 g/g);在10 g/L的尿素溶液中溶胀干燥后的PP-SA的尿素负载量达到最大值66.7%,其在蒸馏水中的尿素释放率可达74%。     

Undesirable effects of heating on hydrogels

Heating is the most conventional drying method for removing water from as‐synthesized hydrogels in laboratory and industry. In this article, the effects of the heating temperature (60–200°C) and time (10 min–24 h) on swelling properties of highly absorbent hydrogels based on 2‐acrylamido‐2‐methylpropane sulfonic acid (AMPS), acrylic acid (AA), potassium acrylate (KA), and acrylamide (AM) were studied. Crosslinkers methylene bisacrylamide (MBA) and poly(ethyleneglycol) dimethacrylate (PEGDMA) were used in the syntheses. Depending on the hydrogel structural composition and its drying temperature and time, the swelling capacities were extremely changed. Generally, AA‐, KA‐, and AM‐based hydrogels showed more hydrolytic‐thermal stability than the corresponding AMPS‐based hydrogels. MBA‐crosslinked hydrogels generally exhibited higher vulnerability against heating. Swelling of PEGDMA‐crosslinked poly(AM‐KA‐AA) hydrogel was greatly increased after heating, whereas its analogousAM‐free sample exhibited huge loss of swelling. PEGDMA‐crosslinked poly(AMPS) samples also exhibited swelling reduction after drying. Rheological studies showed that the storage modulus was highly reduced (～ 5200 Pa) after heating of MBA‐crosslinked poly(AMPS) hydrogels, which reconfirmed the crosslink cleavage. Mechanistic discussions were proposed for the thermal‐induced swelling changes. It was concluded that the chemical nature of both crosslinker and monomer must be taken into consideration to choose the temperature and time of the hydrogel drying. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008