快速响应PNIPA／Fe3O4复合凝胶辐射制备与性能研究

采用化学共沉淀法制备了四氧化三铁粒子，以N-异丙基丙烯酰胺（NIPA）、N，N-亚甲基双丙烯酰胺（MBA）和聚乙二醇（PEG）为原料，以60Coγ，射线为放射源，辐照聚合制备了多孔PNIPA／Fe3O4复合水凝胶，并对其温度敏感性、平衡溶胀率进行了表征。研究发现：磁性四氧化三铁纳米粒子在凝胶中分散均匀；凝胶具有明显的温度敏感性；致孔剂的添加提高了水凝胶的平衡溶胀率，多孔复合水凝胶失水率达96％，比普通磁性水凝胶失水率提高了约76％；致孔剂的添加使复合凝胶的最低临界相转变温度由34℃升高至37℃左右。     

温度敏感PNIPA/膨润土复合水凝胶辐射法合成及其性能研究

本工作以N-异丙基丙烯酰胺(NIPA)为聚合单体,采用辐射法合成了PNIPA/膨润土复合水凝胶材料,研究了钠基膨润土与有机改性膨润土种类、膨润土的含量以及分散条件对水凝胶溶胀性能的影响.溶胀性能测试结果表明,加入膨润土的复合水凝胶其溶胀性能优于均聚PNIPA,加入有机膨润土的复合凝胶平衡溶胀率(SR)最好,且表现较好的温度响应性和快速的相转变特性;随着有机膨润土含量的增加,复合水凝胶的SR和温度响应性均逐渐升高,当膨润土含量为10%时,水凝胶的溶胀性能最优.退溶胀实验结果表明,PNIPA/有机膨润土水凝胶失水最快,在0.5h内,其失水率为83%,PNIPA/钠基膨润土水凝胶失水74%,而PNIPA水凝胶失水则只有50%左右.压缩性能测试结果表明,加入膨润土后,水凝胶的压缩强度、最大压缩力等均有了不同程度的增大,随着土含量的增加,凝胶的压缩性能呈上升趋势,当有机改性土含量为15%时,其压缩强度为均聚PNIPA的2.5倍,压缩屈服力由原来的0.38N增加到5.28N,提高了约14倍.     

辐射法制备壳聚糖/聚丙烯酸水凝胶及其溶胀性能研究

采用电子束对壳聚糖和丙烯酸混合水溶液进行辐照，制得了壳聚糖／聚丙烯酸（CS／PAAc）共聚物水凝胶。研究了pH值、各组分配比和辐照剂量等因素对产物溶胀率的影响。结果表明，水凝胶具有pH敏感性，在强酸性（pH≈1）和碱性（pH〉7）条件下均表现出较好的溶胀性；而在pH2-5范围内溶胀率较小。同时，随着辐照剂量的增大，产物的溶胀率也随之增大，在酸性条件下表现并不明显，而当pH〉6时增大效果较显著。     

层状壳聚糖水凝胶的制备与性能

通过两步低温辐射和冷冻/解冻循环相结合的方法制备聚乙烯醇/聚氧乙烯(PVA/PEO)为基层,聚乙烯醇/壳聚糖(PVA/CS)为上层抗菌功能层的层状壳聚糖水凝胶。通过对吸收剂量、电子束流、聚合物溶液浓度等的研究确定最佳制备工艺,并通过溶胀性能、力学性能、抗菌性能及红外光谱和扫描电镜表征所得层状水凝胶的结构与性能。结果表明,该方法制备的层状壳聚糖水凝胶具有明显的层状结构,层间结合紧密,壳聚糖结构未改变;层状水凝胶的溶胀性能随着壳聚糖含量增大而逐渐增大,60%CS含量平衡溶胀度达到2 200%;层状水凝胶力学强度随着壳聚糖含量增加而先增大后减小,40%CS含量下层状水凝胶从PVA/PEO凝胶的0.35MPa提高到0.47 MPa;抗菌性能测试表明层状水凝胶对大肠杆菌和金黄色葡萄球菌均具有明显的抑菌效果,抑菌性能随着壳聚糖含量的提高而增大。     

用辐射技术制备丙烯酰胺与丙烯酸钠共聚物水凝胶——超级吸水材料

本文描述了丙烯酰胺—丙烯酸钠水溶液辐射共聚—交联制备共聚物水凝胶的研究。在共聚体系中加入少量非离子型表面活性剂,可把单体浓度由通常的20％上下提高到50％,聚合转化率和共聚物的特性粘数也都有相当程度的提高。这一体系经辐射共聚—交联后,可得到溶胀比>1,000的共聚物水凝胶——超级吸水材料。这种共聚物水凝胶的溶胀比不仅受吸收剂量即交联密度的制约,而且与共聚物中羧钠基的含量有密切关系。     

纳米聚N-异丙基丙烯酰胺微凝胶的光引发聚合

选择具有温敏性的高分子单体N－异丙基丙烯酰胺（N－isopropylacrylamide，NIPAM）为主单体，N，N′－亚甲基双丙烯酰胺（methylenebisacrylamide，MBA）为交联剂，运用光引发无皂乳液聚合的方法合成出粒径小于100nm的高分子微凝胶，并研究了在改变体系组成和条件时微凝胶粒径的变化。结果显示，在乳化剂临界胶束浓度以下，随着乳化剂浓度的提高，微凝胶粒子的粒径不断关小且趋向稳定；相比于热引发，产生的微凝胶具有较高的单分散性而且粒径较小。     

DMDAAC-AM辐射接枝淀粉基水凝胶的制备与吸水性能研究

以淀粉(St)、二甲基二烯丙基氯化铵(DMDAAC)、丙烯酰胺(AM)为原料, N,N’-亚甲基双丙烯酰胺作为交联剂,采用辐射引发的方法,制备了DMDAAC-AM接枝的阳离子淀粉凝胶,并用红外分析验证了样品;保持辐照剂量、淀粉两种单体质量都不变的情况下,研究了N,N’-亚甲基双丙烯酰胺用量对产物吸水后溶胀比的影响。结果表明,凝胶的膨胀比与N,N’ 亚甲基双丙烯酰胺交联单体用量的有关,随着交联单体的用量增加而下降。     

聚丙烯酰胺包覆磁性纳米凝胶的光化学法制备及其机理研究

以丙烯酰胺为单体，N，N’-亚甲基双丙烯酰胺为交联剂，采用光化学方法在水溶液体系中制备了聚丙烯酰胺（Polyacrylamide，PAM）包覆的磁性纳米凝胶，用傅立叶变换红外光谱（Fourier transform infrared spectroscopy,FTIR），光子相关光谱（Photo correlation spectroscopy,PCS）和电子自旋共振（Electron spin resonance，ESR）波谱对聚丙烯酰胺磁性纳米凝胶进行了表征。研究了磁性纳米凝胶粒径随反应时间、单体浓度、交联剂浓度的变化规律，并探索了聚丙烯酰胺磁性纳米凝胶的包覆机理。     

P(NIPA-co-HEMA)与PNIPA/P(HEMA)IPN水凝胶的辐射聚合与可控缓释研究

采用辐射聚合方法制备了聚N-异丙基丙烯酰胺(PNIPA)均聚物、N-异丙基丙烯酰胺(NIPA)与甲基丙烯酸2-羟基乙酯(HEMA)共聚物(P(NIPA-co-HEMA))和PNIPA/P(HEMA)互穿网络(Interpenetrating Polymer Network,IPN)水凝胶。研究了水凝胶溶胀度的温度依赖性;讨论了剂量率和吸收剂量对辐射聚合的影响,单体浓度及其配比和聚合介质对水凝胶的相转变温度、溶胀度和溶胀一消溶胀动力学的影响;并以木瓜蛋白酶作为模型药物,对水凝胶进行药物释放测定。实验结果表明,较为适宜的水凝胶在剂量率1kGy／h,吸收剂量30—40kGy,单体浓度10％和聚合介质正丁醇中辐射合成。此类共聚与互穿网络水凝胶适用于药物的可控释放。     

EVA预辐射接枝N－异丙基丙烯酰胺制备热敏性材料

采用预辐射接枝法，将Ｎ－异丙基丙烯酰胺（ＮＩＰＡＡｍ）接枝到乙烯－醋酸乙烯酯共聚物（ＥＶＡ）试片上。研究了各种因素对接枝反应的影响。结果表明，接枝体系具有一般预辐照液－固两相接枝体系的共性，如在接枝反应前期，反应速度不变，以后逐渐下降，接枝率与反应温度成正比，少量的Ｃｕ（ＮＯ３）２，就能使接枝率急剧下降。经ＮＩＰＡＡｍ接枝的ＥＶＡ表面，呈现与ＮＩＰＡＡｍ凝胶相似的热敏性，即在低于“较低临界溶解温度”（ＬＣＳＴ）的温度时溶胀于水，而在高于ＬＣＳＴ时，迅速退溶胀，其ＬＣＳＴ约为３２℃，水含量随温度的变化是可逆的。相比之下，接枝ＮＩＰＡＡｍ的ＥＶＡ表面比ＮＩＰＡＡｍ凝胶具有更灵敏的热敏性。试片的ＬＣＳＴ会随着接枝层的组成变化而漂移。     

PVA/PEO/Chitosan水凝胶膜的辐照法制备及其性能研究

研究了辐照剂量和壳聚糖含量对水凝胶膜性能的影响。以聚乙烯醇(PVA)、聚氧化乙烯(PEO)和壳聚糖(Chitosan)为原料,采用γ射线辐照法制备了一种新型水凝胶膜。结果表明,随着辐照剂量的增大,凝胶分数会增大,溶胀率会降低;辐照剂量达到21kGy时,凝胶分数可以达到70%,辐照剂量大于21kGy以后,拉伸强度和断裂伸长率会随着辐照剂量的增大而降低;随着壳聚糖含量的增加,水凝胶膜的凝胶分数、拉伸强度和断裂伸长率都会减小,而溶胀率会有一定的提高。辐照后壳聚糖的一些特殊官能团没有改变,将会保持它的抑菌性能,从而获得了一种新型水凝胶膜。     

Effect of maleic acid content on the thermal stability, swelling behaviour and network structure of gelatin-based hydrogels prepared by gamma irradiation

The highly swelling Poly (acrylamide/maleic acid/gelatin) P(AAm/MA/G) hydrogels were prepared by gamma-irradiation at low dose rate (0.94 kGy/h) and moderate dose rate (3.84 kGy/h). The hydrogels were confirmed by FTIR. The effect of copolymer composition, dose and dose rate on the swelling behaviour was discussed. Increasing of MA content and G in the initial mixture leads to an increase in the amount of MA and G in the gel system and decrease in the gelation %. The swelling behaviours of the hydrogel prepared at moderate dose rate increased with increasing MA mole content in the gel system but, there is no systematic dependence of swelling on MA content was observed for the hydrogels obtained at low dose rate. Pore structure of the hydrogels was monitored by using scanning electron microscopy. Thermogravimetric analysis (TGA) and the rate of the thermal decomposition of P(AAm/MA/G) hydrogels has been evaluated to give a better understanding of the thermal stability of polymers, The X-ray data of P(AAm/MA/G) hydrogels was discussed to investigate some features namely the degree of ordering and crystallite size.     

Irradiation mediated synthesis of a superabsorbent hydrogel network based on polyacrylamide grafted onto salep

The synthesis and swelling behavior of a new superabsorbent hydrogel based on natural salep grafted with polyacrylamide is described. The new biopolymer was synthesized via simultaneous crosslinking and graft copolymerization of acrylamide monomer onto a salep backbone using radiochemical methods. Various parameters such as relative contents of salep and acrylamide, as well as total dose of γ-rays were examined. The best synthesis condition is reported and a mechanism for superabsorbent hydrogel formation suggested. Factors affecting the swelling behavior of hydrogel were also studied.     

Preparation of macroporous poly(acrylamide) hydrogels by radiation induced polymerization technique

Macroporous poly(acrylamide) [poly(AAm)] hydrogels were prepared by using poly(ethylene glycol) (PEG) with three different molecular weight as the pore-forming agent during the radiation induced polymerization reaction. Scanning electron microscope graphs reveal that the macroporous network structure of the hydrogels can be adjusted by applying different molecular weights of PEG during the polymerization reaction. The swelling ratios of the PEG-modified hydrogels were much higher than those for the same type of hydrogel prepared via traditional method. However, the pulsatile swelling behavior of the PEG-modified hydrogels in water and in acetone was affected slightly by the change in the amount of the PEG.     

含药聚氧化乙烯共聚水凝胶膜的制备及其性能研究

应用冻融循环和辐射交联技术,制备了含有醋酸氨苄磺胺的的聚氧化乙烯共聚水凝胶膜,并对其理化性能和药物释放进行了研究。实验结果显示,与未经冻融循环处理的聚氧化乙烯共聚水凝胶膜比较,增强的了矣氧化乙烯共聚水凝胶膜抗强度明显增加（Ｐ〈０．０１）,凝胶分数和断裂伸长率亦稍有增加,表明冻融循环处理可明显地改善该膜的机械性能,使该膜作为伤口敷料具有理想的柔韧性、交联度和伸缩性。溶用蔗研究显示,该水凝胶膜的平衡水     

γ射线辐照制备聚甲基丙烯酰亚胺微孔材料及其性能表征

以甲基丙烯酸(MAA)、丙烯腈(AN)、丙烯酰胺(AM)和甲基丙烯酸甲酯(MMA)为单体,用γ射线辐射引发聚合,形成MAA\AN\AM的共聚物和PMMA,然后使用热处理酰亚胺化制备了聚甲基丙烯酰亚胺(PMI),同时PMMA降解形成微孔结构.红外光谱分析表明:在选定温度条件下热处理过程中,相应基团酰亚胺化和PMMA降解成...     

Metal sorption and swelling characters of acrylic acid and sodium alginate based hydrogels synthesized by gamma irradiation

Hydrophilic hydrogels based on poly(acrylic acid) as synthetic polymer and sodium alginates as natural polymer (AG) were prepared by gamma irradiation. The AAc/AG hydrogels were characterized by X-ray diffraction (XRD) and thermogravimetric analysis (TGA). The effect of temperature and pH on the degree of swelling in water was studied. In addition, the metal sorption affinity of the prepared hydrogels for Cu⁺², Co⁺² and Ni⁺² was investigated. The XRD spectroscopic analysis indicates the formation of interpenetrating polymer networks. The TGA study showed that the hydrogels based on AAc/AG hydrogels at different ratios displayed lower thermal stability than PAAc hydrogel. The kinetic study of swelling in water showed that PAAc and AAc/AG hydrogels reached the equilibrium swelling state after five hours. However, AAc/AG hydrogels showed degree of swelling in water greater than PAAc hydrogel. The degree of swelling of AAc/AG hydrogels was affected by temperature, it increases within the temperature range 25-40 °C and displayed pH sensitivity within the range 5.5-9 depending on composition. The metal sorption study showed that PAAc hydrogel possessed higher affinity for Cu⁺² ions than AAc/AG hydrogels, whereas AAc/AG hydrogels showed higher affinity for Co⁺² and Ni⁺² ions than PAAc hydrogel.     

γ射线引发甲基丙烯酸十二酯乳液聚合及其吸油性能的研究

讨论了以OP-10、十二烷基苯磺酸钠为乳化剂，γ射线引发甲基丙烯酸十二酯与少量N-羟甲基丙烯酰胺和丙烯酸乳液聚合制备高吸油性树脂。分别采用红外，SEM和TG表征了聚合物的成分、结构和热性能。SEM显示乳液胶束粒子尺寸均一，粒径约为170nm。聚合物在300℃以下时热稳定性良好。研究了反应条件如吸收剂量、剂量率、固含量、N-羟甲基丙烯酰胺和丙烯酸用量等对聚合物的吸煤油性能的影响。聚合物对煤油、氯仿、二甲苯的最大饱和吸油率（g儋）分别为18．1、19．5和15．3。