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1.
用铜试剂(N,N-二乙基二硫代氨基甲酸钠)取代聚氯乙烯中的部分氯原子制备了N,N-二乙基二硫代氨基甲酸聚氯乙烯酯(PVC-SR),研究了紫外光照下PVC-SR引发甲基丙烯酸甲酯(MMA)的聚合反应,考察了光照时间、单体浓度、PVC-SR用量及官能度的影响。结果表明,PVC-SR能有效地引发MMA聚合,其产物是交联型接枝聚合物,且具有高接枝率和接枝效率。  相似文献   

2.
用铜试剂(N,N-二乙基二硫代氨基甲酸钠)取代聚氯乙烯中的部分氯原子制备了N,N-二乙基二硫代氨基甲酸聚氯乙烯酯(PVC-SR),研究了紫外光照下PVC-SR引发甲基丙烯酸甲酯(MMA)的聚合反应,考察了光照时间、单体浓度、PVC-SR用量及官能度的影响.结果表明,PVC-SR能有效地引发MMA聚合,其产物是交联型接枝聚合物,且具有高接枝率和接枝效率。  相似文献   

3.
合成了聚乙烯醇-g-聚丙烯酸接枝聚合物(PVA-g-PAA),分别用KOH、NaOH、LiCl的乙醇-水溶液处理PVA-g-PAA膜。发现离子膜用于乙醇-水的渗透气化分离可以大幅度提高分离系数,特别是用KOH处理,分离系数可达400。  相似文献   

4.
利用聚丙烯等离子体接枝甲基丙烯酸甲酯共聚物(PP-g-PMMA)作增容剂,研究了其在聚丙烯/聚偏氟乙烯(PVDF)共混体系中的作用。增容是通过PMMA与PVDF的偶极-偶极相互作用实现的。接枝共聚物使共混体系的抗张强度和模量均有提高,由不同等离子体处理时间所得的PP-g-PMMA,接枝率在7.7%~300%具有最好的增容效果;而由不同后聚合时间所得的共聚物,接枝率在30%~80%具有最好的增容效果。  相似文献   

5.
选用聚乙烯-丙烯酸(EAA)为接枝母体,首先摸索出2-乙基-2-恶唑啉阳离子开环聚合的规律,得到高转化率端基为活性翁离子的聚(2-乙基-2-恶唑啉)(PEOX),再与EAA羟基侧基进行接枝反应,考察了开环聚合条件及接枝反应条件对接枝率的影响,在一定的条件下得到了接枝率〉25%的聚乙烯-丙烯酸与聚(2-乙基-2-恶唑啉)的接枝共聚物(EAA-g-PEOX)。该接枝物用于聚对苯二甲酸丁醇酯/聚丙烯(P  相似文献   

6.
接枝聚合物PAA—g—PIPA微球的制备及其温控释药研究   总被引:7,自引:0,他引:7  
采用自由基溶液聚合法合成出N-异丙基丙烯酰胺齐聚物(Poly—N—Isopropylamide,PIPA).通过缩合将PIPA接枝在聚烯丙胺盐酸盐(Polya-llyaminehydrochloride,PAA)上得到接枝聚合物PAA—g—PIPA.用化学交联法将PAA-g-PIPA制备成10μm左右的微球.所得微球通过物理法吸附阿霉素(Adriamycin,AD)后,采用动力学透析法测定其体外释药性能.实验数据拟合数学模型得到表征药物微球的释药特性的药物扩散系数Km.Km在30℃—45℃范围内随温度的升高而增大,反映了载药PAA—g—PIPA微球具有温控释药性.  相似文献   

7.
通过流变学手段对聚苯胺溶液的凝胶化行为研究表明,在室温下,聚苯胺(PAn)/N-甲基-2-吡咯烷酮(NMP)溶液有一转折浓度Cg(0.05g/mL),浓度高于此值时,浴液凝胶化速度急剧增大,凝胶速度还与溶剂,PAn分子量及溶液的温度有很大关系。溶液中不溶的PAn的存在会加速凝胶化过程。PAn/NMP凝胶的假塑性和触变性明显地反映出PAVNMP溶液的凝胶化是溶剂参与的PAn分子链间的物理交联过程。  相似文献   

8.
乙酰化淀粉/DL-丙交酯接枝共聚物的合成及降解性能研究   总被引:7,自引:0,他引:7  
用醋酸乙烯酯和玉米淀粉反应制备出了不同取代度乙酰化淀粉,再用乙酰化淀粉同DL-丙交酯接枝共聚合成乙酰化淀粉/DL-丙交酯接枝共聚物。研究了原料配比,淀粉取代度对接枝反应单体转化率(C%),接枝率(G%)接枝效率(GE%)和接枝支链数均分子量(Mn)的影响,结果表明在给定的试验条件下接枝共聚反应的C%,G%,GE%和Mn可分别达到40%,225%,80%和1.4万。接枝共聚物在磷酸缓冲溶液和户外土壤掩埋降解实验表明,在160天内样品失重率分别为71%和60%,表明合成的乙酰化淀粉/DL-丙交酯接枝共聚物具有很好的降解性能。  相似文献   

9.
合成与表征了一系列不同分子量的聚氧化丙烯(PPO)接枝环氧树脂(epoxy-g-PO),考察了这些接枝环氧树脂和它们网络的形态,以及它们与环氧树脂形成接枝网络后的物理性能.实验结果表明,epoxy-g-PO接枝效率为0.96左右;随epoxy-g-PO中侧链长度的改变,导致接枝环氧树脂网络发生部分微观相分离行为.在环氧树脂中适量添epoxy-g-PO能较大幅度地提高环氧树脂网络的韧性,与epoxy-g-PO的形态有关.  相似文献   

10.
制备了聚乙烯醇(PVA)/聚丙烯睛(PAN)渗透汽化复合膜,研究了交联剂用量、底膜结构、进料液组成、操作温度等因素对膜的渗透汽化性能的影响.发现PVA/PAN复合膜对水/醇混合液表现为水优先透过,进料液中乙醇浓度在60~99wt%的范围内,渗透通量Jt与温度之间符合Arrhenius关系,选择分离系数αW/E也随温度上升而增大.进料液为95wt%的乙醇/水混合液时,75℃下Jt高达300~450g/m2h,αW/E为800~1100.对异丙醇/水、异丁醇/水及甘油/水混合体系,复合膜显示出更为优秀的透过、分离性能.就膜的化学、物理结构与其渗透汽化性能间的关系进行了讨论.  相似文献   

11.
电缆用无纺布堵水带高吸水树脂的研究   总被引:1,自引:0,他引:1  
电缆用无纺布堵水带高吸水树脂的研究钟安永,陈德本,周宗华,姚文(四川联合大学(东区)化学系成都610064)关键词高吸水树脂,无纺布堵水带,丙烯酸甲酯-醋酸乙烯共聚物塑料绝缘电力电缆、通讯电缆、光纤电缆等在使用中常常因为护套破损而导致水的纵向渗透,使...  相似文献   

12.
具有界面交联结构藻酸钠复合膜的制备与性能   总被引:1,自引:1,他引:0  
报道了一种具有界面交联结构的新型藻酸钠复合膜及其对醇水和其它有机物水体系的渗透汽化分离性能.该膜的活性层为藻酸钠,支撑层为氨化聚丙烯腈(PAN)多孔膜,在这两层之间存在着界面交联结构.研究了PAN多孔膜的水解时间、进行氨基化的二元胺种类及浓度对复合膜分离性能的影响,用己二胺进行氨基化所得到的复合膜的分离性能明显优于用乙二胺的结果.扫描电镜照片显示水解及氨基化改变了PAN超滤膜的孔结构,这也是影响新型复合膜性能的一个重要原因.  相似文献   

13.
In order to design an effective intratumoral radioisotope carrier, a self-assembled nanoparticle evidencing ionic strength (IS)-sensitivity from a polysaccharide derivative (pullulan acetate nanoparticle (PAN)) was prepared via dialysis. The PAN had a spherical shape in a range of size of 50-130 nm and a low critical aggregation concentration (CAC) (<8 microg/mL). With increases in the IS of the dialysis media (IS(dia)), the CAC of PAN was reduced gradually and the rigidity of the hydrophobic core in PAN was increased. This suggests that the property of PAN was altered more hydrophobically at high IS values. The stabilities of PANs prepared from various IS(dia) were also monitored with changes in the turbidity and particle size in different IS solutions. In the case of PAN prepared at an IS(dia)=0.0, the turbidity was dramatically reduced with increasing IS due to the facilitation of aggregation between the particles, whereas in the other cases, these changes were negligible. This finding indicates that PAN prepared in distilled water (IS=0.0) can be readily injected as the consequence of its nano-size, and accumulates quickly, then remains in the tumor site for a considerable period (IS=0.15). In order to closely estimate the potential of PAN as a radioisotope carrier, the radioisotope labeling efficiency of PAN with no chelating agents was evaluated. PAN evidenced a high degree of (99m)Technetium ((99m)Tc) labeling efficiency (approximately 98%). The percentage retention rate (%RR) of the (99m)Tc-labeled PAN was significantly longer than that of the free (99m)Tc (p<0.05), due largely to PAN's IS-sensitivity. In conclusion, PAN may constitute a new approach to the achievement of maximal radioisotope efficiency with regard to intratumoral administration.  相似文献   

14.
The solubility and the protolytic constants of 1-(2-pyridylazo)-2-naphthol (PAN) have been accurately determined at temperatures between 20.0 and 30.0°C in ethanol–water solutions with ethanol concentrations ranging from 10.0% to 95.0% (v/v). The measurement of the protolytic constants is based on the spectrophotometric determination of the concentrations of the corresponding conjugate acid–base pairs in ethanol–water solutions containing PAN and hydrochloric acid or sodium hydroxide. The traditionally used pH measurements in such studies in non-aqueous solutions are thus avoided. The solubility and the protolytic constants of PAN in pure water have been calculated by extrapolating the ethanol–water results to pure water where PAN is practically insoluble. The determination of the thermodynamic data mentioned above is necessary for elucidating the interactions of PAN with various metal ions in solutions and in cation-exchange membranes (e.g., Nafion®) used as PAN-based optodes.  相似文献   

15.
Asymmetric ultrafiltration (UF) membranes were prepared from blends of polyethersulfone (PES)/polyacrylonitrile (PAN) via phase inversion method induced by immersion precipitation. Polyethylene glycol (PEG) with four different molecular weights was used as pore former and hydrophilic polymeric additive. N,N‐dimethylformamide (DMF) and water were used as solvent and coagulant (nonsolvent), respectively. The effects of different proportion of PES/PAN and molecular weight of PEG on morphology and performance of the prepared membranes were investigated. Performance of the membranes was evaluated using UF experiments of pure water and buffered bovine serum albumin (BSA) solution as feed. The contact angle measurements indicated that the hydrophilicities of PES/PAN membrane increase by increasing the PAN concentration in the casting solution. However, performance of the membranes improves by increasing the PAN concentration in the casting solution up to 20% and then decreases with further addition of PAN. It was found out that the rejection of BSA decreases with increasing the PAN concentration in the casting solution. Furthermore, it was found that the performance of the membranes increases by increasing the molecular weight of PEG up to 1500 Da and then decreases with the higher molecular weights. The morphology of the prepared membranes was studied by scanning electron microscopy. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

16.
以聚丙烯腈/二甲基亚砜/N,N'-二甲基甲酰胺三元体系为纺丝液、3℃水浴为接收介质,通过静电纺丝制备了具有纳米孔结构的静电纺聚丙烯腈多孔超细纤维.探讨了溶剂比例、接收介质、聚丙烯腈浓度、纺丝电压及接收距离等因素对纤维直径和表面孔隙率的影响.结果表明最佳制备条件为混合溶剂质量比1∶1、纺丝电压16 kV、聚丙烯腈浓度15 wt%、接收距离5 cm、纺丝速率0.7 mL/h、环境温度25℃、相对湿度40%~70%.在此条件下得到的聚丙烯腈多孔超细纤维直径在420~490 nm,平均直径468 nm,表面孔隙率3.4%,纤维内部形成大量孔径为8~30 nm的孔结构,且孔径分布均匀,孔形状相对一致.N2吸附脱附测试表明,聚丙烯腈多孔纤维的BET比表面积达43.86 m2/g,是相同直径无孔聚丙烯腈纤维比表面积理论值的6倍.通过研究聚丙烯腈/(二甲基亚砜+N,N'-二甲基甲酰胺)/水的三元相图,提出非溶剂致相分离是主要成孔机理.  相似文献   

17.
Polyacrylonitrile (PAN) nanofibers were applied to metal adsorption. PAN nanofibers (prepared by an electrospinning technique) were chemically modified with amidoxime groups, which are suitable for metal adsorption due to their high adsorption affinity for metal ions. The adsorption of the amidoxime-modified PAN (PAN-oxime) (25% conversion) nanofibers followed Langmuir isotherm. The saturation adsorption capacities for Cu(II) and Pb(II) of 52.70 and 263.45 mg/g (0.83 and 1.27 mmol/g), respectively, indicating that the monolayer adsorption occurred on the nanofiber mats. In addition, over 90% of metals were recovered from the metal-loaded PAN-oxime nanofibers in a 1 mol/L HNO3 solution after 1 h.  相似文献   

18.
有机皂土的PAN修饰及其对水中镉离子的吸附行为   总被引:2,自引:0,他引:2  
采用十六烷基三甲基溴化铵(CTMAB)对皂土进行改性,用1-(2-吡啶偶氮)-2-萘酚(PAN)对其表面进行修饰,制备了新型固态吸附剂。用傅立叶变换红外光谱对该吸附剂进行了表征。以火焰原子吸收为检测手段,研究了该吸附剂对水中镉离子的吸附行为。结果表明,用CTMAB改性后,PAN可负载于皂土上,制备的固态吸附剂对水中镉离子具有较强的吸附能力。吸附量受介质的pH值、温度和吸附时间的影响。其吸附行为符合Langmuir吸附等温模型和HO准二级动力学方程式,该吸附反应为吸热的自发过程。吸附在PAN修饰有机皂土上的镉离子可用1mol/L的HNO3溶液洗脱。建立了PAN修饰有机皂土吸附富集,火焰原子吸收法测定水中痕量镉的新方法,应用于地表水中痕量镉的测定,结果满意。  相似文献   

19.
Possibility of uranium extraction on titanium oxide (TiO)–polyacrylonitrile (PAN) and sodium titanate (NaTiO)–PAN composite absorbers prepared from hydrated TiO and NaTiO embedded into a matrix of PAN binder was studied. Both TiO–PAN and NaTiO–PAN absorbers might be advantageous for repeated extraction of uranium from fresh water. Appropriate flow rates were found up to 60 BV h?1 for both the absorbers. Elution of uranium and regeneration of both the absorbers may be accomplished by hydrochloric acid solutions of concentration 0.1 mol L?1 and more. Practical sorption capacity (up to 10 % break-through) from tap water containing 2.3 μg U mL?1 was ~4.6 and ~1.5 mg of uranium per 1 mL of swollen TiO–PAN and NaTiO–PAN absorber, respectively.  相似文献   

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