Synthesis and Characterization Superabsorbent Polymers Made of Starch,Acrylic Acid,Acrylamide, Poly(Vinyl Alcohol), 2-Hydroxyethyl Methacrylate, 2-Acrylamido-2-methylpropane Sulfonic Acid

Three polymers with excellent absorption properties were synthesized by graft polymerization: soluble starch-g-poly(acrylic acid-co-2-hydroxyethyl methacrylate), poly(vinyl alcohol)/potato starch-g-poly(acrylic acid-co-acrylamide), poly(vinyl alcohol)/potato starch-g-poly(acrylic acid-co-acrylamide-co-2-acrylamido-2-methylpropane sulfonic acid). Ammonium persulfate and potassium persulfate were used as initiators, while N,N′-methylenebisacrylamide was used as the crosslinking agent. The molecular structure of potato and soluble starch grafted by synthetic polymers was characterized by means of Fourier Transform Infrared Spectroscopy (FTIR). The morphology of the resulting materials was studied using a scanning electron microscope (SEM). Thermal stability was tested by thermogravimetric measurements. The absorption properties of the obtained biopolymers were tested in deionized water, sodium chroma solutions of various concentrations and in buffer solutions of various pH.     

P(MMA/EA)/PEG-TPE半互穿网络聚合物的合成

为提高聚甲基丙烯酸甲酯/聚乙二醇聚氨酯(PMMA/PEG-TPE)半互穿网络聚合物的相容性,探索了在PEG-TPE中将甲基丙烯酸甲酯(MMA)与丙烯酸乙酯(EA)共聚形成P(MMA/EA)/PEG-TPE半互穿网络聚合物(S-IPN).红外光谱和核磁共振氢谱分析表明丙烯酸酯基本反应完全,PEG-TPE的单体转化率达到89%; 动态热机械分析(DMA)显示P(MMA/EA)/PEG-TPE的玻璃化转变温度峰较同组成比例的PMMA/PEG-TPE内移,甚至在组成比为10/90,30/70的体系中形成了单一的玻璃化转变峰,且扫描电镜(SEM)中表面形貌也变得较柔顺,表明体系的相容性和互穿程度进一步提高.     

玻璃纤维增强光固化树脂基齿科生物复合材料的半互穿网络结构界面的形成及力学性能

采用不同浓度的聚甲基丙烯酸甲酯(PMMA)丙酮溶液对玻璃纤维进行表面处理，并对不同处理条件下的玻璃纤维表面化学组成、PMMA的吸附量及齿科树脂基复合材料的力学和界面性能进行了分析和测试。结果表明，经过表面处理，玻璃纤维表面吸附上PMMA，且吸附量随PMMA溶液浓度的增大而增大。控制玻纤表面吸附的PMMA质量分数在1%左右，可以设计其与齿科树脂形成半互穿网络结构的良好界面。与未处理的玻纤复合材料相比，用质量分数为5%的PMMA溶液处理的玻纤/光固化树脂基复合材料的弯曲强度提高29.6%，弯曲模量提高30%，可以作为一种齿科修复用的新型生物复合材料应用。     

Facile Fabrication of Poly(vinyl alcohol)/Polyquaternium-10 (PVA/PQ-10) Anion Exchange Membrane with Semi-Interpenetrating Network

Anion exchange membranes (AEMs) are one of the core components of AEM fuel cells. A series of poly(vinyl alcohol)/polyquaternium-10 (PVA/PQ-10) AEMs with semi-interpenetrating networks (s-IPNs) are prepared by a simple solution-casting method using glutaraldehyde (GA) as a cross-linking agent. Subsequently, the prepared PVA/PQ-10 cross-linked membranes are characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, mechanical analysis, water uptake and swelling ratio tests, ion exchange capacity (IEC) tests, ionic conductivity measurements, and oxidative/alkaline stability tests. The effects of the mass ratio of PVA and PQ-10 and the amount of cross-linking agent GA on the performance of the PVA/PQ-10 cross-linked membranes are systematically explored. The results show that the cross-linked PVA/PQ-10 AEMs have high IEC and low water uptake and swelling ratio, and its maximum ionic conductivity can reach 79.37 mS cm^–1 at 80 °C. In addition, the PVA/PQ-10 cross-linked membrane has good oxidative and alkaline stability under optimal preparation conditions. These results may provide valuable insights toward more effective scheme designs and new, simple preparation methods for AEMs with s-IPN structures.     

CMCS/PNIPA/粘土纳米复合水凝胶的结构与性能

以无机粘土作为交联剂制备了pH/温度双重响应的羧甲基壳聚糖/聚(N-异丙基丙烯酰胺)/粘土半互穿网络(CMCS/PNIPA/Clay semi-IPN)纳米复合水凝胶,对其结构、形态及溶胀行为等进行了研究。实验表明,无机粘土被剥离成纳米尺寸的片层,均匀分散在凝胶网络中,起交联剂的作用,CMCS以线性大分子存在于水凝胶中。CMCS/PNIPA/Clay纳米复合水凝胶在33℃出现体积相转变,与传统PNIPA凝胶一致;当pH值在CMCS的等电点附近时,凝胶的溶胀度出现最小值。     

The usability of (sodium alginate/acrylamide) semi-interpenetrating polymer networks on removal of some textile dyes

In this study, (sodium alginate/acrylamide) interpenetrating polymer networks ((NaAlg/AAm)IPN) have been prepared at definite composition. The aqueous solution of 3% (w/v) sodium alginate and 50% (w/v) acrylamide was irradiated with ⁶⁰Co-γ rays at a dose rate of 0.07 kGy/h up to 5 kGy. The percent conversion was determined gravimetrically and 100% gelation was achieved at 5 kGy dose. To understand whether the semi-interpenetrating polymer network of sodium alginate is performed, Fourier Transform Infrared (FTIR) spectra of polyacrylamide (PAAm), sodium alginate, and the semi-interpenetrating polymer network were recorded. It is found that the FTIR spectra of PAAm, NaAlg, and the semi-interpenetrating polymer network are different. The thermograms of PAAm, sodium alginate, and the semi-interpenetrating polymer network were recorded for investigating their thermal character. (NaAlg/AAm)IPN hydrogels were immersed to swell in a solution of pH 7, at a temperature of 25°C. The swelling results at pH 7.0 indicated that (NaAlg/AAm)IPN hydrogel, containing 3% NaAlg showed maximum % swelling in water but swelling increased in the order of water > Magenta > Methylene Blue > Safranine-O > Methyl Violet. Diffusion of water and aqueous solution of dyes within (NaAlg/AAm)IPN hydrogels was found to be of Fickian character at the initial stage of swelling with regard to values calculated for diffusion coefficient of (NaAlg/AAm)IPN hydrogels in water and aqueous solution of dyes. Some diffusion parameters were calculated from swelling of (NaAlg/AAm)IPN in water and dyes and their adsorption isotherms were plotted. In the adsorption experiments, the efficiency of (NaAlg/AAm)IPN hydrogels to adsorb Magenta, Safranine-O, Methylene Blue, and Methyl Violet dyes from water was studied. (NaAlg/AAm)IPN hydrogels showed different adsorption for different aqueous solution of dyes at pH 7.0. Adsorption isotherms were constructed for (NaAlg/AAm)IPN-dye systems. S type adsorption in the Giles classification system was found. Thermal and spectroscopic characterization of semi-interpenetrating polymer network of sodium alginate and acrylamide and dye adsorbed semi-interpenetrating polymer network of sodium alginate and acrylamide was recorded. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

New hydrogels based on maleilated collagen with potential applications in tissue engineering

New hydrogels based on maleic anhydride (MA) modified collagen were prepared with the aim of overcoming the high degradation rate displayed by collagen that is not otherwise chemically crosslinked. Semi-interpenetrated matrices were obtained by free radical polymerization of maleilated collagen (CM) and 2-hydroxyethyl methacrylate (HEMA) in the presence of ammonium persulfate (APS) and N,N,N′,N′-tetramethylethylenediamine (TEMED) as initiating system. The resulting matrices (CMH) had a sharp decrease in degradation, when compared to pure collagen. FTIR and H¹ NMR spectroscopies were used to confirm the incorporation of MA on the collagen peptide chains. The final composition of CMH was found to be strongly dependent by the concentration of maleilated collagen. The morphology of the hydrogels was studied by Scanning electron microscopy (SEM) and the macro-gel structure was confirmed. Water uptake of the synthetised hydrogels is influenced by both composition and the porosity of the matrices.     

丝胶含量对温敏凝胶形态和热性能的影响

采用半互穿网络技术制备得到不同丝胶(SS)含量的丝胶基聚(N-异丙基丙烯酰胺)水凝胶。采用XRD、SEM、DSC和TGA-DTG分别考察了水凝胶的结构、相容性和热稳定性, 以及凝胶的内部孔洞形态和体积相转变行为。结果表明: 丝胶多肽链和凝胶分子链存在微弱的氢键作用力; 随着丝胶质量分数由0增加至20%, 凝胶的内部孔径增加1~2倍, 且均呈结构完好的蜂窝状结构; 丝胶分子链均匀地分散在凝胶基体中, 无相分离发生; 丝胶分子链引入使聚(N-异丙基丙烯酰胺)水凝胶的体积相转变温度增加0.2~0.3℃; 最大热分解温度和DTG分解峰温度呈缓慢增加趋势。     

低密度交联硬质聚氯乙烯泡沫塑料的研究

以酸酐和异氰酸酯为交联组分,糊用聚氯乙烯为基体树脂,制备了低密度交联硬质聚氯乙烯(Crosslinked-PVC)泡沫塑料。考察了甲基六氢苯酐、偏苯三酸酐和对苯二甲酸与甲苯二异氰酸酯及多亚甲基多苯基多异氰酸酯的不同官能度配比对模压块和泡沫塑料交联度的影响,酸酐/异氰酸酯配比对泡沫塑料的性能影响,不同[K]值PVC树脂对泡沫塑料的性能影响。研究表明,异氰酸酯和酸酐的官能度对模压块和泡沫塑料的交联度影响十分显著,模压块中过早产生交联对后续发泡过程不利。随着酸酐/异氰酸酯摩尔比的增加,泡沫密度减小,压缩强度降低,且泡沫密度达到最低密度的时间缩短。当糊用PVC树脂[K]值过小时,发泡体系容易发生并泡和中间鼓泡;当[K]值过大时,压缩性能反而下降。制备的Crosslinked-PVC泡沫塑料具有半互穿聚合物网络结构。     

纤维素/聚氨酯半互穿网络的制备及性能

利于聚氨酯对纤维素进行改性研究,介绍了纤维素/聚氨酯半互穿网络的制备方法,并利用红外光谱（FT-IR）、扫描电子显微镜（SEM）、X射线衍射（XRD）、力学性能及电学性能的测试对纤维素/聚氨酯半互穿网络的特征进行研究。结果表明,在半互穿网络中纤维素和聚氨酯具有明显的相分离现象;线性纤维素分子穿插于已交联的聚氨酯网中,形...