Synthesis of an amino-terminated waterborne polyurethane-based polymeric dye for high-performance dyeing of biomass-derived aldehyde-tanned chrome-free leather

An amino-terminated waterborne polyurethane-based polymeric dye (AWPUD) was synthesized for the high-performance dyeing of chrome-free leather tanned by biomass-derived aldehyde (BAT). Fourier transform infrared spectroscopy (FTIR) and ¹H NMR spectra illustrated the successful synthesis of AWPUD via incorporating small-molecule dyes (SMDs) (C.I. Acid Red 14) and sodium 2,4-diaminobenzenesulfonate into the polyurethane skeleton. The amino group content of AWPUD was tested to be 1.34 wt% (based on dry weight), which included 0.65 wt% of terminal amino groups. The characteristic absorption peaks of AWPUD were observed at 538 nm and 573 nm, similar to those of SMDs. AWPUD-dyed crust leathers exhibited better dyeing performances than SMD-dyed crust leather in terms of comparable dye penetration degree, lower chroma of wastewater, and higher filler-dye uptake ratio. In addition, AWPUD-dyed crust leathers had higher dyeing uniformity, dry-wet rubbing resistance, and thermal stability. Meanwhile, AWPUD-dyed crust leathers had better comprehensive physical properties in terms of higher mechanical strengths, comparable softness, and smooth grain surface. These results suggest that AWPUD has the great potential to be used in the high-performance dyeing of BAT-tanned leather.     

Synthesis,characterization, and evaluation of polymeric oil sorbent for remediation of hydrocarbons spillage

The preparation and evaluation of polymeric oil sorbent based on styrene acrylate ester and ethylhexyl acrylate (EHA) are the main target of this work. In this respect, poly styrene-co-p-chloromethyl styrene (PSCMS) was synthesized through radical copolymerization of p-CMS with styrene in the presence of benzoyl peroxide initiator. Then, the PSCMS was reacted with acrylic acid to produce macromonomer containing polymerizable C?C poly {styrene-co-[4-(methyl acrylate) styrene]} (PSSMA) that subsequently copolymerized with EHA in the presence of a cross-linker to obtain the cross-linked copolymers PSSMA/EHA (organogel). The prepared compounds were characterized by using FTIR, ¹H NMR, and gel permeation chromatography. The thermal properties of the cross-linked oil absorbents were investigated using thermogravimetric analysis, and the morphology was characterized by scanning electron microscope (SEM). The oil absorbency of oil gel was determined through oil absorption tests; the highest oil absorbencies of oil gel were found to be 82.6, 74.4, 46.7, and 38.1 g/g in N,N-dimethyl formamide, CHCl₃, toluene, and diesel, respectively.     

Preparation and characterization of sponge-like composites by cross-linking hyaluronic acid and carboxymethylcellulose sodium with adipic dihydrazide

The objective of this study was to develop a novel kind of hyaluronic acid-based biomaterials which had the great potentials to be used as dermal fillers or applied in tissue augmentation or filling. A series of sponge-like composites were prepared by cross-linking different amounts of hyaluronic acid (HA) and carboxymethylcellulose sodium (CMC-Na). Adipic dihydrazide (ADH) was employed as the cross-linker and water-soluble 1-ethyl-3-[3-(dimethylaminopropyl)] carbodiimide (EDC) as the carboxyl-activating agent. Fourier-Transform Infrared (FT-IR) analysis was performed to characterize the expected amide linkages in the cross-linked composites, and the scanning electron microscopic (SEM) analysis was carried out to view the microstructures of the composites. Furthermore, the physico-chemical properties, such as swelling property, thermostability, the resistance to hyaluronidase (HAse) degradation and the antioxidant abilities against hydroxyl free radical (OH), were characterized. The presence of the amide peak at 1476.11 cm⁻¹ in FT-IR spectra indicated the cross-linking between HA and CMC-Na by ADH. As demonstrated by scanning electron microscopy (SEM), the microstructures of the composites were dependent on HA content. The equilibrium swelling ratio was 20.091 ± 0.070, indicating the excellent water-uptake abilities of the composites. The HA-CMCNa composites showed a thermal stability up to 237 °C, independent of the composition of the prepared biomaterials. When exposed to phosphate-buffered saline (PBS) solution containing HAse (100 U/ml), all of the composites could be degraded quickly in 15 h. But when the concentrations of ADH and EDC in the cross-linking reaction system were increased up to 10 mmol/L, respectively, the degradation process lasted for 60 h. The prepared composites possessed great antioxidant abilities against OH and the ability to scavenge OH depended on the composition. With the high water-keeping ability and improved physico-chemical stabilities, the prepared biocompatible HA-CMCNa composites could be used as ideal alternatives for dermal fillers, tissue augmentation/filling biomaterials.     

Modulus-switching viscoelasticity of electrorheological networks

To form an electrorheological network (ERN), semiconducting nanoparticles were embedded in a polymer that was cross-linked to restrict particle motion. The microstructure ranged from random to aligned, depending on the degree of field-induced particle alignment during chemical network formation. We investigated in detail the softness effects of the matrix, having a relatively low storage modulus, on the dynamic rheological behavior of the ERN and analyzed its anisotropy. The anisotropy of the microstructure was probed rheologically with the modes of small-amplitude oscillatory shear (loading perpendicular to the field direction) and compression (loading in the field direction). The storage shear modulus was found to be a function of the applied electric field, particle volume fraction, and the pre-alignment electric field strength during the cross-linking reaction of the matrix, which governs the thickness of particle columns and intercolumn distance. Nonlinear behavior at small strain (below 0.1%) was conspicuous; this nonlinear viscoelasticity was accompanied by only a limited deformation of ordered connectivity. Throughout this study, we fabricated the ERN with the highly controllable modulus-switching effect acting in a shear-mode operation. Managing this anisotropy of an ERN by the electrical and chemical process is important in the design of smart materials that will provide improved stability and mechanical strength compared with fluid-type electrorheological materials and faster response time compared with that of conventional charged polymer gel.     

可自交联超支化聚醚醚酮的合成与热性能研究

近15年来,由于超支化聚合物所具有的三维椭球状结构,良好的溶解性,大量末端官能团等独特的物理、化学特性及其在涂料、添加剂、药物载体、基因载体、大分子建筑“砌块”、超分子科学等领域的潜在应用,已成为高分子研究领域的一个热点．超支化聚合物在光通讯及微电子等领域的应用也已引起人们广泛而高度的重视．聚合物具有良好的热稳定性及溶解性是作为微电子和光学集成线路所必需的．本文以含有大侧基的“功能性”A：单体2．（4-苯氧基苯基）．1,4．苯二酚（POP）与B单体1,3,5-三[（4．（4．氟苯酰基）苯氧基]苯进行缩聚反应,得到全芳结构超支化聚醚醚酮（HPOP-PEEK）．     

丝素纳米颗粒的制备及应用于L-天冬酰胺酶的固定化

丝素蛋白纤维溶于高浓度中性盐溴化锂溶液或氯化钙-乙醇-水三元溶剂中, 经过透析和纯化可以制成3种液态丝素. SDS-PAGE分析结果表明, 其分子量分布范围明显不同. 应用能与水混溶的有机溶剂如丙酮等可将这种丝素制成丝素纳米颗粒, 用SEM观察到丝素纳米颗粒粒径分布范围为50~120 nm. 以戊二醛为交联剂, 将治疗急性淋巴性白血病常用酶制剂L-天冬酰胺酶共价结合在丝素纳米颗粒上. 酶活性分析结果表明, 由肽链断裂较少的丝素制备的纳米颗粒更适合于酶的生物结合. 酶动力学研究结果表明, 这种固定化酶活性回收率为44%, 热稳定性较游离酶有明显提高, 最适pH值范围加宽为6.0~8.0, 最适反应温度提高10 ℃; 抗胰蛋白酶水解能力明显增强. 结果表明, 丝素纳米颗粒与丝素蛋白膜一样, 是一种酶固定化的良好载体, 在药物缓释系统方面具有潜在的研究和开发价值.     

交联结构对肝素/壳聚糖层层组装多层膜内皮细胞相容性的影响

采用1-乙基-(3-二甲基氨基丙基)碳酰二亚胺交联技术对具有抗凝血抗菌作用的肝素/壳聚糖多层膜进行交联, 研究了交联结构对多层膜稳定性和血管内皮细胞亲和性的影响. QCM-D结果显示, 交联可有效地提高多层膜的稳定性, 在模拟人体血液流速(3.0 cm/s)下保持良好的稳定. 体外内皮细胞的研究结果显示, 多层膜的交联可有效地调节肝素/壳聚糖多层膜表面粘弹性, 并显著增加内皮细胞的粘附与生长. 交联的肝素/壳聚糖多层膜有望成为理想的心血管功能界面涂层材料.     

聚乙烯亚胺小孔壳聚糖的研制及吸附性能

对壳聚糖致孔剂致孔、交联及胺化条件进行了优化,以聚乙烯亚胺为胺化剂,制备了一种新型的锥孔、高胺含量壳聚糖(PEI-CTS)树脂.树脂胺含量为8.61mmol/g,粒径分布范围100μm～200μm,耐酸性强.电镜照片显示小孔属不透孔.BET测得其平均孔径为35nm,颗粒比表面1.03m2/g.同时研究了树脂对Cu2 、Ni2 的吸附,结果显示溶液pH=5.0时树脂的吸附能力最强,其饱和吸附量分别为1.71mmol/g和0.718mmol/g,且多次再生吸附量改变不大.     

INFRARED AND RAMAN SPECTROSCOPY IN PAPER AND PULP ANALYSIS

Infrared and Raman spectroscopy are essential analytical tools for the structural analysis of paper and pulp chemistry. The studies of cellulose, hemicellulose, lignin, thermal- and photo-induced oxidation; cross-linking; and various chemical treatments of pulp and paper products are all made possible using these forms of molecular spectroscopy. In this review, containing 70 references, a broad range of applications into pulp and paper materials, components, and processes is described from recent and classic research over predominantly the past 20 years.     

Degradation kinetics of functionalized novolac resins

We report the relationships between the degradation behaviors (i.e. the degradation kinetics, degradation activation energy, weight loss conversion, and char formation) and the structure features in three modified novolac resins bearing different curable functional groups and aromatic units i.e. Carbonyl phenyl azo novolac resin (CPAN), 4-(4-hydroxyphenyl azo) benzyl ester novolac resin (HPDEN) and Carbonyl phenyl 4-(4-hydroxyphenyl azo) benzyl ester novolac resin (CHABN). These modifications enhanced the thermal stability of the cured novolac resins by delaying the decomposition temperature up to 30-100 °C and produced prominent residue char yield up to 68% (CPAN), 56% (HPDEN) and 64% (CHABN), respectively. The two heavily cross-linked samples, CPAN and CHABN displayed even higher Ea than HPDEN. All modified novolacs displayed much higher decomposition activation energy (over 237 KJ/mol*K) compared with the generic phenolic (PN).