Preparation and application in drug controlled delivery of pH‐sensitive P(CE‐co‐DMAEMA‐co‐MEG) hydrogel

A pH‐sensitive hydrogel [P(CE‐co‐DMAEMA‐co‐MEG)] was synthesized by the free‐radical crosslinking polymerization of N,N‐dimethylaminoethyl methacrylate (DMAEMA), poly(ethylene glycol) methyl ether methacrylate(MPEG‐Mac) and methoxyl poly(ethylene glycol)‐poly(caprolactone)‐methacryloyl methchloride (PCE‐Mac). The effects of pH and monomer content on swelling property, swelling and deswelling kinetics of the hydrogels were examined and hydrogel microstructures were investigated by SEM. Sodium salicylate was chosen as a model drug and the controlled‐release properties of hydrogels were pilot studied. The results indicated that the swelling ratios of the gels in stimulated gastric fluids (SGF, pH = 1.4) were higher than those in stimulated intestinal fluids (SIF, pH = 7.4), and followed a non‐Fickian and a Fickian diffusion mechanism, respectively. In vitro release studies showed that its release rate depends on different swelling of the network as a function of the environmental pH and DMAEMA content. SEM micrographs showed homogenous pore structure of the hydrogel with open pores at pH 1.4. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40737.     

Safe amine based zinc dithiocarbamates for the vulcanization of carbon black reinforced natural rubber

Binary combination of three safe amine based synthesized zinc dithiocarbamates (ZDC), namely zinc (N‐benzyl piperazino) dithiocarbamate (ZBPDC), zinc (N‐ethyl piperazino) dithiocarbamate (ZEPDC), and zinc (N‐phenyl piperazino) dithiocarbamate (ZPPDC) with mercapto benzothiazole disulfide (MBTS) as an effective accelerator system for the vulcanization of carbon black (N330, N550, and N774) filled natural rubber (NR) composites are studied. A comparison between the safe amine based zinc dithiocarbamates with the unsafe zinc dimethyl dithiocarbamate (ZDMC) in the light of mechanical and aging resistance behavior, introduces the non carcinogenic rubber additives in the filled vulcanization of rubber. Both accelerator and filler have the major importance for improving the mechanical as well as aging resistance behavior of the resultant vulcanizate. Variation in the filler and also filler to oil ratio are done to optimize the mechanical properties. SEM studies of different types of filler with different amounts show that N330 at 30 phr loading composites forms more homogeneity and less aggregated structures. Natural rubber systems with N330 carbon black show the best results with respect to tensile strength, but after the aging N774 carbon black filled system indicates better retention in the tensile strength. ZPPDC‐MBTS accelerated vulcanizate shows the better age resistance behavior than ZDMC‐MBTS accelerated vulcanizate. From both the points of age resistance and mechanical properties, ZBPDC‐MBTS accelerator system is the suitable substitute for ZDMC‐MBTS accelerated system in the filled vulcanization of natural rubber composites. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2014 , 131, 39988.     

In situ cross‐linked‐PDMS/BPPO membrane for the recovery of butanol by pervaporation

In this study, an in situ crosslinked polydimethylsiloxane/brominated polyphenylene oxide (c‐PDMS/BPPO) membrane on ceramic tube has been prepared for the recovery of butanol by pervaporation. A series of BPPO with different bromide‐substituted ratio were firstly synthesized through Wohl–Ziegler reaction. BPPO and PDMS were sequentially assembled and in situ crosslinked to form the final c‐PDMS/BPPO membrane. The results of solid‐state NMR and Differential Scanning Calorimeter demonstrated that the c‐PDMS/BPPO copolymer has a crosslinking structure and the SEM result proved the coverage of ceramic tube by copolymer layer. The effects of preparation conditions including dipping time and bromide‐substituted ratio of BPPO on the membrane performance were studied. The pervaporation experiments of butanol–water mixture indicated that the c‐PDMS/BPPO membrane exhibited an acceptable flux of 220 g·m^?2·h^?1 and high separation factor of 35 towards butanol, when the bromide‐substituted ratio was 34 wt % and the dipping time was 1.33 h. Moreover, the c‐PDMS/BPPO membrane performed excellent stability in an about 200 h continuous butanol recovery, as compared to the PDMS membrane. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2014 , 131, 40004.     

Crosslinked polystyrene beads modified with polar groups for the separation of aromatic/aliphatic hydrocarbons

Crosslinked polystyrene (CPS) beads modified with polar groups for the separation of aromatic/aliphatic hydrocarbons were successfully prepared. The synthesized beads were characterized by Fourier transform infrared spectroscopy, X‐ray photoelectron spectroscopy, and thermogravimetric analysis. The effects of the crosslinking agents and polar groups on the swelling and selectivity performances toward n‐heptane/toluene mixtures were studied. Impressively, the results indicated that the sulfone‐modified CPS beads obtained a high toluene selectivity. Further adsorption tests with a variety of aromatic/aliphatic hydrocarbons were carried out at 50°C with initial aromatic concentrations of 13 wt %, and the results showed that the beads had a preferential selectivity for aromatic hydrocarbons, in particular, a higher separation factor of 6.76 for benzene/cyclohexane mixtures. We expect that modified CPS beads will serve as an effective material for the selective separation of aromatic/aliphatic hydrocarbons in chemical and petrochemical fields. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40156.     

From topological gels to slide‐ring materials

A novel type of gel, called a topological gel, has been recently developed with a supramolecular architecture with topological characteristics. In the topological gel, polymer chains with bulky end groups are neither covalently crosslinked as in chemical gels nor attractively interacting as in physical gels but are topologically interlocked by figure‐eight shaped crosslinks. Hence, these crosslinks can pass along the polymer chains freely to equalize the tension of the threading polymer chains similarly to pulleys; this is called the pulley effect. This concept can be applied not only to gels but also to a wide variety of polymeric materials without solvents. Then, polymeric materials with movable crosslinks are referred to as slide‐ring materials (SRMs) in a wider sense. Here, we review the synthesis, structure, physical properties, and applications of topological gels and SRMs. In particular, slide‐ring elastomers show remarkable scratch‐proof properties for application to coating materials for automobiles, cell phones, mobile computers, golf clubs, and so on. © 2014 The Authors Journal of Applied Polymer Science Published by Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40509.     

Synthesis and characterization of a soybean oil‐based macromonomer

An acrylate‐functional soybean oil‐based macromonomer (SoyAA‐1) was synthesized in high yields utilizing sequential amidation and acrylation processes to serve as an internal plasticizer in emulsion polymers. The structure and structure–property relationships of this unique macromonomer were validated with FTIR, NMR, and LC‐MS. The viability of SoyAA‐1 as a comonomer in emulsion polymerization was established via copolymerization with methyl methacrylate (MMA) at varying copolymer weight compositions. The effect of increasing SoyAA‐1 levels and concomitantly higher allylic functionality was measured through film coalescence, minimum film forming temperature, and initial and progressively increasing glass transition temperature(s). The results indicate that synthetic modification of a renewable resource, soybean oil, can yield a valuable monomer that can be copolymerized in high yields via emulsion polymerization to produce practical and mechanically stable latexes for a variety of coatings applications. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40249.     

EVA/SBR发泡材料的研究

乙烯-醋酸乙烯酯共聚物(EVA)与丁苯橡胶(SBR)共混,用过氧化二异丙苯(DCP)引发交联,偶氮二甲酰胺(AC)发泡,得到了交联闭孔式发泡材料。研究了DCP、AC用量以及发泡温度和发泡时间对其力学性能的影响。研究结果表明:DCP用量为0.6%、AC用量为6%、发泡温度为130℃、发泡时间为15min时,发泡材料具有优异的力学性能。     

聚氯乙烯增韧改性研究新进展

综述了聚氯乙烯增韧改性的2种改性方法即物理共混改性法和化学交联改性法的研究进展,并介绍了聚氯乙烯增韧改性的机制。     

非异氰酸酯聚氨酯-环氧树脂涂膜的制备及性能研究

通过甲氧基聚丙二醇环碳酸酯与二乙烯三胺反应制备线型非异氰酸酯聚氨酯预聚体,再与环氧树脂作用形成互穿聚合物网络的杂化非异氰酸酯聚氨酯-环氧树脂涂膜。采用FTIR对产物的结构进行了表征,测定了涂膜的性能,并对涂膜断面进行了扫描电镜分析。该涂膜硬度(铅笔)≥H;耐冲击性为4.9J;对水、汽油、盐雾分别在96、48、500h不起泡、不变色、不脱落,对金属底材有优异的附着力。     

多重交联紫外光固化水性聚氨酯涂料

通过环氧树脂改性以及多元醇内交联、六甲撑二异氰酸酯(HDI三聚体)交联改性、固化剂交联和紫外光交联等四重交联,并加入季戊四醇三丙烯酸酯(PETA)作为接枝化合物,合成了紫外光固化水性聚氨酯丙烯酸酯分散体(WPUD)。研究了环氧树脂改性以及PETA含量对漆膜性能的影响。结果表明,经过环氧改性,采用2.5%的HDI三聚体和13.6%的PETA合成的水性聚氨酯丙烯酸酯分散体,其漆膜吸水率为6.3%,耐丙酮擦洗360次,摆杆硬度0.79。所得漆膜达到或超过了溶剂型紫外光固化涂料的要求。