共查询到20条相似文献，搜索用时 15 毫秒
1.
Ming Jin Haoran Xu Hong Hong Chunyan Bao Hongting Pu Decheng Wan Linyong Zhu 《应用聚合物科学杂志》2013,130(6):4099-4106
A new single‐/two‐photon sensitive monomer, (E)‐5‐(4‐ethoxystyryl)?2‐nitrobenzyl methacrylate (ENbMA), was synthesized and copolymerized with methyl methacrylate (MMA) to form a series of photosensitive copolymers P(ENbMA–MMA)s that were well characterized by 1H NMR and GPC. The photochemical and photophysical properties of both photosensitive monomer and copolymers upon visible light irradiation were studied by UV–Vis, FTIR, and HPLC spectra, which confirmed that 5‐(4‐ethoxystyryl)‐2‐nitrobenzyl ester can be photolyzed effectively with generation of the corresponding 5‐(4‐ethoxystyryl)‐2‐nitrosobenzaldehyde and carboxylic acid groups. The successful photocleavage endowed the optimized copolymers with excellent micropatterning property due to the effective generation of alkaline‐soluble carboxylic acid groups. Moreover, the high two‐photon absorption cross‐sections (over 20 GM at 800 nm) and the comparable photolysis upon two‐photon NIR light irradiation of the chromophores provided the copolymers with significant application in two‐photon microfabrication. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 4099–4106, 2013 相似文献
2.
Hideaki Kiminami Yasufumi Imae Eiji Takahashi Hong Wei Satoshi Oomura Yoshihiko Abe 《应用聚合物科学杂志》2016,133(23)
We investigated the effects of electron‐beam (EB) sterilization on syringe barrels manufactured from cyclo olefin polymer (COP). The chemical structure of the polymer was determined by interpreting the 13C NMR and DEPT‐135 spectra of the COP resin. The antioxidants in the resin were identified by analyzing the liquid chromatography‐photo diode array‐mass spectrometry (LC‐PDA‐MS) data for the methanol extract of the resin and the gas chromatography‐mass spectrometry (GC‐MS) data for the supercritical methanol degradation products of the extract. NMR and LC‐PDA‐MS analyses revealed that EB sterilization produces degradation products in the COP main chain and reduces the quantity of the antioxidants in the COP resin. ESR spectra of the EB‐sterilized syringe barrels indicated the presence and location of alkyl radicals, which were generated in the COP main chain by EB sterilization. ESR analyses also indicated that the quantity of alkyl radicals decreased over time. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43498. 相似文献
3.
Poly(methyl methacrylate), poly(methyl methacrylate-co-2-hydroxyethyl methacrylate), poly(methyl methacrylate-co-itaconic acid), poly(methyl methacrylate-co-maleic anhydride), poly(methacrylic acid-co-itaconic acid), poly(methacrylic acid-co-maleic anhydride), and poly(itaconic acid) were prepared by copolymerization of the appropriate amounts of the two monomers at 50°C for 24–40 h using benzoyl peroxide as initiator. Selected samples were γ-irradiated with a total dose ranging from 2 to 12 Mrad. The unexposed and degraded polymers were dissolved in tetrahydrofuran and their molecular weight distribution was determined by gel permeation chromatography. It was found that M?n decreased drastically with increasing irradiation dose. The presence of various functional groups in both unexposed and irradiated samples was confirmed by infrared spectroscopy. The copolymer thermodynamic compatibility with various solvents was evaluated on the basis of their fractional solubility parameters. The Gs values of these copolymers were determined using the gel permeation chromatography data. It was established that, among those studied, poly(methyl methacrylate-co-maleic anhydride) is the best material for positive resist application based on a Gs value of 8 9 scissions per 100eV. 相似文献
4.
Li Wen Liwen Wang Shuyi Fang Lei Bao Dongdong Hu Yuan Zong Ling Zhao Tao Liu 《应用聚合物科学杂志》2018,135(23)
Two newly‐designed hydrocarbon surfactants, that is, poly(vinyl acetate)‐block‐poly(1‐vinyl‐2‐pyrrolidone) (PVAc‐b‐PVP) and PVP‐b‐PVAc‐b‐PVP, were synthesized using reversible addition–fragmentation chain transfer polymerization and used to form CO2/water (C/W) emulsions with high internal phase volume and good stability against flocculation and coalescence up to 60 h. Their structures were precisely determined by nuclear magnetic resonance, gel permeation chromatography, thermal gravimetric analysis, and differential scanning calorimetry. Besides low temperature and high CO2 pressure, the surfactant structures were the key factors affecting the formation and stability of high internal phase C/W emulsions, including the polymerization degrees of CO2‐philic block (PVAc) and hydrophilic block (PVP), as well as the number of hydrophilic tail. The surface tension of the surfactant aqueous solution and the apparent viscosity of the C/W emulsions were also measured to characterize the surfactants efficiency and effectiveness. The surfactants with double hydrophilic tails showed stronger emulsifying ability than those with single hydrophilic tail. The great enhancement of the emulsions stability was due to decrease of the interface tension as well as increase of the steric hindrance in the water lamellae, preventing a frequent collision of CO2 droplets and their fast coalescence. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46351. 相似文献
5.
It is shown that the effective number of the polymeric macromolecule reactive centers depends on the macromolecular coil structure. The quantitative characteristic of the latter one can be received within the framework of the fractal analysis. The increase in macromolecular coil fractal dimension, meaning the rise of a degree of its compactness, results in lowering the effective number of the reactive (accessible to the molecules of oxidant) sites of a polymeric macromolecule. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1764–1767, 2003 相似文献
6.
Maria Cecilia Basso Samuele Giovando Antonio Pizzi Harald Pasch Nadine Pretorius Luc Delmotte Alain Celzard 《应用聚合物科学杂志》2014,131(13)
Open cell foams obtained by the simultaneous coreaction of condensed flavonoid tannins with an alkoxylated fatty amine and polymeric diphenylmethane isocyanate yielded highly flexible/elastic polyurethane foams. Copolymerized amine/isocyanate/tannin oligomers were identified by 13C NMR and MALDI‐TOF spectroscopy. In general, between 30% and 50% of natural tannins is added to the components used to obtain polymerisation of the polyurethane. The characteristic of these new, partially biosourced polyurethanes is that the tannin present slows down burning, some of them can be made flame self‐extinguishing and if burning they neither flow nor asperge flaming material around, contrary to what occurs with normal polyurethanes. This limits the possibility of transmitting fire to other materials in the same environment. Cyclic compression tests were carried out showing that after 50 cycles foam recovery was in excess of 80%. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40499. 相似文献
7.
Eduardo Lopez‐Gonzalez L. O. Salmazo A. Lopez‐Gil E. Laguna‐Gutierrez M. A. Rodriguez‐Perez 《应用聚合物科学杂志》2018,135(22)
Different crosslinked high‐density polyethylene based cellular polymers have been produced by a free foaming process using a chemical blowing agent. The polymer matrix was crosslinked by electron beam irradiation using different doses ranging from 25 to 175 kGy. The main aim of this work is to study the effect of the different irradiation doses on the density, cellular structure, and foaming mechanisms. Results show that irradiation doses as high as 175 kGy have to be used to obtain cellular materials with a low relative density (0.06), cell sizes of around 50 μm, and cell densities of 1.6 × 107 cells cm?3. The strain hardening of the polymer matrix increases with the irradiation dose leading to an increase of the polymer resistance to be stretched, which helps to avoid undesirable cellular degeneration processes. Irradiation doses lower than 175 kGy are not able to stabilize the cellular structure leading to foams with relative densities higher than 0.1 and degenerated cellular structures. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46276. 相似文献
8.
Ordered nanowells with diameters of ca. 40 nm and depth of 1–2 nm were prepared on a poly(methyl methacrylate) (PMMA) spherical domain, which was exposed on the polystyrene‐block‐poly(methyl methacrylate) (PS‐b‐PMMA) copolymer thin film. The PS‐b‐PMMA film formed spherical PMMA domains after the film was annealed above the order–disorder transition temperature. CO2 was dissolved into the PS‐b‐PMMA thin film at 8.6 MPa and at a temperature of 20 °C. The release of CO2‐pressure at the same temperature created the nanowell on the PMMA domain. The temperature and pressure to create nanowells in the PMMA domain affected the possibility of nanowell's formation.
9.
A thermally labile polymer, poly(propylene glycol), was modified to obtain PPG having an amino end group. PPG was incorporated into a partially aliphatic polyimide based on an alicyclic dianhydride, and this afforded triblock copolymers containing various amounts of PPG blocks. The thermal properties of the copolymers were investigated by thermogravimetric analysis and differential scanning calorimetry. The thermal decomposition of the PPG block in the copolymers was carried out at 240°C under various pressures to obtain porous polyimide films. The pores remained during the thermolysis under a reduced pressure of 710 mmHg, whereas they collapsed under (near) atmospheric pressure. The pore size increased as the amount of the PPG block in the copolymers increased. The dielectric constants of the porous polyimides varied from 2.60 to 2.42 with the original copolymer composition. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 532–538, 2006 相似文献
10.
Multi‐purpose polyacrylamide (PAM) and polyacrylamide‐co‐sodiumpolyacrylate (PAM‐co‐NaPA) impregnated polyurethane foams (PUF) loaded with iodine have been prepared by in situ free radical polymerization. The prepared hydrogel networks displayed higher capacity for absorbing biological fluids as compared to regular PUF sheets and cotton matrices used in hospitals for maintaining hygiene conditions in cases of blood spillage and leakages. PAM‐impregnated‐PUF showed 910, 605, and 172% absorption in water, saline, and blood, respectively, whereas PAM‐co‐NaPA‐impregnated‐PUF showed absorption of 1545, 1395, and 269% in water, saline, and blood, respectively in 24 h. Exposure to nuclear, biological, and chemical (NBC) environment has become a grave predicament in today's world necessitating prevention of radiological contaminations especially in medical facilities. PAM‐co‐NaPA‐impregnated‐PUF displayed 97% absorption of Tc99 from whole blood whereas PUF sheets were highly hydrophobic and showed only 1% absorption of Tc99 from whole blood. It was also demonstrated that modified foams have long‐term broad‐spectrum antimicrobial properties due to sustain release of ionic iodine. Thus, PAM‐co‐NaPA‐impregnated‐PUF sheets have strong potential to be used as matrices for carrying the injured patients, from field conditions to hospitals expose to NBC environment. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43625. 相似文献
11.
In this article, we report the alumina‐supported, microwave (MW)‐induced synthesis of Cassia marginata seed gum‐graft‐polyacrylamide (MWS‐GP). No initiator or catalyst was required in the synthesis, and the conditions for the grafting were optimized by variation of the acrylamide concentration, MW power, and exposure time. At an identical monomer concentration, a higher level of grafting was observed in the solid‐supported method than under aqueous conditions (the MW‐assisted or redox‐initiated thermal method). The used alumina support was easily separated from MWS‐GP and reused for another three cycles without any significant loss in its efficiency as a solid support. MWS‐GP synthesized under optimum conditions was characterized with Fourier transform infrared spectroscopy, 13C‐NMR, thermogravimetric analysis, and X‐ray diffraction, with C. marginata gum as a reference. The properties of MWS‐GP and its saponified derivative were studied to explore the applicability areas of the copolymer in hydrogel formation. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 相似文献
12.
A new type of mono‐sheet bipolar membrane was produced from a porous polyethylene (PE) substrate using simultaneous irradiation grafting polymerization of acrylic acid (AA) on one side and chloromethylstyrene (CMS) on the other side. PE film with absorbent filter paper absorbing AA on one side and paper absorbing CMS on the other side was irradiated in the cobalt‐60 gamma ray irradiation field, followed by quaternization with trimethylamine aqueous solution. AA and CMS were grafted on the substrate membrane simultaneously. The performance of the final membrane is significantly affected by the irradiation time. For short irradiation time, the prepared membrane behaves as a bipolar membrane; whereas for long irradiation time, the final membrane behaves as a charge mosaic membrane. Therefore, by controlling the conditions, a bipolar membrane with good current rectification can be prepared, across which the voltage drop is ～2.0 V at the current density 800 A/m2 in 1.0 M NaOH. This preparation method is simple and can be applied both in laboratory and in industry. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 572–576, 2003 相似文献
13.
Hao Chen Chaorong Peng Yongyi Yao Jingxia Wang Zhuping Chen Zhirong Yang Lijun Xia Siyang Liu 《应用聚合物科学杂志》2009,114(5):3152-3157
A copolymer, poly(L ‐lactide)‐g‐poly(N‐vinyl pyrrolidone) (PLLA‐g‐PVP) was prepared with poly(L ‐lactide) (PLLA) and N‐vinyl pyrrolidone in the presence of methanol as a solvent by γ‐ray irradiation. The structure of PLLA‐g‐PVP was characterized by 1H‐NMR and Fourier transform infrared spectroscopy. The PLLA‐g‐PVP graft ratio calculated by the percentage increase in weight increased with the increase of absorbed dose, and the percentage crystallinity of PLLA‐g‐PVP decreased with increasing graft ratio. The introduction of the poly(N‐vinyl pyrrolidone) chain into PLLA resulted in a decrease in the contact angle of PLLA‐g‐PVP with increasing graft ratio. In vitro degradation testing showed that PLLA‐g‐PVP had a higher degradation rate both in the weight‐loss test and molecular weight measurement because of a lower crystalline percentage and higher hydrophilicity compared to PLLA. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 相似文献
14.
Graft copolymers of cassava starch and methyl methacrylate (MMA) were synthesized by free‐radical polymerization with benzoyl peroxide (BPO) as an initiator in an aqueous medium at 80°C. The formation of graft copolymers was confirmed by analysis of the obtained products with Fourier transform infrared spectroscopy and scanning electron microscopy. The effects of the amount of cassava starch, the amount of MMA monomer, the amount of BPO, and the reaction time on the grafting characteristics were studied. The optimum condition for grafting were obtained when 5 g of cassava starch, 5 g of MMA, 0.1 g of BPO, and a reaction time of 3 h were used. These condition provided a graft copolymer with 25.00% add‐on, 81.40% monomer conversion, 54.30% homopoly(methyl methacrylate) formed, 45.70% grafting efficiency, 37.20% grafting ratio, and 95.54% yield. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4083–4089, 2006 相似文献
15.
We report the preparation of a closed‐cell polypropylene (PP) foam material by supercritical carbon dioxide foaming with the assistance of γ‐ray radiation crosslinking. Styrene–ethylene–butadiene–styrene (SEBS) copolymer was added to PP to enhance radiation crosslinking and nucleation. Radiation effects on the foaming of the PP/SEBS blend with different ratios were investigated. A significant improvement in the foaming of the crosslinked PP/SEBS blend was achieved as compared to pristine PP. The cell density of the crosslinked PP/SEBS foam greatly increased at a dose of 10 kGy and a high closed‐cell ratio was obtained. The tensile strength of the crosslinked PP/SEBS foams (10 kGy) was improved from 14 to 20.7 MPa compared to pristine PP foam (0 kGy). In addition, the crosslinked PP/SEBS blend exhibited a wider foaming temperature window (10 °C) as compared to the non‐crosslinked ones (4 °C). © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45809. 相似文献
16.
Jose Antonio Reglero Ruiz Cristina Saiz‐Arroyo Michel Dumon Miguel A Rodríguez‐Perez Leo Gonzalez 《Polymer International》2011,60(1):146-152
Microcellular foaming of a (methyl methacrylate)–(butyl acrylate)–(methyl methacrylate) triblock copolymer was carried out by means of supercritical CO2 in a single‐step process. The experiments were performed at 40 °C using a pressure of 300 bar (30 MPa) during 24 h. The depressurization times were modified from 2 to 30 min, leading to cell sizes from 10 to 100 µm, and relative densities from 0.11 to 0.17. It was found that the key parameter to control cell size and density was depressurization time: longer depressurization times generated larger cell sizes and lower densities. The thermal conductivity of these materials was measured using the transient plane source technique, and it was found that this decreased as the density was reduced. Various models for the prediction of thermal conductivity by conduction were tested. It was found that all the models underestimated the experimental results due to a significant contribution of radiation heat flow for these materials. Copyright © 2010 Society of Chemical Industry 相似文献
17.
A rigid polyisocyanurate–waterglass foam (PIWGRF) composite was prepared with polyaryl poly(methylene isocyanate) and waterglass (WG) as the main materials; water as a blowing agent, and no polyols. We speculated the formation mechanism of the PIWGRFs on the basis of the analysis of experiment data, scanning electron microscopy characterization, and transmission electron microscopy. The results show that three‐dimensional nanoflakes derived from the cured WG was observed; this was connected with polyisocyanurate by secondary bonding (Si? O? H?N). Thermogravimetric testing indicated that the thermal stability and residual mass (34%) of the PIWGRFs were significantly higher than those of rigid traditional polyurethane foams (T‐PUFs). When the core density of the PIWGRFs was 32.6 kg/m3, the strength was up to 162.9 KPa by excessive filling. The flame retardancy of the PIWGRFs, including the time to ignition, heat‐release rate, total smoke of release, and limiting oxygen index, was obviously better than that of the T‐PUFs. The structure of the residual char was more dense and orderly; this was also an effective barrier layer. The reason was attributed to the fact that the WG did not contain combustible elements. So, the PIWGRFs had excellent thermal stability, flame retardancy, and environmental friendliness. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46182. 相似文献
18.
Yintao Wang Feng Wang Quanxiao Dong Wenjing Yuan Peng Liu Yanfen Ding Shimin Zhang Mingshu Yang Guoqiang Zheng 《应用聚合物科学杂志》2018,135(39)
Encapsulation of expandable graphite (EG) particles by organic or inorganic shells has been proved to efficiently enhance the expandability of EG, and thus to improve the flame‐retardant efficiency of EG. In this study, magnesium hydroxide (MH) nanosheets were utilized to fabricate core–shell EG@MH flame‐retardant particles through a heterocoagulation method. It was observed that after the encapsulation by MH nanosheets, the edges of the char residue of the EG layer were sealed after combustion, which contributed to the enhancement of expandability. The expansion volume of EG@MH increased dramatically to 456 mL/g, in contrast to 338 mL/g for pure EG. By incorporating 11.5 wt % of flame‐retardant particles, polyurethane foam containing EG@MH (here PU‐EG@MH) displayed excellent flame retardancy. Compared with the physically mixed sample, PU‐EG+MH, the limiting oxygen index value for the PU‐EG@MH sample increased from 29.8% to 32.6%. Furthermore, the shell of MH nanosheets was beneficial for improving the interfacial adherence between EG and the rigid polyurethane foam (RPUF) matrix, due to the reaction between isocyanate functional groups and MH. The cell structure and storage modulus of PU‐EG@MH were improved. In other words, the shell of MH nanosheets successfully improved the flame‐retardant efficiency and enhanced the interface adhesion between EG and the matrix. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46749. 相似文献
19.
The thermal decomposition behavior of rigid polyurethane foams blown with water was studied by dynamic thermogravimetric analysis (TGA) in both nitrogen and air atmosphere at several heating rates ranging from room temperature to 800°C. The kinetic parameters, such as activation energy (E), degradation order (n), and pre‐exponential factor (A) were calculated by three single heating rate techniques of Friedman, Chang, and Coats–Redfern, respectively. Compared with the decomposition process in nitrogen, the decomposition of foams in air exhibits two distinct weight loss stages. The decomposition in nitrogen has the same mechanism as the first stage weight loss in air, but the second decomposition stage in air appears to be dominated by the thermo‐oxidative degradation. The heating rates have insignificant effect on the kinetic parameters except that the kinetic parameters at 5°C/min have higher values in nitrogen and lower values in air, indicating different degradation kinetics in nitrogen and air. The kinetic parameters of foam samples blown with different water level in formulation decline firstly and then increase when water level increases from 3.0 to 7.0 pph. According to the prediction for lifetime and half‐life time of foams, water‐blown rigid foams have excellent thermostability, when used as insulation materials below 100°C. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:4149–4156, 2006 相似文献
20.
辐照在高分子材料制备与改性研究中的新动向 总被引：1，自引：2，他引：1
扼要介绍了含氟聚合物辐射交联、聚烯烃辐照改性、辐照过程中自由基形成机理、通过辐照制备具有某些特殊结构和性能聚合物的方法、辐照效应与聚合结构和辐照条件关系等领域研究的最近进展。 相似文献