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1.
A polymeric material commonly used as a superabsorbent in the sanitary industry is proposed for the first time for analytical purposes. Specifically, we have evaluated in this work the possibility of using this material in a programmed-temperature vaporizer (PTV) injector for the introduction of large volume samples. To that end, the viability of this superabsorbent polymer as a retaining material was first studied by testing the stability of its absorption capacity in the presence of various solvents and at various temperatures. Subsequently, its effectiveness in the isolation of menthol and its isomers from Mentha piperita essential oil as well as gamma-lactones from peach essential oil was assessed. For that purpose, optimization of different variables, namely PTV temperatures during sampling, purge times, and desorption temperatures, involved in the solvent elimination was performed. Additionally, the information obtained was compared with that acquired for the adsorbent material Tenax TA. The results shown in this work proved not only the viability of using this superabsorbent polymer in analytical procedures but also demonstrated its advantages over the adsorbent Tenax TA in attaining internal GC concentration of a sample by introducing large volumes via PTV. 相似文献
2.
A novel biopolymer-based superabsorbent hydrogel was synthesized through chemically crosslinking graft copolymerization of acrylic acid (AA) onto kappa-carrageenan (κC), in the presence of a crosslinking agent and a free radical initiator. A proposed mechanism for κC-g-polyacrylic acid was suggested and the affecting variables onto graft polymerization (i.e. the crosslinker, the monomer and the initiator concentration, the neutralization percent and reaction temperature) were systematically optimized to achieve a hydrogel with swelling capacity as high as possible. Maximum water absorbency of the optimized final product was found to be 789 g/g. The swelling capacity of the synthesized hydrogels was also measured in various salt solutions. The time-temperature profile of the polymerization reaction, in order to investigate the effect of molecular oxygen was conducted in terms of the absence and presence of the atmospheric oxygen. The overall activation energy (Ea) of the graft polymerization reaction was found to be 2.93 KJ/mol. 相似文献
3.
P. Cerruti G. Santagata G. Gomez d’AyalaV. Ambrogi C. CarfagnaM. Malinconico P. Persico 《Polymer Degradation and Stability》2011,96(5):839-846
A polyphenol-containing extract from winery bio-waste (EP) has been used as an additive for a starch-based polymer (Mater-Bi). EP was used to tailor Mater-Bi properties, thus avoiding the use of synthetic polymer additives. It was found that EP was able to efficiently modulate the processing, mechanical, thermal and biodegradation properties. The observed decrease in melt viscosity showed that EP could improve productivity in polymer processing. Owing to the plasticizing activity of the additive, larger values of elongation at break were found. Moreover, the Mater-Bi crosslinking, which occurs upon thermal aging, was delayed in the presence of EP. Finally, the bio-disintegration rate of doped Mater-Bi decreased, thus suggesting that EP acted as an antimicrobial agent by interfering with the bio-digestion of the polymer films. 相似文献
4.
El-Refaie Kenawy Mohamed M. Azaam Esraa M. El-nshar 《Arabian Journal of Chemistry》2019,12(6):847-856
Sodium alginate-g-poly(acrylic acid-co-2-hydroxyethyl methacrylate)/montmorillonite superabsorbent composites (SACs) were prepared by graft copolymerization of acrylic acid (AA) and 2-hydroxyethyl methacrylate (HEMA) onto sodium alginate (Na-Alg) in the presence of montmorillonite (MMT) using N,N′-methylenebisacrylamide (MBA) as a crosslinker and potassium persulfate (KPS) as an initiator in aqueous solution. The composite structures were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Thermal Gravimetric Analysis (TGA) and Scanning Electron Microscope (SEM). The effect of % initiator, crosslinker amount and clay ratio on the swelling capacity was investigated. The results indicated that the highest swelling capacity of the composites in distilled water was 752 g/g by using 1.25% KPS and 0.06% MBA, 75% AA, 6.25% HEMA and 12.5% Na-Alg. Different samples were loaded with urea to evaluate their release potentials, and the release was studied by measuring the conductivity. The amount of urea release increased with increasing MMT amount. 相似文献
5.
Wu Gongsheng 《高等学校化学研究》1990,(2)
Grafting copolymerizations of methyl acrylate(MA) and ethyl acrylate(EA) onto corn starch, respectively, initiated by potassium persulfate-sodium thiosulphate (KPS-STS) redox system, were studied. The structures of poly(MA)-g-starch and poly(EA)-g-starch were characterized by IR, SEM and X-ray diffraction. Experimental results show that KPS-STS is an efficient initiation system for grafting of MA and EA onto corn starch. The maximum percent grafting was obtained at [KPS] of 6.0× 10~3 mol/L, [STS] of 1.8× 10 5 mol/L, [M] of 6. 0× 101 mol/L, S:L=4:100 at 40℃ for 6 h. The reactivity order is MA>EA. 相似文献
6.
Somayyeh Mohammadian-Gezaz Ismaeil Ghasemi Abdolrasool Oromiehie 《Polymer Testing》2009,28(5):534-542
The effect of styrene maleic anhydride (SMA) on the anionic polymerization of ?-caprolactam was investigated. Poly-caprolactam (PA6) was prepared at three levels of hexamethylene diisocyanate (HDI) as the microactivator and three levels of SMA in an internal mixer at 200 °C. Then, the polymerization characteristics obtained from the mixing torque curves were compared. With increasing HDI content, reaction time decreased and the reaction rate increased. Final torque, which is attributed to the molecular weight of the synthesized polymer, showed a peak in the average level of HDI. In the presence of SMA, final torque had the same trend, but reaction time increased and reaction rate decreased. Monomer conversion increased by raising both the HDI and SMA contents. In solvent separation by formic acid, samples were found to behave differently. Anionic polymerized polyamides with no SMA formed a uniform and transparent solution, while SMA-containing samples turned into a canescent solution having a colloidal suspension part. The remaining small amount of SMA after solvent separation proved the attribution of SMA in the reaction.FTIR spectra of samples indicated that SMA acts as a macroactivator in the anionic polymerization of ?-caprolactam. Also, samples containing SMA showed only one glass transition temperature which was higher than that of samples without SMA, suggesting the existence of a copolymer of SMA and PA6, which raises the Tg. 相似文献
7.
Kubo T Hosoya K Nomachi M Tanaka N Kaya K 《Analytical and bioanalytical chemistry》2005,382(7):1698-1701
A molecularly imprinted polymer was prepared using a water-soluble crosslinking agent. An ionic complex was utilized as the assembly for the template molecule and the functional monomer, and water as porogenic solvent during preparation of the imprinted polymer. The results of chromatographic evaluations for the prepared polymer suggested that the polymer had much lower hydrophobicity compared with usual octadecyl group bonded silica or the usual molecular imprinted polymer prepared from ethyleneglycol dimethacrylate, and the selective recognition ability for template molecule in the completely aqueous condition. 相似文献
8.
By adopting “grafting from” manner, polystyrene was grafted onto the surface of silica gel particles with an average size
of 125 μm in a solution polymerization system, and grafted particle PSt/SiO2 was prepared. Using 1,4-bis (chloromethoxy) butane (BCMB, it is nontoxic.) as chloromethylation reagent, chloromethylation
reaction for the grafted particle PSt/SiO2 was performed in the presence of Lewis acid catalyst SnCl4. At the same time, cross-linked styrene-divinylbenzene copolymer (CPS) microsphere also was chloromethylated with the same
reagent as PSt/SiO2, so that two kinds of chloromethylated polystyrene particles were obtained, and they are chloromethylated grafted particle
(CMPS/SiO2) and chloromethylated cross-linked polystyrene (CMCPS) microsphere, respectively. The chemical structures and compositions
of the two particles were characterized using Fourier transform infrared and Volhard method. The effects of various factors
on the chloromethylation reactions were mainly investigated. The experimental results show that the process to prepare the
two kinds of chloromethylated polystyrene particles not only has the character of environment friendness and low cost but
also is convenient to control via adjusting various reaction conditions. The main reaction conditions affecting the chloromethylation
reactions are reaction time, the added amount of BCMB, and the used amount of solvent and catalyst. They influence the reaction
in two respects: (1) the chloromethylation degrees of polystyrene are different under different conditions; (2) Friedel–Crafts
cross-linking reaction between polystyrene macromolecules is accelerated or inhibited under different conditions (for CPS
microsphere, this cross-linking reaction also is called the additional cross-linking). Under suitable conditions, the two
kinds of chloromethylated polystyrene particles with a high chlorine content (about 17%, this chlorine content was calculated
based on polystyrene weight) can be gained using SnCl4 as catalyst and CH2Cl2 as solvent at room temperature for 10 h and basically without cross-linking or additional cross-linking. 相似文献
9.
Wen-Tien Tsai Kuo-Jong Hsien Hsin-Chieh Hsu 《Journal of Sol-Gel Science and Technology》2009,49(3):261-267
This paper describes the preparation of novel zeolite particles by the hydrothermal method in a stirred reactor. The variations
between certain properties of the resulting zeolites, such as morphology by the scanning electron microscopy (SEM), pore properties
(i.e., surface areas, pore volume, and porosity) by the surface area & porosity analyzer, crystallinity by the X-ray diffraction
(XRD) and Si/Al ratio by the inductively coupled plasma-atomic absorption spectrometer (ICP-AES), and the process parameters,
such as aging time, agitation speed, temperature and pressure, were studied at a specific gel composition. The optimal value
of the Brunauer–Emmett–Teller (BET) surface area was found to be over 400 m2/g in the resulting microporous zeolite, indicating that the size was centered on about 0.5 nm. The XRD image was indicative
of the probable formation of zeolite-P2 in the hydrothermal synthesis. 相似文献
10.
Yoo Jin Kim Seok Ju Hong Woo Seung Shin Yong Rok Kwon Seung Ho Lim Hae Chan Kim Jung Soo Kim Jin Woong Kim Dong Hyun Kim 《先进技术聚合物》2020,31(2):273-283
A superabsorbent polymer (SAP) is a special polymer material that can absorb up to 500 times its own weight of pure water, but has a problem that it does not biodegrade itself and cause environmental pollution. Therefore, we aim to prepare a biodegradable SAP by using biomass‐based IA. The SAP must be able to retain absorbed water and absorb water under a given pressure. We have carried out studies to improve the surface hardness of the SAP to enhance absorption of water under a given pressure by surface‐crosslinking. Four types of surface‐crosslinkers, ethylene glycol diglycidyl ether (EGDGE), ethylene carbonate (EC), 1,4‐butanediol (BD), or glycerol, were used. We confirmed the water absorption capacity of the SAP by measuring its centrifuge retention capacity (CRC) and absorbency under load (AUL). The structural characteristics of the SAP were confirmed by attenuated total reflection (ATR) and X‐ray photoelectron spectroscopy (XPS), and the surface characteristics were confirmed by scanning electron microscopy (SEM). 相似文献
11.
UV-induced graft polymerization of acrylamide on cellulose by using immobilized benzophenone as a photo-initiator 总被引:1,自引:0,他引:1
Kyung Hwa Hong 《European Polymer Journal》2009,45(8):2443-1959
Photo-active moiety, benzophenone, was incorporated onto cotton fabrics by using butyl tetracarboxylic acids (BTCA). Then, grafting of polyacrylamide on the cotton fabrics was performed by exposing the fabrics to longer UV wavelength irradiation. The chemical structure and thermal properties of the polyacrylamide grafted cotton fabrics were investigated by SEM, FTIR, XRD, and TGA, and the results verified the successful grafting of polyacrylamide on cotton fabrics. Also, it was observed that active chlorine contents were created on the polyacrylamide grafted cotton fabrics through simple chlorination process, and the chlorine treated cotton fabrics showed excellent antibacterial abilities like the powerful cyclic amide halamines. 相似文献
12.
Three types of the novel polymer ligands in which 6,8,15,17-tetramethyl-dibenzo-5,9,14,18-tetraaza-cyclotetradecene (L) is present as an integral part of the polymer backbone have been prepared. These polymer ligands are oligomers whose polymerization degree may be about five. Their complexing abilities and extractabilities for copper(II) and nickel(II) have been investigated. Among the polymer ligands, Poly-L3, which contains triethyleneglycol bis(p-phenylene) group as a linkage group, was found to be an excellent extractant for copper(II). 相似文献
13.
14.
Peter J. Dowding James W. Goodwin Brian Vincent 《Colloids and surfaces. A, Physicochemical and engineering aspects》2001,180(3):301-309
The work described focuses on a two-stage process for the production of large porous suspension polymer beads of defined particle size and narrow size distribution. Emulsification has been performed using purpose built cross-flow membrane equipment, which allows controlled production of large emulsion droplets with a much narrower size distribution. The work described compares the production of large emulsion droplets of monomer prepared both by agitation and using a cross-flow membrane. The effects of variations in the pore size of the membrane and flow-rates on the size of the emulsion droplets produced are also investigated. The second stage of the process is polymerisation of performed monomer emulsion droplets using a continuous tubular reactor. Samples polymerised using such a method show a narrower size distribution than similar systems polymerised as a batch. 相似文献
15.
采用反应条件温和的原子转移自由基聚合法(ATRP),以N-异丙基丙烯酰胺(NIPAAm)和丙烯酰胺(AAm)为功能单体,以N-(3-二甲氨基丙基)甲基丙烯酰胺(DMAPMA)为辅助功能单体,制备了以牛血清白蛋白(BSA)和溶菌酶(Lyz)为双模板蛋白质的表面印迹聚合物(Bi-MIP)。对印迹过程中辅助功能单体的量进行了考察,结果表明,在单一蛋白质溶液和混合蛋白质溶液中,当DMAPMA为20 μL时,制备的Bi-MIP对模板蛋白质BSA和Lyz有较好的吸附容量与选择性。通过静态吸附实验考察了Bi-MIP的吸附性能,并结合Langmuir吸附模型得到聚合物对模板蛋白质BSA和Lyz的最大吸附容量分别为10.2 mg/g和19.2 mg/g。且该印迹聚合物在实际样品中对模板蛋白质也表现出较强的吸附能力和较高的选择性。该方法将为复杂生物样品中同时对双/多种目标蛋白质的识别提供一种新的途径。 相似文献
16.
17.
Tomoyuki Ohta Shinji Takeoka Eishun Tsuchida Han Yu Feng Zheng Sheng Fu Yun Pu Wang 《先进技术聚合物》1992,3(8):433-436
Ion-conductive polymer which shows an ionic conductivity (σi) of 1.4 × 10?4S/cm at 25°C when mixed with LiClO4 (molar ratio in Li/OE = 0.05) was used as a separator of electrodes in a lithium secondary battery. The effect of high ionic conductivity on the performance of the battery was studied. The polymer structure was and the cathode was comprised of poly(1,3,4-thiadiazole disulfide), graphite powder and the polymer electrolyte. The cell [(?)Li/polymer electrolyte/graphite–poly(disulfide) (+)] had an open circuit voltage (Voc) of 3.25 V, a plateau voltage of 2.75 V, a discharge density (id) of 0.05 mA/cm2 with the cathode utilization of 63%, and achieved over several tens of cycles at 25°C. 相似文献
18.
Lijun Chen Fengqin Wu 《Colloids and surfaces. A, Physicochemical and engineering aspects》2011,392(1):300-304
A series of acrylic polymer colloids were prepared via semi-continuous seeded emulsion polymerization of BA and MMA in water phase when OP-10 and AIBI is used to be emulsifier and initiator, respectively. FTIR spectrum identifies the formation of copolymers of P (MMA-co-BA). DSC confirms that the colloid is a kind of random copolymer and the consistency among the chain segment is fairly good. The emulsion polymerization conditions of preparing acrylic polymer colloid are optimized. Results show that the conversion rate is high and the coagulum is low and the particle size of the acrylic polymer colloids is small when the amount of AIBI is 0.75 g. The polymerization temperature is 70 °C, which is lower than the one that the emulsion polymerization is initiated with the persulfate. 相似文献
19.
Preparation of CTA-based polymer inclusion membrane using calix[4]arene derivative as a carrier for Cr(VI) transport 总被引:1,自引:0,他引:1
Ahmet Kaya Canan Onac Ahmet Surucu Emin Karapinar Hamza K. Alpoguz Begum Tabakci 《Journal of inclusion phenomena and macrocyclic chemistry》2014,79(1-2):103-111
In this work, the transport of Cr(VI) ions from an aqueous donor phase solution to an acceptor phase that contained an acetic acid/ammonium acetate buffer at pH 5 through a polymer inclusion membrane (PIM) containing p-tert-butylcalix[4]arene amine derivative as carrier was studied. The Cr(VI) passed through a PIM comprised of cellulose triacetate as a support and 2-NPOE as a plasticizer. The transport efficiency of Cr(VI) was studied under various experimental conditions, such as effect of carrier concentration, acceptor phase pH, type of plasticizer in the membrane, stirring rate and membrane thickness. The kinetic parameters were calculated as rate constant (k), permeability coefficient (P), and flux (J). The transport efficiency of Cr(VI) was observed to be 95.07 % after 10 h under optimized conditions. The prepared PIM was characterized with Fourier transform infrared spectroscopy and the atomic force microscopy techniques as well as with contact angle measurements. This is an effective method for the removal of Cr(VI) which is toxic for human body and environment from the waste water. 相似文献
20.
Alizadeh T 《Analytica chimica acta》2008,623(1):101-108
One of the main challenges in the molecularly imprinted polymers (MIP) field is the proper MIP design for water-soluble compounds because of appearance of serious drawbacks in polar solvents and insolubility of those compounds in non-polar solvents which are commonly used for MIP synthesis. In this work a novel and simple method for synthesis of molecularly imprinted polymers for a water-soluble compound was introduced. Pyridoxine was chosen as a target molecule and the ion-pair complex formed between pyridoxine ion (Py+) and dodecyl sulfate ion (DS−) was transferred into the chloroform via liquid-liquid extraction. Then polymerization was carried out in chloroform. The molecular mechanics and density functional theory were proposed to screen proper monomer. Binding energy, ΔE, of a template and a monomer as a measure of their interaction was considered. Ion-pair [Py+-DS−] was supposed as a template molecule and acrylic acid, methacrylic acid, allyamine, vinylpridine and 2-hydroxy ethyl methacrylate were as tested monomers. The MIP synthesized using acrylic acid showed the highest selectivity to pyridoxine as predicted from the ΔE calculation. The obtained MIP showed very high affinity against vitamin B6 in comparison to non-imprinted polymers (NIP). It was proved that the obtained MIP with introduced method was much better than that prepared in methanol as porogen. It was showed that the MIP prepared by this new method could be used as an adsorber for extraction and determination of pyridoxine in real and synthetic samples. 相似文献