排序方式: 共有20条查询结果,搜索用时 15 毫秒
1.
V. Najafi K. Kabiri F. Ziaee H. Omidian M. J. Zohuriaan-Mehr H. Bouhendi H. Farhadnejad 《Journal of Polymer Research》2012,19(6):9866
Alcohol absorbents based on poly(ethylene glycol methyl ether methacrylate) and vinyl phosphonic acid (VPA) were prepared
via solution polymerization using poly(ethylene glycol dimethacrylate) macrocrosslinker. Swelling capacity of these materials
was measured in water, ethanol and methanol. Alcohol absorbency was increased with increase of VPA content that can be attributed
to ability of VPA in formation of H-bonding and disassociation of phosphonic acid group to produce mobile ions. The alcogels
could absorb ethanol and methanol up to 15.1 and 17.8 g/g respectively. Thermo-gravimetric analysis showed that increase in
VPA concentration increased char yield and decreased the initial decomposition temperature (IDT) due to forming anhydride
crosslinks during heating. Based on rheological measurements, the storage modulus was increased with increase in PEGMEMA content.
The prepared alcogels were further characterized using FTIR, NMR and DMTA. 相似文献
2.
3.
Kourosh Kabiri Sara Hesarian Mohammad-Jalal Zohuriaan-Mehr Ahmad Jamshidi Hossein Bouhendi Mohammad-Reza Pourheravi Seyd-Ali Hashemi Hossein Omidian Soheila Fatollahi 《Journal of Polymer Research》2011,18(6):1863-1870
Residual monomer is an important factor, particularly in hygienic materials such as superabsorbent polymer (SAP) hydrogels.
Recently, we reported different approaches to minimizing residual monomer content in SAPs. In this paper, the effect of a
long-chain monomer, poly(ethylene glycol) methylether methacrylate (PEG.MEMA), on the residual monomer content of SAP networks
of partially neutralized acrylic acid–PEG.MEMA is investigated. The aim of using PEG.MEMA in SAP synthesis was to reduce the
glass transition temperature (T
g) of SAP. As the temperature that is conventionally used to dry SAP (70–110 °C) is lower than the T
g of ordinary SAPs, the polymer is in the glassy state during the heating stage. It was assumed that converting SAP from the
glassy state to the rubbery state during drying would facilitate the removal of acrylic acid monomer (AA) from the gel, thus
reducing the residual monomer content. The results showed that the use of PEG.MEMA led to a reduction in residual AA when
the drying temperature was 100 °C. The residual AA was decreased from 169 to 95 ppm when the drying time was increased from
3 to 15 hours at 100 °C. This positive effect of PEG.MEMA on the level of unwanted residual AA became insignificant at a higher
drying temperature (140 °C). The effects of PEG.MEMA content on the thermal and mechanical properties (in the dried state)
and the rheological properties (in the water-swollen state) of the SAP hydrogels were also investigated. The swelling capacity
and rate was studied in relation to the PEG.MEMA content. It was found that a high level of PEG.MEMA restricted both the absorption
capacity and the rate of water absorption. 相似文献
4.
Mohsen Zolghadr Alireza Shakeri Mohammad Jalal Zohuriaan-Mehr Ali Salimi 《应用聚合物科学杂志》2019,136(40):48015
Novel self-healing Diels–Alder (DA) polymer and the corresponding semi-interpenetrated polymer networks (semi-IPNs) were synthesized and characterized. Initially, a furan-functionalized resin (FFR) was synthesized through the ring-opening reaction of a conventional epoxy resin [diglycidyl ether bisphenol A (DGEBA)] with furfuryl alcohol as a bio-based compound. Subsequently, semi-IPNs with different compositions were obtained through the blending of DGEBA, FFR, 4,4′-diaminodiphenylmethane, and 1,1′-(methylenedi-1,4-phenylene) bismaleimide in the molten state by following a predetermined time–temperature program. Fourier transform infrared and nuclear magnetic resonance analyses confirmed the successful synthesis of the materials. Thermoreversibility via retro-DA (rDA) reaction was evidenced by differential scanning calorimetry (DSC) and sol–gel transition tests. Repeated DSC cycle was successfully performed thrice on the DA polyadduct which corroborated repeatability of the DA/rDA association/dissociation. Self-healing and mechanical properties were preliminarily evaluated by scanning electronic microscopy and flexural testing analyses, respectively. The self-healing efficiencies were around 80 and 95% for semi-IPN and DA polyadduct, respectively, based on flexural strength. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48015. 相似文献
5.
Kourosh Kabiri Speideh Lashani Mohammad Jalal Zohuriaan-Mehr Malihe Kheirabadi 《Journal of Polymer Research》2011,18(3):449-458
Alcohol-specific superabsorbing gels (super-alcogels) based on non-neutralized acrylic acid (AA, 60–94 mol%) and 2-acrylamido-2-methylpropane sulfonic acid (AMPS) were prepared
via solution polymerization in water. Polyethylene glycol dimethacrylate and potassium persulfate were used as crosslinker
and initiator, respectively. Characterization of samples was performed using FTIR, 1H-NMR and thermomechanical analyses. Glass transition temperature and modulus of dried samples were found to be directly changed
with their AA content. The gels exhibited enormous ability for absorbing and retaining a variety of mono- and poly-hydric
alcohols. For example, in lieu of one gram of a typical sample composing 25 mol% AMPS, its absorption capacity was measured
to be 53.0 g methanol, 42.1 g ethanol, 12.1 g n-propanol, 3.4 g iso-propanol, 41.2 g ethylene glycol, 20.7 g propylene glycol, 37.8 g 1,3-propanediol and 32.9 g glycerol. The absorbencies were
superior to those of a known commercial poly(AA) sample, Carbopol. The alcohol absorbency was improved with increase of AMPS
incorporated. It was recognized to be dependant on the alcohol characteristics such as H-bonding ability, OH/C ratio, electronic
features (e.g. dielectric constant), steric hindrance of the neighboring groups of the solvent OH group, as well as the solvent
viscosity. Normal phase transitions were observed in the gel swelling behavior in the alcohol-water binary mixtures. Rheological
measurements of the water-swollen gel showed that more AMPS content resulted in gels with inferior storage modulus. All the
empirical observations were discussed based on the related physicochemical principles. 相似文献
6.
Ipakchi Hossein Shegeft Atefeh Rezadoust Amir Masoud Zohuriaan-Mehr Mohammad Jalal Kabiri Kourosh Sajjadi Samahe 《Iranian Polymer Journal》2020,29(4):287-299
Iranian Polymer Journal - Toward sustainability of polymer-matrix composites, this study aimed to prepare and evaluate glass fiber reinforced (GFR) biocomposites of fully bio-based furan resin, and... 相似文献
7.
M. R. Yavari-Gohar K. Kabiri M. J. Zohuriaan-Mehr S. A. Hashemi 《Journal of Polymer Research》2010,17(2):151-159
N,N′-Methylenebisacrylamide (MBA) is a conventional crosslinker most often used to produce hydrogels. We have previously shown
that MBA-crosslinks were thermo-hydrolytically cleaved upon heating during oven-drying, particularly in hydrogels based on
2-acrylamido-2-methylpropane sulfonic acid (AMPS). The present paper deals with the effect of comonomer acrylamide (AM, ranged
0–100%) and an organomodified clay on swelling stability of MBA-crosslinked poly(AMPS–AM) superabsorbing composite hydrogels.
It was found that either AM or the organoclay had constructive effects on thermo-hydrolytic stability of the network through
delaying or stopping the undesirable swelling changes originated from the crosslink cleavage, de-crosslinking. The incorporated
organomodified clay, however, exhibited fewer stabilizing effect rather than AM, when AM content was higher than 15%. The
swelling of hydrogels was turned out to be stable during heating even at high temperature (200 °C) when they composed at least
15% AM. Based on rheometrical studies, swollen gel strength of heated composite hydrogel was typically shown to be significantly
higher than that of the clay-free counterpart. 相似文献
8.
Zahra Mohamadnia Mohammad J. Zohuriaan-Mehr Kourosh Kabiri Mohammad Razavi-Nouri 《Journal of Polymer Research》2008,15(3):173-180
A large number of cyanide functional groups were introduced onto the carbohydrate biopolymer tragacanth gum to yield hydrophobic
graft copolymer, tragacanth gum-g-polyacrylonitrile. Thus, graft copolymerization of monomer acrylonitrile (AN) was carried
out under nitrogen atmosphere using ceric ammonium nitrate (CAN) as an initiator. The highest percentage of grafting (543%)
and the lowest homopolymer content (10%) were achieved through a systematic optimization of the polymerization variables,
including reaction time, temperature, and concentration of CAN, AN and the gum. Evidence of grafting was examined by comparing
FTIR spectra. The optimally prepared tragacanth gum-g-polyacrylonitrile copolymer was also characterized thermally and morphologically.
It was hydrolyzed in alkaline medium to achieve an in-situ crosslinked hybrid network with ultra high water absorption capacity
(swelling in water, 30700%; swelling in saline, 6550%). The swelling characteristic of the semi-synthetic super-absorbent
hydrogel was preliminarily investigated. The chemical structure, thermal characteristics and morphology of the hydrogel hybrid
product were briefly studied. 相似文献
9.
N. Esmaeili M. J. Zohuriaan-Mehr S. Mohajeri K. Kabiri H. Bouhendi 《Holz als Roh- und Werkstoff》2017,75(1):71-80
Considering the importance of urea–formaldehyde (UF) resins in the wood industry, this work reports on a new bio-based modification of UF resins. The use of 5-hydroxymethyl furfural (HMF) is motivated by the current concerns about the effects of formaldehyde on human health. UF and urea–HMF–formaldehyde (UHF) resins were synthesized by an alkaline-acid method and characterized by FTIR, thermogravimetric analysis, and differential scanning calorimetry. The UHF, as a newly modified polymeric resin, was thermally characterized, and it was found that its thermo-stability and char yield was improved. In order to investigate the performance of the UHF, the preparation of particleboards with the UHF as adhesive, as well as its film formation ability have been studied. The UHF films formed on wood panels were uniform without any crack. Film formation ability of the UHF resin was improved due to the presence of more hydroxyl groups as well as furan rings of the HMF moieties resulting in more activated groups to be bonded by wood. Furthermore, formaldehyde release of the particleboards bonded by UHF was significantly lower than that of which bonded by the UF resin. Lab particleboards using the UHF resins showed higher modulus of rupture, modulus of elasticity, and internal bond compared to boards with UF resins, as well as lower water absorption and thickness swelling. Based on these results UHF resin can be considered as a possible candidate as adhesive for wood and wood based panels. 相似文献
10.
DSC studies on synthesis of superabsorbent hydrogels 总被引:2,自引:0,他引:2
Reaction scheme of acrylic-based superabsorbing polymers was monitored by a differential scanning calorimeter. Differential scanning calorimetry (DSC) was used to study the heat effects during the polymer synthesis in DSC pan as a micro-scale reactor. Two distinct observations, i.e. inhibition period (IP) and onset of gel formation were recorded during polymerization. The effect of reaction temperature and initiator (K2S2O8) concentration was assessed on these general observations. It was found that unrestricted access of the reaction mixture to oxygen and unrestricted loss of water could complicate the polymerization behavior of sodium acrylate in aqueous system. A conceptual kinetic approach was followed to describe the complex process. Finally, DSC observations were compared with their corresponding bench-scale figures. 相似文献