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1.
Preparation and characterization of novel transparent plasticized poly(butylene terephthalate)‐co‐poly(alkylene glycol terephthalate) gel 下载免费PDF全文
Hong Xia Yoshio Hashimoto Toshihiro Hirai 《Journal of Polymer Science.Polymer Physics》2015,53(12):829-832
Transparent plasticized gels with good mechanical, optical, and dielectric properties have important applications in various fields. We prepared a new gel using a poly(butylene terephthalate)‐co‐poly(alkylene glycol terephthalate) (PBT‐co‐PAGT) copolymer and a plasticizer, dibutyl adipate (DBA). This method improved the polymer crystallinity, and suppressed particle formation in cast‐films when the polymer was dissolved in 1,1,1,3,3,3‐hexafluoro‐2‐propanol, followed by solvent evaporation, and enabled uniform swelling of the polymer network by the plasticizer to form a transparent and flexible gel. The dielectric constants of the developed PBT‐co‐PAGT/DBA gels are much higher than those of PBT‐co‐PAGT films at low frequency. We believe that these PBT‐co‐PAGT/DBA gels could be used as photovoltaic, dielectric, and actuator materials. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015 , 53, 829–832 相似文献
2.
A gel is a kind of water-swellable but water-insoluble, crosslinked polymer. Some kinds of gels can respond to external temperature
changes. This specific property is useful in biomedical and other technological fields. In this paper the synthesis of a novel,
thermosensitive gel by the copolymerization of N-isopropylacrylamide or N,N- diethylacrylamide with 3-methacryloxypropyltrimethoxy silane (MPTMS) is reported. The formation of the gel is caused through
the interaction of MPTMS under acidic condition. This thermosensitive gel can deswell and reswell quickly in response to the
external temperature changes, this behavior probably being due to the heterogeneous structure of the gel produced. This fast-response
gel may be useful both in biomedical and biotechnological fields.
Received: 17 March 1999 Accepted on revised form: 9 June 1999 相似文献
3.
The swelling and shrinking kinetics of thermosensitive gels based on N-isopropylacrylamide (NiPAAm) and N-n-propylacrylamide (NnPAAm) were studied. Four gels cylindrical in shape were prepared by two different methods: γ-ray irradiation
to aqueous solutions of poly(NiPAAm) (PNiPAAm) or poly(NnPAAm) (PNnPAAm) and redox polymerization of NiPAAm or NnPAAm monomer
using N,N′-methylenebisacrylamide as a crosslinker. There were a few differences in the swelling kinetics among these gels. However,
a marked difference was observed in the shrinking processes, the rate of which was faster in the order of radiation-crosslinked
PNiPAAm gel > radiation-crosslinked PNnPAAm gel > chemically crosslinked PNnPAAm gel > chemically crosslinked PNiPAAm gel.
This difference was discussed in terms of the microscopic structure of the gels, which was studied by light scattering techniques.
It was found that the static inhomogeneities frozen in the chemically and radiation-crosslinked gels play a key role in their
shrinking kinetics. 相似文献
4.
水凝胶是指一种网络结构中含大量水,而不溶于水的高分子材料。近年来,发现聚乙烯醇(PVA)水溶液在低温冷冻一段时间,可形成强度较高的水凝胶弹性体,用这种水凝胶制得的固定化增殖细胞凝胶,在生物工程材料开发中取得了很好的效果。本文旨在研究低分子物质在PVA水凝胶中的扩散性能。 相似文献
5.
Md. Zulhash Uddin Masashi Watanabe Hirofusa Shirai Toshihiro Hirai 《Journal of Polymer Science.Polymer Physics》2003,41(18):2119-2127
Four different plasticizers were applied to make different poly(vinyl chloride) (PVC) gels, poly(vinyl chloride)‐bis(2‐ethylhexyl)phthalate (PVC‐DOP), poly(vinyl chloride)‐di‐n‐butylphthalate, poly(vinyl chloride)‐bis(2‐ethylhexyl)adipate, and poly(vinyl chloride)‐tris(2‐ethylhexyl)trimellitate. In our previous work, we reported that PVC‐DOP gel exhibits novel and reversible deformations of creeping and jointlike bending induced by direct current electric fields. In this article, we scrutinize the effects of plasticizers on electromechanical actuations, that is, reversible creeping and bending actuation with four of the different aforementioned gels. We measured the relative creeping distance, creeping area, creeping velocity, current observed, and bending angle as a function of applied electric fields for different PVC gels and found significant differences among them. To explain these variations, we compared the utility of plasticizers on the basis of the properties of different PVC gels, such as plasticizer‐retention ability, bending modulus, elongation at break, and the dielectric constant. The mentioned properties of the PVC gels played vital roles on their electromechanical actuations. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 2119–2127, 2003 相似文献
6.
A. Tuncel 《Colloid and polymer science》2000,278(12):1126-1138
Spherical and swellable gel beads were obtained by the suspension polymerization of poly(ethylene glycol) methacrylate macromonomer
(PEG-MA). The average size and size distribution properties, the equilibrium swelling behaviour and the protein adsorption
characteristics of PEG-MA-based gel beads were determined. In the suspension polymerization system, the organic phase including
monomer, cross-linker and diluent solution was dispersed in an aqueous medium by using poly(vinylpyrrolidone) as the stabilizer.
The diluent solution was prepared by mixing cyclohexanol and octanol at different volume ratios. The suspension polymerization
experiments were designed in two separate parts. In the first part, ethylene glycol dimethacrylate was selected as the cross-linker
and swellable PEG-MA-based gel beads were obtained by changing the cross-linker concentration, the monomer/diluent ratio and
the stirring rate. In the second part, a more hydrophobic structure, divinylbenzene (DVB) was tried as a cross-linker. In
this part, PEG-MA-DVB copolymer beads were obtained by changing the DVB/PEG-MA feed ratio. Then, the hydrophicility of the
resulting gel beads could be controlled by changing the feed ratio of hydrophilic macromonomer to hydrophobic cross-linker.
This property was also used to control the extent of nonspecific protein adsorption onto the surface of the gel beads. The
non specific albumin adsorption onto the gel beads decreased with increasing PEG-MA content. No significant nonspecific adsorption
at the isoelectric point of albumin was detected onto the gel beads produced with the higher PEG-MA/DVB feed ratios. For specific
albumin adsorption, a triazinyl dye (i.e., cibacron blue, CB F3G-A) was covalently attached onto the surface of the copolymer
beads via terminal hydroxyl groups of PEG-MA. The results of albumin adsorption experiments with the CB F3G-A carrying beads
indicated that an appreciable specific albumin adsorption capacity could be obtained with the gel beads produced with a PEG-MA/DVB
feed ratio of 1.5/4.0.
Received: 16 August 1999/Revised: 27 December 1999 相似文献
7.
Effects of magnetization on the complex modulus of kappa-carrageenan magnetic gels have been investigated. The magnetic gel was made of a natural polymer, kappa-carrageenan, and a ferrimagnetic particle, barium ferrite. The complex modulus was measured before and after magnetization of the gel by dynamic viscoelastic measurements with a compressional strain. The gels showed a giant reduction in the storage modulus of approximately 10(7) Pa and also in the loss modulus of approximately 10(6) Pa due to magnetization. The reduction increased with increasing volume fraction of ferrite, and it was nearly independent of the frequency. It was also found that the change in the modulus was nearly independent of the magnetization direction and irradiation time of the magnetic fields to the gel. The magnetic gels demonstrating the giant reduction in the dynamic modulus showed a large nonlinear viscoelastic response. It was observed that the magnetic gel was deformed slightly due to magnetization. The observed giant complex modulus reduction could be attributed to the nonlinear viscoelasticity and deformation caused by magnetization. Magnetism, nonlinear viscoelasticity, and effects of magnetization on the morphological and shape changes were discussed. 相似文献
8.
Satish Mishra Rosa M. Badani Prado Song Zhang Thomas E. Lacy Xiaodan Gu Santanu Kundu 《Journal of Polymer Science.Polymer Physics》2019,57(15):1014-1026
Mechanical properties including the failure behavior of physically assembled gels or physical gels are governed by their network structure. To investigate such behavior, we consider a physical gel system consisting of poly(styrene)‐poly(isoprene)‐poly(styrene)[PS‐PI‐PS] in mineral oil. In these gels, the endblock (PS) molecular weights are not significantly different, whereas, the midblock (PI) molecular weight has been varied such that we can access gels with and without midblock entanglement. Small angle X‐ray scattering data reveals that the gels are composed of collapsed PS aggregates connected by PI chains. The gelation temperature has been found to be a function of the endblock concentration. Tensile tests display stretch‐rate dependent modulus at high strain for the gels with midblock entanglement. Creep failure behavior has also been found to be influenced by the entanglement. Fracture experiments with predefined cracks show that the energy release rate scales linearly with the crack‐tip velocity for all gels considered here. In addition, increase of midblock chain length resulted in higher viscous dissipation leading to a higher energy release rate. The results provide an insight into how midblock entanglement can possibly affect the mechanical properties of physically assembled triblock copolymer gels in a midblock selective solvent. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019 , 57, 1014–1026 相似文献
9.
Dr. Carmen C. Piras Dr. Clare S. Mahon Prof. David K. Smith 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(38):8452-8457
This Full Paper reports the formation of silver (Ag) NPs within spatially resolved two-component hydrogel beads, which combine a low-molecular-weight gelator (LMWG) DBS-CONHNH2 and a polymer gelator (PG) calcium alginate. The AgNPs are formed through in situ reduction of AgI, with the resulting nanoparticle-loaded gels being characterised in detail. The antibacterial activity of the nanocomposite gel beads was tested against two drug-resistant bacterial strains, often associated with hospital-acquired infections: vancomycin-resistant Enterococcus faecium (VRE) and Pseudomonas aeruginosa (PA14), and the AgNP-loaded gels showed good antimicrobial properties against both types of bacteria. It is suggested that the gel bead format of these AgNP-loaded hybrid hydrogels makes them promising versatile materials for potential applications in orthopaedics or wound healing. 相似文献
10.
The properties of the aged gels of high molecular weight syndiotacticity-rich poly(vinyl alcohol)s (HMW S-PVAs) with different
syndiotactic diad (s-diad) contents were investigated. HMW S-PVA gels with s-diad content of 61.5% and 58.2% showed the rapid increases of the syneresis and the turbidity from the early stage of aging
time, which is ascribable to the phase separation, while that with s-diad content of 55.7% did not. From the morphological study, it was confirmed that the phase separation in HMW S-PVA gel
with s-diad content of 61.5% occurred without the liquid-liquid phase separation in sol state, whereas both the liquid-liquid phase
separation in sol state and the subsequent phase separation in gel state occurred in the case of HMW S-PVA gel with s-diad content of 58.2%. On the other hand, HMW S-PVA gel with s-diad content of 55.7% showed neither the liquid-liquid phase separation in sol state nor the phase separation in gel state
in the long period of time. It was also confirmed from wide angle X-ray diffractogram that the crystallization was accompanied
by the phase separation in gel state in the aging process of PVA gel. However, the crystallization was hindered by the fast
network formation at the initial stage of time. Later the syndiotacticity promoted the crystallization. The tensile modulus
of HMW S-PVA gel with higher syndiotacticity increased more significantly with time.
Received: 2 December 1999/Accepted: 12 July 2000 相似文献