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1.
Kazunori Yamada Toshihiro Aoki Naoya Ikeda Mitsuo Hirata Yoji Hata Katsuya Higashida Yukihiro Nakamura 《应用聚合物科学杂志》2008,107(4):2723-2731
An investigation was undertaken on the application of dilute chitosan solutions gelled by melB tyrosinase‐catalyzed reaction with 3,4‐dihydroxyphenethylamine (dopamine). The tyrosinase‐catalyzed reaction with dopamine conferred water‐resistant adhesive properties to the semi‐dilute chitosan solutions. The viscosity of the chitosan solutions highly increased by the tyrosinase‐catalyzed quinone conversion and the subsequent nonenzymatic reactions of o‐quinones with amino groups of the chitosan chains. The viscosity of chitosan solutions highly increased in shorter reaction times by addition of melB tyrosinase. Therefore, in this study, the gelation of a chitosan solution was carried out without poly(ethylene glycol) (PEG), which was added for the gelation of chitosan solutions using mushroom tyrosinase. The highly viscous, gel‐like modified chitosan materials were allowed to spread onto the surfaces of the glass slides, which were tightly lapped together and were held under water. Tensile shear adhesive strength of over 400 kPa was observed for the modified chitosan samples. An increase in either amino group concentration of the chitosan solutions or molecular mass of the chitosan samples used effectively led to an increase in adhesive strength of the glass slides. Adhesive strength obtained by chitosan materials gelled enzymatically was higher than that obtained by a chitosan gel prepared with glutaraldehyde as a chemical crosslinking agent. In addition, the use of melB tyrosinase led to a sharp increase in adhesive strength in shorter reaction times without other additives such as PEG. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 相似文献
2.
Katsuhiko Noto Saeko Matsumoto Yasuhiro Takahashi Mitsuo Hirata Kazunori Yamada 《应用聚合物科学杂志》2009,113(6):3963-3971
An investigation was undertaken on application of dilute chitosan solutions modified by tyrosinase‐catalyzed reaction with 3,4‐dihydroxyphenetylamine (dopamine) to adhesion of the low‐density polyethylene (LDPE) plates surface‐grafted with hydrophilic monomers. Tensile shear adhesive strength effectively increased with an increase in the grafted amount for methacrylic acid‐grafted and acrylic acid‐grafted LDPE (LDPE‐g‐PMAA and LDPE‐g‐PAA) plates. In particular, substrate breaking was observed at higher grafted amounts for LDPE‐g‐PAA plates. The increase in the amino group concentration of the chitosan solutions and molecular mass of the chitosan samples led to the increase in adhesive strength. Adhesive strength of the PE‐g‐PMAA plates prepared at lower monomer concentrations sharply increased at lower grafted amounts, which indicates that the formation of shorter grafted PMAA chains is an effective procedure to increase adhesive strength at lower grafted amounts. Infrared measurements showed that the reaction of quinone derivatives enzymatically generated from dopamine with carboxyl groups was an important factor to increase adhesive strength in addition to the formation of the grafted layers with a high water absorptivity. The above‐mentioned results suggested that enzymatically modified dilute chitosan solutions can be applied to an adhesive to bond polymer substrates. The emphasis is on the fact that water is used as a solvent for preparation of chitosan solutions and photografting without any organic solvents. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 相似文献
3.
An investigation was carried out on the application of dilute chitosan solutions modified by a tyrosinase‐catalyzed reaction with 3,4‐dihydroxyphenetylamine (dopamine) to the adhesion of low‐density polyethylene (LDPE) and high‐density polyethylene (HDPE) plates photografted with carboxyl‐group‐containing hydrophilic monomers, such as methacrylic acid (MAA) and acrylic acid (AA). In the case where photografting was carried out at lower monomer concentrations or at lower temperatures, the adhesive strength sharply increased with lower grafted amounts. A sharp increase in the adhesive strength was found to be due to the formation of shorter grafted polymer chains at lower monomer concentrations and/or the restriction of the location of grafting to the outer surface region at lower temperatures. In addition, the adhesive strength also sharply increased at even lower grafted amounts for photografting onto the HDPE plates and/or that of AA because the location of grafting was restricted to the outer surface region. For the AA‐grafted LDPE and HDPE plates, substrate breaking was observed. This was attributed to the coverage of the substrate surfaces with grafted poly(acrylic acid) chains at lower grafted amounts and a high water absorptivity of the grafted layer. X‐ray photoelectron spectroscopy (XPS) analysis of the grafted LDPE plates incubated in a dopamine solution containing tyrosinase suggested that the increase in the adhesive strength was caused by the penetration of enzymatically modified chitosan solutions in the grafted layers and the subsequent reaction of quinone derivatives enzymatically generated with grafted polymer chains. In addition, the surface analysis of the failed surfaces by XPS showed that as the adhesive strength increased, the location of failure was shifted from the interface between the layers mixed with enzymatically modified chitosan materials and grafted polymer chains to the inside the grafted layer containing enzymatically modified chitosan materials. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 相似文献
4.
Viscoelastic properties of chitosan (CH), chitosan‐poly(ethylene glycol) 400 (CH‐PEG), and chitosan‐poly(ethylene glycol) 400 with glyoxal as crosslinking agent (CH‐PEG‐Gly) systems were studied to analyze the effect of chitosan concentration (from 0.83 to 1.67%). Dynamic moduli increase as chitosan concentration increases for all systems. For CH and CH‐PEG systems the loss modulus (G″) is greater than the storage modulus (G′) with predominance of the viscous over the elastic behavior. This corresponds to the characteristic behavior of solutions (nonstructured systems). The presence of PEG 400 induces a complementary reinforcement of the mechanical properties of the system. Except for the lowest chitosan concentration, when glyoxal was added to the CH‐PEG systems, a gelled matrix was obtained. In this case, G′ is greater than G″, and practically independent of frequency. This behavior is typical of three‐dimensional networks and indicates true gel formation, showing clear elastic behavior (tan δ < 1). In creep and recovery analysis, CH‐PEG‐Gly systems exhibited distinct regions that were mathematically modeled using Burger's model. This analysis shows that the CH‐PEG‐Gly matrices (from 1.25 to 1.67%) recover almost totally (100%). Therefore, these matrices could be useful as systems for the development of films for topical hydrophilic drug delivery, and the levels of the residual viscosity (η0) or the complex viscosity (η*) could be used to control drug release. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007 相似文献
5.
Tae K. Kim Byung K. Kim Yong S. Kim Yang L. Cho Sang Y. Lee Youn B. Cho Joe H. Kim Han M. Jeong 《应用聚合物科学杂志》2009,114(2):1169-1175
A reactive hot melt adhesive (RHMA) consisting of thermoplastic polyurethane (TPU) was modified with sodium montmorillonite (Na‐MMT) intercalated with poly(ethylene glycol) (PEG), and their effects on the adhesion, rheological, and mechanical properties of the RHMA were examined. The Na‐MMT intercalated with PEG (Na‐MMT/PEG) effectively enhanced the initial bond strength development of the RHMA, although the amounts of Na‐MMT/PEG in the RHMA were less than 0.2%. The increase of the complex viscosity and pseudo‐solid like behavior observed at low shear rate indicates that there are intimate interactions between the RHMA molecules and Na‐MMT/PEG. The improved modulus and tensile strength of the cured RHMA film in the presence of Na‐MMT/PEG demonstrates that Na‐MMT/PEG effectively reinforced the RHMA. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 相似文献
6.
Qiming Yan Zhongxiang Lin Xing Lin 《Journal of Adhesion Science and Technology》2018,32(20):2282-2297
A series of phthalate polyester polyols (PEs) were synthesized via a polycondensation reaction with phthalic anhydride (PA) and different glycols, such as neopentyl glycol (NPG), ethylene glycol (EG), diethylene glycol (DEG), 2-methy-1,3-propanediol (MPO), 1,4-butylene glycol (1,4-BDO) and trimethylolpropane (TMP). Reactive hot melt polyurethane adhesive (HMPUR) with high initial bonding strength was then prepared by poly(propylene glycol) 2000 (PPG-2000), Dynacoll 7360 with these resultant PEs. Effects of different glycols on the glass transition temperature (Tg) and viscosity of the PEs were investigated. Besides, influences of these resultant PEs on the water resistance, bonding strength, thermal stability and surface morphology of the HMPUR were further discussed. The experimental results showed that Tg and viscosity of the PEs decreased with the increase of the chain flexibility of diols. The initial bonding strength of the HMPUR increased with the increase of Tg of the PEs. The hydrogen bonds and cross-linking structure of the HMPUR will also lead to the increase of the bonding strength. In addition, the water resistance of HMPUR was improved by the cross-linking structure and lateral methyl groups of the PEs, while the thermal stability changed little. The surface morphology of the HMPUR showed that all samples have two phase structures and the HMPUR based on DEG and 1,4-BDO exhibited weak phase separation. 相似文献
7.
Ayumi Tamura Erika Satoh Ayumi Kashiwada Kiyomi Matsuda Kazunori Yamada 《应用聚合物科学杂志》2010,115(1):137-145
Mushroom tyrosinase was covalently immobilized on a poly(acrylic acid)‐type, weakly acidic cation‐exchange resin (Daiaion WK10, Mitsubishi Chemical Corp., Tokyo, Japan) with 1‐ethyl‐3‐(3‐dimethylaminopropyl)carbodiimide hydrochloride salt as a water‐soluble carbodiimide. Ion‐exchange resins immobilized with tyrosinase were packed in one column, and crosslinked chitosan beads prepared with epichlorohydrin were packed in another column. The enzymatic activity was modified by covalent immobilization, and the immobilized tyrosinase had a high activity in the temperature range of 30–45°C and in the pH range of 7–10. When solutions of various alkylphenols were circulated through the two columns packed with tyrosinase‐immobilized ion‐exchange resins and crosslinked chitosan beads at 45°C and pH 7 (the optimum conditions determined for p‐cresol), alkylphenols were effectively removed through quinone oxidation with immobilized tyrosinase and subsequent quinone adsorption on chitosan beads. The use of chemically crosslinked chitosan beads in place of commercially available chitosan beads was effective in removing alkylphenols from aqueous solutions in shorter treatment times. The removal efficiency increased with an increase in the amount of crosslinked chitosan beads packed in the column because the rate of quinone adsorption became higher than the rate of enzymatic quinone generation. The activity of tyrosinase was iteratively used by covalent immobilization on ion‐exchange resins. One of the most important findings obtained in this study is the fact that linear and branched alkylphenols suspected of weak endocrine‐disrupting effects were effectively removed from aqueous solutions. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 相似文献
8.
Electron beam‐curable urethane methacrylate oligomers were prepared which, when cured, produce pressure‐sensitive adhesives. The effect of replacing hydrophobic blocks with more hydrophilic polyols in the prepolymer, in order to increase the moisture vapor transmission rates (MVTRs), was investigated. Subsequent effects on the resulting adhesive properties were also monitored. The MVTRs of the adhesives were found to increase upon incorporation of poly(ethylene glycol) but with a detrimental effect on the adhesive properties. The nature of the change in properties was related to the distribution of ethylene oxide units in the prepolymer. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 2313–2318, 1999 相似文献
9.
聚酯型WPU(水性聚氨酯)具有较高的力学强度和粘接强度,但是其较高的结晶性会导致胶膜透明性较差。以聚丙二醇(PPG)、聚己二酸丁二醇酯二醇(PBA)、异佛尔酮二异氰酸酯(IPDI)、2,2′-二羟甲基丙酸(DMPA)和1,4-丁二醇(BDO)等为原料,制备PPG改性聚酯型WPU。研究结果表明:PPG改性聚酯型WPU的黏度适中,储存稳定性良好;随着PPG含量的不断增加,WPU胶膜的透明性因结晶受阻程度增大而变好,相应胶粘剂的T型剥离强度和拉伸强度下降,而断裂伸长率升高;当w(PPG)=10%~20%时,相应WPU胶粘剂的透明性、T型剥离强度(≥1.97 N/mm)、拉伸强度(≥14.7 MPa)和断裂伸长率(≥421%)俱佳。 相似文献
10.
Poly(ethylene glycol) (PEG) crosslinked chitosan films with various PEG to chitosan ratio and PEG molecular weight were successfully prepared via the epoxy‐amine reaction between chitosan and PEG‐epoxy. The thermal and mechanical properties and swelling behavior were studied for the PEG crosslinked chitosan films. The mechanical strength of chitosan films were greatly enforced by the introduction of PEG‐epoxy, achieving an elongation of about 80%. It was found that the crosslinked chitosan films form hydrogel in water, achieving a swelling ratio higher than 20 times of original weight. The swelling behavior of chitosan films relied greatly on the molecular weight of the crosslinker PEG‐epoxy and the weight percent of PEG‐epoxy. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008 相似文献
11.
Hideki Tatehata Akira Mochizuki Toru Kawashima Shuzo Yamashita Hiroyuki Yamamoto 《应用聚合物科学杂志》2000,76(6):929-937
The sequential polytripeptides and polydipeptides, (X‐Tyr‐Lys)n, (XGly, Ala, Pro, Ser, Leu, Ile, Phe), (Y‐Lys)n, (YGly, Tyr), and (Gly‐Tyr)n, which imitate a mussel adhesive protein, have been synthesized. The molecular weights of the polypeptides were estimated to be 7,200 ∼ 13,400 (19 ∼ 42 repeating units), and the polypeptides were found to have satisfactory amino acid sequences. The polypeptides were crosslinked by tyrosinase, and the optimal pH in the crosslinking reaction was 7.4 in the case of the polytripeptide, (Gly‐Tyr‐Lys)n. The optimal tyrosinase amount for the adhesive strength of (Gly‐Tyr‐Lys)n was 0.34 unit/mg (polypeptide) at pH 7.4. The shear adhesive strength of the polytripeptide increased with an increase in the polytripeptide concentration, and was not influenced by the third amino acid, X. The shear adhesive strengths of polytripeptides (X‐Tyr‐Lys)n were equal to one of the synthetic polydecapeptides, (Ala‐Lys‐Pro‐Ser‐Tyr‐Pro‐Pro‐Thr‐Tyr‐Lys)n and (Gly‐Pro‐Lys‐Thr‐Tyr‐Pro‐Pro‐Thr‐Tyr‐Lys)n which were the model polydecapeptides for blue mussel and Californian mussel, respectively. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 929–937, 2000 相似文献
12.
Nitrocellulose (NC), a rigid natural polymer, was modified by gradient interpenetrating polymer networks containing poly(ethylene glycol dimethacrylate) (PEGDMA) to obtain both high strength and large toughness across the thickness from surface to the core of samples. PEGDMA content decreased with distance from the surface to core of nitrocellulose with a gradient of poly(ethylene glycol dimethacrylate) (NC/grad. PEGDMA) determined by elemental chemical analysis. The distribution of the guest component across the NC/grad. PEGDMA semi‐IPNs sample thickness was reciprocal function. SEM micrographs of NC/grad. PEGDMA semi‐IPNs revealed that, when the content of guest component was about 23%, the gradient system showed almost single phase morphology. At the same time, the tensile test results showed that NC/grad. PEGDMA featured both higher tensile strength and larger toughness. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007 相似文献
13.
测定了聚乙二醇(PEG)在十二烷基硫酸钠(SDS)和琥珀酸双-2-乙己酯磺酸钠(AOT)水溶液中的粘度,讨论了SDS和AOT在水溶液中聚集形态的差异对PEG与SDS和AOT相互作用的不同影响,结果表明:PEG-SDS与PEG-AOT体系粘度均明显增加,而PEG-SDS与PEG-AOT体系粘度变化机制不同,根本原因是表面活性剂在高分子溶液中聚集行为不同,SDS分子在PEG链上聚集,形成类胶束,使高分子链带电,表现出聚电解质的粘度行为;PEG链吸附于AOT囊泡,不同PEG链对囊泡的吸附可能造成高分子链更加伸展,PEG特性粘数增大,使溶液粘度上升。 相似文献
14.
We synthesized a methoxy poly(ethylene glycol) grafted chitosan (ChitoPEG) copolymer to prepare a retinoic acid (RA) encapsulated polymeric micelle. The RA‐encapsulated polymeric micelle of the ChitoPEG copolymer had a particle size of 100–500 nm and a spherical shape when observed by transmission electron microscopy. In a 1H‐NMR study, the specific peaks of RA and chitosan as a drug‐carrying inner core disappeared in deuterium oxide, and only the specific peak of methoxy poly (ethylene glycol) (MPEG) was observed, whereas specific peaks of MPEG, RA, and chitosan appeared in dimethyl sulfoxide. This indicated that the RA/ChitoPEG ion complexes were composed of a polymeric micelle with a core–shell structure and that free drug did not exist in the polymeric micelle formulations. Other evidence of drug incorporation into the polymeric micelle was witnessed in a differential scanning calorimetry analysis. The melting peaks of RA and chitosan were 182 and 220°C, respectively. The melting peak of the polymeric micelle was 200°C, whereas the melting peaks of the physical mixtures were those of both RA and the ChitoPEG copolymer. The lyophilized polymeric micelle was successfully reconstituted into phosphate‐buffered saline without the aid of cryoprotectants. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007 相似文献
15.
The pullulans grafted with poly(ethylene glycol) with different degrees of substitution (DS: 0.02–0.2) are synthesized by reaction of pullulan and poly(ethylene glycol) terminated with carboxylic acid. The structure of the resulting modified pullulans is characterized with 1H‐NMR and FTIR spectra. The DS of the products increase with the amount of the poly(ethylene glycol) added. The appearances of the products change considerably and the solubility in organic solvent is enhanced visibly. It was found that pullulan derivative is biodegradable. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1217–1221, 2004 相似文献
16.
Mohammad Mizanur Rahman 《Journal of Adhesion Science and Technology》2013,27(23):2592-2602
Waterborne polyurethane (WBPU) adhesives were prepared using poly(tetramethylene oxide glycol), 4,4’-dicyclohexylmethane diisocyanate (H12MDI), hydrophilic agent dimethylol propionic acid and chain extender of 2,2,3,3-tetrafluoro-1,4-butanediol (TFBD), ethylene diamine (EDA), and 1,4-butanediol. All three chain extenders have been used as single and mixed (different ratio) content during synthesis, and the effect of chain extender and their content to the properties of tensile strength, Young’s modulus, water swelling (%), and adhesive strength was investigated. The adhesive strength value was higher using EDA as a single-chain extender; however, the potentiality of adhesive strength under water was improved using mixed-chain extenders of EDA and TFBD in WBPU adhesives. The maxima potentiality was observed with 6.31 mole% TFBD and 2.10 mole% EDA in WBPU adhesives. 相似文献
17.
Copolyesters were synthesized through the condensation of 0.0025 mol of 1,1′‐bis(3‐methyl‐4‐hydroxyphenyl)cyclohexane, 0.0025 mol of ethylene glycol/propylene glycol/1,4‐butanediol/1,6‐hexane diol, and 0.005 mol of terephthaloyl chloride with water/chloroform (4:1 v/v) as an interphase, 0.0125 mol of sodium hydroxide as an acid acceptor, and 50 mg of cetyl trimethyl ammonium bromide as an emulsifier. The reaction time and temperature were 2 h and 0°C, respectively. The yields of the copolyesters were 81–96%. The structures of the copolyesters were supported by Fourier transform infrared and 1H‐NMR spectral data and were characterized with the solution viscosity and density by a floatation method (1.1011–1.2697 g/cm3). Both the intrinsic viscosity and density of the copolyesters decreased with the nature and alkyl chain length of the diol. The copolyesters possessed fairly good hydrolytic stability against water and 10% solutions of acids, alkalis, and salts at room temperature. The copolyesters possessed moderate‐to‐good tensile strength (11–37.5 MPa), good‐to‐excellent electric strength (19–45.6 kV/mm), excellent volume resistivity (3.8 × 1015 to 2.56 × 1017 Ω cm), and high glass‐transition temperatures (148–195°C) and were thermally stable up to about 408–427°C in a nitrogen atmosphere; they followed single‐step degradation kinetics involving 38–58% weight losses and 34–59% residues. The copolyesters followed 2.6–2.9‐order degradation kinetics. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007 相似文献
18.
Graft copolymers of chitosan and vinyl acetate were synthesized by free radical technique using cerium (IV) as the initiator. Under controlled conditions, as much as 92% grafting with a grafting yield of 30–40% could be achieved. Chitosan‐g‐poly(vinyl alcohol) copolymers were derived by the alkaline hydrolysis of the chitosan‐g‐poly(vinyl acetate) precursor. Thermogravimetric, FTIR, and X‐ray diffraction analyses of chitosan and the copolymers confirmed the grafting reaction between chitosan and vinyl acetate and also the subsequent hydrolysis. Both the copolymers possessed very good film‐forming properties. Grafting resulted in a significant increase in mechanical strength of both the copolymers in the dry condition. Chitosan‐g‐poly(vinyl acetate) (CH‐PVAc) proved more hydrophobic than did pure chitosan, whereas chitosan‐g‐poly(vinyl alcohol) (CH‐PVOH) exhibited enhanced hydrophilicity as evident from their swelling characteristics and contact angle measurements. The enhanced swelling of CH‐PVOH was ascribed to the presence of the pendant poly(vinyl alcohol) group. At pH 1.98, the CH‐PVAc copolymer films showed greater stability than do pure chitosan films, which is highly beneficial for specific biomedical applications. Both the copolymers showed lower glass transition temperature than do pure chitosan. Grafting did not affect the overall thermal stability, and the differential thermogram substantiated the grafting. The investigations indicate that the synthetic–natural hybrid copolymers having desirable mechanical properties and tailored hydrophilic/hydrophobic characteristics are realizable. These polymers could be exploited for varied biomedical applications. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1852–1859, 2007 相似文献
19.
Due to their low melt viscosity, competitive adhesive properties, and the stimuli‐responsive nature of supramolecular interactions, various supramolecular polymers have recently been investigated as adhesives with on‐demand (de)bonding capability. The adhesive properties of a series of hydrogen‐bonded supramolecular polymer networks based on a telechelic poly(ethylene‐co‐butylene) (PEB) terminated with isophthalic acid (IPA) groups and a series of bifunctional pyridines (Py) are reported herein. These supramolecular polymers microphase segregate into an IPA‐Py rich hard phase and an amorphous low‐glass‐transition PEB phase, and their properties depend on the nature of the pyridine‐carrying monomer. Rheological measurements show that the polymers disassemble into low‐viscosity melts when heated above the melting or glass transition temperature of the hard phase. Lap joints bonded with the polymers display a shear strength of up to 1.3 MPa, and debonding is possible in less than 10 s upon heating or exposure to UV–light; to enable rapid light‐induced (de)bonding, a light–heat converter is introduced. Cyclic bonding/debonding experiments reveal that the shear strength remains unchanged over five cycles and demonstrate that the process is very robust. 相似文献
20.
废聚苯乙烯泡沫塑料再生胶粘剂 总被引:6,自引:0,他引:6
介绍了以甲苯2,4-二异氰酸酯(TDI)和环氧树脂作为改性剂对废弃聚苯乙烯泡沫塑料进行改性制备再生胶粘剂的方法。同时,就改性剂的选择、溶剂的选择、溶剂比的确定、改性剂的用量、两种改性剂的配比、改性反应时间的优选以及填料的加入量等诸多影响再生胶粘剂性能的因素进行了讨论,确定出了最佳的改性方案。所制得的这种再生胶粘剂质优价廉,固含量在40%左右,旋转粘度大于1 5Pa·s,常温拉伸剪切强度可达4 8MPa,游离甲醛、苯、甲苯、二甲苯等有害物质限量全部达到标准要求。可作为非结构胶粘剂用于粘结金属、玻璃、陶瓷、塑料、木材等。这是一条将废聚苯乙烯泡沫塑料变废为宝的较佳途径。 相似文献