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1.
Polyurethane dispersions were prepared and urethane/acrylic composite latices were synthesized with polyurethane dispersions as the seed, and core‐shell emulsion polymerization. Fourier‐transform infrared spectroscopy coupled with attenuated total reflectance (FTIR‐ATR) analyses showed that the films obtained from the composite latices were rich in polyurethane component or segments at air‐facing and substrate‐facing surfaces, in comparison with their average composition. Moreover, the substrate‐facing surface contained even more polyurethane component or segments than the air‐facing surface. X‐ray photoelectron spectroscopy (XPS) detection also indicated that the polyurethane component or segments preferentially migrated to the surface layer of the films from the bulk, and that the films from blend latices displayed more polyurethane component or segments near the surface layer. Both FTIR‐ATR and XPS analyses suggested that some reorientation had happened in synthesizing the composite latices and/or after film formation. This structure and composition endow urethane/acrylic composite films with both surface properties (such as mar‐resistance, adhesion, wettability) from pure polyurethane, and film hardness from acrylic copolymers. © 2001 Society of Chemical Industry 相似文献
2.
A new synthesis pattern of adamantoyl esters of cellulose (AdTMSC) is described. The process was approached by two steps. The first one consists in the obtaining of trimethylsilylcellulose (TMSC), by reacting cellulose in N,N‐dimethylacetamide/lithium chloride (DMA/LiCl) solution with chlorotrimethylsilane and hexamethyldisilazane. The AdTMSC was synthesized by reacting trimethylsilylcellulose with 1‐adamantanecarbonyl chloride, at 130°C. The obtained compounds were characterized by elemental analysis, 1H and 13C NMR, FTIR spectroscopy, thermogravimetry method, and X‐ray diffraction. From 1H NMR spectroscopy and elemental analyses, the degree of substitution (DS) of the cellulose derivatives was established. The AdTMSC is soluble in common organic solvent like chloroform, THF, and DMSO. As revealed by 13C NMR spectroscopy, a faster reaction takes place at the O (6)H group from AGU compared with O (2)H or O(3)H groups. Furthermore, other important properties were established by X‐ray diffraction and thermogravimetry method. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 105–112, 2006 相似文献
3.
Theodor Stern 《应用聚合物科学杂志》2012,126(1):216-225
A series of di‐polyester diamides was synthesized via a nucleophilic ring opening polymerization process. FTIR investigations revealed the spectral characteristics evidencing the newly formed chemical bonds as well as the changes in the relative intensity of the characteristic peaks, due to the increasing side‐block lengths of the different members of the series. 1H‐NMR analysis of the described materials confirmed the chemical structures seen by FTIR analysis. The side segment length of the different di‐polyester diamides was calculated from the integration ratios in the NMR spectra. The molecular weight results exhibited relatively small deviations from the stoichiometrically calculated values. All the members of the triblock series, with side blocks of up to 120 lactoyl units, were essentially amorphous and glassy at room temperature. The presence of two separate glass transitions indicated a segmented and microphase separated morphology. It was deducted that the amorphous nature of the relatively long poly(lactic acid) side blocks occurs due to the dominance of the hydrogen‐bonded central segment. Synthesis of a di‐polyester diamide containing a reduced number of hydrogen‐bond‐forming groups in the central segment yielded a partial side‐block crystallization. The di‐polyester diamide with 120 lactoyl unit‐long side blocks was eventually able to crystallize in solid state, following thermal treatment during thermal analysis. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 相似文献
4.
In this article, milled wood lignin (MWL) was isolated and purified from retted kenaf fiber, the lignin obtained was characterized by elemental analysis, FTIR, 1H‐NMR, and 13C‐NMR spectroscopy. The C9 formula is calculated for kenaf fiber MWL as C9H9.32O3.69(OCH3)1.30. The spectra of FTIR, 1H‐NMR, and 13C‐NMR show the kenaf fiber lignin to be of the G/S type with high proportion of syringyl (S) unit. The numbers of phenolic and aliphatic hydroxyl groups in the kenaf fiber MWL are estimated to be 0.14 and 1.31, respectively, per C9 unit. The OHaliph is 90.3% in total numbers of hydroxyl groups of kenaf fiber MWL, and the OHph is 9.7%. It is evident that the β‐O‐4 structures are mainly linkage in the MWL of kenaf fiber, which contain more erythro stereochemistry type in β‐O‐4 units than thero stereochemistry type. In general, the characteristics of lignin of kenaf fiber are similar to that of hardwood. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 相似文献
5.
This work analyzes the influence of thermal degradation on the microstructure and the mechanical properties of low‐density polyethylene subjected to aging at 70°C in the dark for times up to 21 months. It is found that the polymer shows a gradual increase of its elastic modulus and a dramatic reduction of its ductility, due to secondary crystallization. Infrared spectroscopy (FTIR) reveals the autoaccelerated oxidation of the polymer after 5 months aging. It is observed that the unsaturated vinylidene groups initially present in the material are gradually overridden by vinyl groups and, eventually, by t‐vinylene groups. Nuclear magnetic resonance (13C NMR) shows that the initial butyl chain branches are progressively completed by shorter ramifications, namely ethyl branches. These results are discussed in term of macromolecular mechanisms: (i) oxidation, (ii) chain scission, and (iii) crosslinking. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 相似文献
6.
Muhammad Tahir Klaus Werner Stöckelhuber Nasir Mahmood Hartmut Komber Gert Heinrich 《大分子材料与工程》2015,300(2):242-250
7.
Abolfath Akbarzadeh Javad Mokhtari Shirin Kolkoohi Mohammad Amin Sarli 《应用聚合物科学杂志》2012,126(3):1097-1104
Insect repellency of fiber is a property which makes the fiber to be of interest in the field of military and health. The insect‐repellent substrate could be prepared using either functional finishing or applying an insect‐repellent dye. In this article, insect‐repellent nylon 6 is obtained using a novel insect‐repellent reactive dye containing N,N‐diethyl‐m‐toluamide. To do this, N,N‐diethyl‐m‐toluamide (DEET) was first nitrated at the p‐position relative to amide functionality. The nitrated product was reduced in the presence of C2H5OH, SnCl2, and HCl. The produced amine was then condensed with 2,4,6‐trichloro‐1,3,5‐triazine (cyanuric chloride) as a reactive group in below 5°C. The resultant adduct was finally reacted with an amino group present in 6‐amino‐1‐hydroxy naphthalene‐3‐sulfonic acid (J‐acid) to produce 7‐(4‐chloro‐6‐(4‐(diethylcarbamoyl)‐2‐methylphenylamino)‐1,3,5‐triazin‐2‐ylamino)‐4‐hydroxynaphthalene‐2‐sulfonic acid. To synthesis azo dye, sulfanilic acid was diazotized using HCl and NaNO2 and then coupled to the above prepared component to produce insect‐repellent reactive dye. An analog dye was prepared via the same route without insect‐repellent group making stage. The chemical structures of the novel dyes were characterized using FTIR and 1H‐NMR spectroscopy. The spectroscopic properties of the dyes were determined in terms of λmax and εmax in aqueous solution. The novel dyes were then reacted with nylon 6 and bonded to it covalently to provide permanent insect‐repellent substrate. The insect‐repellent efficacy of the reacted nylon 6 was studied using standard methods for Anophele mosquito repellent. The insect‐repellent dye reacted nylon 6 showed insect‐repellent activity. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 相似文献
8.
Polyurethane dispersion and urethane/acrylate composite latex were synthesized and characterized by using a particle size analyzer, gel permeation chromatograph (GPC), Fourier transform infrared spectroscopy coupled with attenuated total reflectance (FTIR‐ATR), dynamic mechanical analysis (DMA), and instron test machine. The amount of solvent and dimethylolpropionic acid (DMPA) used during synthesis of polyurethane resin straightway affected the average particle size and stability of aqueous polyurethane dispersion. The particle size of polyurethane dispersion had nothing to do with that of composite latex. FTIR‐ATR analyses displayed both air‐facing and substrate‐facing surfaces, containing more polyurethane component than the average composition. Some crosslinking reactions occurred in preparing urethane/acrylic composite latex, as indicated by FTIR analyses and solvent extraction. DMA demonstrated three glass transitions for the film from composite latex. Instron tests exhibited better film performance properties for the composite latex than for the corresponding blend latex. A possible particle growth mechanism for preparing urethane/acrylate composite latex was proposed. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1620–1628, 2002; DOI 10.1002/app.10526 相似文献
9.
Acrylic acid and acrylamide were polymerized by a peroxydisulfate–suberic acid redox system under a nitrogen atmosphere both in the presence and in the absence of ultrasound (at constant frequency). The rate of polymerization was determined for different concentrations of monomer, initiator, and activator and for different percentages of ultrasonic intensity. The polymers were characterized by X‐ray diffraction and 1H‐NMR spectroscopy. A probable mechanism is proposed to explain the experimental results obtained. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3685–3692, 2003 相似文献
10.
Methylmethacrylate (MMA) and octadecyl acrylate (OA) were grafted to poly(methylhydrosiloxane) (PMHS) by hydrosilylation, respectively, with hexachloroplatinic acid as catalyst, and the former was further hydrolyzed to prepare methacrylic acid (MAA)‐graft‐PMHS under the alkaline condition. Through orthogonal experiment, main factors affecting the graft reaction between OA and PMHS were discussed and arranged in a decreasing order according to their abilities of the effect on the hydrosilylation of OA with PMHS: catalyst dosage, reaction temperature, reaction time, material ratio, and solvent dosage. It was found that the hydrosilylation of OA with PMHS was easier to that of MMA with PMHS. Under optimal conditions, the grafting ratios of MMA with PMHS and OA with PMHS reached about 90 and 95%, respectively. FTIR and 1H NMR spectra indicated that the hydrosilylation reactions followed the Markovnikov's rule and played a strong preference toward β‐1,2‐addition. The test of contact angle indicated that surface energy of a system was mainly dependent on the polar groups. The surface energy of OA‐graft‐PMHS (35.07 mN/m) was similar to those of PMHS (35.62 mN/m) and polyoctadecyl acrylate (36.57 mN/m), and lower than that of MAA‐graft‐PMHS (43.50 mN/m). © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008 相似文献
11.
The products and mechanism of the thermal oxidative degradation at 180 °C and the photo‐oxidative degradation at 40 °C of polytetrahydrofuran have been investigated using 1H NMR, 13C NMR and GPC. The NMR analysis was assisted by the use of DEPT 13C spectra, two‐dimensional NMR spectroscopy (COSY, HMQC and HMBC) and chemical shift simulation software. The NMR spectra of both thermally and photolytically degraded samples were similar showing that the degradation mechanisms were similar. GPC indicated that both chain scission, leading to lower molar mass products, and chain extension, leading to higher molar mass products, occurred initially. NMR analysis of the initial soluble degraded polymers showed that chain scission resulted in formate, aldehyde, propyl ether, butyl ether and propanoyl chain ends, and in‐chain ester groups were also formed. For longer periods of degradation, crosslinked gels were formed but these were not amenable to detailed structural characterisation by high‐resolution NMR to determine the crosslink mechanism. Copyright © 2004 Society of Chemical Industry 相似文献
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The development of glossy topcoat one-pot exterior paint formulations using water-based polyurethane/acrylates hybrid binders as well as the assessment of its properties through different conventional tests is discussed in this work. Polyurethane (PU) anionomer having 2-ethoxymethacrylate terminal groups was prepared following a prepolymer mixing process. This prepolymer was chain extended in aqueous solution and after addition of acrylic monomers radical polymerized. Paints were prepared using titanium dioxide as unique pigment. Panels coated with air-dried paints with three pigment to volume concentration (PVC) values were subjected to standardized tests including adhesion, flexibility, gloss and color determination. Accelerated weathering tests were carried out to evaluate changes in properties, especially gloss and color, of painted panels. Solvent-based acrylic and polyurethane paints were included as high gloss quality reference coatings. It was found that air-dried formulations based on hybrid polyurethane/acrylic with up to 50 wt.% of acrylic component, show a gloss as high as 70 and the relative gloss change after accelerated weathering test is lower than the pure solvent-based acrylic and polyurethane paints. 相似文献
14.
A normalized and universally applicable calibration function for the Fourier‐transformed infrared (FTIR) quantification of the glycidyl methacrylate (GMA) grafting yield in polymers of known compositions having ethylene block sequences was established. The 1H nuclear magnetic resonance (1H‐NMR) spectroscopy results achieved on different GMA‐grafted ethylene/propylene/diene rubber (EPDM‐g‐GMA) and ethylene/GMA copolymers were correlated to their FTIR data to calibrate the relative determination of the FTIR method. Both direct and indirect standardization approaches were followed and evaluated. The calibration deduced was used to investigate the free radical grafting reaction of GMA on EPDM rubber in the melt phase. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 2616–2624, 1999 相似文献
15.
Jia-Wun Li Yung-Hsin Cheng Hsun-Tsing Lee Chyung-Chyung Wang Chih-Wei Chiu Maw-Cherng Suen 《应用聚合物科学杂志》2020,137(36):49062
This study successfully incorporated a short-segment fluorine-containing chain extender (2,2,3,3-tetrafluoro-1,4-butanediol [TF]) into castor oil-based polyurethane (COPU) to synthesize TF/COPUs. The interactions between TF and COPU components were identified by Fourier transform infrared and X-ray photoelectron spectroscopies, the results revealed that the increase in the TF content increased the van der Waals forces in C F…CO and the hydrogen bonding force in C F…H N. Atomic force microscopy indicated that the addition of more TF contributed to a higher level of microphase separation in the TF/COPUs. Thermogravimetric analysis showed that the TF component can enhance the thermal resistance of TF/COPUs. Differential scanning calorimetry and dynamic mechanical analysis indicated that the glass transition temperature (Tg) of TF/COPUs increased with the TF content. The stress–strain testing showed that the tensile strength and elongation at break values decreased with the TF content. This tensile behavior may be due to the molecular weight of a TF/COPU decreased with the TF content as evidenced by the gel permeation chromatography results. The hydrolytic degradation tests of dipping TF/COPUs in 3 wt% NaOH solution indicated that TF could lower the surface free energy and enhance the degradation stability of TF/COPUs. 相似文献
16.
Polyurethane dispersions (PUDs) have been an active area of research since the early 1940s because of legislative restrictions on the use of organic solvents in conventional solvent‐based products and also because PUDs exhibit almost the same high performance levels as solvent‐borne polyurethanes. In the present study, properties of conventional waterborne PUDs are modified with epoxy‐acrylic graft copolymer blocks. The epoxy‐acrylic graft copolymers were first modified with ethylene diamine to give amine‐terminated blocks which in turn reacted with isocyanate‐terminated prepolymer (prepolymer mixing process) to give modified PUDs. Several experimental sets were prepared with varying compositions. The experimental sets were also prepared using conventional poly(ethylene glycol) blocks and ethylene diamine chain‐extenders. The physico‐chemical properties and film characteristics of the experimental sets show the dramatic improvement in important mechanical properties of PUDs due to grafting with epoxy‐acrylic copolymer blocks. Copyright © 2004 Society of Chemical Industry 相似文献
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18.
《国际聚合物材料杂志》2012,61(8):832-839
The possibility of using ultrasonic waves in the reaction between methylene diphenyl diisocyanate (MDI) and polypropylene glycol (PPG) to create polyurethanes is described in this article. This normally slow reaction without chemical catalysts was found to occur to completion within minutes in the presence of ultrasonic waves. A commercially available ultrasonic apparatus was used and characterized for the ultrasonic power. The effect of varying the isocyanate/alcohol groups (NCO/OH) ratio in the presence of ultrasonic waves was also studied. These ratios were found to have a strong effect on the reaction time and mechanical properties of the materials. They also influence the thermal stabilities of the products. Higher NCO/OH ratios lead to faster curing times and harder but brittle materials. 相似文献
19.
High solids content PU/(meth)acrylics latexes for application as pressure sensitive adhesives (PSAs) were successfully synthesized by miniemulsion photopolymerization in a continuous tubular reactor at room temperature. It was shown that the process is very flexible and the polymer microstructure can be widely changed by simply controlling the radical initiation using different photoinitiator types and concentrations and varying the incident light irradiance. PSAs presenting a whole spectrum adhesive properties were obtained, some of them having the desired and unusual combination of high work of adhesion and maximum shear adhesion failure temperature (SAFT > 210 °C). The adhesive properties were analyzed in terms of the molecular weight distribution of the whole sample measured by asymmetric flow field flow fractionation. 相似文献