首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 59 毫秒
1.
Enzymatically treated cellulose was dissolved in a NaOH/ZnO solvent system and mixed together with poly(ethylene‐co‐acrylic acid) (PE‐co‐AA) or poly(acrylamide‐co‐acrylic acid) (PAA‐co‐AA) polymers, in order to improve the properties of dissolved cellulose and to prepare homogeneous cellulose‐based blends for films and coatings. The solution stage properties of the blends were evaluated by rheological methods and the precipitated dry blends were characterized by dynamic mechanical analysis, differential scanning calorimetry, and scanning electron microscopy. Paperboard coating tests done at laboratory scale showed dissolved cellulose/acrylic acid copolymer‐based blends function well as coating materials. All of the tested blends showed a good resistance against grease in the coating trials, having grease resistance from 60 to 69 days despite a very thin (~2 µm) coating layer. In addition, cellulose/PE‐co‐AA coating showed improved water vapor and oxygen barrier properties when compared with neat dissolved cellulose‐coated paperboard. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40286.  相似文献   

2.
A series of superabsorbent polymer composites based on sericin hydrolyzed with alkaline protease (AP) were prepared by grafting with acrylic acid (AA) and acrylamide (AM). The properties of the superabsorbent polymers (SAP) by using hydrolyzed sericin with different amount of alkaline protease (nAPh‐sericin) were compared. It was found that the polymer prepared from 5APh‐sericin (the mass ratio of AP to sericin was 5.0 mg g−1) showed the highest graft percentage and water absorbency, this phenomenon may be attributed to the change of molecular weight of resulting sericin molecules. The molecular structure of the grafted polymers was proved by thermal gravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FTIR) measurements. Comparing with PAA‐AM (poly AA‐co‐AM) and 0APh‐sericin/PAA‐AM polymer, 5APh‐sericin/PAA‐AM polymer had the most excellent water retention capacity and enzyme degradability. The morphological features of the polymers with different drying methods were evidenced by SEM images. The water absorbencies of 5APh‐sericin/PAA‐AM polymer prepared with freeze‐drying were 896 g g−1 in deionized water, 424 g g−1 in tap water, and 83 g g−1 in 0.9 wt% aqueous NaCl solution. POLYM. COMPOS., 35:509–515, 2014. © 2013 Society of Plastics Engineers  相似文献   

3.
Acrylic acid is often used to make water‐soluble polymers while styrene is often modified to add special functions to polymers. However, when styrene and acrylic acid are copolymerized, the resulting polymer is much less water soluble. To regain water solubility, the effect of styrene sulfonic acid on solubility of poly(acrylic acid‐co‐styrene) copolymers was investigated. Even though acrylic acid polymers are known for their water solubility, the presence of styrene units within acrylic acid copolymers reduces the solubility of the copolymer substantially at the natural pH of the solutions. By adding styrene sulfonic acid as a termonomer, polymers that are water soluble at the natural pH of the polymerization could be obtained. The solubility of the polymer after removal of the solvent and by redissolving at different concentrations and pH levels is also reported. Solubility increases at higher pH especially with low styrene concentration in the copolymer. It was found that incorporation of as little as 5 mol % of styrene into poly(acrylic acid) reduced the aqueous solubility to less than 0.5 g dL?1 at pH 7. Upon adding 7 mol % styrene sulfonic acid as a termonomer, the water solubility increased to 5 g dL?1 at pH 7. At higher levels of styrene, more styrene sulfonic acid was needed, especially at low pH. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013  相似文献   

4.
A new cellulose‐based superabsorbent polymer, carboxymethyl cellulose‐graft‐poly(acrylic acid‐co‐acrylamide), was prepared by the free‐radical grafting solution polymerization of acrylic acid (AA) and acrylamide (AM) monomers onto carboxymethyl cellulose (CMC) in the presence of N,N′‐methylenebisacrylamide as a crosslinker with a redox couple of potassium persulfate and sodium metabisulfite as an initiator. The influences of reaction variables such as the initiator content, crosslinker content, bath temperature, molar ratio of AA to AM, and weight ratio of the monomers to CMC on the water absorbency of the carboxymethylcellulose‐graft‐poly(acrylic acid‐co‐acrylamide) copolymer were investigated. The copolymer's structures were characterized with Fourier transform infrared spectroscopy. The optimum reaction conditions were obtained as follows: the bath temperature was 50°C; the molar ratio of AA to AM was 3 : 1; the mass ratio of the monomers to CMC was 4 : 1; and the weight percentages of the crosslinker and initiator with respect to the monomers were 0.75 and 1%, respectively. The maximum water absorbency of the optimized product was 920 g/g for distilled water and 85 g/g for a 0.9 wt % aqueous NaCl solution. In addition, the superabsorbent possessed good water retention and salt resistance. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1382–1388, 2007  相似文献   

5.
Melamine resin polymers exhibit high transmittance, high pencil hardness, and high refractive index. However, high temperatures and long reaction times are required to obtain the desired condensation products. In this study, acrylic‐modified melamine resins were synthesized that were cured by irradiation with ultraviolet (UV) light. The synthesized acrylic‐modified melamine resins could be cured rapidly due to the radical reaction of the acrylic groups and retained high transparency and high refractive index as features of the melamine resin polymers. The polymerized film by UV curing had low shrinkage and high refractive index. Compared with general multifunctional moiety‐type acrylic monomers such as pentaerythritol triacrylate and dipentaerythritol hexaacrylate, the acrylic‐modified melamine resins had the same degree of hardness. In addition, flexibility, a feature of the urethane moiety, was imparted to the polymer by the reaction of residual hydroxyl groups with isocyanate. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci 000: 000–000, 2010  相似文献   

6.
In the past work, the shear resistance of pure poly(n‐butyl acrylate) was low, even incorporation of inorganic filler, silica in the composition. It is well‐known that the copolymerization of n‐butyl acrylate (BA) with methyl methacrylate (MMA) will increase the glass transition temperature, and enhance the shear resistance of acrylic polymers. In the current work, the preparation of a series of acrylic water‐borne pressure‐sensitive adhesives (PSAs) with the controlled composition and structure for the copolymerization of BA and acrylic acid (AA) with different MMA contents, poly(BA‐co‐MMA‐co‐AA) was reported and its effects on adhesive properties of the latices were investigated. The latices of poly(BA‐co‐MMA‐co‐AA) were prepared at a solid content of 50% by two‐stage sequential emulsion polymerization, and this process consisted of a batch seed stage giving a particle diameter of 111 nm, which was then grown by the semicontinuous addition of monomers to final diameter of 303 nm. Dynamic light scattering (DLS) was used to monitor the particle diameters and proved that no new nucleation occurred during the growth stage. Copolymerization of BA with MMA raised the glass transition temperature (Tg) of the soft acrylic polymers, and had the effect of improving shear resistance, while the loop tack and peel adhesion kept relatively high. The relationship between pressure‐sensitive properties and molecular parameters, such as gel content and molecular weight, was evaluated. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011  相似文献   

7.
Latex polymers are frequently used as substitutes for solvent‐borne coatings in environmental friendly technologies. However, the relationship between the copolymer composition and the latex film performance must be established. The preparation of a series of styrene–n‐butyl acrylate latexes functionalized with different amounts of acrylic acid through semicontinuous emulsion polymerization is presented. In this work, latexes were employed to study the modification of the latex film properties by the addition of acrylic acid during the polymerization; mainly, the adhesion to the substrate, the water vapor permeability, and the electrical film resistance were examined. The most advantageous acrylic acid content was established by a balance of the tested properties. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009  相似文献   

8.
Water‐reducible acrylic–alkyd resins were synthesized from the reaction between monoglycerides prepared from modified palm oil and carboxy‐functional acrylic copolymer followed by neutralization of carboxyl groups with diethanolamine. Modified palm oil was produced by interesterification of palm oil with tung oil at a weight ratio of 1 : 1, using sodium hydroxide as a catalyst, whereas carboxy‐functional acrylic copolymer was prepared by radical copolymerization of n‐butyl methacrylate and maleic anhydride. The amount of acrylic copolymer used was from 15 to 40% by weight, and it was found that homogeneous resins was obtained when the copolymer content was 20–35 wt %. All of the prepared water‐reducible acrylic–alkyd resins were yellowish viscous liquids. Their films were dried by baking at 190°C and their properties were determined. These films showed excellent water and acid resistance and good alkali resistance. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1170–1175, 2005  相似文献   

9.
Acrylic‐based superabsorbent polymers with partial‐neutralized acrylic acid were synthesized by inverse suspension polymerization. The effects of reaction parameters, including the concentration of crosslinking agent and initiator, the neutralization degree of monomer, the monomer concentration, and phase ratio of a system, on the water absorption have been investigated. Furthermore, to improve the properties of salt‐resistance and antielectrolyte for the polymer, acrylamide monomer containing nonionic and hydrophilic groups was introduced into the system, which can suppress the salt effect and homoion effect. The water absorption Q5/3 is proportional to the reciprocal of ionic strength, 1/S, which follows Flory's elasticity gel theory. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 619–624, 2004  相似文献   

10.
Low molecular weight poly(acrylic acid‐co‐vinyl aminomethylene phosphonic acid)s were prepared by consecutively applying the Hofmann degradation and the Mannich reaction to polyacrylamide and poly(acrylamide‐co‐acrylic acid)s. 1H‐NMR, 31P‐NMR, and microanalysis were used for structural analyses. These polymers were tested as anti‐scalent and they showed better anti‐scalent effect than commercial poly(acrylic acid)s. The scale inhibition properties of copolymers increased with increasing amount of aminomethylene phosphonic acid groups. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 870–874, 2000  相似文献   

11.
Novel diastereomeric acrylic ketal monomers derived from (+)‐camphor and (±)‐camphor were synthesized. To investigate the applications of the camphor derivatives on positive‐tone photoresists, the acrylic ketal monomers were copolymerized with methyl methacrylate, methacrylic acid, and n‐butyl methacrylate. The optical activities of the chiral monomers and polymers were all evaluated. After UV irradiation and postexposure baking, the optical activity of the polymers decreased because of the decomposition of the acid‐labile pendant chiral groups. The existence of alicyclic camphyl groups increased the etching resistance of the photoresists. The thermogravimetric properties of the copolymers, the exposure curves, the lithographic evaluation of the positive‐tone photoresists, and the effects of alicyclic groups on the plasma etching resistance of the copolymers were all investigated. A resolution of a line‐and‐space pattern of 0.3 μm was achieved. Acid‐catalyzed dehydration crosslinking was also found in this system. Sufficient UV irradiation and heat treatment could cause the acid‐catalyzed dehydration crosslinking of pendant carboxyl groups and thereby increase the efficiency of the thermal resistance of the polymers. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2969–2978, 2003  相似文献   

12.
Potassium silicate binder of zinc‐rich coating was modified by adding water‐based acrylic resin. Several series of coatings containing 5, 10, and 15 wt % of acrylic and acrylic/styrene binders were added to potassium silicate. The coatings were applied on steel and the corrosion resistance of coatings was evaluated by conventional methods such as electrochemical impedance spectroscopy, corrosion potential, salt spray, and scanning electron microscopy. The results indicated that the modification of silicate binder with acrylic and acrylic/styrene led to shortening the curing time, improved corrosion protection, better dispersion of zinc particles, and enhanced salt spray resistance of resultant coatings. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40370.  相似文献   

13.
Polycarbonate-modified acrylic polymers for coating materials   总被引:3,自引:0,他引:3  
Reactivities of six-membered cyclic carbonates (1) were studied and a carbonate-modified acrylic polymer was synthesized, which was expected to show good water resistance. The carbonates (1) reacted with several alcohols under acidic conditions giving the corresponding alkyl 3-hydroxypropyl carbonates, quantitatively. The reactivities of 1 with alcohol depended on their steric hindrance, on the acidity of the catalyst and on the basicity of the solvents. 13C NMR analysis indicated that the reaction proceeded by interaction between the CO group of 1 and the acid catalyst, followed by ring-opening of 1 via the nucleophilic attack by the alcohol on the CO group. This reaction of 5,5-dimethyl-1,3-dioxane-2-one (1a) with n-butanol produced polymers (2) at 50°C in toluene, using methane sulfonic acid as a catalyst. The molecular weights ranged from 2530 to 9310 and 1H NMR showed that the polymerization was initiated from n-butanol. Also the ring-opening reaction enabled the production of both a carbonate-modified acrylic polymer (4a) containing carbonate units in their side chains by the reaction of 1a with poly(styrene-co-2-hydroxyethyl methacrylate) (3a) and methacrylic monomers (HEMAC) containing 3-hydroxyneopentyl carbonate units by reaction of 1a with 2-hydroxyethyl methacrylate (HEMA). Free radical copolymerization of HEMAC also produced carbonate-modified acrylic polymer (4c). A carbonate-modified acrylic polymer showed excellent hydrolysis resistance when compared with -caprolacton-modified acrylic polymer (5a). Waterborne coatings, consisting of a carbonate-modified acrylic polymer (4c) and a melamine resin, showed excellent storage stability at 40°C when compared with a similar coatings based on an -caprolactone-modified acrylic polymer (5b), and the 4c melamine coating showed nearly the same curability to that of the 5b melamine coating when baked at 140°C for 30 min.  相似文献   

14.
The present study reports the synthesis and characterization of waterborne interpenetrating network (IPN) of epoxy‐acrylic‐oleic acid (EpAcO) with butylated melamine formaldehyde (BMF). The effect of BMF on the formation of IPN was investigated in terms of physicochemical, spectral, morphological, and thermal analyses. The coating properties of the IPN were investigated for their physicomechanical, corrosion resistance, and antimicrobial activity. The formation of the IPN was confirmed by FTIR and 1H NMR analyses as well as physicochemical properties. The EpAcO‐BMF IPN coatings were found to exhibit far superior corrosion resistance performance and good thermal stability when compared with the reported waterborne epoxy acrylic‐melamine formaldehyde systems [EpAc‐MF]. The preliminary antimicrobial investigations of the IPNs were carried out by agar diffusion method against some bacteria and fungi. The results revealed that antimicrobial activities were enhanced upon the formation of IPN. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009  相似文献   

15.
A variety of poly(alkyl methacrylate‐co‐acrylic acid) (PS) copolymers were synthesized under conditions resembling those used in industrial processes. The interfacial tension dependence on the composition, the concentration of the polymers, and the presence of water‐soluble quaternary ammonium salt (octadecyltrimethylammonium chloride) were investigated. The studies reveal that the presence of a quaternary ammonium salt decreases the interfacial tension to a high degree and improves the dispersing properties of the synthesized copolymers. Some examples of using PS copolymer with 15 mol % acrylic acid content as a dispersant in inverse suspension copolymerization process of acrylamide and acrylic acid are presented. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3736–3743, 2004  相似文献   

16.
Two new ester‐type monomers were synthesized by the condensation of acrylic acid with the products of the hydroxyethylation of 4‐nonylphenol or 4‐tert‐butylphenol. The hydroxyethylation reaction was performed with 1,3‐dioxolan‐2‐ona in the presence of alkalies. By hydroxyethylation, the phenols were changed into alcoholic derivatives able to react with acrylic acid to give acrylic esters. The insertion of the aryl–alkyl groups into the structure of the acrylic esters, and implicitly of the corresponding polymers, was carried out with the intention of increasing their thermostability and improving their behavior as pressure‐sensitive adhesives on the whole. The monomers and the polymers were characterized by elemental and thermogravimetric analyses, IR and 1H‐NMR spectroscopy, and other special methods. The results of these investigations confirmed the formulated suppositions. The inherent viscosities of the resulting polymers were in the range of 47–64 mL/g, and their thermal stability was up to 315–320°C, far higher than that of the polyacrylates used. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 802–814, 2002  相似文献   

17.
A series of amphoteric, superabsorbent polymers [poly(acrylic acid‐co‐diallyldimethylammonium chloride)] with different molar ratios of anionic groups to cationic groups were prepared by solution polymerization to investigate their swelling behaviors and the controlled release of agrochemicals. Various factors, including the solution pH, the concentrations of different salt solutions, and the temperature, were studied. The dynamic parameters of hydrogels at different temperatures suggested that diffusion was Fickian at lower temperatures, whereas non‐Fickian diffusion prevailed at higher temperatures. A copolymer hydrogel with a low anionic‐group/cationic‐group ratio showed a higher swelling capacity in water and higher salt tolerance. Also, the anionic‐group/cationic‐group ratio was not the dominant factor in determining the water retention. A poly(acrylic acid‐co‐diallyldimethylammonium chloride) hydrogel could control the release of agrochemicals effectively. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 986–991, 2006  相似文献   

18.
Acrylic acid–1,7‐octadiene resin was synthesized in beaded form by a two‐step process: suspension polymerization of ethylacrylate and 1,7‐octadiene monomers, followed by hydrolysis using either 98% H2SO4 or 10 M NaOH. Acrylic acid–divinylbenzene resins were also synthesized by the same process for the purpose of comparing a rigid divinylbenzene with a flexible 1,7‐octadiene crosslinkage in the acrylic acid resins. Swelling of the resins in distilled water shows that replacing divinylbenzenes with 1,7‐octadiene makes the resin achieve greater swelling in a significantly shorter time. 1,7‐Octadiene also allowed for an increase in crosslinkage to 20% compared to 4% in the case of divinylbenzene, without compromising the loading rates of toxic heavy metal ions like Pb2+, Cu2+, and Cr3+ from water samples. The acrylic acid–1,7‐octadine resin was found useful for removal of the toxic heavy metal ions from wastewater samples. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41038.  相似文献   

19.
Two‐phase partitioning bioreactors (TPPBs) have been recently demonstrated to be capable of using solid polymers as the absorbing/desorbing phase. In this paper, we examine the possibility of using a siloxane‐based copolymer as this phase. Copolymers were prepared using vinyl terminated oligo(dimethylsiloxane‐co‐diphenylsiloxane), copolymerized with varying amounts of the comonomers ethylene glycol dimethacrylate (EGDMA), N‐vinyl pyrrolidone (NVP), or acrylic acid (AA), via free radical polymerization. The absorption rate of phenol as a representative pollutant into these polymers from water was measured. The inclusion of a water‐soluble comonomer resulted in swelling of the polymers in water, enhanced total phenol absorption, but reduced phenol diffusivity.  相似文献   

20.
Highly water‐absorbing polymers of neutralized poly(acrylic acid‐co‐acrylamide) were synthesized in an effort to investigate the influences of reaction parameters on water absorption. In addition, the extent of water absorption and the absorption rate were studied to determine their relationship with the reaction parameters. This article explains the synthesis technique, characterization of the water‐absorbing copolymers, and their properties. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 1349–1366, 1999  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号