Co-reporter:Jie Shen;Jing Xu;Yang Hu;Junpei Li
Colloid and Polymer Science 2017 Volume 295( Issue 4) pp:679-688
Publication Date(Web):2017 April
DOI:10.1007/s00396-017-4059-z
Using N,N′-dimethylaminoethyl methacrylate (DMAEMA) as functional co-monomer and styrene (St) as main monomer, the amino-containing hollow latexes were fabricated via one-step emulsion copolymerization and following stepwise acid-alkali post-treatment. Influences of DMAEMA content and post-treatment condition on the morphology and volume expansion of the P(St-co-DMAEMA) latex particles were investigated based on the TEM characterization, and the hollow-forming mechanism was proposed. Results showed that the introduction of 2-butonane promoted the mobility of the polymer chains and the hollow structure generated under moderate post-treatment conditions. Many factors should be balanced to obtain fine hollow particles, an appropriate content of DMAEMA was 15 mol% to all the monomers, and the optimized post-treatment conditions were at 70 °C for 1 h both for acid treatment (initial pH 4.0) and for alkali treatment (initial pH 9.0). Under the optimized conditions, the mean diameter and volume expansion of the resulted hollow particles were 264 nm and 934%, respectively. Finally, the hollow P(St-co-DMAEMA)/laponite composite latex particles were fabricated simply by electrostatic adsorption process, and the resulted composite hollow particles loaded 4.1 wt% of laponite platelets and showed better thermal stability. This simple and facile method can be applied to fabricate the functional hollow latex particles with amino groups including polymeric and polymeric-inorganic composite materials.
Co-reporter:Xinyi Huang;Lingxiao Li;Min Xu;Jing Xu;Yiming Jiang
Journal of Applied Polymer Science 2015 Volume 132( Issue 37) pp:
Publication Date(Web):
DOI:10.1002/app.42541
ABSTRACT
In order to obtain novel hollow latexes with both opaque and self film-forming properties, the four-layer core/shell latex particles—sequentially consisting of a high carboxyl-containing soft core, a transition layer, a rigid supporting layer, and an outermost film-forming layer—are first designed and prepared by emulsion polymerization, and then treated with alkali to fabricate self film-forming hollow latexes. On the basis of the previous research on the three-layer core/shell latex, influences of the composition and thickness of the film-forming layer on the properties and morphologies of the four-layer core/shell and the final hollow latexes are investigated. Results show that under optimized conditions with butyl acrylate/styrene (BA/St) mass ratio of 2/1, divinyl benzene (DVB) content of 1 wt %, and core/film-forming layer mass ratio of 1/6 in the film-forming layer preparation, the final hollow latex particles exhibit best morphology considering both light scattering efficiency and film-forming capability at room temperature. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42541.
Co-reporter:Guanzhi Cheng, Xinyi Huang, Hong Zhang, Yang Hu and Chengyou Kan
RSC Advances 2014 vol. 4(Issue 55) pp:29042-29049
Publication Date(Web):29 May 2014
DOI:10.1039/C4RA01360C
Modified poly(styrene-co-methyl acrylic acid) (P(St-co-MAA)) latex particles were first fabricated via soap-free emulsion polymerization followed by surface carboxyl oxidization, and then P(St-co-MAA)/CeO2 composite microspheres were prepared through the in situ chemical deposition of CeO2 nanoparticles in the presence of hydrogen peroxide. Then, these microspheres were used to catalyze the oxidative degradation of methyl orange (MO) by H2O2. The preparation processes were monitored with Fourier transform infrared spectroscopy (FT-IR) and fluorescence spectrophotometry, and the morphology of the composite microspheres was characterized by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Powder X-ray diffraction (XRD) and nitrogen adsorption–desorption isotherms (BET) were employed to characterize the structure and specific surface area of the composite microspheres, respectively. Results showed that the recipe and pH had significant effects on the morphology of the composite microspheres. When the mass ratio of P(St-co-MAA), H2O2 and water was 0.1:0.4:9.6, uniform P(St-co-MAA)/CeO2 composite microspheres were obtained at pH 6.0 using 0.02 mol L−1 of cerous nitrate. UV-Vis absorption analysis indicated that the apparent rate of MO degradation catalyzed by the composite microspheres was up to 0.0330 min−1, which was 15.7 times that of commercial CeO2. Reusability tests proved that the activity of the composites remained unchanged after 4 cycles. The mechanism of the formation of P(St-co-MAA)/CeO2 composite microspheres was proposed.
Co-reporter:Yi-ming Jiang;Bo-tian Li;Wei Deng;Xue-yan Li
Chinese Journal of Polymer Science 2014 Volume 32( Issue 1) pp:21-28
Publication Date(Web):2014 January
DOI:10.1007/s10118-014-1391-3
In order to prepare hollow latex particles with optimum morphology based on osmotic swelling principle, threelayer core/shell latex particles with 40 wt% MAA in the core were first prepared via multistep seeded emulsion copolymerization, in which monomers were added by a semi-continuous process with monomer addition under two different forms: pure monomers’ mixture (monomer addition), and pre-emulsified monomers (pre-emulsion addition). Then, the hollow latex particles with different morphologies were obtained after alkali post-treatment. Influences of the monomer feeding mode on the emulsion polymerization and the particle morphology were investigated. Results showed that the preemulsion addition could significantly improve the polymerization stability in each step, and greatly enhance the uniformity of shell encapsulation. The sizes of the core and core/shell latex particles obtained by the pre-emulsion addition were smaller and more uniform than those synthesized by the monomer addition, and the hollow latex particles with intact morphology were generated by alkali post-treating of the core/shell latexes prepared from the pre-emulsion addition. As the core size increased, the morphology of the post-treated particles underwent evolution from hollow to collapse. Moreover, the mechanism of the particle morphological evolution was proposed.
Co-reporter:Yi-ming Jiang;Bo-tian Li;Wei-jia Wang;Min Xu
Chinese Journal of Polymer Science 2014 Volume 32( Issue 2) pp:177-186
Publication Date(Web):2014 February
DOI:10.1007/s10118-014-1387-z
Three-layer core/shell latex particles with various shell crosslinking level and shell thickness were prepared by multistep emulsion polymerization, and the hollow latex particles with different morphologies were then obtained after alkali post-treatment. Influences of divinyl benzene (DVB) content and the core/shell mass ratio on emulsion polymerization and particle morphology were investigated. Results showed that with the increase of DVB content, the percentage of total amount of -COOH on the particle surface and free in aqueous phase (PSFa) decreased, and the morphology of the post-treated particles underwent evolution from cracked, intact hollow to deficient swelling structure. Decreasing the core/shell mass ratio could not only make more carboxyl groups encapsulated by the shell, but also increase the shell resistance to the swelling of the core. The uniform hollow latex particles with intact morphology were obtained when the DVB content was 3.54 wt% and the core/shell mass ratio was 1/6.
Co-reporter:Ji-shuai Wang;Yang Hu;Jie Shen;Xin-yi Huang
Chinese Journal of Polymer Science 2014 Volume 32( Issue 5) pp:519-523
Publication Date(Web):2014 May
DOI:10.1007/s10118-014-1438-5
Crosslinked x-P(St-MAA) seed latex was first prepared via soap-free emulsion copolymerization of styrene (St) and methyl methacrylic acid (MAA) with divinyl benzene as crosslinker and ammonium persulfate as initiator, and x-P(St-MAA)/x-P(St-NaSS) core/shell latex particles were then synthesized through a novel seeded emulsion copolymerization of St and sodium styrene sulphonate (NaSS) in the presence of water-soluble crosslinker N,N′-methylene bisacrylamide (BAA) using oil-soluble 2,2-azobis isobutyronitrile as initiator. TEM observation indicated that narrow dispersed core/shell latex particles were obtained, and element analysis showed that NaSS unit content in the whole particle and in the shell reached 22.8 wt% and 51.2 wt%, respectively.
Co-reporter:Botian Li;Jie Shen;Yiming Jiang;Jishuai Wang
Journal of Applied Polymer Science 2013 Volume 129( Issue 3) pp:1484-1490
Publication Date(Web):
DOI:10.1002/app.38848
Abstract
1-(6-acrylamidohexylamino)-4-(methylamino)anthraquinone (AHMAQ), a blue polymerizable dye, was first synthesized from an anthraquinone derivative, and its chemical structure was confirmed by 1H-NMR and IR. Then, a series of covalently colored polymer latexes were prepared by semi-continuous emulsion copolymerization of styrene (St), butyl acrylate (BA), and AHMAQ using 4,4′-azobis(4-cyanovaleric acid) (ACVA) as initiator, and the influences of AHMAQ and ACVA on the emulsion polymerization as well as the properties of the resulted copolymer latexes were investigated. Results showed that both the conversion of the dye monomer and the molecular weight of the latex polymer decreased with the increase of AHMAQ amount from 0 to 0.3 wt %. Increasing the ACVA amount resulted in higher monomer conversion but larger gel ratio, and optimum amount of ACVA was 1.2 wt % to the total monomers. Comparing with the noncovalently blue latex film colored with the unreactive dye, the light fastness of the blue P(St-BA-MAA-AHMAQ) latex films was greatly promoted by the covalent incorporation of chromophores with polymer matrix. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Co-reporter:Botian Li;Jie Shen;Wenjiao Ji;Guanzhi Cheng
Chinese Journal of Chemistry 2012 Volume 30( Issue 10) pp:2338-2342
Publication Date(Web):
DOI:10.1002/cjoc.201200541
Abstract
Covalently-colored polymer latex was synthesized via batch emulsion copolymerization of styrene, butyl acrylate and methacrylic acid in the presence of red polymerizable dye monomer consisting of anthraquinone chromophore, alkyl spacer and acryloyl group, and the influences of the initiator, surfactant and polymerizable dye on the polymerization and the latex properties were investigated. Results showed that the initiator amount was a determinative factor for the monomer conversion, and a high conversion of the polymerizable dye could be achieved when the ammonium persulfate amount was equal to or more than 1 wt% to the total monomers. Most of the chromophores were covalently bonded to the polymer chains if the polymerizable dye was used in the range of 0–1.5 wt%. The light fastness of the resulting latex film was much better than that of the noncovalently-colored polymer film.
Co-reporter:Wen-jiao Ji;Yi-ming Jiang;Bo-tian Li;Wei Deng
Chinese Journal of Polymer Science 2012 Volume 30( Issue 4) pp:595-602
Publication Date(Web):2012 July
DOI:10.1007/s10118-012-1160-0
Soap-free hydrophilic-hydrophobic core-shell latex particles with high carboxyl content in the core of the particles were synthesized via the seeded emulsion polymerization using methyl methacrylate (MMA), butyl acrylate (BA), methacrylic acid (MAA), styrene (St) and ethylene glycol dimethacrylate (EGDMA) as monomers, and the influences of MMA content used in the core preparation on polymerization, particle size and morphology were investigated by transmission electron microscopy, dynamic light scattering and conductometric titration. The results showed that the seeded emulsion polymerization could be carried out smoothly using “starved monomer feeding process” when MAA content in the core preparation was equal to or less than 24 wt%, and the encapsulating efficiency of the hydrophilic P(MMA-BA-MAA-EGDMA) core with the hydrophobic PSt shell decreased with the increase in MAA content. When an interlayer of P(MMA-MAA-St) with moderate polarity was inserted between the P(MMA-BA-MAA-EGDMA) core and the PSt shell, well designed soap-free hydrophilic-hydrophobic core-shell latex particles with 24 wt% MAA content in the core preparation were obtained.
Co-reporter:Botian Li;Jie Shen;Ruibin Liang;Wenjiao Ji
Colloid and Polymer Science 2012 Volume 290( Issue 18) pp:1893-1900
Publication Date(Web):2012 December
DOI:10.1007/s00396-012-2718-7
Novel polymerizable red and yellow dyes, consisting of anthraquinone chromophore, alkyl spacer, and acryloyl group, were first synthesized and then used as comonomers in the semicontinuous emulsion copolymerization of styrene, butyl acrylate, and methacrylic acid to fabricate polymer latexes. The influences of the dye monomers on the emulsion polymerization process, the latex particle size and its distribution, the molecular weight of the latex polymer, as well as the light fastness of the polymer latex films, were investigated. Results indicated that, despite of the inhibition effect of the polymerizable dyes on polymerization, stable colored polymer latexes could be prepared with high conversion of total monomers, whereas the conversion of the polymerizable dye decreased as increasing the amount of dye. The light fastness of the covalently colored polymer latex films was proved to be much better than that of the noncovalently colored polymer latex films due to the covalent bond of dye and polymer chains.
Co-reporter:Wei Deng;Mengjun Zhang;Wenjiao Li
Chinese Journal of Chemistry 2011 Volume 29( Issue 4) pp:853-856
Publication Date(Web):
DOI:10.1002/cjoc.201190169
Abstract
Monodisperse polar gradient particles were synthesized via a three-step emulsion polymerization using poly(butyl acrylate-methyl methacrylate-methacrylic acid-ethylene glycol dimethacrylate) (P(BA-MMA-MAA-EGDMA)) as core, poly(methyl methacrylate-methacrylic acid-styrene) (P(St-MMA-MAA)) as interlayer and polystyrene (PSt) as shell. The particle growth and encapsulation in each emulsion polymerization step were followed by transmission electron microscopy (TEM), dynamic light scattering (DLS) and conductometric titration. Results indicated that the feeding mode and the interlayer were essential to prepare the polar gradient latex particles with hydrophilic core and hydrophobic shell. The morphologies of the two-layer core/interlayer and three-layer core/interlayer/shell particles were observed in TEM micrographs, and the sequential encapsulations of the carboxyl-containing core and the core/interlayer particles were confirmed by an increase in the particle size as well as an increase in the buried carboxyl percentage.
Co-reporter:Lian Kun Jia, Li Xiang Gong, Wen Jiao Ji, Cheng You Kan
Chinese Chemical Letters 2011 Volume 22(Issue 11) pp:1289-1292
Publication Date(Web):November 2011
DOI:10.1016/j.cclet.2011.05.043
In order to prepare the polyol with all bio-based components as raw materials, cottonseed oil was first epoxidized by peroxyformic acid generated in situ from hydrogen peroxide and formic acid, and the cottonseed oil based polyols with variable hydroxyl value were then prepared by the ring-opening of epoxidized cottonseed oil with sorbitol, which is a multi-functional hydroxyl compound derived from a natural source. The chemical structure of the products was characterized with FTIR analysis, and the residual epoxy oxygen content and hydroxyl value of the polyol versus the ring-opening time were investigated.
Co-reporter:Ji-shuai Wang;Yun-shen Chen;Wei Deng
Chinese Journal of Polymer Science 2011 Volume 29( Issue 1) pp:111-116
Publication Date(Web):2011 January
DOI:10.1007/s10118-011-1001-6
Submicron-sized P(St-NaSS) latexes were prepared via a semi-continuous emulsion copolymerization of styrene (St) and sodium styrene sulphonate (NaSS) in the presence of anionic surfactant, in which NaSS aqueous solution and St were separately dropwise charged into the polymerization system at the same time. The hydrodynamic diameter of the latex particles was measured by dynamic light scattering (DSL) method, and the NaSS unit content of the purified copolymer by water extraction was calculated based on the elementary analysis. Results showed that the copolymerization could be performed smoothly with the monomer conversion more than 96% in the absence of crosslinker, and PNaSS homopolymer could be removed from the latex product by water extraction for 28 h. The weight loss in the water extraction tended to decrease and the NaSS unit content of the purified copolymer tended to increase with the increase of monomer feeding time, and both of them increased with the increase of NaSS/St mole ratio in the charge. The introduction of divinyl benzene (DVB) could decrease the weight loss in the water extraction and increase the NaSS unit content of the purified copolymer. When 25/75 mole ratio of NaSS/St and 11 mol% DVB of total NaSS and St were used in the recipe, and the monomer feeding time was 3 h in copolymerization, the NaSS unit content of the purified copolymer reached 7.31 mol%.
Co-reporter:Wei Deng, Ronglong Li, Mengjun Zhang, Lixiang Gong, Chengyou Kan
Journal of Colloid and Interface Science 2010 Volume 349(Issue 1) pp:122-126
Publication Date(Web):1 September 2010
DOI:10.1016/j.jcis.2010.05.033
Soap-free P(St–MAA) latex particles with variable styrene (St)/methacrylic acid (MAA) ratio were synthesized by batch emulsion copolymerization at 70 °C for 7 h, and the particles with porous structure were obtained after stepwise alkali/acid post-treatment. The effects of MAA amount on the particle morphologies after the alkali and the stepwise alkali/acid post-treatments were investigated by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Results indicated that the alkali-treated latex particles showed anomalous structure with rough surface, and no hollow was clearly identified inside them. When these alkali-treated particles were further treated with acid solution, the particle surface became much smoother, and porous morphology appeared. It was found that when the MAA amount was less than or equal to 4 mol%, no obvious morphological variation was observed; while the latex particles showed clearly porous structure as the MAA amount increased to 6 mol%; with the further increase of MAA amount to 8 mol%, the pore size decreased distinctly.The amount of MAA intensively influenced the morphology of P(St–MAA) latex particles, and the particles showed different morphology after alkali and stepwise alkali/acid post-treatment.
Co-reporter:Wei Deng, Man Yi Wang, Guo Chen, Cheng You Kan
European Polymer Journal 2010 Volume 46(Issue 6) pp:1210-1215
Publication Date(Web):June 2010
DOI:10.1016/j.eurpolymj.2010.03.009
Multistage carboxyl-containing polymer latex particles were synthesized by multistep emulsion copolymerization using methyl methacrylate (MMA), butyl acrylate (BA), methacrylic acid (MAA), ethylene glycol dimethacrylate (EGDMA) and styrene (St) as raw materials, and the latex particles with diverse morphologies including multihollow, hollow and “bowl-like” were obtained by post-treating the multistage latex particles under alkali condition. The morphological evolution of the particles in the alkali post-treatment process was characterized with electron microscopy, and effects of alkali treatment conditions including treatment temperature, time as well as initial pH on particle morphology were investigated. Results indicated that the alkali treatment temperature and initial pH were the key parameters to control the morphology of the treated particles. When the alkali treatment temperature was below 60 °C or the initial pH was lower than 8.5, the particle morphology was almost unchanged no matter how long the treatment time was prolonged. The multihollow and hollow particles could be formed as alkali treatment temperature exceeded 60 °C in the range of initial pH from 8.8 to 9.5. While the latex particles with “bowl-like” morphology were observed when the multistage latex was alkali treated at 90 °C for 3 h with initial pH 9.8. Furthermore, extending alkali treatment time was beneficial to get the swelling equilibrium of the latex particles.
Co-reporter:Ji Shuai Wang, Wei Deng, Yun Shen Chen, Cheng You Kan
Chinese Chemical Letters 2010 Volume 21(Issue 10) pp:1259-1262
Publication Date(Web):October 2010
DOI:10.1016/j.cclet.2010.04.019
In this study, P(St–MAA) seed latex particles were first prepared via soap-free emulsion polymerization of styrene (St) and methacrylic acid (MAA), then the seed particles were allowed to swell with St at room temperature, and the P(St–MAA)/P(St–NaSS) core/shell latex particles were then synthesized via seeded emulsion copolymerization of St and sodium styrene sulphonate (NaSS) using AIBN as initiator in the presence of N,N′-methylenebisacrylamide (BAA, water-soluble crosslinker). Results showed that the polymerization could be carried out smoothly when the ratio of BAA to total monomers was less than 3 mol%, the narrow dispersed P(St–MAA) seed particles with the diameter of 150 nm and the P(St–MAA)/P(St–NaSS) core/shell latexes with the particle size of about 200 nm were synthesized. When the 25/75 mole ratio of NaSS/(St + MAA) and 2 mol% of BAA were used in the seeded emulsion polymerization, the resulted P(St–MAA)/P(St–NaSS) latex product showed a low weight loss after water extraction, and the NaSS unit content in the whole particle and in the shell reached 11.7 mol% and 34.6 mol%, respectively.
Co-reporter:Yun Shen Chen, Ji Shuai Wang, Zhao Sheng Hou, Cheng You Kan
Chinese Chemical Letters 2010 Volume 21(Issue 2) pp:234-236
Publication Date(Web):February 2010
DOI:10.1016/j.cclet.2009.08.016
Poly(styrene-co-sodium styrene sulphonate) (P(St-NaSS)) latex particles were prepared using the mixture of ethanol and water as continuous phase in the presence of surfactant by dispersion–emulsion combined polymerization. The influence of recipes on polymerization process as well as the content of sulphonate group in the purified products was investigated. Results showed that the copolymerization could be performed smoothly. When the mole ratio of NaSS/St/divinyl benzene (DVB) was 25/75/2 and the weight ratio of ethanol/water was 2/11, the product showed a low weight loss in methanol extraction purification, and the NaSS unit ratio in the purified product reached 20.6 mol%, which was close to its theoretical value of 24.9 mol%.
Co-reporter:Wei Deng;Jishuai Wang;Manyi Wang
Macromolecular Symposia 2010 Volume 297( Issue 1) pp:61-64
Publication Date(Web):
DOI:10.1002/masy.200900091
Abstract
Summary: Monodisperse P(BA-MMA-MAA-EGDMA)/P(St-MAA-DVB) core/shell latex particles were first synthesized by a four-step emulsion polymerization, and a new kind of latex particles with “bowl-like” morphology were obtained by post-treating the resultant core/shell particles under alkali condition. Results indicated that the feeding rates of the monomer mixture and initiator aqueous solution were the key parameters to obtain monodisperse core/shell latex particles in the emulsion polymerization process, and the latex particles with “bowl-like” morphology could be generated only when the treatment temperature was equal or higher than 70 °C.
Co-reporter:Kai Kang;Deshan Liu;Yi Du
Polymers for Advanced Technologies 2006 Volume 17(Issue 3) pp:193-198
Publication Date(Web):27 MAR 2006
DOI:10.1002/pat.714
Soap-free poly(methyl methacrylate-ethyl acrylate-acrylic acid or methacrylic acid) [P(MMA-EA-AA or MAA)] particles with narrow size distribution were synthesized by seeded emulsion polymerization of methyl methacrylate (MMA), ethyl acrylate (EA) and acrylic acid (AA) or methacrylic acid (MAA), and the influences of the mass ratio of core/shell monomers used in the two stages of polymerization ([C/S]w) and initiator amount on polymerization, particle size and its distribution were investigated by using different monomer addition modes. Results showed that when the batch swelling method was used, the monomer conversion was more than 96.0% and particle size distribution was narrow, and the particle size increased first and then remained almost unchanged at around 600 nm with the [C/S]w decreased. When the drop-wise addition method was used, the monomer conversion decreased slightly with [C/S]w decreased, and large particles more than 750 nm in diameter can be obtained; with the initiator amount increased, the particle size decreased and the monomer conversion had a trend to increase; the particle size distribution was broader and the number of new particles was more in the AA system than in the MAA system; but the AA system was more stable than the MAA system at both low and high initiator amount. Copyright © 2006 John Wiley & Sons, Ltd.
Co-reporter:Kai Kang;Cheng You Kan;Yi Du;De Shan Liu
Journal of Applied Polymer Science 2006 Volume 99(Issue 4) pp:1934-1939
Publication Date(Web):7 DEC 2005
DOI:10.1002/app.22681
Monodispersed soap-free poly(methyl methacrylate/ethyl acrylate/methacrylic acid) latex particles were synthesized by the seeded emulsion polymerization of methyl methacrylate, ethyl acrylate, and methacrylic acid (MAA), and particles with a porous morphology were obtained after an alkali posttreatment. The effects of the unsaturated acid and crosslinking agent on the properties and morphology of the latex particles were investigated. The results showed that the particle size decreased and its distribution widened when the concentration of MAA was greater than 10.0 mol % or the concentration of ethylene glycol dimethacrylate (EGDMA) was greater than 1.5%. When more than 4.0 mol % MAA was used, a porous structure could be detected clearly under a transmission electron microscope, and the particle volume and pore size first gradually increased to a maximum and then decreased rapidly with an increase in the MAA concentration. The porous morphology disappeared completely as the MAA concentration reached 16.0 mol %. A multihollow morphology was generated when the EGDMA concentration exceeded 1.0%, and the particle volume decreased monotonously with the concentration of EGDMA increased. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1934–1939, 2006
Co-reporter:Anthony Yeung;Kai Kang;Deshan Liu
Macromolecular Bioscience 2005 Volume 5(Issue 4) pp:344-351
Publication Date(Web):8 APR 2005
DOI:10.1002/mabi.200400178
Summary: The covalent immobilization of trypsin onto poly[(methyl methacrylate)-co-(ethyl acrylate)-co-(acrylic acid)] latex particles, produced by a soap-free emulsion polymerization technique, was carried out using the carbodiimide method. The catalytic properties and kinetic parameters, as well as the stability of the immobilized enzyme were compared to those of the free enzyme. Results showed that the optimum temperature and pH for the immobilized trypsin in the hydrolysis of casein were 55 °C and 8.5, both of which were higher than that of the free form. It was found that Km (Michaelis constant) was 45.7 mg · ml−1 and Vmax (maximal reaction rate) was 793.0 μg · min−1 for immobilized trypsin, compared to a Km of 30.0 mg · ml−1 and a Vmax of 5 467.5 μg · min−1 for free trypsin. The immobilized trypsin exhibited much better thermal and chemical stabilities than its free counterpart and maintained over 63% of its initial activity after reusing ten times.
Co-reporter:Kai Kang, Chengyou Kan, Yi Du, Anthony Yeung, Deshan Liu
European Polymer Journal 2005 Volume 41(Issue 7) pp:1510-1518
Publication Date(Web):July 2005
DOI:10.1016/j.eurpolymj.2005.01.027
Soap-free poly(styrene–ethyl acrylate–acrylic acid) latex particles with narrow size distribution and with surface carboxyl groups were synthesized by semicontinuous emulsion polymerization, and the particles with homogeneous multihollow structure were obtained after alkali posttreatment. Effects of treatment conditions and crosslinking agents on particle morphology were investigated. Results showed that the multihollow structure can be formed inside the uncrosslinked particles only when the treatment temperature exceeded 50 °C, the pH was higher than 10.0, the amount of 2-butanone was more than 3.0 ml and the treatment time was longer than 30 min. Furthermore, the volume expansion of the particles increased with the temperature increased to 90 °C, the pH to 12.5 or the amount of 2-butanone to 7.0 ml, and this value increased first and then decreased with the treatment time prolonged. Fine pores can be generated in the shell of particles crosslinked by 0.2 g of ethyl glycol dimethylacrylate (EGDMA), while no hollow structure formed inside particles when 0.4 g of EGDMA or 0.2 g of divinyl benzene was used.
Co-reporter:Yi Du;Kai Kang;Deshan Liu
Polymers for Advanced Technologies 2004 Volume 15(Issue 11) pp:676-682
Publication Date(Web):5 NOV 2004
DOI:10.1002/pat.529
Poly(methyl methacrylate-ethyl acrylate-acrylic acid) P(MMA-EA-AA) latices with narrow particle size distribution and “clean” particle surface were first synthesized by batch soap-free emulsion polymerization, and the latex particles with anomalous morphology were obtained by alkali post-treatment. Effects of treatment temperature and time, initial pH value, as well as 2-butanone amount, on the morphology of latex particles were investigated. Results showed that anomalous structure of the dried latex particles could be easily identified using transmission electron microscopy (TEM) observation under the conditions of temperature >60°C, initial pH > 10.5 and 4.0–7.0 ml of 2-butanone used. The higher the pH value is, the earlier the anomalous structure will occur. The volume expansion (ΔV) of the particle increased with the increase in treatment temperature and 2-butanone amount. However, with the increase of initial pH value and treatment time, ΔV increased first and then decreased, and different maximum of ΔV values were observed based on different conditions. Copyright © 2004 John Wiley & Sons, Ltd.
Co-reporter:Huaping Li;Yi Du;Deshan Liu
Polymers for Advanced Technologies 2003 Volume 14(Issue 3‐5) pp:212-215
Publication Date(Web):23 APR 2003
DOI:10.1002/pat.293
Seed latex particles of P(styrene-butyl acrylate) with narrow diameter distribution were first prepared by using ammonium persulfate as initiator at 80 °C for 3 h, then seeded-emulsion polymerization of styrene, butyl acrylate, methacrylic acid and diacetone acrylamide onto the P(styrene-butyl acrylate) seed particles was carried out at 85 °C in the absent of emulsifier. In order to investigate the relationship between the polymerization conditions and particle morphology, three different processes of batch, swelling and semi-continuous monomer additions were used. It was found that latex particles prepared using the swelling process showed no signs of multiphase morphology, while both batch and semi-continuous processes gave a strawberry-like particle morphology. A series of polymerizations was carried out using the semi-continuous process. Results showed that the more acrylamide monomer that was used, the more distinct the phase separation was, and that different monomer feed rates resulted in the same type of particle morphology. Copyright © 2003 John Wiley & Sons, Ltd.
![1-[(6-aminohexyl)amino]anthracene-9,10-dione](http://img.cochemist.com/ccimg/131100/131011-90-0.png)
![1-[(6-aminohexyl)amino]anthracene-9,10-dione](http://img.cochemist.com/ccimg/131100/131011-90-0_b.png)
