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1.
Micron-sized, monodispersed, poly(methyl methacrylate) (PMMA)/polystyrene (PS)/PMMA/PS multilayered composite particles were
successfully produced by three-step seeded dispersion polymerizations in methanol/water media. The first seeded dispersion
polymerization was carried out with 2-μm-sized, monodispersed PMMA particles. 相似文献
2.
Production of micron-sized monodispersed core/shell composite polymer particles by seeded dispersion polymerization 总被引:1,自引:0,他引:1
The effect of the weight ratio of seed polymer/monomer on the morphology of the poly(methyl methacrylate) (PMMA)/polystyrene
(PS) monodispersed composite particles produced by batch seeded dispersion polymerization of styrene with 1.64-μm-sized monodispersed
PMMA seed particles in a methanol/water medium (4/1 w/w) was examined. In the PMMA/PS weight ratios of 3/1 and 2/1, the composite
particles had a clear morphology consisting of a PMMA core and a PS shell. In the ratio of 1/1, a lot of small PS domains
were observed in the PMMA core though the PS shell was still formed. By stepwise addition of styrene monomer, the formation
of the small PS domain was depressed and complete core/shell morphology was formed. Absorption/release treatments of toluene
into/from the PMMA/PS (1/1 w/w) composite particles resulted in a drastic morphological change from the core/shell structure
to a multi- layered one.
Received: 2 February 1999 Accepted in revised form: 7 April 相似文献
3.
Micron-sized, monodispersed polystyrene (PS)/poly (n-butyl methacrylate) (PBMA) composite particles, in which the PS domain(s) were dispersed in a PBMA continuous phase, were
produced by seeded polymerization for dispersions of n-butyl methacrylate (BMA) swollen PS particles in a wide range of PS/BMA ratios in the presence of NaNO2 as a water-soluble inhibitor. Moreover, in order to change the diameter of the composite particles at same PS/BMA ratio,
PS/PBMA (1/150 w/w) composite particles were produced using five kinds of PS particles in a range of diameters from 0.64 to
3.27 μm as seeds. The percentages of the PS/PBMA composite particles having double and triple and over PS domains, which were
thermodynamically unstable morphologies, increased with the increase in the diameter of BMA swollen PS particles. There was
a clear influence of the size of the swollen particles on the morphology of the PS/PBMA composite particles produced.
Received: 30 September 1999/Accepted: 18 April 2000 相似文献
4.
Micron-sized monodispersed polymethyl methacrylate (PMMA)/polystyrene (PS) (PMMA/PS=2/1, wt ratio) composite particles consisting
of PMMA-core and PS-shell were successfully produced by seeded dispersion polymerization of styrene in a methanol/water medium
in the presence of about 2 μm-sized monodispersed PMMA particles. From the view point of thermodynamic equilibrium, such a
morphology is difficult to form by usual seeded polymerization in a polar medium such as water. It is concluded that seeded
dispersion polymerization in which almost all monomers and initiators exist in the medium has an advantage to produce core/shell
polymer particles in which polymer layers accumulate in their order of the production regardless of the hydrophobicity of
polymers, because of high viscosity in polymerizing particles.
Received: 9 December 1996 Accepted: 26 February 1997 相似文献
5.
Snowman/confetti-shaped, micron-sized, monodisperse composite particles were prepared by seeded dispersion polymerizations of n-butyl methacrylate (nBMA) with 1.28 and 2.67 m-sized polystyrene (PS) seed particles, respectively, in an ethanol/water (80/20, w/w) medium. These nonspherical composite particles consisted of one or several poly(nBMA) protuberances on the surfaces of the spherical PS particles.Part CCLXII of the series Studies on Suspension and Emulsion 相似文献
6.
C.-F. Lee 《Colloid and polymer science》2002,280(2):116-123
Composite polymer particles which contain poly(methyl methacrylate) (PMMA) and polystyrene (PS) components (PMMA/PS composite
particle) were synthesized by the method of multistage soapless seeded emulsion polymerization. In this study, the process
of multistage soapless seeded emulsion polymerization included two-stage polymerization, three-stage polymerization or four-stage
polymerization. The morphologies of the PMMA/PS composite particles were studied. The kinetic factor was the main force to
control the morphology of the linear PMMA–PS composite particles which were synthesized by the method of two-stage reaction.
Both the kinetic factor and the thermodynamic factor decide the morphology of the linear composite particles which were synthesized
by the method of either three-stage or four-stage reaction. However, the thermodynamic factor cannot influence the morphology
of the PMMA/PS composite particles with a cross-linked structure which were synthesized by the method of three-stage reaction.
The cross-linked composite polymer particles had the morphology of a multilayer structure, which showed that the polymer layers
accumulated in their order of production.
Received: 9 January 2001 Accepted: 14 June 2001 相似文献
7.
Masayoshi Okubo Teruhisa Fujibayashi Akinori Terada 《Colloid and polymer science》2005,283(7):793-798
Micron-sized, monodisperse polymer particles having unique disc-like and polyhedral shapes were produced by seeded dispersion polymerization of various methacrylates with 1.57 m-sized polystyrene seed particles in the presence of saturated hydrocarbon droplets in methanol/water. Such nonspherical shapes were controllable by the polymerization conditions.Part CCLX of the series Studies on Suspension and Emulsion 相似文献
8.
Monodispersed polystyrene (PS)/poly(n-butyl methacrylate) (PBMA) composite particles having 9.4 μm in diameter were produced by seeded polymerization for the dispersion
of highly n-butyl methacrylate (BMA)-swollen PS particles, and their morphologies were examined. The highly BMA-swollen PS particles
(about 150 times the weight of the PS seed particles) were prepared by mixing monodispersed 1.8 μm-sized PS seed particles
and 0.7 μm sized BMA droplets prepared with an ultrasonic homogenizer in ethanol/water (1/2, w/w) medium at room temperature.
After NaNO2 aqueous solution as inhibitor was added in the dispersion, the seeded polymerization was carried out at 70 °C. In an optical
microscopic observation, one or two spherical high contrast regions which consisted mainly of PS were observed inside PS/PBMA
composite particles. In the PS domain, there were many fine spherical PBMA domains. Such morphologies were based on the phase
separation of PS and PBMA within the homogeneous swollen particles during the seeded polymerization.
Received: 04 June 1997 Accepted: 27 August 1997 相似文献
9.
Production of micron-sized monodispersed composite polymer particles by seeded polymerization utilizing the dynamic swelling method 总被引:1,自引:0,他引:1
In order to develop the seeded polymerization technique utilizing the dynamic swelling method (DSM) proposed by authors for
the production of micron-sized mono-dispersed “composite” polymer particles consisting of two kinds of polymers, the seeded
polymerization for the dispersion of ethyl methacry-late (EMA)-swollen PS particles prepared utilizing DSM was carried out.
Monodispersed PS/poly(ethyl methacrylate) (PEMA) composite particles having 7 μm in diameter were produced by the addition
of NaCl to lower the solubility of EMA in medium and by the addition of CuCl2 as a water-soluble inhibitor to depress the by-production of submicron-sized PEMA particles.
Received: 16 July 1996 Accepted: 10 October 1996 相似文献
10.
Micron-sized, monodispersed polystyrene/poly(3,5-xylidine) composite polymer particles were produced by chemical oxidative
seeded polymerization of 3,5-xylidine with 1.37-μm-sized, monodispersed polystyrene seed particles. The chemical oxidative
seeded polymerization was conducted in an aqueous medium at 25 °C in the presence of poly(vinyl alcohol) as a stabilizer using
ammonium persulfate as an oxidant. The composite particles had a multihollow structure.
Received: 30 June 1999/Accepted in revised form: 21 October 1999 相似文献
11.
Micron-sized monodispersed polystyrene (PS)/poly(3,5-xylidine) (PXy) composite particles were produced by chemical oxidative
seeded dispersion polymerization of 3,5-xylidine at 20 °C with 1.6-μm-sized monodispersed PS seed particles in HCl aqueous
solution, the pH of which was always kept at 2.5 with a pH stat. The composite particles produced consisted of a PS core and
a PXy shell.
Received: 16 December 1998 Accepted in revised form: 25 March 1999 相似文献
12.
Morphology of micron-sized monodispersed poly(butyl methacrylate)/polystyrene composite particles produced by seeded dispersion polymerization 总被引:1,自引:0,他引:1
In order to develop the seeded dispersion polymerization technique for the production of micron-sized monodispersed core/shell
composite polymer particles the effect of polymerization temperature on the core/shell morphology was examined. Micron-sized
monodispersed composite particles were produced by seeded dispersion polymerizations of styrene with about 1.4-μm-sized monodispersed
poly(n-butyl methacrylate) (Pn-BMA) and poly(i-butyl methacrylate) (Pi-BMA) particles in a methanol/water (4/1, w/w) medium in the temperature range from 20 to 90 °C. The composite particles,
PBMA/polystyrene (PS) (2/1, w/w), consisting of a PBMA core and a PS shell were produced with 2,2′-azobis(4-methoxy-2,4-dimethyl
valeronitrile) initiator at 30 °C for Pn-BMA seed and with 2,2′-azobis(isobutyronitrile) initiator at 60 °C for Pi-BMA seed. The polymerization temperatures were a little above the glass-transition temperatures (T
g) of both Pn-BMA (20 °C) and Pi-BMA (40 °C). On the other hand, when the seeded dispersion polymerizations were carried out at much higher temperatures than
the T
g of the seed polymers, composite particles having a polymeric oil-in-oil structure were produced.
Received: 14 October 1998 Accepted in revised form: 2 June 1999 相似文献
13.
Production of submicron-size monodisperse polymer particles having aldehyde groups by seeded aldol condensation polymerization 总被引:2,自引:0,他引:2
Submicron-size monodisperse polystyrene/polyglutaraldehyde composite particles having aldehyde groups at the surfaces were produced by seeded aldol condensation polymerization of glutaraldehyde in the presence of polystyrene particles prepared by emulsifier-free emulsion polymerization. This technique is expected to be useful for the production of size-controlled polymer particles having aldehyde groups.Part CXXXVI of the series Studies on Suspension and Emulsion 相似文献
14.
The release behavior of toluene from the hollow-inside, micron-sized, monodispersed, cross-linked, polystyrene/polydivinylbenzene
composite particles which had various cross-linking densities and shell thicknesses was examined. The hollow particles were
produced by seeded polymerization utilizing the dynamic swelling method which we proposed in 1991. In comparison with that
from hollow-free particles, there was a clear difference. The cross-linking density and shell thickness of the hollow composite
particles did not affect the release rate in the former period, but did it in the latter one.
Received: 2 February 2000/Accepted: 30 August 2000 相似文献
15.
Micron-sized monodispersed polystyrene (PS)/poly(n-butyl methacrylate) composite particles were produced as follows. First, 1.77 μm-sized monodispersed PS seed particles produced
by dispersion polymerization were dispersed in ethanol/water (1/2, w/w) medium dissolving poly(vinyl alcohol) as a stabilizer.
n-Butyl methacrylate (BMA) monomer dissolving benzoyl peroxide initiator was emulsified in ethanol/water (1/2, w/w) solution
of sodium dodecyl sulfate as emulsifier with ultrasonic homogenizer, and the BMA monomer emulsion was mixed with the PS seed
emulsion. The PS seed particles absorbed with a large amount of BMA (about 150 times weight of the seed particles) for 2 h
to about 10 μm in diameter while keeping good monodispersity and BMA droplets disappeared finally. The seeded polymerization
was carried out at 70 °C after a certain amount of water was added to depress the redissolving of BMA from the swollen particles
into the medium by raising from room temperature to the polymerzation temperature.
Received: 21 February 1996 Accepted: 4 September 1996 相似文献
16.
Micron-sized, monodispersed, electrically conductive polystyrene (PS)/polyaniline (PAn) composite particles were produced
by chemical oxidative seeded dispersion polymerization of aniline at 0 °C with 1.37-μm-sized, monodispersed PS seed particles
in HCl aqueous solution, where the pH value was kept at 2.5 with a pH stat. The composite particles consisted of a PS core
and a PAn shell. A pellet of the composite particles had a conductivity of 3.4 × 10−3 S/cm.
Received: 5 April 2000 Accepted: 10 August 2000 相似文献
17.
Micron-sized, monodisperse, “rugby-ball-like” polymer particles were produced by seeded polymerization for the dispersion
of (divinylbenzene/vinylbiphenyl/xylene)-swollen polystyrene particles prepared by utilizing the dynamic swelling method which
the authors proposed in 1991. The shape of the composite polymer particle was reversibly transformed between a rugby-ball-like
shape and a spherical one by absorbing/releasing toluene.
Received: 24 January 2001/Accepted: 18 April 2001 相似文献
18.
Recently, we found that “golf ball”-like polystyrene (PS)/polybutyl acrylate (PBA) composite particles could be produced
by seeded emulsion polymerization of butyl acrylate (BA) with PS seed particles. In this article, the effects of the polymerization
temperature, BA monomer concentration, and the presence of 1-octanol, which is a good solvent for PBA and a poor solvent for
PS in the polymerization, on the morphology was studied.
Received: 25 February 1997 Accepted: 4 October 1997 相似文献
19.
Polymer particles having single hollow in the inside were successfully prepared by suspension polymerization for divinylbenzene/
toluene droplets dissolving polystyrene (PS) in an aqueous solution of poly(vinyl alcohol). Such a hollow polymer particle
was not obtained without PS. The hollow structure was affected by the molecular weight and the concentration of PS.
Received: 3 December 1997 Accepted: 27 March 1998 相似文献
20.
Micron-sized, monodisperse composite polymer particles having "disc-like" and "polyhedral" shapes were prepared by seeded dispersion polymerization of 2-ethylhexylmethacrylate (EHMA) with 2.67-mum-sized polystyrene (PS) seed particles in methanol/water media in the presence of droplets of various saturated hydrocarbons and evaporation of the hydrocarbon after the polymerization. Such nonspherical shapes were based on the volume reduction due to the evaporation. The primary factors influencing the particle shape seemed to be the absorption rate of the hydrocarbon into the resulting PS/poly(EHMA)/hydrocarbon composite particles during the polymerization, which affected the viscosities and the volumes of the PS and poly(EHMA) phases. It was found that the morphological development during the polymerization was retarded at "hamburger-like" morphology, which is a precursor of the disc-like particle, although this morphology is a thermodynamically metastable state. 相似文献