The use of distributed parameter model is becoming a common approach for simulating liquid–solid flow in loop polymerization reactors. However, there are still several issues with it. One of them is the absence of modeling of distributed pressure, as no thermodynamic state-equation is incorporated into the model. In this work, inner pressure of the reactor was associated with temperature using a thermodynamic state-equation for high-pressure liquid. The thermodynamic state-equation was solved together with a dynamically distributed reactor model based on the mass, energy, and momentum conservation as well as polymerization kinetics to predict the dynamic trajectories of component concentration, temperature, pressure, and bulk mass velocity in the reactor. Industrial steady-state data were used for model validation. The application of the model was demonstrated by simulating the effect of recycle ratio on the above distributed reactor parameters. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

The double-hydrophobic well-defined polydimethylsiloxane-block-poly(methyl methacrylate) (PDMS-b-PMMA) diblock copolymers were synthesized via atom transfer radical polymerization (ATRP). Their chemical compositions and the structure were investigated. The micellization behavior of the double-hydrophobic diblock copolymers with equal block length was thoroughly studied. The results showed that their self-assembly behavior was analogous to the star-like micelles. Furthermore, the effect of temperature on the aggregates was investigated to verify that the resulting copolymer (PDMS-b-PMMA) was to some extent temperature sensitive. Till date, there have been few reports on the utilization of nonamphiphilic block copolymers to synthesize and confine metal nanoparticles in aggregates. In this study, we explored the role of double-hydrophobic block copolymers as a mediator for organically dispersible silver nanoparticles (AgNPs) and it offered to be an effective stabilizer for preparing AgNPs. Besides, AgNPs generated in organic solvent is an important addition to the hitherto predominantly water-based processes for producing nanoparticles inside the polymer surfactant. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers

In this work, fluorinated nonamphiphilic gradient copolymers of tert-butyl acrylate (tBA) and 2,2,3,3,4,4,4-heptafluorobutyl methacrylate (HFBMA) [poly(tBA-grad-HFBMA)] were first synthesized by semibatch atom transfer radical copolymerization of tBA and HFBMA. Their hydrolysis at acidic conditions led to amphiphilic poly(acrylic acid-grad-HFBMA). The chemical compositions and structures of these copolymers were characterized by proton nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy, and gel permeation chromatography. Their surface properties were evaluated with water contact angle measurement and x-ray photoelectron spectroscopy. The micellization behaviors of amphiphilic copolymer were also studied by transmission electron microscopy and dynamic light scattering. The results showed that the fluorinated and amphiphilic gradient copolymers could self-assemble in a dilute solution to form aggregates of morphologies. Furthermore, the effect of pH on the aggregates was investigated to verify that the resulting gradient copolymers were to some extent pH sensitive. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013

Well-defined polydimethylsiloxane-block-polystyrene (PDMS-b-PS) diblock copolymers were prepared by reversible addition-fragmentation chain transfer (RAFT) polymerization using a functional PDMS-macro RAFT agent. The RAFT polymerization kinetics was simulated by a mathematical model for the RAFT polymerization in a batch reactor based on the method of moments. The model described molecular weight, monomer conversion, and polydispersity index as a function of polymerization time. Good agreements in the polymerization kinetics were achieved for fitting the kinetic profiles with the developed model. In addition, the model was used to predict the effects of initiator concentration, chain transfer agent concentration, and monomer concentration on the RAFT polymerization kinetics. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Poly(γ-methacryloxypropyltrimethoxysilane) (PMPTS)-grafted silica hybrid nanoparticles were prepared by surface-initiated atom transfer radical polymerization (SI-ATRP). The resulting PMPTS-grafted silica hybrid nanoparticles were characterized using Fourier transform infrared spectroscopy (FTIRS), nuclear magnetic resonance (NMR), gel permeation chromatography (GPC), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), scanning electron microscopy (SEM), static water contact angle (WCA) measurement, and thermogravimetric analysis (TGA). Combined FTIRS, NMR, XPS, SEM, and TGA studies confirmed that these hybrid nanoparticles were successfully prepared by surface-initiated ATRP. SEM and AFM studies revealed that the surfaces of the nanoparticles were rough at the nanoscale. In addition, the results of the static WCA measurements showed that the nanoparticles are of low surface energy and their surface energy reaches as low as 6.10 mN m⁻¹. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Recent studies have demonstrated that gradient copolymers exhibit unique thermal properties. Although these properties can be determined by copolymer composition, other factors such as chain and sequence lengths and their distributions can also influence them. Accordingly, the synthesis of gradient copolymers requires simultaneously tailor-made chain structure and thermal properties. In this work, we carried out a systematic study on the preparation of poly(methyl methacrylate-grad-2-hydroxyethyl methacrylate) [poly(MMA-grad-HEMA)] with synchronously tailor-made chain composition distribution and glass transition temperature (T_g) through semibatch atom transfer radical polymerization. First, a comprehensive model for simultaneously predicting gradient copolymer microstructure and T_g was presented using the concept of pseudo-kinetic rate coefficients and Johnston equation. The model was validated by comparing simulation results with the classical reference data. Furthermore, the model was used to guide the experimental synthesis of the poly(MMA-grad-HEMA) gradient copolymers potentially as excellent damping material. The thermal properties of these gradient copolymer samples were evaluated. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012

A coupled-single-particle and Monte Carlo model was used to simulate propylene polymerization. To describe the effects of intraparticle transfer resistance on the polymerization kinetics, the polymeric multilayer model (PMLM) was applied. The reaction in each layer of the PMLM was described with the Monte Carlo method. The PMLM was solved together with the Monte Carlo model. Therefore, the model included the factors of the mass- and heat-transfer resistance as well as the stochastic collision nature of the polymerization catalyzed with single-site-type/multiple-site-type catalysts. The model presented results such as the polymerization dynamics, the physical diffusion effect, and the polymer molecular weight and its distribution. The simulation data were compared with the experimental/actual data and the simulation results from the uniform Monte Carlo model. The results showed that the model was more accurate and offered deeper insight into propylene polymerization within such a microscopic reaction–diffusion system. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Well-defined poly(dimethylsiloxane)-block-poly(methyl methacrylate)-block-poly(2,2,3,3,4,4,4-heptafluorobutyl methacrylate) (PDMS-b-PMMA-b-PHFBMA) triblock copolymers were synthesized via atom transfer radical polymerization (ATRP). Surface microphase separation in the PDMS-b-PMMA-b-PHFBMA triblock copolymer films was investigated. The microstructure of the block copolymers was investigated by transmission electron microscopy (TEM) and atomic force microscopy (AFM). Surface composition was studied by X-ray photoelectron spectroscopy (XPS). The chemical composition at the surface was determined by the surface microphase separation in the PDMS-b-PMMA-b-PHFBMA triblock copolymer films. The increase of the PHFBMA content could strengthen the microphase separation behavior in the PDMS-b-PMMA-b-PHFBMA triblock copolymer films and reduce their surface tension. Comparison between the PDMS-b-PMMA-b-PHFBMA triblock copolymers and the PDMS-b-PHFBMA diblock copolymers showed that the introduction of the PMMA segments promote the fluorine segregation onto the surface and decrease the fluorine content in the copolymers with low surface energy. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

This investigation reported the preparation of fluorinated and nonamphiphilic well-defined poly(styrene)-block-poly(2,2,3,3,4,4,4-heptafluorobutyl methacrylate) (PS-b-PHFBMA) diblock copolymers via atom transfer radical polymerization (ATRP). Their chemical composition, structure, and bulk morphology were thoroughly investigated. In addition, their self-assembly behavior in a dilute organic mixture solution was investigated. It was found that that the ATRP could be used to prepare the well-defined fluorinated and nonamphiphilic PS-b-PHFBMA diblock copolymers in a controlled manner. The results also showed that abundant morphologies including sphere, worm-like structure, and vesicle could be formed with different volume ratios of these two solvents, which proves that the nonamphiphilic fluorinated diblock copolymers can self-assemble in a dilute solution, and the aforementioned reason for self-assembly was also discussed preliminarily in this work. Finally, the effect of temperature on the aggregates was investigated to verify whether the self-assembly behavior was to some extent temperature sensitive. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011

Both silica/polystyrene (SiO₂/PS) and silica/polystyrene-b-polymethacryloxypropyltrimethoxysilane (SiO₂/PS-b-PMPTS) hybrid nanoparticles were synthesized via surface-initiated atom transfer radical polymerization (SI-ATRP) from SiO₂ nanoparticles. The growths of all polymers via ATRP from the SiO₂ surfaces were well controlled as demonstrated by the macromolecular characteristics of the grafted chains. Their wettabilities were measured and compared by water contact angle (WCA) and surface roughness. The results show that the nanoparticles possess hydrophobic surface properties. The static WCA of SiO₂/PS-b-PMPTS hybrid nanoparticles is smaller than that of SiO₂/PS hybrid nanoparticles, meanwhile, the surface roughness of SiO₂/PS-b-PMPTS hybrid nanoparticles is yet slightly rougher than that of SiO₂/PS hybrid nanoparticles, which shows that the combination and competition of surface chemistry and roughness of a solid material can finally determine its wettability. POLYM. ENG. SCI., 2011. © 2010 Society of Plastics Engineers

A series of superhydrophobic poly(methacryloxypropyltrimethoxysilane, MPTS-b-2,-2,3,3,4,4,4-heptafluorobutyl methacrylate, HFBMA)-grafted silica hybrid nanoparticles (SiO₂/PMPTS-b-PHFBMA) were prepared by two-step surface-initiated atom transfer radical polymerization (SI-ATRP). Under the adopted polymerization conditions in our previous work, the superhydrophobic property was found to depend on the SI-ATRP conditions of HFBMA. As a series of work, in this present study, the effects of polymerization conditions, such as the initiator concentration, the molar ratio of monomer and initiator, and the polymerization temperature on the SI-ATRP kinetics and the interrelation between the kinetics and the surface properties of the nanoparticles were investigated. The results showed that the SI-ATRP of HFBMA was well controlled. The results also showed that both the surface microphase separation and roughness of the hybrid nanoparticles could be strengthened with the increase of the molecular weight of polymer-grafted silica hybrid nanoparticles. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010

In this study, the kinetics of propylene polymerization catalyzed with the fourth heterogeneous Ziegler-Natta catalyst is studied. More than one type of active site is present in the propylene polymerization based on an analysis of the GPC curves. A multiple active site kinetic model (MSmodel) is proposed by using Monte Carlo technique. Good agreements in the polymerization kinetics are achieved for fitting the kinetic profiles with the MSmodel. In addition, the MSmodel is used to describe the dynamic evolutions of the active sites and their effects on the propylene polymerization. The simulated results indicate that different types of active sites have different polymerization kinetics and the site type can affect the propylene polymerization kinetics. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Well-defined poly(dimethylsiloxane-b-styrene) diblock copolymers were prepared by reversible addition–fragmentation chain-transfer (RAFT) polymerization. Monohydroxyl-terminated polydimethylsiloxane was modified to form a functional polydimethylsiloxane/macro-RAFT agent, which was reacted with styrene to form the diblock copolymers. The chemical compositions and structures of the copolymers were characterized by proton nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy, and gel permeation chromatography. The surface properties and morphology of the copolymers were investigated with static water contact-angle measurements, X-ray photoelectron spectroscopy, transmission electron microscopy, and atomic force microscopy, which showed a low surface energy and microphase separation surfaces that were composed of hydrophobic domains from polydimethylsiloxane segments. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

The design and synthesis of two aromatic amines with dendritic structures, i.e. 3,4,5-tribenzyloxyaniline (3,4,5-G₁-NH₂) and 2,5-dibenzyloxyaniline (2,5-G₁-NH₂), were conducted. A coupling reaction of three or two equivalents of benzyl bromide to one equivalent of methyl hydroxybenzoate generated methyl 3,4,5-tribenzyloxybenzoate (3,4,5-G₁-COOCH₃), methyl 2,5-dibenzyloxybenzoate (2,5-G₁-COOCH₃) and 2,6-dibenzyloxybenzoate (2,6-G₁-COOCH₃) in high yields. All G₁-COOCH₃ derivatives were studied by X-ray analysis. The results show that these dendrons have sufficient volume to be used as the fine ligands for certain catalysts. The amide intermediates (benzamide, G₁-CONH₂) were obtained by reaction between ammonia and G₁-COOCH₃. Interestingly, 2,6-dibenzyloxybenzamide (2,6-G₁-CONH₂) can not be prepared in the same condition, which may be due to the overlarge steric block. Sodium hypochlorite was an effective oxidant to generate methyl carbamates G₁- NHCO₂CH₃.

Poly(siloxane-fluoroacrylate)-grafted silica hybrid nanoparticles were prepared by surface-initiated atom transfer radical polymerization (SI-ATRP). The silica nanoparticles with α-bromo-ester initiator group for copper-mediated ATRP were prepared by the self-assembled monolayers of (3-aminopropyl)triethoxysilane and 2-bromoisobutyrate bromide. Well-defined diblock copolymer brushes consisting of poly(methacryloxypropyltrimethoxysilane) and poly(2,2,3,3,4,4,4-heptafluorobutyl methacrylate) blocks were obtained by using initial homopolymer brushes as the macroinitiators for the SI-ATRP of the second monomer. Chemical compositions and structures of the nanoparticles were characterized by Fourier transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, and gel permeation chromatography. Surface properties and morphology of the nanoparticles were investigated with X-ray photoelectron spectroscopy, scanning electron microscopy, atomic force microscopy, and water contact angle measurement. It is revealed that the surfaces of the nanocomposites are rough at the microscale and nanoscale. The formation reason of the superhydrophobic surfaces was also discussed in this work. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010

Microphase separation behavior on the surfaces of poly(dimethylsiloxane)-block-poly(2,2,3,3,4,4,4-heptafluorobutyl methacrylate) (PDMS-b-PHFBMA) diblock copolymer coatings was investigated. The PDMS-b-PHFBMA diblock copolymers were successfully synthesized via atom transfer radical polymerization (ATRP). The chemical structure of the copolymers was characterized by nuclear magnetic resonance and Fourier transform infrared spectroscopy. Surface composition was studied by X-ray photoelectron spectroscopy. Copolymer microstructure was investigated by atomic force microscopy. The microstructure observations show that well-organized phase-separated surfaces consist of hydrophobic domain from PDMS segments and more hydrophobic domain from PHFBMA segments in the copolymers. The increase in the PHFBMA content can strengthen the microphase separation behavior in the PDMS-b-PHFBMA diblock copolymers. And the increase in the annealing temperature can also strengthen the microphase separation behavior in the PDMS-b-PHFBMA diblock copolymers. Moreover, Flory-Huggins thermodynamic theory was preliminarily used to explain the microphase separation behavior in the PDMS-b-PHFBMA diblock copolymers.© 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

The poly(dimethylsiloxane)-block-poly(ethyl methylacrylate) diblock copolymers (PDMS-b-PEMA) were synthesized by atom transfer radical polymerization (ATRP). The chemical structure of the copolymers was characterized by nuclear magnetic resonance (NMR) and Fourier transform infrared (FTIR) spectroscopy. Thermal behaviors were observed via differential scanning calorimetry (DSC). In the DSC curve, the resulting copolymers appear two glass transition temperatures (T_g's), one at −123°C corresponding to the PDMS block and the other at 65°C ascribed to the PEMA segment. Moreover, the copolymer microstructure was investigated by transmission electron microscopy (TEM). The results show that the diblock copolymers are microphase separated if the bulk contains enough PEMA segment. The surface properties of the PDMS-b-PEMA diblock copolymers were searched by contact angle. The PDMS-b-PEMA diblock copolymers are of low surface energy. The polymerization kinetics was also investigated, and the results show that the reaction proceeds in a living manner. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

In the present study, a model is established to describe the propylene polymerization kinetics catalyzed by the typical catalysts with single-/multi-active site type in a liquid phase stirred-tank reactor using the Monte Carlo simulation method, regardless of the mass and heat diffusion effects within the polymer particles. Many kinetic data, including polypropylene yield, concentration transformation of catalyst active sites, number–average molecular weight, etc., are obtained by the model. The simulated kinetic results are found to be in agreement with the reference ones obtained in a population balance model. Furthermore, the comparisons of the kinetic data between the polymerization catalyzed by the catalyst with single-active site type (typically silica-supported metallocene) and the catalyst with multi-active site type (typically MgCl₂-supported Ziegler-Natta catalyst) have been studied using the model. Especially, the effects of hydrogen on the polymerization are studied using the model. The studied results show that the theory of catalyst active site can be used to explain the different propylene polymerization kinetics catalyzed by the typical catalyst with single-/multi-active site type. In addition, the role of hydrogen in the propylene polymerization needs to be emphasized. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008