Search

National Ministry of Science and Technology of China [2012CB21500402]; National Natural Science Foundation of China [21276213, 21076171]

National Natural Science Foundation of China [21076171]; National Ministry of Science and Technology of China [2012CB21500402]; State-Key Laboratory of Chemical Engineering of Tsinghua University [SKL-ChE-10A03]

National Natural Science Foundation of China [20406016]; Nation Defense Key Laboratory of Ocean Corrosion and Anti-corrosion of China [51449020205QT8703]; Fujian Province Science and Technology Office of China [2005H040]

National Natural Science Foundation, China [20406016, 21076171]; Nation Defense Key Laboratory of Ocean Corrosion and Anticorrosion, China [51449020205QT8703]; Fujian Province Science and Technology Office, China [2005H040]

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

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

National Natural Science Foundation of China [20406016]; Fujian Petrochemical Company of SINOPEC

National Natural Science Foundation of China [20406016]; Nation Defense Key Laboratory of Ocean Corrosion and Anti-corrosion of China [51449020205QT8703]; Fujian Province Science and Technology Office of China [2005H040]

In the present study, a model is established to describe the propylene polymerization kinetics cata- lyzed 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 ki- netic 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 metallo- cene) 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. V C 2008 Wiley Periodicals, Inc. J Appl Polym Sci 110: 3360-3367, 2008

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 (Tg'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