Study on the phase behavior of ethylene–vinyl acetate copolymer and poly(methyl methacrylate) blends by in situ polymerization

This study examines the phase behavior of ethylene–vinyl acetate copolymer (EVA) and poly(methyl methacrylate) (PMMA) blends during MMA polymerization. The ternary PMMA/MMA/EVA mixtures are considered to create a triangular phase diagram, which responds the phase changes during polymerization. The phase changes during MMA polymerization are also examined by optical microscope and photometer. Since the PMMA and EVA are well‐known immiscibles, the polymer solution undergoes phase separation at the initial stage of the MMA polymerization. Additionally, the phase inversion occurs as the conversion of MMA between 13.8 and 20.8%. On the other hand, the EVA‐graft‐PMMA, which can reduce the dispersed EVA particle size, is induced efficiently by taking tert‐butyl peroctoate (t‐BO) as initiator during MMA polymerization. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1001–1008, 2003     

Miniemulsion copolymerizations of methyl methacrylate and butyl acrylate in the presence of reactive costabilizer

The storage stability and free radical polymerizations of miniemulsions comprising methyl methacrylate (MMA), butyl acrylate (BA), and a reactive costabilizer stearyl methacrylate (SMA) were investigated. The Ostwald ripening rate increases with increasing MMA content in the monomer mixture. Both the pseudo‐two‐component model and empirical equation with one adjustable parameter k adequately predicted the Ostwald ripening rate data. For the empirical model, the least‐squares best fit technique gave a value of k equal to 677.5 and values of Ostwald ripening rate and water solubility equal to (8.8 ± 0.2) × 10^?21 cm³/s and 1.8 × 10^?9 cm³/cm³ for SMA, respectively. These two models were combined to impart some physical insight to the parameter k. The kinetic studies showed that the polymerization rate increased with increasing MMA content. This is closely related to the nature of the constituent monomers MMA and BA and the particle nucleation mechanisms. The reactive costabilizer SMA is not hydrophobic enough to completely eliminate the Ostwald ripening effect, thereby increasing the probability of polymer reactions in the continuous aqueous phase. Thus, in addition to monomer droplet nucleation, particle nuclei can be generated in the aqueous phase via homogeneous nucleation. The extent of homogeneous nucleation increased with increasing MMA content and, as a result, the number of reaction loci available for the major polymerization to take place followed the same trend. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Polymer–leather composites. II. Kinetics of the deposition of selected acrylate monomers by polymerization into chrome-tanned cattlehide

Limited kinetic information on a convenient process for depositing polymer in 5-oz cattlehide is presented in this article. The work includes a systematic study of the total polymerization rate and of the derived rates of deposition into the fibrous matrix, of bound polymer formation, and of polymer production in the external aqueous phase (the float) for three acrylic monomers. The monomers used, with a persulfate–bisulfite redox initiating system at 27°C, were methyl methacrylate (MMA), n-butyl acrylate (BA) and a fixed mixture of n-butyl acrylate and methyl methacrylate (BA + MMA). The effects of the reaction variables on rate, as measured by their intensity exponents, were not in agreement with a rate expression proposed to describe grafting in homogeneous polymerization, nor were they wholly compatible with classical and modified Smith–Ewart theories for heterogeneous emulsion polymerization. The experimental behavior, however, was in harmony with self-nucleation in the aqueous phase. Exponential orders of dependence were initiator > 0.5 (MMA, 0.72; BA + MMA, 0.66); monomer, zero; surfactant, ～0.5. The approximately 0.6 order dependence (MMA, 0.9) on leather amount was shown to be largely apparent and to decline as total polymerization proceeded. Thus a dominant grafting reaction was not supported. In support of this conclusion, simple impregnation of the matrix with preformed emulsion polymer yielded the same amount of bound polymer as that formed in situ. It was concluded that monomer is initiated largely from active centers formed initially near fibers or fibrils to form embryo polymer particles, which join penetrating swollen polymer particles and become unstable. These nucleate a polymer front, containing occluded radicals, which grows by diffusion regulated transport of monomer to complete deposition.     

Ternary hydrogen-bonded polymer solutions

Ternary-phase diagrams have been experimentally determined at 100°C for systems containing a series of poly(n-alkyl methacrylates), poly(ethylene oxide) (PEO), and a solvent [4-ethyl phenol (EPh)]. A totally miscible phase diagram is experimentally determined for the poly(methyl methacrylate)/PEO/EPh system, while a closed-loop diagram is observed for the analogous system containing poly(ethyl methacrylate). The corresponding phase diagrams of analogous mixtures containing poly(n-propyl methacrylate) or poly(n-butyl methacrylate) exhibit large heterogeneous areas. Theoretically predicted phase diagrams calculated using an association model developed in our laboratory are in general accord with these observations for ternary hydrogen-bonded polymer/polymer solutions. © 1998 John Wiley & Sons, Inc. J. Appl. Polym. Sci. 70: 1265–1271, 1998     

Simultaneous interpenetrating networks of a polyurethane and poly(methyl methacrylate). II. Partitioning of MMA monomer in the last stages of polymerization

In a model polyurethane/poly(methyl methacrylate) (PU/PMMA) system, the partitioning of unreacted methyl methacrylate monomer (MMA) is studied in the late stages of its polymerization, simulated by incorporating controlled amounts of MMA in otherwise fully cured simultaneous interpenetrating networks (SIN) samples. Glass transitions temperatures (T_g) were determined using dynamic mechanical spectroscopy and differential scanning calorimetry as a function of MMA content of the SINs. The lowering of T_g in each phase due to the plasticization effect of MMA is used to calculate a plasticization coefficient for each phase, finally allowing calculation of the partition coefficient of MMA between the two phases. It is found that the MMA monomer distributes itself almost uniformly across the two phases of the current SIN system, leading to speculation as to the locus of late SIN polymerization. © 1995 John Wiley & Sons, Inc.     

Synthesis of methacrylate copolymers and their effects as pour point depressants for lubricant oil

In this study, polymethacrylate polymers were synthesized by free‐radical polymerization for use as pour point depressants in lubricant oil, and their low‐temperature properties were investigated. Four methacrylate monomers were synthesized by the esterification of methyl methacrylate (MMA) with four kinds of fatty alcohols. The purification step was performed to prepare the pure monomers. Two polymerization experiments were carried out with four kinds of methacrylate monomers obtained previously and MMA. Copolymers, which were made from one kind of monomer and MMA, and terpolymers, which were made from two kinds of monomers and MMA, were prepared. The molecular structures of the synthesized methacrylate monomers and polymethacrylate polymers were verified by ¹H‐NMR, and the molecular weight data were obtained by gel permeation chromatography. The pour points of the base oils containing 0.1 wt % polymethacrylate polymers were measured according to ASTM D 97‐93. The pour points of most base oils containing each polymer decreased compared to that of the pure base oil. Particularly, poly(dodecyl methacrylate‐co‐hexadecyl methacrylate‐co‐methyl methacrylate), made of dodecyl methacrylate, hexadecyl methacrylate, and MMA at a molar ratio of 3.5 : 3.5 : 3, showed the best low‐temperature properties. This terpolymer dropped the pour point of the base oil by as much as 23°C, and its yield was 93.5%. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Miniemulsion copolymerizations of styrene and methyl methacrylate in the presence of reactive costabilizer

Miniemulsion stability of three‐component disperse phase systems comprising styrene [ST (1)], methyl methacrylate [MMA (2)], and stearyl methacrylate [SMA (3)] was investigated. The Ostwald ripening rate (ω) increases with increasing MMA content in the monomer mixture. The empirical equation 1 /ω = k(φ₁/ω₁ + φ₂/ω₂) + φ₃/ω₃ was proposed to adequately predict the miniemulsion stability data. The empirical parameter k was determined to be 555.77, and the Ostwald ripening rate (ω₃) and water solubility of SMA were estimated to be 8.77 × 10^?21 cm³/s and 1.90 × 10^?9 mL/mL, respectively. A water‐insoluble dye was used as a molecular probe to study particle nucleation mechanisms in the miniemulsion copolymerizations. In addition to the primary monomer droplet nucleation, homogeneous nucleation also plays an important role in the formation of particle nuclei, and this mechanism becomes more important for the polymerization systems with higher MMA contents as a result of the enhanced aqueous phase polymer reactions. The polymer composition data suggest that, during the early stage of polymerization, MMA is consumed more rapidly by free radical polymerization compared with ST. The final latex particle surface potential data also support this conclusion. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Preparation of polymer‐supported polyethylene glycol and phase‐transfer catalytic activity in benzoate synthesis

The crosslinked polymeric microspheres (GMA/MMA) of glycyl methacrylate (GMA) and methyl methacrylate (MMA) were prepared by suspension polymerization. Polyethylene glycol (PEG) was grafted on GMA/MMA microsphers via the ring‐opening reaction of the epoxy groups on the surfaces of GMA/MMA microspheres, forming a polymer‐supported triphase catalyst, PEG‐GMA/MMA. The Phase‐transfer catalytic activity of PEG‐GMA/MMA microspheres was evaluated using the esterification reaction of n‐chlorobutane in organic phase and benzoic acid in water phase as a model system. The effects of various factors on the phase transfer catalysis reaction of liquid–solid–liquid were investigated. The experimental results show that the PEG‐GMA/MMA microspheres are an effective and stable triphase catalyst for the esterification reaction carried out between oil phase and water phase. The polarity of the organic solvent, the ratio of oil phase volume to water phase volume and the density of the grafted PEG on PEG‐GMA/MMA microspheres affect the reaction rate greatly. For this investigated system, the solvent with high polarity is appropriate, an adequate volume ratio of oil phase to water phase is 2:1, and the optimal PEG density on the polymeric microspheres is 15 g/100 g. Triphase catalysts offer many advantages associated with heterogeneous catalysts such as easy separation from the reaction mixture and reusability. The activity of PEG‐GMA/MMA microspheres is not nearly decreased after reusing of 10 recycles. © 2009 American Institute of Chemical Engineers AIChE J, 2010     

相转化法聚合物/溶剂/非溶剂铸膜体系的热力学计算

计算了相转化法铸膜体系中常见的典型三元相图,分析了聚合物与溶剂之间、聚合物与非溶剂之间、溶剂与非溶剂之间的相互作用参数对聚合物/溶剂/非溶剂铸膜液体系相图的影响,以及体系温度和聚合物摩尔体积对聚合物/溶剂/非溶剂铸膜液体系相图的影响。根据溶剂-非溶剂汽液平衡数据和溶解度参数得到了溶剂-非溶剂、溶剂与聚合物以及非溶剂与聚合物之间的Flory-Huggins相互作用参数,从而获得了几种常见铸膜液体系的相图。同时,利用聚合物/溶剂/非溶剂铸膜液体系的相图数据对热力学模型的参数进行了优化,取得了与实验结果较一致的计算结果。     

Gas‐phase‐assisted surface polymerization of methyl methacrylate with Fe(0)/TsCl initiator system

To obtain a high polymer coated Fe(0) surface, gas‐phase‐assisted surface polymerization (GASP) of methyl methacrylate (MMA) was investigated using a zero‐valent iron (Fe(0))/p‐toluene sulfonylchloride (TsCl) initiator system, resulting in successful high polymer production on the solid surface. GASP was found to be initiated by radical species that might have been generated via redox reactions with Fe(0), Fe(II), Fe(III), and TsCl. From ¹H‐NMR analysis, the p‐toluene sulfonyl group was found at one end of the polymer chain. The molecular weight of obtained PMMA drastically decreased with increase in the composition ratio of Fe(0) in the initiator system, and increased with increase in polymer yield. From the results, it was assumed that the physically controlled polymerization of MMA proceeded by immobilized active species at gas–solid interfaces. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1879–1886, 2007     

甲基丙烯酸甲酯/丙烯酸/水反相无皂微乳液体系的聚合

采用滴定法描绘了甲基丙烯酸甲酯（MMA）/丙烯酸（AA）/H₂O无皂微乳液体系的三元相图,用电导率法对单相微乳液区域进行了类型划分.在相图研究的基础上,考察了引发剂（AIBN）用量、体系AA含量和水含量对MMA/AA/H₂O反相无皂微乳液体系聚合速率的影响.结果表明,聚合速率随引发剂用量和AA含量的增加逐步加快,随体系水含量的提高出现极大值.得到动力学关系,表明AA的乳化促进作用显著,聚合在连续相进行的同时亦在分散相液滴内进行.此外,环境扫描电镜的测试结果表明,所得聚合产物具有明显的孔穴结构.     

Triblock copolymers of methyl methacrylate/N‐vinyl pyrrolidone and their hydrophilication effects on poly(vinylidene fluoride) porous membranes

The new amphiphilic triblock copolymers of poly(N‐vinyl pyrrolidone‐b‐methyl methacrylate‐b‐N‐vinyl pyrrolidone) (P(VP‐b‐MMA‐b‐VP)) were synthesized via a reversible addition fragmentation chain transfer polymerization route. Using these copolymers as additives in casting solutions, the porous blend membranes of poly (vinylidene fluoride) and P(VP‐b‐MMA‐b‐VP) were prepared following a typical nonsolvent induced phase separation process. The influences of P(VP‐b‐MMA‐b‐VP) on the morphologies of the blend membranes were observed by scanning electron microscopy. The chemical compositions in membrane surface layers were measured by X‐ray photoelectron measurement. Water contact angle and water flux experiments were used to evaluate the hydrophilicity and permeation properties of the blend membranes. It was found that the P(VP‐b‐MMA‐b‐VP) copolymers could be retained in membrane stably in membrane formation and application process. The copolymers could enrich in surface layer and endowed the blend membrane with efficient hydrophilicity and higher water permeation flux. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Liquid–liquid phase separation in polysulfone/polyethersulfone/N‐methyl‐2‐ pyrrolidone/water quaternary system

To construct a phase diagram of the polysulfone (PSF)/polyethersulfone (PES)/N‐methyl‐2‐pyrrolidone (NMP)/water quaternary system, cloud point measurements were carried out by a titration method. The miscible region in the PSF/PES/NMP/water quaternary system was narrow compared to the PSF/NMP/water and PES/NMP/water ternary systems. The binary interaction parameters between PSF and PES were estimated by water sorption experiments. The calculated phase diagram based on the Flory–Huggins theory fit the experimental cloud points well. In addition to the usual polymer–liquid phase separation, polymer–polymer phase separation, which resulted in a PSF‐rich phase and a PES‐rich phase, was observed with the addition of a small amount of nonsolvent. The boundary separating these two modes of phase separation could be well described and predicted from the calculated phase diagrams with the estimated binary interaction parameters of the components. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 2113–2123, 1999     

Kinetics of emulsifier–free emulsion polymerization of methyl methacrylate

The influences of polymerization temperature, initiator and monomer concentrations, ionic strength of the aqueous phase, as well as ethylene glycol dimethacrylate (EGDM) co-monomer, on the kinetics of the emulsifier-free emulsion polymerization of methyl methacrylate (MMA) and on the properties of the resulting poly(methyl methacrylate) (PMMA) lattices were studied. The polymerizations were carried out using potassium persulfate (KPS) as the initiator. Monodisperse PMMA lattices with particle diameters varying between 0.14–0.37 μm and polymer molecular weights of the order 0.4 × 10⁶ to 1.2 × 10⁶ g/mol were prepared. The initial rate of polymerization increases with increasing temperature, KPS-MMA mole ratio, EGDM content, or with decreasing ionic strength of the aqueous phase. It was shown that the bead size can be limited by reducing the monomer concentration or by using the cross-linking agent EGDM. The ionic strength of the aqueous phase has a dominant effect on final particle diameter and polymer molecular weight. The uniformity of the latex particles increases as the temperature increases or as the initiator concentration decreases. The experimental results can be reasonably interpreted by the homogeneous nucleation mechanism of the emulsifier-free emulsion polymerization of MMA. © 1996 John Wiley & Sons, Inc.     

Aliphatic polyamidoamine hyperbranched polymers/layered silicate nanocomposites

Polyamidoamine hyperbranched polymer (Hyp)/clay nanocomposites were synthesized by using both of montmorillonite and laponite clays. Poly amidoamine hyperbranched polymer (Hyp) was prepared by one‐pot polymerization via couple monomer methodology. Afterward, the amino ends of Hyp were modified with methyl methacrylate (MMA), styrene (St) and butyl methacrylate (n‐BuMA) polymers which were previously prepared via ATRP (atom transfer radical polymerization) to form the corresponding new hyperbranched polymers Hyp₁, Hyp₂ and Hyp₃. Those formed polymers were inserted into the modified clay, such as montmorillonite and laponite to form their nanocomposites. The formed polymer/clay nanocomposites were characterized via XRD, TEM, and thermal analyses. The formed hyperbranched polymers generally showed intercalation behavior more than the exfoliation one mostly because of the bulkiness of the hyperbranched skeleton. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

The effects of polymer‐nanofiller interactions on the dynamical mechanical properties of PMMA/CaCO3 composites prepared by microemulsion template

We prepared novel poly(methyl methacrylate) (PMMA)/CaCO₃ nanocomposites by using reverse micelle as a template. The nanoparticles of CaCO₃ were prepared by the reverse microemulsion with functional monomer, methyl methacrylate (MMA) as oily phase, and the PMMA/CaCO₃ nanocomposite was obtained via polymerization of MMA monomer. The SEM image showed that the nanoparticles of CaCO₃ were dispersed in the polymer matrix. Dynamic mechanical analysis (DMTA) was performed to investigate the interaction between the nanoparticles and the polymer chains. In the low‐temperature ripening process, two tan δ peaks were observed in the nanocomposite, corresponding to the glass transitions of the matrix and the interface layer. In the high‐temperature ripening process, only one tan δ peak was observed, suggesting that the interface layer forms a continuous phase. The nanoparticles behave as a physical crosslinker in the interface layer. Modification of the surface of nanoparticles with polyacrylamide and poly(N,N′‐methylenedisacrylamide) in the nanocomposite did not show an appreciable effect on the interaction of nanoparticles with the matrix. Upon removal of the aqueous phase around the nanoparticles, we obtained surface‐capped nanoparticles by using an improved reverse microemulsion technique. Another PMMA/CaCO₃ nanocomposite was also obtained with these modified nanoparticles. DMTA analysis of this nanocomposite demonstrated that the aqueous phase layer around the nanoparticles does not significantly affect the interaction between the nanoparticles and the polymer chains. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2739–2749, 2004     

Graft copolymerization of methyl methacrylate and other vinyl monomers onto cotton fabric using ferrous cellulose thiocarbonate–N-bromosuccinimide redox initiation system

The cellulose thiocarbonate, in the fabric from, was treated first with a freshly prepared ferrous ammonium sulphate (FAS) solution. The sotreated fabric formed, with N-bromosuccinimide (NBS), an effective redox system capable of initiating grafting of methyl methacrylate (MMA) and other vinyl monomers onto the cotton fabric. The effect of the polymerization conditions the polymer criteria, namely, graft yeild, homopolymer, total conversion, and grafting efficiency, was studied. These polymer criteria were found to depend extensively upon concentrations of the Fe²⁺ ion (activator), NBS (initiator), and MMA; pH of the polymerization medium, and duration and temperature of polymerization. Based on detailed investigation of these factors, the optimal conditions for grafting were as follows: Fe²⁺, 1 × 10⁻³ mol/L; NBS, 1 × 10⁻² mol/L; MMA, 4%; pH, 2: polymerization time, 150 min; polymerization temperature, 60°C; material/liquor ratio, 1: 100. Under these optimal conditions, the rates of grafting of different vinyl monomers were in the following sequence: methyl methacrylate ≫ methyl acrylate > acrylonitrile. Other vinyl monomers namely, acrylic acid, and methacrylic acid have no ability to be grafted to the cellulosic fabric using the said redox system. A tentative mechanism for the polymerization reaction is suggested. © 1996 John Wiley & Sons, Inc.     

Morphologies of polybutylacrylate/poly(styrene‐co‐methyl methacrylate) latex prepared by starved emulsion polymerization Part I. Thermodynamics equilibrium morphology

Heterogeneous latexes were prepared by a semicontinuous seeded emulsion polymerization process under monomer starved conditions at 80 °C using potassium persulfate as the initiator and sodium dodecyl sulfate as the emulsifier. Poly(butyl acrylate) latexes were used as seeds. The second‐stage polymer was poly(styrene‐co‐methyl methacrylate). By varying the amounts of methyl methacrylate (MMA) in the second‐stage copolymer, the polarity of the copolymer phase could be controlled. Phase separation towards the thermodynamic equilibrium morphology was accelerated either by ageing the composite latex at 80 °C or by adding a chain‐transfer agent during polymerization. The morphologies of the latex particles were examined by transmission electron microscopy (TEM). The morphology distributions of latex particles were described by a statistical method. It was found that the latex particles displayed different equilibrium morphologies depending on the composition of the second‐stage copolymers. This series of equilibrium morphologies of [poly(butyl acrylate)/poly(styrene‐co‐methyl methacrylate)] (PBA/P(St‐co‐MMA)) system provides experimental verification for quantitative simulation. Under limiting conditions, the equilibrium morphologies of PBA/P(St‐co‐MMA) were predicted according to the minimum surface free energy change principle. The particle morphology observed by TEM was in good agreement with the predictions of the thermodynamic model. Therefore, the morphology theory for homopolymer/homopolymer composite systems was extended to homopolymer/copolymer systems. © 2002 Society of Chemical Industry     

Isothermal phase diagrams and phase‐inversion behavior of poly(vinylidene fluoride)/solvents/additives/water systems

Isothermal ternary phase diagrams of poly(vinylidene fluoride) (PVDF)/solvents/nonsolvent systems were produced using four different solvents, N,N‐dimethylacetamide (DMAc), 1‐methyl‐2‐pyrrolidinone (NMP), N,N‐dimethylformamide (DMF), and triethyl phosphate (TEP), and using water as a nonsolvent. The effects of the additives polyvinylpyrrolidone (PVP, M_w = 10,000), ethanol, and lithium perchlorate (LiClO₄) on the phase‐inversion behavior of PVDF/DMAc/water ternary system were investigated, with additive concentrations of 2 and 6 wt %, at temperatures of 25 and 70°C, respectively. Ethanol, glycerol, and water were used to study the cloud points of 10, 15, and 20 wt % PVDF/DMAc concentrations, at solution temperatures ranging from 30 to 70°C. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2150–2155, 2003     

Polymerization‐induced phase separations in branched poly(methyl methacrylate) synthesis

Methyl methacrylate and ethylene glycol dimethacrylate or 1,6‐hexanediol dimethacrylate (HDDMA) were copolymerized in the presence of a nonsolvent (heptane) for poly(methyl methacrylate) (PMMA) to examine the phenomenon of polymerization‐induced phase separations (PIPS) in branched PMMA synthesis. The process was dependent upon the amount of nonsolvent and crosslinker in the reaction mixture. Gel particles were obtained in the majority of phase‐separated systems, and their formation was promoted by the preferential partition of monomer and crosslinker into the precipitated polymer phase during the phase separation process. Experimental data showed that, because of its lower solubility parameter, HDDMA can be used as crosslinker to minimize gel particle formation in systems where PIPS is present. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1462–1468, 2005