Modified suspension‐PVC particles as absorbents of ortho‐dichlorobenzene from water

Modified porous PVC particles are studied as absorbents of o‐dichlorobenzene (DCB), from water. The modified particles were produced by an in‐situ stabilizer‐free polymerization/crosslinking of a monomer/crosslinker/peroxide solution absorbed within commercial porous suspension‐type PVC particles. The modifying monomers used include styrene with divinyl benzene (DVB) as a crosslinking comonomer, methyl methacrylate (MMA), butyl acrylate (BA), or ethylhexyl acrylate (EHA) with ethylene glycol dimethacrylate (EGDMA) as a crosslinking comonomer. The effect of the nature of the monomers, morphology, porosity, surface area and composition of the modified PVC particles on DCB absorption was studied. Batch experiments (absorption rate and isotherms) were used to screen the PVC absorbents on the basis of absorption rate and absorption capacity. Continuous absorption column experiments were conducted to study the parameters characterizing the absorption process. Both the unmodified and modified PVC particles absorb DCB from water. The PBA and PEHA‐modified PVC particles approach equilibrium capacity faster and have greater absorption capacity than neat PVC, PS‐modified PVC and PMMA‐modified PVC particles. The absorption characteristics are influenced by the modifying polymer's T_g. The rubbery nature of PBA and PEHA yields better absorption in spite of the significantly lower surface area and porosity obtained in the modified PVC particles. Thus, indicating that fast adsorption followed by bulk absorption of DCB is taking place. A clear influence of the crosslinking effect was not established. The continuous absorption experiments were found more efficient than the batch absorption experiments. Copyright © 2003 John Wiley & Sons, Ltd.     

Synthesis and characterization of new flame-retardant microspheres by dispersion polymerization of pentabromobenzyl acrylate

New flame-retardant nano/micro particles of sizes ranging between 0.06 ± 0.01 and 1.70 ± 0.23 μm were formed by dispersion polymerization of the pentabromobenzyl acrylate monomer (PBBA) in methyl ethyl ketone as a continuous phase. The effect of various polymerization parameters, e.g., monomer concentration, initiator type and concentration, stabilizer concentration and crosslinker monomer concentration, on the size, size distribution and polymerization yield of the produced poly(pentabromobenzyl acrylate) particles has been elucidated. Poly(pentabromobenzyl acrylate)/polystyrene (PPBBA/PS) nano/micro blends of the contents of different PPBBA particles were prepared by mixing the PPBBA particles with a PS solution in methylene chloride, followed by evaporation of the methylene chloride from the mixture. The thermal stability of these blends was also studied.     

Investigation of stabilizer‐free dispersion polymerization process of styrene and maleic anhydride copolymer microspheres

The copolymer microspheres of styrene (St) and maleic anhydride (MA) were synthesized by stabilizer‐free dispersion polymerization, and the polymerization process was explored in detail. The results showed that the homopolymerization of St formed in initial polymerization period served as stabilizer, and reaction solvent of closer solubility parameter would benefit the stabilizer‐free dispersion polymerization. In addition, some principal factors affecting the microspheres size, such as reaction time, reaction temperature, monomer concentration, molar feed ratio, reaction media, and cosolvent, were investigated as well. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

Preparation of polymer nanoparticles from renewable biobased furfuryl alcohol and maleic anhydride by stabilizer‐free dispersion polymerization

The spherical polymer nanoparticles of biobased renewable monomers, furfuryl alcohol (FA) and maleic anhydride (MAn), with diameters (D_n) in the range of 120 to 500 nm have been prepared by stabilizer‐free dispersion copolymerization. In acetate or its mixture, the conversion of the monomers greatly depended on the concentration of AIBN. When the molar ratio of AIBN/monomers was 3.6% (wt), the monomer conversion could be as high as 80%. The aggregations of the solvated polymer chains formed the nuclei of the polymer particles. After the nucleation stage, both the monomer conversions and particle sizes increased steadily, while the coefficient of variation of the particle size decreased. The almost linear relationship between the D_n³ and the weight of polymer suggested that there is no significant secondary nucleation. The copolymer of FA and MAn could not dissolve in common organic solvents. Elemental analyses, FTIR and ¹³CP‐MAS spectra showed that the copolymer was close to the alternative copolymer of FA and MAn irrespective to the molar ratios of FA/MAn in monomer feed. Furthermore, the two 2,5‐ and 3,4‐dihydrofuran ring configurations exist in the copolymer and the later is the major one. The reaction of copolymer particles with triethylenetetramine confirmed the reactivity of the succinic anhydride groups at the surface of copolymer particles. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Rate enhancement for nitroxide stable free radical polymerization of n‐butyl acrylate by dodecylbenzenesulfonic acid

Dodecylbenzenesulfonic acid, DDBSA, was chosen as a new rate‐accelerating additive for 2,2,6,6,‐teramethyl‐1‐piperidinyloxy (TEMPO)‐mediated stable free radical polymerization of n‐butyl acrylate (n‐BA) monomers with 2,2′‐azobisisobutyronitrile (AIBN). It was found that the number‐average molecular weight of polymers could reach about ten thousand with a narrow polydispersity index (PDI) of 1.4 in a few minutes, which was faster than other systems reported previously. But, at higher conversion, the molecular weight distribution of polymers became broad, and a bimodal distribution occurred. The macro‐initiators isolated from the former polymers with narrow PDI could be extended by polymerization with monomers by the addition of DDBSA. Furthermore, a proposed kinetic model demonstrated that the decay of the concentration of DDBSA would reduce the living polymer concentration and retard the growth of the polymers, which could be further propagated by the supplement of DDBSA. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 42–49, 2005     

Graft copolymerization of butyl acrylate and 2‐ethyl hexyl acrylate from labile chlorines of poly(vinyl chloride) by atom transfer radical polymerization

Trace amounts of labile chlorines present in poly(vinyl chloride) (PVC) were found to act as initiation sites for the preparation of graft copolymers of PVC by copper‐mediated atom transfer radical polymerization (ATRP). High grafting yields were attained during the graft copolymerizations of n‐butyl acrylate (161.8%) and 2‐ethyl hexyl acrylate (51.2%) in 7.5 h. In both cases, the grafting proceeded with first‐order kinetics with respect to the monomer concentrations, this being typical for ATRP. Gel permeation chromatography traces of the resulting products did not exhibit additional peaks attributable to the formation of free homopolymers. The presented procedure offers an efficient means of preparing self‐plasticized PVC structures. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3457–3462, 2003     

Synthesis and characterization of benzocyclobuten-4-yl acrylate monomer and its radical polymerization

<正>A benzocyclobuten-4-yl acrylate(1) monomer was prepared by esterification of 4-hydroxybenzocyclobutene with acryloyl chloride.The radical homopolymerization of 1 and copolymerization of 1 with styrene or n-butyl acrylate were carried out to produce linear polymers 2a,2b and 2c.Heating of these linear polymers under thermal initiation gave corresponding cross-linked polymers 3a,3b and 3c.The ring-opening reaction in the cross-linking process was confirmed by on-line infrared spectra.Differential scanning calorimetry showed that the glass transition temperatures of linear polymers 2a and 2b were 83.2℃and 68.1℃,respectively.Thermogravimetric analysis of the cross-linked polymers showed that they all exhibited good thermal stability.     

Ultraviolet–ultraviolet dual‐cure process based on acrylate oxetane monomers

A dual‐cure process consisting of two subsequent ultraviolet‐initiated radical and cationic polymerizations was investigated. The process was studied with two acrylate oxetane monomers, one of them having a spacer between the two polymerizable moieties. It was shown by Fourier transform infrared (FTIR) that the first (radical) step was performed successfully for both systems. As for the second (cationic) step, only the monomer with the spacer was able to polymerize, allowing the crosslinking of the polyacrylic chains generated by the first step. The efficiency of the process was confirmed by differential scanning calorimetry because the glass‐transition temperatures of the cured films were ?16 and + 34 °C after the first and second steps, respectively. The dual cure of this system was further analyzed by real‐time FTIR, which showed that 86% of the acrylate and 80% of the oxetane moieties were converted after 20 and 50 s of light exposure, respectively. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 469–475, 2003     

Are o‐nitrobenzyl (meth)acrylate monomers polymerizable by controlled‐radical polymerization?

We report on the controlled‐radical polymerization of the photocleavable o‐nitrobenzyl methacrylate (NBMA) and o‐nitrobenzyl acrylate (NBA) monomers. Atom transfer radical polymerization (ATRP), reversible addition‐fragmentation chain transfer polymerization (RAFT), and nitroxide‐mediated polymerization (NMP) have been evaluated. For all methods used, the acrylate‐type monomer does not polymerize, or polymerizes very slowly in a noncontrolled manner. The methacrylate‐type monomer can be polymerized by RAFT with some degree of control (PDI ∼ 1.5) but leading to molar masses up to 11,000 g/mol only. ATRP proved to be the best method since a controlled‐polymerization was achieved when conversions are limited to 30%. In this case, polymers with molar masses up to 17,000 g/mol and polydispersity index as low as 1.13 have been obtained. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 6504–6513, 2009     

Effect of bio‐based monomers on the scratch resistance of acrylate photopolymerizable coatings

Photopolymerizable clear coatings based on bio‐sourced acrylates, dedicated to the protection of polycarbonate substrates, were studied. The bio‐sourced compounds were not based on triglycerides but were smaller, industrially available molecules similar to classical petro‐based monomers. Their polymerization kinetics was studied by photo‐DSC and was shown to allow high acrylate conversions even at 25 °C. Closely related coatings enriched in alkyl segments, or in monoacrylates to decrease the crosslinking density, were compared. The material composition affects its nanomorphology deduced from X‐ray diffraction. Although these changes in composition can slightly shift the mechanical relaxation, it remains wide, and the elastic modulus remains high (>10⁸ Pa) for all the tested materials. Microscratch experiments highlighted the efficiency of all the new coatings in terms of protection against scratches. Incorporating a monoacrylate, particularly isobornyl acrylate, can improve the scratch resistance especially in terms of critical load (up to 175% increase compared with a classical petro‐based coating). © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015 , 53, 379–388     

Tailor‐made poly(ethyl acrylate) by atom transfer radical polymerization

Atom transfer radical polymerization (ATRP) of ethyl acrylate (EA) was carried out using different initiators, CuBr or CuCl as catalyst in combination with different ligands e.g., 2,2′‐bipyridine (bpy) and N,N,N′,N″N″‐pentamethyl diethylenetriamine (PMDETA). Use of PMDETA as ligand resulted in faster polymerization rate (95% conversion in 15 min) than those using bipyridine (～58% conversion in 10.5 h). This is due to the lower reduction potential of copper‐amine than that of copper‐bpy complex, resulting in higher rates of activation of dormant halides. Use of ethylene carbonate as solvent lead to faster polymerization rate and better control in polymerization when compared with p‐xylene as solvent. The reaction temperature had a positive effect on polymerization rate and the optimum reaction temperature was found to be 90 °C. An apparent enthalpy of activation of ～85 kJ/mol was determined for the ATRP of ethyl acrylate, corresponding to an enthalpy of equilibrium of ～64 kJ/mol. By judicious choice of the reaction parameters it was possible to tailor the end group of the final polymer. MALDI‐TOF‐MS analysis and the chain extension experiment of poly(ethyl acrylate) (PEA) prepared using bpy as ligand showed the presence of ? Br as the end group. On the contrary, when PMDETA was used as the ligand, the mass spectra analysis showed hydrogen terminated polymer as the major species towards the end of polymerization. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1661–1669, 2007     

Activity of the furfuryl ring in the free radical polymerization of acrylic monomers

The effect and the participation of the furfuryl ring, in particular the hydrogen at position C-5 in the free radical polymerization are analyzed following the polymerization of furfuryl acrylate (FA) and furfuryl methacrylate (FM) initiated by AIBN under photochemical activation. The results obtained indicate that the polymerization of FA deviates from the classical free radical kinetic scheme, giving rise to crosslinked polymers even at a degree of conversion lower than 7%. This behavior is well explained taking into consideration the participation of the furfuryl ring which acts as a degradative transfer agent. This was demonstrated by the kinetic analysis of the free radical polymerization of MMA initiated by the thermal decomposition of AIBN in the presence of different concentrations of furfuryl acetate. © 1996 John Wiley & Sons, Inc.     

Crosslinked polynorbornene particles synthesis by ring‐opening metathesis polymerization in dispersion

This article proposes the first report on the synthesis of nanometric crosslinked polynorbornene particles by ring‐opening metathesis polymerization in dispersion using ruthenium‐based complex (PCy₃)₂Cl₂Ru?CHPh as initiator. Stable but raspberry‐shaped particles were obtained. In this study, a particular attention was paid to the influence of the crosslinker nature and addition mode on reaction kinetics and morphology of the latex particles. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Facile synthesis of poly(hydroxyethyl acrylate) by frontal free‐radical polymerization

We report the first synthesis of poly(hydroxyethyl acrylate) (PHEA) without solvent by free‐radical frontal polymerization (FP) at ambient pressure. In a typical run, the appropriate amounts of reactant (hydroxyethyl acrylate) and initiator (1,1‐di(tert‐butylperoxy)‐3,3,5‐trimethylcyclohexane) (Luperox 231) were mixed together at ambient pressure. FP was initiated by heating the wall of the tube with a soldering iron, and the resultant hot fronts were allowed to self‐propagate throughout the reaction vessel. Once initiated, no further energy was required for polymerization to occur. To study the macrokinetics, we also produced PHEA frontally with ammonium persulfate as initiator and dimethyl sulfoxide as the solvent. The dependences of the front velocity and front temperature on the initiator concentration and reactant dilution were investigated. The front temperatures were between 124 and 157 °C, depending on the ammonium persulfate concentration. Thermogravimetric analysis indicates that PHEA prepared by FP with ammonium persulfate as initiator had higher thermal stability than solvent‐free frontally prepared PHEA with Luperox 231 as initiator. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 873–881, 2007     

Synthesis,polymerization, and curing of N‐substituted citraconimidyl acrylate

Several N‐(substituted phenyl) citraconimides containing phenolic hydroxyl groups (I) were prepared. I were esterified with acryloyl chloride producing the corresponding acrylate esters (II). II were free radically polymerized yielding linear polyacrylates (III). The citraconimidyl vinyls did not participate in the polymerization. The resulting polymers (III) were cured thermally or through the crosslinking agent N,N‐(p‐phenylene)dimaleimide. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 427–433, 1999     

Synthesis and characterization of oxazoline-functional polymer particles by free radical nonaqueous dispersion polymerization

A novel oxazoline-functional methacrylate was prepared and employed as comonomer to produce nonaqueous dispersions of oxazoline-functional polymer particles. In nonaqueous free radical dispersion copolymerization of methylmethacrylate in the presence of oxazoline-functional methacrylate, ethyleneglycoldimethacrylate crosslinking agent, AIBN initiator, and polystyrene-block-poly(ethene-alt-propene) dispersing agent, the average polymer particle size, varying between 100 and 500 nm, was controlled by the dispersing agent contents. According to titration with HClO₄ all oxazoline groups regardless of their location at particle surface or bulk, were accessible. Glass transition temperature decreased from 120 to 0°C when oxazoline functional methacrylate was increased from 0 to 95 mol %. As imaged by atomic force microscopy incorporation of the new oxazoline-functional methacrylate improved film formation. Oxazoline-functional polymer particles were easy to redisperse in a variety of other diluents. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 2539–2548, 1997     

Tailor‐made hybrid nanostructure of poly(ethyl acrylate)/clay by surface‐initiated atom transfer radical polymerization

Hybrid nanoarchitecture of tailor‐made Poly(ethyl acrylate)/clay was prepared by surface‐initiated atom transfer radical polymerization (SI‐ATRP), by tethering ATRP initiator on active hydroxyl group, present in surface as well as in the organic modifier of the clay used. Extensive exfoliation was facilitated by using these initiator modified clay platelets. Poly(ethyl acrylate) chains with controlled polymerization and narrow polydispersities were forced to be grown from within the clay gallery (intergallery) as well as from the outer surface (extragallery) of the clay platelets. The polymer chains attached onto clay surfaces might have the potential to provide the composites with enhanced compatibility in blends with common polymers. Attachment of the initiator on clay platelets was confirmed by Fourier transform infrared spectroscopy (FTIR), X‐ray photoelectron spectroscopy (XPS), elemental analysis, Wide‐angle X‐ray diffraction (WAXD), and microscopic analysis. Finally, end group analysis (by Matrix‐Assisted Laser Desorption Ionization Mass Spectrometry, and chain extension experiment) of the cleaved polymer and morphological study (by WAXD, Transmission Electron Microscopy), performed on the polymer grafted clays examined the effect of grafting on the efficiency of polymerization and the degree of dispersion of clay tactoids in polymer. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 5014–5027, 2008     

Synthesis of polybutadiene‐based particles via dispersion ring‐opening metathesis polymerization

Latex particles based on 1,4‐polybutadiene were synthesized via dispersion ring‐opening metathesis copolymerization of 1,5‐cyclooctadiene with a α‐norbornenyl poly(ethylene oxide) macromonomer. Stable but polydisperse colloidal dispersions in the 50 nm to 10 μm size range were obtained. In this work, particular attention was paid to the effects of the kinetics of copolymerization on the structure of the graft copolymers formed and on the onset of turbidity. Strategies to prepare monodisperse polybutadiene particles were also designed through the growth of a polybutadiene shell from a well‐defined polynorbornene seed. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 1154–1163, 2004     

顶空气相色谱-质谱联用法测定胶粘剂中的残余单体

建立了一种测定胶黏剂中6种丙烯酸酯和甲基丙烯酸酯类残余单体的分析方法。样品经100 ℃、30 min顶空加热后,通过DB-WAX色谱柱(30 m×0.25 mm×0.25 μm)分离和质谱选择离子模式检测,内标法定量。结果表明,6种残余单体能达到良好的分离,检出限(信噪比为3)为0.069～0.096 mg/kg,定量限(信噪比为10)为0.23～0.32 mg/kg,平均回收率为96.0%～104.6%,相对标准偏差(RSD)小于7.2%。该方法操作简便、准确、重复性好、灵敏度高,可用于胶黏剂中丙烯酸酯和甲基丙烯酸酯类残余单体的快速测定。