Synthesis of high molecular weight polyacrylamide flocculant by radiation polymerization

The radiation-induced polymerization of acrylamide was studied to prepare a high molecular weight and highly effective polyacrylamide flocculant. Among various solvents, mixtures of water–tert-butyl alcohol and water–acetone were found to be suitable for the synthesis of the high molecular weight polyacrylamide. For polymerization in acetone–water mixtures, the molecular weight of polymer increases with monomer concentration; but at the high concentration, intermolecular imidation of amide groups tends to take place during the polymerization to from crosslinked and water-insoluble polymer. The water-soluble polymer with the largest molecular weight of 6.7 × 10⁶ is produced in the polymerization with monomer concentration of 2.91 moles/1. at 0°C at a dose rate of 6.2 × 10² rad/hr in acetone–water mixture containing 60 vol-% water. The crosslinking of polymer of the formation of water-insoluble polymer could be avoided by the addition of K₂CO₃ or NaOH to raise the pH of the reaction mixture above 6.5. The flocculation effects were evaluated from sedimentation speed of kaolin suspension and transparency of the separated water. The sedimentation speed is proportional to the intrissic viscosity of the polymer in the range of 4 to 23 dl/g. The polymers prepared in this study show much higher sedimentation speed than commercial polyacrylamide flocculants. The transparency of the separated water is higher than 93%, similar to the results with commercial flocculants.     

Tailoring of energetic groups in acroyloyl polymers

Acryloyl based novel energetic monomers having nitro acrylates and nitro triazole acrylates were synthesized and further used for polymerization. Due to scavanging properties of nitro groups, syntheses of nitro aromatic polymers are not facile at normal conditions. In this regard, we report a simple protocol to synthesize these energetic group embeded acroloyl polymers. These polymers were characterized by FTIR, and NMR spectroscopic techniques. gel permeation chromatography (GPC) technique was employed in order to understand molecular mass of these polymers along with average molecular weight, number average weight and poly dispersity index. Glass transition temperature (T_g) was determined by using DSC analysis. It was observed that with increase in nitro groups in polymers there is a decrease in glass transition temperature. Two steps degradation were depicted in the TGA thermograph in nitro containing polymers. Heat release during this reaction was found up to 951 J/g. Increase in nitrogen content in polymer unit enhanced the heat release of polymers.     

聚丙烯酰胺对氨水中有机悬浮物絮凝作用的研究

对氨水中的有机悬浮物采用聚丙烯酰胺(PAM)进行絮凝。通过絮团特征、清液特征、絮团聚集程度以及氨水中絮团体积的变化率同絮凝时间的关系,比较了不同添加量、不同种类的PAM絮凝效果。结果表明,采用阴离子型聚丙烯酰胺和阳离子型聚丙烯酰胺相结合的絮凝方式,能较好地絮凝氨水中的有机悬浮物。较好的絮凝方式是:在140 r/m in搅拌中,往氨水中加入分子量为1100万、浓度为1‰的阴离子型聚丙烯酰胺15 mL/L,搅拌1 m in;调转速为60 r/m in,加入离子度为20%~25%、浓度为1‰的阳离子型聚丙烯酰胺5 mL/L,搅拌5 m in,静止1 h。     

Preparation of ultra‐high‐molecular‐weight polyacrylamide by vertical solution polymerization technique

A straightforward and novel methodology has been developed for the synthesis of ultra‐high‐molecular weight polyacrylamide (PAM) by vertical solution polymerization technique. By varying the concentrations of acrylamide monomer, three different grades of polymers (PAM‐V₁, PAM‐V₂, and PAM‐V₃) have been synthesized and compared with the series of different grades of PAM (PAM‐C₁, PAM‐C₂, and PAM‐C₃) synthesized through conventional solution polymerization technique. The synthesized grades PAM‐V₁, PAM‐V₂, PAM‐V₃, PAM‐C₁, PAM‐C₂, and PAM‐C₃ have been characterized by ¹H NMR, infrared spectroscopy, intrinsic viscosity measurement, molecular weight determination by gel permeation chromatography, and thermal analysis. Rheological analysis has been carried out on the aqueous solutions of various grades of PAMs. Swelling behavior of ultra‐high‐molecular weight PAMs has also been investigated. The flocculation performances of all grades have been investigated in kaolin suspension by settling and jar test methods. POLYM. ENG. SCI., 59:1175–1181 2019. © 2019 Society of Plastics Engineers     

Synthesis and properties of cationic polyacrylamide containing pyridine quaternary salt

The copolymer P(AM‐co‐4VP) of acrylamide (AM) and 4‐vinylpyridine (4VP) was synthesized by radical copolymerization in solution, and then the copolymer was quaternarized using dimethyl sulfate to produce cationic P(AM‐co‐4VP) (CPAV), a cationic polyacrylamide containing quaternary pyridine salt. Two series of CPAV have been synthesized. The structure and composition of the copolymer and the cationic copolymer were characterized by their FTIR, ¹H NMR and ultraviolet spectra Flocculation and corrosion inhibition properties of the cationic copolymer were studied in detail and effects of cationic degree and molecular weight on the flocculation and corrosion inhibition properties were discussed. The results showed that cationic polyacrylamide containing quaternary pyridine salt possesses excellent flocculation, corrosion inhibition and other functions. The higher the degree of cationization, the better are these functions, and the molecular weight also effects the functions significantly. Copyright © 2003 Society of Chemical Industry     

Synthesis,characterization, and flocculation properties of poly(acrylamide‐methacryloxyethyltrimethyl ammonium chloride‐methacryloxypropyltrimethoxy silane)

A novel hydrophobically modified and cationic flocculant poly(acrylamide‐methacryloxyethyltrimethyl ammonium chloride‐methacryloxypropyltrimethoxy silane) (P(AM‐DMC‐MAPMS)) was synthesized by inverse emulsion polymerization. The molecular structure of hydrophobically cationic polyacrylamide (HCPAM) was characterized by FTIR and ¹H‐NMR. The effects of DMC and MAPMS feed ratio on intrinsic viscosity and solubility were measured. The effects of hydrophobically cationic flocculants on reactive brilliant red X‐3B solution and kaolin suspension were studied. It was found that the introduction of MAPMS could increase the intrinsic viscosities of P(AM‐DMC‐MAPMS) and enhance the flocculation properties to anionic dye solution and kaolin suspension, but reduced their water‐solubility. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

The adiabatic compressibility of poly(acrylic acid) and polyacrylamide in aqueous solution

The results of adiabatic compressibility measurements of poly(acrylic acid) and polyacrylamide along with their corresponding monomers and two poly(sodium acrylates) obtained by neutralizing the polyacid 25% and 100% with sodium hydroxide have been described. The total adiabatic compressibility of poly(acrylic acid) solution is higher than that of the corresponding salt solutions or of polyacrylamide solutions. The unneutralized acid does not dissociate much, even in dilute solution, and the magnitude of electrostriction in polyamide is greater than in acid. The ΦV₂ and ΦK₂ values for monomers and polymers are seen to be almost concentration independent, and so are the sodium salts of the polyacid. Poly(acrylic acid) and poly(acrylamide) are structurally closely related polymers, and water must be bound to them through polar groups either by hydrogen bonding or by dipole attraction. The hydrophobic part of the solute, because of compact orientation of water and solute in the boundary region, causes a decrease in solvent volume and therefore in the values of ΦV₂ and ΦK₂. On the other hand, intermolecular hydrogen bonding between the polar groups increases the volume and counterbalances the hydrophobic effect. Because of these two counteracting effects, the observed ΦV₂ and ΦK₂ values are seen to be concentration independent. Contrary to the observation with poly(methacrylic acid)¹ and its sodium salts, the solvated counter-ions in case of poly(sodium acrylates) make no special contribution in the dilute region. In 100% neutralized polyacid, the dissociation of counterions is complete, and the magnitude of electrostriction is highest in this case. Accordingly, lowest ΦV₂ and ΦK₂ values (37.0 cc/mole and ?50.50 × 10^?3 cc bar^?1 mole^?1) are observed. However, the dissociation and therefore the magnitude of electrostriction are somewhat reduced in the presence of 1.0M NaCl solution; and, accordingly, the values increase to 42.80 cc/mole and ?33.0 × 10^?4 cc bar^?1, mole^?1, respectively. The limiting values for the apparent molal volume and the apparent molal compressibility for the polymers show a considerable decrease over those of the monomers. The values of ΦV₂⁰ and ΦK₂⁰ per methyl group are less in the polymers than in the monomers, and this has been attributed to water clusters that become stronger and better formed as the molecules grow larger and larger. The molar volumes of acrylic acid and methacrylic acid are decreased, while those of acrylamide and methacrylamide are increased when dissolved in water to form an infinitely dilute solution.     

Effect of molecular weight on spherulitic growth rate of poly(ϵ‐caprolactone) and poly(ϵ‐caprolactone)‐b‐poly(ethylene glycol)

The spherulitic growth rates of a series poly (?‐caprolactone) homopolymers and poly(?‐caprolactone)‐b‐ poly(ethylene glycol) (PCL‐b‐PEG) block copolymers with different molecular weights but narrow polydispersity were studied. The results show that for both PCL homopolymers and PCL‐b‐PEG block copolymers, the spherulitic growth rate first increases with molecular weight and reaches a maximum, then decreases as molecular weight increases. Crystallization temperature has greater influence on the spherulitic growth rate of polymers with higher molecular weight. Hoffman–Lauritzen theory was used to analyze spherulitic growth kinetics and the free energy of the folding surface (σ_e) was derived. It is found that the values of σ_e decrease with molecular weight at low molecular weight level and become constant for high molecular weight polymers. The chemically linked PEG block does not change the values of σ_e significantly. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Ring-opening polymerization of <Emphasis Type="SmallCaps">l</Emphasis>-lactide catalyzed by a novel molybdenum-based catalytic system

As a transparent material that can be completely biodegradable, poly(l-lactide) (PL-LA) has recently received considerable attention. In this study, it our first efforts to fabricate l-lactide (L-LA) by a novel molybdenum-based catalytic system consisting of molybdenum pentachloride (MoCl₅) as the main catalyst and m-cresol substituted alkyl aluminum Al(OPhCH₃)(i-Bu)₂ as the co-catalyst. The effects of different types of phosphorus ligands, Al:Mo molar ratios, catalyst contents,catalyst components (separate catalysis of m-cresol aluminum and cocatalysis of Al/Mo system) and polymerization temperature were investigated. The T_g and T_m of the resulting poly(l-lactide) (PL-LA) were characterized by differential scanning calorimetry (DSC), and the molecular weight and molecular weight distribution were determined by gel permeation chromatography (GPC). The GPC results showed that the molecular weight of the PL-LA was higher than that 10⁴ g/mol and the molecular weight distribution was narrow. The structures of PL-LA was detected by ¹H NMR spectroscopy (¹H NMR) and X-ray diffraction (XRD) validation, which demonstrated that a moalr ratio of Mo/Al/l-lactide?=?1:30:1000 showed the higher conversion rate and molecular weight. In comparison to the separate catalysis of m-cresol aluminum, the molecular weight of PL-LA prepared by the cocatalysis of Al/Mo system was slightly improved, and the molecular chains were relatively regular and the crystallinity was higher.     

Synthesis of cationic polyacrylamide by aqueous two‐phase polymerization in poly(ethylene glycol) chloride solution

Aqueous two‐phase copolymerization of acrylamide(AM) and acryloyloxyethyl trimethyl ammonium chloride (DAC) was performed in poly(ethylene glycol) (PEG) solution and in PEG chloride(Cl‐PEG) solution, respectively. Series of cationic polyacrylamide(CPAM) aqueous dispersion were prepared using potassium persulfate (KPS) as initiator. The effect of total amount of monomers, the dosage of initiator, the content of dispersant, the mass ratio of AM to DAC, and the temperature on the conversion, molecular weight, cationic degree, and stability of aqueous dispersion were studied in detail. It is found that the increase of initiator and reaction temperature resulted in the increase of the final conversion, whereas the increase of DAC and PEG concentration resulted in the decrease of the final conversion. The optimum reaction conditions of synthesis were as follows: (1) PEG‐H₂O system: PEG 7.5 g, AM 8 g, DAC 2 g, KPS 0.05 g, H₂O 100 mL, 70°C. In this process conditions, the molecular weight of CPAM was 3.21 × 10⁶, the cationic degree of CPAM was 24.4%, the storage stability of the aqueous dispersion was over 3 months. (2) Cl‐PEG‐H₂O system: Cl‐PEG 7.5 g, AM 8 g, DAC 2 g, KPS 0.05 g, H₂O 100 mL, 65°C. In this process conditions, the molecular weight was 3.68 × 10⁶, the cationic degree was 23.3%, and the storage stability of the aqueous dispersion was over 6 months. In general, the stability of CPAM aqueous dispersion in Cl‐PEG system is much better than in PEG system. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Characterization and comparison of diblock and triblock amphiphilic copolymers of poly(δ‐valerolactone)

Three types of pegylated amphiphilic copolymers of poly(δ‐valerolactone) (PVL) were copolymerized with methoxy poly(ethylene glycol) (MePEG) and poly(ethylene glycol) (PEG₄₀₀₀ and PEG_10,000), respectively. Pegylation of PVL allowed copolymers possessing amphiphilic property and efficiently self‐assembled to form micelles with a low critical micelle concentration (CMC) in the range of 10^?7–10^?8M. The average molecular weight of copolymers was in the range of 10,000–20,000 Da, and the polydispersity of copolymers was about 1.7–1.8. Higher mobility of low molecular weight PEG (i.e., MePEG and PEG₄₀₀₀) than high molecular weight PEG_10,000 allowed valerolactone ring opening more efficient in terms of PVL/MePEG and PVL/PEG₄₀₀₀ copolymers possessing longer chain length in hydrophobic domain. Pegylated PVL with low CMC and triblock structure was preferred to encapsulate drug during micelle formation. Although all of these amphiphilic copolymers exhibited controlled release character, the micelles formed by triblock copolymer possessed a more stable core‐shell conformation than that by diblock copolymer, and resulted in the release of drug from triblock micelles slower than that from diblock micelles. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1836–1841, 2006     

Factors effecting a loss of flocculation activity of polyacrylamide solutions: Shear degradation,cation complexation,and solution aging

Polyacrylamide and poly(acrylamide-co-acrylic acid) flocculant solutions were subjected to shear degradation in a rotating cone instrument. At constant shear rate, shear degradation was minimized (highest limiting intrinsic viscosity) by the use of a lower solution concentration and high ionic strength of the polymer solution. Resistance to shear degradation also increased with increasing anionic character of the polyacrylamide. Sheared polymers showed reduced performance as flocculants of coal preparation plant tailings, their major commerical application in the U.K. Partially anionic polyacrylamide solutions were completely inactivated in the presence of certain multivalent cations. Aluminium, iron_III, lead, copper, and zinc ions formed complexes with the carboxyl groups on the polymer, resulting in zero flocculation activity. Nonionic polyacrylamides were unaffected. Viscosity–aging of polyacrylamide solutions was observed over a period of several months, but was insufficient to affect the flocculation activity. In the presence of 3% ethanol or methanol, no aging was observed in solutions stored for over a year.     

Synthesis and characterization of biodegradable poly(ester‐urethanes) based on bacterial poly(R‐3‐hydroxybutyrate)

A series of poly(R‐3‐hydroxybutyrate)/poly(ε‐caprolactone)/1,6‐hexamethylene diisocyanate‐segmented poly(ester‐urethanes), having different compositions and different block lengths, were synthesized by one‐step solution polymerization. The molecular weight of poly(R‐3‐hydroxybutyrate)‐diol, PHB‐diol, hard segments was in the range of 2100–4400 and poly(ε‐caprolactone)‐diol, PCL‐diol, soft segments in the range of 1080–5800. The materials obtained were investigated by using differential scanning calorimetry, wide angle X‐ray diffraction and mechanical measurements. All poly(ester‐urethanes) investigated were semicrystalline with T_m varying within 126–148°C. DSC results showed that T_g are shifted to higher temperature with increasing content of PHB hard segments and decreasing molecular weight of PCL soft segments. This indicates partial compatibility of the two phases. In poly(ester‐urethanes) made from PCL soft segments of molecular weight (M_n ≥ 2200), a PCL crystalline phase, in addition to the PHB crystalline phase, was observed. As for the mechanical tensile properties of poly(ester‐urethane) cast films, it was found that the ultimate strength and the elongation at the breakpoint decrease with increasing PHB hard segment content. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 703–718, 2002     

Preparation of isotacticity‐rich poly(tert‐butyl vinyl ether) by the cationic polymerization of tert‐butyl vinyl ether with dimethyl[rac‐ethylenebis(indenyl)]zirconium and tri(pentafluorophenyl)borane

tert‐Butyl vinyl ether (tBVE) was polymerized with the catalyst dimethyl[rac‐ethylenebis(indenyl)] zirconium (ansa‐zirconocene) with tri(pentafluorophenyl) borane [B(C₆F₅)₃] as a cocatalyst. The effects of various polymerization conditions, such as the polymerization time, type of polymerization solvent, polymerization temperature, and catalyst concentration, on the conversion of tBVE into poly(tBVE), its molecular weight and molecular weight distribution, and its stereoregularity were investigated. The maximum conversion of tBVE into poly(tBVE) was over 90% at a polymerization temperature of ?30°C with an ansa‐zirconocene and B(C₆F₅)₃ concentration of 3.0 × 10^?7 mol/mol of tBVE, respectively. The number‐average molecular weights of poly(tBVE) ranged from approximately 14,000 to 20,000, with a lower polydispersity index (weight‐average molecular weight/number‐average molecular weight) ranging from 1.48 to 1.77, at all polymerization temperatures. The number‐average molecular weight of poly(tBVE) increased with decreases in the polymerization temperature and catalyst concentration. The mm triad sequence fraction of poly(tBVE) polymerized with ansa‐zirconocene/B(C₆F₅)₃ at ?30°C was much higher than that of poly(tBVE) polymerized with the B(C₆F₅)₃ catalyst at ?30°C, and this indicated that the ansa‐zirconocene/B(C₆F₅)₃ catalyst system affected the isospecific polymerization of tBVE. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Porous biodegradable polyesters. II. Physical properties,morphology, and enzymatic and alkaline hydrolysis of porous poly(ϵ‐caprolactone) films

Porous poly(?‐caprolactone) (PCL) films were prepared by water extraction of poly(ethylene oxide) (PEO) from their solution‐cast phase‐separated blend films and the dependence of their blend ratio [X_PCL = PCL/(PEO + PCL)] and molecular weight of PEO on the porosity, pore size, crystallinity, crystalline thickness, mechanical properties, morphology, and enzymatic and alkaline hydrolysis of the porous PCL films were investigated. The film porosity or extracted weight ratio was in good agreement with the expected values, irrespective of X_PCL and molecular weight of PEO. The maximum pore size was larger for the porous films prepared using PEO having a lower molecular weight, compared with films prepared using PEO having a higher molecular weight at the same X_PCL. Differential scanning calorimetry of the porous PCL films revealed that their crystallinity and crystalline thickness were almost constant, regardless of X_PCL and molecular weight of PEO. The Young's modulus and tensile strength of the porous films decreased, whereas the elongation‐at‐break increased with decreasing X_PCL. The enzymatic and alkaline hydrolysis rates of the porous films increased with a decrease in X_PCL and an increase in the molecular weight of PEO. The porous PCL films having Young's modulus in the range of 2–24 kg/mm² and enzymatic hydrolysis rate in the range of one‐ to 20‐fold that of the nonporous PCL film could be prepared by altering X_PCL and the molecular weight of PEO. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2281–2291, 2001     

The shear degradation of high-molecular-weight flocculant solutions

Solutions of polyacrylamide and poly(acrylamide-co-sodium acrylate) flocculants with varying molecular weights were shear degraded under a range of mixing conditions. The viscosity and flocculant activity of the solutions generally decreased with time to limiting values dependent on the mixing intensity. The activity of 10 and 20% anionic flocculants displayed quite different trends from those for nonionic flocculants of equivalent molecular weight, with less apparent degradation due to mixing, particularly at low dosages. However, viscosity measurements on sheared solutions diluted with a salt buffer suggest that nonionic and anionic flocculants with similar initial molecular weights were degraded to the same degree. Multiangle laser light-scattering measurements were used to confirm that the shearing process resulted in a reduction in molecular weight which was independent of anionic character. The apparent shear resistance of anionic flocculation mechanisms for the nonionic and anionic flocculants. © 1996 John Wiley & Sons, Inc.     

Zur Frage der Instabilität von Polyacrylamidlösungen

The solution instability (also called ageing or degradation) of high purity polyacrylamides(PAAm) was examined for a number of different molecular weights. This instability set in by a decrease of the solution viscosity and of [η] depending on time with simultaneous loss of flocculation activity. The instability appears only at molecular weights M? > 1,5 mill. in aqueous solutions; in formamide and ethyleneglycole PAAm-solutions however are stable. The viscosity loss was observed at a concentration range c = 0,001 to 5%. The standardization of several pH-values at a range from 1 to 12 by means of buffer substances as well as the addition of hydrochinone, chinone, NaNO₂ and Na₂SO₃ do not lead to a stable solution. Only at pH = 5 a stable solution was obtained but by changing the buffer substance at the same pH the solution became instable again. Addition of isopropanol leads to stable aqueous PAAm-solutions from technical products as well as high purity polyacrylamides. The mechanism of the solution instability is not a decrease of the molecular weight due to chain scission but a change of conformation of the solution structure from single molecules based on hydrogen bonds.     

Glass transition temperatures of poly(alkyl α-cyanoacrylates)

The glass transition temperatures of the poly(alkyl α-cyanocrylates) were determined by the dilatometric technique, and some of the values were checked by differential thermal analysis. The data indicate that the T_g's appear to decrease with increase in the size of the alkyl group, for a given molecular weight range. It was also found that the T_g of poly(methyl or butyl α-cyanoacrylate) increased with molecular weight. All cyanoacrylates, excepting methyl and ethyl esters, formed only low molecular weight polymers in aqueous surroundings. Therefore, they have characteristic low glass transition temperatures, causing coalescence at low temperatures.     

The synthesis of high molecular weight polybutene‐1 catalyzed by Cp★ Ti(OBz)3/MAO

A new stereoregular polybutene‐1 was synthesized with a novel catalyst precursor η⁵‐pentamethyl cyclopentadienyl titanium tribenzyloxide (CpTi(OBz)₃) and methylaluminoxane (MAO). The effects of polymerization conditions on the catalytic activity, molecular weight and stereoregularity of the products were investigated in detail. It was found the catalyst exhibited highest activity of 91.2 kgPB mol Ti⁻¹ h⁻¹ at T = 30 °C, Al/Ti = 200. The catalytic activity and molecular weight were sensitive to the Al/Ti (mole/mole), polymerization temperature; they also depended on the Ti concentration. The molecular weight of the products increased with decreasing temperature. The structure and properties of the polybutene‐1 were characterized by ¹³C NMR, GPC, DSC and WAXD. The result showed the microstructure of polybutene‐1 extracted by boiling heptane was stereoregular, whereas the ether‐soluble fraction was atactic. The molecular weight of polybutene‐1 was over one million g mol⁻¹ and its molecular weight distribution ( M _w/ M _n) was from 1.1 to 1.2. © 2001 Society of Chemical Industry     

Formation of monodisperse polyacrylamide particles by radiation‐induced dispersion polymerization. I. Synthesis and polymerization kinetics

Highly monodisperse polyacrylamide (PAM) microparticles were directly prepared by radiation‐induced dispersion polymerization at room temperature in an aqueous alcohol media using poly(N‐vinylpyrrolidone) (PVP) as a steric stabilizer. Monomer conversion was studied dilatometrically and polymer molecular weight was determined viscometrically. The gel effect was found evidently from the polymerization kinetics curves. The influence of the dose rate, monomer concentration, stabilizer content, medium polarity, polymerization temperature on the polymerization rate, and the molecular weight of the polymer was examined. The polymerization rate (Rp) can be represented by Rp ∝ D^0.15[M]^0.86[S]^0.47[A/W]^0.64 and the molecular weight of the polymer can be represented by M_w ∝ D^?0.19 [M]^1.71[S]^0.43[A/W]^0.14 at a definite experimental variation range. The overall activation energy for the rate of polymerization is 10.57 kJ/mol (20–35°C). Based on these experimental results, the polymerization mechanisms were discussed primarily. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2567–2573, 2002