Template polymerization of sodium methacrylate onto poly(allylamine) hydrochloride

The radical polymerization in aqueous solution of sodium methacrylate in the presence of poly(allylamine) hydrochloride as a template was studied using dilatometry. The properties of the polyelectrolyte complexes resulting from these template polymerizations were investigated and compared with those of the poly(sodium methacrylate)/poly(allylamine) hydrochloride complexes obtained by simple mixing of the preformed polymers. The kinetic study provides evidence for the presence of a strong template effect and indicates that the polymerization occurs by a zip mechanism. The results of the different characterization analyses have shown that the complexes obtained by template polymerization have a more ordered structure than the complexes prepared by mixing the two polymers.     

Kinetics and reaction mechanism of template polymerization investigated by conductimetric measurements. 2. Radical polymerization of sodium methacrylate in the presence of poly(allylamine) hydrochloride

The polymerization of sodium methacrylate in water was investigated using conductimetry and dilatometry. Conductimetry was shown to be a reliable tool for the determination of the kinetic parameters of the blank polymerization (order of reaction with respect to monomer and initiator, activation energy). The conductimetric investigation of template polymerization of the acrylic monomer onto poly(allylamine) hydrochloride at low monomer concentration indicates that the reaction proceeds by a ‘zip’ mechanism. © 1999 Society of Chemical Industry     

Kinetics and reaction mechanism of template polymerization investigated by conductimetric measurements Part 4. Radical polymerization of acrylic acid in the presence of poly(vinyl alcohol): characterization of resulting polymer blends

The radical polymerization of acrylic acid in the presence of poly(vinyl alcohol) as a template in aqueous solution has been studied using conductimetry, which shows template influences on the reaction rate. A comparison is made between data obtained by differential scanning calorimetry and infrared spectroscopy for poly(acrylic acid)–poly(vinyl alcohol) blends prepared either by template polymerization or by casting of the preformed polymers. Evidence for more significant interpolymer interactions in blends prepared by template polymerization than in those obtained by simple mixing is given. © 2001 Society of Chemical Industry     

Synthesis of high-molecular weight poly(vinyl alcohol) by low-temperature emulsifier-free emulsion polymerization of vinyl acetate and saponification

High-molecular weight (HMW) poly(vinyl alcohol) (PVA) was prepared via an emulsifier-free emulsion polymerization of vinyl acetate (VAc) using a redox initiation system in low temperatures, and the subsequent saponification with potassium hydroxide in methanol. The effect of the polymerization conditions on the conversion, molecular weight, and branching degree was investigated. PVA with maximum viscosity-average degree of polymerization (DP) of 8270 could be prepared by saponification of poly(vinyl acetate) (PVAc), with DP of 10,660 obtained at temperature of 10°C, monomer concentration of 30%, potassium persulfate molar ratio to monomer of 1/2000, agitation speed of 160 rpm. The conversion was above 90%. From the emulsifier-free emulsion polymerization of VAc in low temperature, PVAc with HMW and high linearity was effectively prepared, which might be useful for the preparation of high-strength and high-modulus PVA fiber. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Grafting and adsorption of poly(vinyl) alcohol in vinyl acetate emulsion polymerization

Poly(vinyl alcohol) is often used in vinyl acetate emulsion polymerization as a protective colloid, but its role is complex and controversial since it partakes in grafting reactions with the monomer, influencing process mechanisms, and affecting the colloidal properties of the latex. Furthermore, in industrial operations, the wide scatter of macromolecular properties of the commercial types of poly(vinyl alcohol) causes process irreproducibilities. In this work different types of polyvinyl alcohol were used to perform a series of polymerizations, and their kinetics were compared. A selective solubilization procedure was applied to separate the three fractions of poly(vinyl alcohol) in the final latex: free in the water phase, physically adsorbed onto the polymer particles and chemically grafted. These results were compared with those obtained from pure adsorption measurements of polyvinyl alcohol onto ‘emulsifier-free’ polyvinyl acetate dispersions. The rheological behavior of the different latexes was also compared, and the results were used to formulate an hypothesis on the interaction mechanisms acting in these systems.     

Thermal characterization of poly(vinyl chloride) samples prepared by living radical polymerization: Comparison with poly(vinyl chloride) prepared by free radical polymerization

Poly(vinyl chloride) (PVC) samples were synthesized by a living radical polymerization (LRP) method and compared with commercial PVC prepared by the conventional free radical polymerization (FRP). The differences were assessed, for the first time, in terms of viscosimetry parameters and thermal analysis. The LRP method used to prepare the PVC‐LRP samples is the only one available to obtain this polymer free of structural defects, being of commercial interest in a view of preparing a new generation of PVC‐based polymer with outstanding performance. The polymerization temperature selected (35°C) to prepare the LRP samples is currently used in the industry to prepare PVC‐FRP grades with moderate to high molecular weight. Since the thermal stability is a direct consequence of the polymer structure, this study is of vital importance to understand the potential of new PVC‐LRP. The thermoanalytical measurements demonstrate an enhanced thermal stability of PVC‐LRP when compared with its FRP counterpart. The PVC‐LRP sample with very low molecular weight reveals a higher thermal stability than the most stable PVC‐FRP sample. It is the first report dealing with thermal analysis of PVC prepared by LRP. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

In-situ polymerization of n-butyl acrylate in poly(vinyl chloride)

The in situ polymerization of n-butyl acrylate with poly(vinyl chloride) has been studied. Butyl acrylate was polymerized using a peroxydicarbonate initiator and a thiol chain transfer agent in the presence of poly (vinyl chloride) beads suspended in water. The products were examined, after pressing into sheets, for optical clarity and by dynamic mechanical analysis. It was found that if 10% butyl acrylate was peesent in the mixture homogeneous blends were formed but if 15% or more butyl acrylate was present two phase mixtures were formed. If homogeneous blends prepared as above were reswollen in butyl acrylate, and the latter then polymerized, homogeneous blends containing more poly(butyl acrylate) could be prepared. The interaction parameters between both poly(vinyl chloride' and poly(butyl acrylate) and butyl acrylate were estimated by inverse gas chromatography. Using these and an estimate of the polymer/polymer interaction parameter the three component phase diagram could be qualitatively explained.     

Effect of degree of polymerization on gelation and flow processability of poly(vinyl chloride)

The effect of degree of polymerization (DP) on the gelation and flow processability of poly(vinyl chloride) (PVC) was studied. Sheets with adjusted degree of gelation were prepared by rolling rigid pipe formulation suspension PVC compounds with DPs of 800, 1050 and 1300 by changing the milling temperature. Their degrees of gelation were measured with DSC and their capillary flow properties were measured with a capillary rheometer at 150, 170 and 190°C and the effect of DP on the relation between gelation and flow processabilities was studied. Because of the higher shearing heat during milling, the sample with the higher DP had a higher history temperature and thus tended to show a higher degree of gelation. The viscosity increased as the gelation increased. The dependency of viscosity on DP was higher at higher milling and extrusion temperatures and thus at a higher degree of gelation and a lower shear rate. This was assumed to be attributed to the more prominent uniform molecular flow as against the particle flow. The die swell increased with increasing the milling and extrusion temperatures and hence with increasing the gelation. A sample with a lower DP tended to show a larger die swell and this tendency was even more pronounced at the higher extrusion temperature. The melt fracture easily occurred when a sample with advanced gelation was extruded at low temperature. Whereas at low milling temperatures a sample with the lower DP showed a lower critical shear rate at onset of melt fracture, and thus easily generating melt fracture, at high milling temperatures it showed a higher critical shear rate and hence scarcely generated melt fracture. These experimental results were explained by the fact and concept that a sample with a lower DP shows a higher increase in the gelation during extrusion and/or the slighter feature of particle flow as against the uniform molecular flow at the same gelation level. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1915–1938, 2004     

Synthesis of poly(vinyl alcohol) combs via MADIX/RAFT polymerization

Poly(vinyl acetate) combs have been prepared via macromolecular design via interchange of xanthate (MADIX)/reversible addition-fragmentation chain-transfer (RAFT) polymerization using xanthate functionalized polymer cores. The comb backbones were prepared using well-defined poly(vinyl alcohol) PVA polymers with a degree of polymerization of 20, 100 and 170, respectively. Functionalization with xanthates via R-group or a Z-group approach resulted in the formation of macromolecular MADIX agents. While Z group designed macromolecular xanthate agents appeared to inhibit the polymerization of vinyl acetate (VAc), R group designed macromolecular xanthate agents achieved to mediate efficiently the bulk polymerization of VAc affording PVAc combs. However, the growth of the combs was accompanied at low conversions by the formation of linear polymer chains as a result of the constant initiation (AIBN) and shoulders, which can be attributed to intermolecular coupling reactions. The proportions of single chains and termination products were observed to increase with the degree of polymerization of the macromolecular MADIX agents broadening the molecular weight distribution. As a result of a stable ester link between the branches and the PVA backbone, the branched PVAc architectures were finally hydrolyzed to afford poly(vinyl alcohol) combs.     

Synthesis and characterization of poly(vinyl chloride‐co‐vinyl acetate)‐graft‐poly[(meth)acrylates] by atom transfer radical polymerization

The graft polymerization of methyl methacrylate and butyl acrylate onto poly(vinyl chloride‐co‐vinyl acetate) with atom transfer radical polymerization (ATRP) was successfully carried out with copper(I) thiocyanate/N,N,N′,N′,N″‐pentamethyldiethylenetriamine and copper(I) chloride/2,2′‐bipyridine as catalysts in the solvent N,N‐dimethylformamide. For methyl methacrylate, a kinetic plot of ln([M]₀/[M]) (where [M]₀ is the initial monomer concentration and [M] is the monomer concentration) versus time for the graft polymerization was almost linear, and the molecular weight of the graft copolymer increased with increasing conversion, this being typical for ATRP. The formation of the graft polymer was confirmed with gel permeation chromatography, ¹H‐NMR, and Fourier transform infrared spectroscopy. The glass‐transition temperature of the copolymer increased with the concentration of methyl methacrylate. The graft copolymer was hydrolyzed, and its swelling capacity was measured. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 183–189, 2005     

Influences of individual and composed poly(vinyl alcohol) suspending agents on particle morphology of suspension poly(vinyl chloride) resin

Effects of individual and composed poly(vinyl alcohol) (PVA) suspending agents on the particle morphology of poly(vinyl chloride) (PVC) resins were investigated and discussed in the view of PVA absorption at the oil/water interface and interfacial behavior. It was shown that the percentage and surface coverage of PVA at the oil/water interface decreased with the increase of the degree of hydrolysis (DH) of PVA in the DH range of 70–98 mol %, while the interfacial tension of VC/PVA aqueous solution increased linearly with the increase of DH of PVA. PVC resin with more regular particle shape, increased agglomeration and fusion of primary particles, lower porosity and higher bulk density, was prepared by using PVA with a higher DH as a suspending agent. This was caused by the occurrence of drop coalescence at the very early stage of VC polymerization, the increase of particle shrinkage, and the lower colloidal protection to primary particles. It was also shown that the interfacial tension of VC/water in the presence of composed PVA suspending agents varied linearly with the weight composition of the composed PVA suspending agents. The particle properties of PVC resin prepared by using the composed PVC suspending agents were usually situated in between the properties of PVC resins prepared by using the corresponding individual PVA suspending agent. The particle morphology and properties of PVC resin could be controlled by the suitable choice of the composed PVA suspending agents. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3848–3855, 2003     

Yttrium fumaropimarat as a novel heat stabilizer for poly(vinyl chloride)

Yttrium fumaropimarat (YFPA) was synthesized with fumaropimaric acid and yttrium acetate as raw materials. The structure of the product was analyzed and characterized by Fourier transform infrared spectrometer, scanning electron microscope, energy dispersive X‐ray microanalysis, and X‐ray diffraction. The results showed that the product was amorphous state, three‐dimensional reticulation compound by the ionic bond of COO^? and Y³⁺. The effect of YFPA on poly(vinyl chloride) (PVC) thermal stability was researched by means of Congo red method and heat oven aging method. The experimental results showed that YFPA was a good long‐term PVC thermal stabilizer and could greatly improve PVC thermal stability and initial stage stainability mixing calcium stearate, zinc stearate, and pentaerythrite. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 45015.     

Drug selective poly(vinyl chloride)-based sensor of desipramine hydrochloride

The novel ion-pair ([TPB]⁻ [DH]⁺) of the quaternary ammonium drug desipramine hydrochloride, 3-(5,6-dihydrobenzo[b][1]benzazepin-11-yl)-N-methylpropan-1-amine, has been synthesized and incorporated into a poly(vinyl chloride)-based membrane sensor for the quantification of desipramine hydrochloride in different pharmaceutical preparations. The influence of the membrane composition on the potentiometric responses of the membrane sensor has been found to substantially improve the performance characteristics. The best performance was reported with membranes having the composition (in mg) of ([TPB]⁻ [DH]⁺) (5): PVC (150): o-NPOE (150). The proposed sensor (sensor no. 4) exhibits a Nernstian response in the concentration range of 2.2 × 10⁻⁶ to 1.0 × 10⁻² M with a detection limit of 1.2 × 10⁻⁶ M. The membrane sensor performs satisfactorily over the pH range of 2.8-7.4 with a fast response time of 12 s. The sensor no. 4 can tolerate a non-aqueous content of up to 20% and can be utilized for the determination of drug concentration in pharmaceutical preparation (tablets) and in body fluids such as urine and blood samples. The results were comparatively evaluated with liquid chromatography (LC). It was observed that the concentration of drug was greater in the blood sample than in the urine sample, as most of the drug is metabolized in the liver before discharge to urine.     

Study of electrospinning of sodium alginate,blended solutions of sodium alginate/poly(vinyl alcohol) and sodium alginate/poly(ethylene oxide)

Alginate is an interesting natural biopolymer for many of its merits and good biological properties. This paper investigates the electrospinning of sodium alginate (NaAlg), NaAlg/PVA‐ and NaAlg/PEO‐ blended systems. It was found in this research that although NaAlg can easily be dissolved in water, the aqueous NaAlg solution could not be electrospun into ultrafine nanofibers. To overcome the poor electrospinnability of NaAlg solution, synthetic polymers such as PEO and PVA solutions were blended with NaAlg solution to improve its spinnability. The SEM images of electrospun nanofibers showed that the alginate (2%, w/v)–PVA (8%, w/v) blended system in the volume ratio of 70 : 30 and the alginate (2%, w/v)–PEO (8% w/v) blended system in the volume ratio of 50 : 50 could be electrospun into finest and uniform nanofibers with average diameters of 118.3 nm (diameter distribution, 75.8–204 nm) and 99.1 nm (diameter distribution, 71–122 nm), respectively. Rheological studies showed a strong dependence of spinnability and fiber morphology on solution viscosity and thus on the alginate‐to‐synthetic polymer (PVA or PEO) blend ratios. FTIR studies indicate that there are the hydrogen bonding interactions due to the ether oxygen of PEO (or the hydroxyl groups of PVA) and the hydroxyl groups of NaAlg. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Synthesis of poly(vinyl propionate) from poly(vinyl alcohol) in nonaqueous medium using ethyl nitrate dimethyl sulfoxide as a catalyst

Poly(vinyl alcohol) (PVA) can be dissolved in a nonaqueous medium in the presence of catalytic concentration of ethyl nitrate dimethyl sulfoxide, C₂H₅ONO₂·DMSO. From the PVA solution, poly(vinyl propionate), PVPR was prepared by the homogeneous esterification of PVA with propionic acid. The ester thus formed contained some unconverted hydroxyl group. The formation of the ester was confirmed by the IR and ¹H‐NMR spectra. The molecular weight of the ester was determined by GPC and intrinsic viscosity (η) was determined by viscometric method. Glass transition temperature, T_g, was obtained from differential scanning calorimetric (DSC) analysis. Thermal stabilities of the ester were checked by thermogravimetric analysis (TGA) and differential thermogravimetric (DTG) analysis. The efficiency of the ester as a flow improver of crude oil was also examined. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5675–5679, 2006     

A mucoadhesive polymer prepared by template polymerization of acrylic acid in the presence of poly(vinyl alcohol) for mucosal drug delivery

The interpolymer complexes composed of PVA and PAA were prepared by template polymerization of acrylic acid in the presence of PVA with different molecular weights and degrees of saponification. The carbonyl absorption band of the PAA in the PAA/PVA interpolymer complexes was shifted to a lower wavenumber due to H‐bonding between the carboxyl group of PAA and the hydroxyl group of PVA. The swelling ratio and the degree of dissolution of the PVA/PAA interpolymer complexes were dependent on the pH of the medium, the molecular weight, and the degree of saponification of the PVA. The release rate of a model drug, lidocaine, from the complexes decreased with increasing degree of saponification of the PVA due to the lower swelling degree of the complex. The adhesive force of the PVA/PAA interpolymer complexes with a plastic plate (poly propylene) was stronger than that of the commercial Carbopol 971P. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 327–331, 2004     

Networks of photocrosslinked poly(meth)acrylates in linear poly(vinyl chloride)

Five different multifunctional acrylic monomers (trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, and dipentaerythritol pentaacrylate) were photopolymerized alone or in a matrix of linear poly(vinyl chloride) (PVC) with 2,2‐dimethyl‐2‐hydroxyacetophenone as a photoinitiator. The course of photopolymerization was estimated with Fourier transform infrared spectroscopy. The amount of insoluble gel formed during photopolymerization was determined gravimetrically. The crosslinked polymerization of pure monomers was much faster than that in the presence of PVC. However, the efficiency of the reaction was higher when it was carried out in a PVC blend because of the higher mobility of the propagating macroradicals. The influence of the monomer structure and functionality on the polymerization course was examined. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3725–3734, 2002     

Living cationic polymerization of isobutyl vinyl ether (II): Photoinduced living cationic polymerization in a mixed solvent of toluene and diethyl ether

A new method of preparation of living cationic polymer of isobutyl vinyl ether via photoinduced polymerization in the presence of diphenyliodonium iodide (DPII, initiator) and zinc iodide in a mixed solvent of toluene/diethyl ether, which was irradiated at ?78°C for short period, was completed within 15 min. The reaction was allowed for further reaction in the dark until monomer was fully consumed. It was found that increase in the conversion of monomer to polymer during the irradiation is very limited. Confirmation of the linear dependence of number‐average molar mass of resulting polymer on % conversion together with the fact that polymerization proceeds until monomer consumption, and controllability of number‐average molar mass of resulting polymer, depending on the molar ratio of monomer and initiator, strongly suggests the living nature of this polymerization, unless reaction temperature becomes higher than 0°C, i.e., the absence of chain breaking process. The narrow molar mass distribution, whose polydispersity index values are less than 1.2, reveals that the rate of initiation where irradiation is usually completed within 15 min is much faster than that of propagation in cationic nature in this system. Effect of some major factors, such as solvent polarity and temperature, on the living nature of the polymerization was also investigated. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3581–3586, 2006