Preparation and characterization of porous poly(vinyl ester) resin monoliths as separation media

Porous poly(vinyl ester) resin monolithic supports were first prepared by radical polymerization of the continuous phase of oil in water high‐internal‐phase emulsions. Vinyl ester (VE) resin was used as the monomer, ethylene glycol dimethacrylate was used as a crosslinker, and poloxamer 127 was used as the emulsifier in the emulsion polymerization. The prepared columns were evaluated by scanning electron microscopy, mercury intrusion porosimetry, and Fourier transform infrared spectroscopy to observe the morphological characteristics and confirm the absorbance based on the VE resin polymer. The obtained monolith showed not only higher column permeability but also lower back pressure and higher column efficiency. To investigate the absorption performance of the monolithic column, a maximum loading capacity experiment was also applied with lysozyme (Lys), and the results show that the maximum adsorption of the poly(vinyl ester) resin monolith was 1.579 mg/g. Moreover, the capabilities of separation on this column in conjunction with high‐performance liquid chromatography were investigated. Immunoglobulin could be separated from human plasma and chicken egg yolk with high resolution within 4 min. Additionally, fast separation of two mode proteins (interleukin‐18 and Lys) was achieved on the monolith within 2 min at the rate of 1445 cm/h, which demonstrated the potential of the poly(vinyl ester) resin monolith for the fast separation of proteins. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Plasma‐graft polymerization of vinyl monomer with an acid amide group onto a surface of carbon fiber and its adhesion to epoxy resin

The mechanical properties of a fiber‐reinforced plastic are influenced by the adhesion between a reinforced fiber and a matrix resin. In this work it is shown how to obtain strong adhesion between a carbon yarn and an epoxy resin through the formation of covalent bonds. Acid amide groups reactive with epoxy groups were introduced onto a surface of the yarn by means of plasma‐graft polymerization of acrylamide. The density of active radicals formed on a surface of the yarn by the plasma irradiation was first increased with increasing discharge power and plasma irradiation time, and then the rates of the increase were largely decreased. The degree of grafting was linearly increased with increasing the surface density of active radicals. The yarn embedded in diglycidyl ether of bisphenol‐A/triethylenetetramine mixture was pulled out to obtain pull‐out force after curing. Pull‐out force was increased with increasing degree of grafting and the failure in pulling out of the yarn was cohesive. The covalent bonds formed in the graft layer will result in an increment of pull‐out force. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 284–290, 2000     

Mechanical characterization and chemical resistances of cured unsaturated polyester resins modified with vinyl ester resins based on recycled poly(ethylene terephthalate)

Unsaturated polyester resin (UP) was prepared from glycolyzed oligomer of poly(ethylene terephthalate) (PET) waste based on diethylene glycol (DEG). New diacrylate and dimethacrylate vinyl ester resins prepared from glycolysis of PET with tetraethylene glycol were blended with UP to study the mechanical characteristics of the cured UP. The vinyl ester resins were used as crosslinking agents for unsaturated polyester resin diluted with styrene, using free‐radical initiator and accelerator. The mechanical properties of the cured UP resins were evaluated. The compressive properties of the cured UP/styrene resins in the presence of different vinyl ester concentrations were evaluated. Increasing the vinyl ester content led to a pronounced improvement in the compression strength. The chemical resistances of the cured resins were evaluated through hot water, solvents, acid, and alkali resistance measurements. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3175–3182, 2007     

Polymers for information storage systems. II. Polymerization kinetics for preparation of highly crosslinked polydimethacrylates

Polymers of ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, and tetraethylene glycol dimethacrylate were prepared by photoinitiated polymerizations in the presence of 2,2-dimethoxy-2-phenyl-acetophenone at 27°C. The reactions led to highly crosslinked polymeric networks. The volume shrinkage observed during polymerization was a function of the number of ethylene glycol units in the dimethacrylate monomer. The kinetic rate constants of polymerization, as determined from the photopolymerization characteristics using a dilatometric technique, were again dependent on the number of ethylene glycol units in the monomer. The importance of these results on the crosslinked structure of the prepared networks is discussed.     

Molecularly imprinted polymer microspheres prepared by precipitation polymerization using a sacrificial covalent bond

Molecularly imprinted polymer microspheres were prepared by precipitation polymerization using a sacrificial covalent bond. In the present model, cholesteryl (4‐vinyl)phenyl carbonate was used as a template monomer. The imprinted microspheres were prepared using ethylene glycol dimethacrylate (EDMA) and divinylbenzene (DVB) as crosslinker. The base‐labile carbonate ester bond was easily hydrolyzed to leave imprinted cavities in the resulting polymers. Radioligand binding analysis, elemental analysis, and scanning electron microscopy were used to characterize the imprinted materials. Imprinted microspheres prepared from DVB crosslinker had larger and more defined spherical shape, and displayed better imprinting effect than did the EDMA‐based microparticles. For comparison, imprinted bulk polymers were also prepared in the same reaction solvent as that used in precipitation polymerization. Elemental analysis results indicated that imprinted microspheres contained more template monomer units than bulk materials. The efficiency of template removal by hydrolysis treatment for microspheres was also higher than that for bulk polymers. For DVB‐based polymers, imprinted microspheres displayed higher specific cholesterol uptake than did the corresponding bulk polymer. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1390–1398, 2006     

An investigation of vinyl–ester?styrene bulk copolymerization cure kinetics using Fourier transform infrared spectroscopy

A Fourier transform infrared (FTIR) spectroscopy technique was developed to investigate the effects of reaction temperature and reactant composition on the isothermal curing kinetics of commercial vinyl nester resins comprised of vinyl–ester monomer (dimethacrylate of diglycidyl ether of bisphenol A DGEBA) and styrene. This technique enables a more complete evaluation of the bulk copolymerization reaction of vinyl–ester styrene systems by monitoring the depletion of vinyl–ester and styrene double bonds independently. The results indicate that the rate of fractional conversion of styrene double bonds is initially less than that of vinyl–ester vinyl groups. However, styrene monomer continues to react after conversion of vinyl–ester double bonds has ceased. In addition, the overall extent of conversion was found to increase with increasing isothermal cure temperature, and it was observed that higher styrene concentration enhances final conversion of vinyl–ester double bonds and not styrene double bonds. Increasing styrene monomer concentration also resulted in lowering the apparent activation energy for the reaction of vinyl groups from both monomers as characterized by an empirical autocatalytic model used to fit the conversion results for styrene and vinyl–ester double bonds independently. The results of this work demonstrate that reaction temperature and resin composition significantly affect the cure behavior of vinyl–ester resins and provide insight into the development of the resulting network structure. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 1572–1582, 2000     

Synthesis and properties of oil absorption resins filled with polybutadiene

Polybutadiene (PB) is used to fill an oil absorption resin as a physical crosslinker to construct a kind of 3‐dimensional network with a high degree crosslinking and low crosslink density. A series of acrylic resin particles with various compositions are prepared by suspension polymerization, using benzoyl peroxide (BPO) as an initiator and ethylene glycol dimethacrylate (EGDMA) as a chemical crosslinker. The effects of the polymerization temperature, initiator concentration, monomer feed ratio, and chemical and physical crosslinker concentrations on the oil absorbency and gel fraction (degree of crosslinking) are studied. The recipe and operation conditions are optimized as follows: a mass ratio of 3:1 for styrene (St)/dodecyl methacrylate or St/butyl acrylate, 0.5 wt % BPO, and 80°C for 7–8 h. The effect of the physical crosslinker (PB) concentration is complex. The oil absorbency increases with increasing PB at lower EGDMA concentrations. However, under this same condition, particles cannot be formed if the PB concentration is higher than a certain value. By contrast, there is an optimum PB concentration when the EGDMA concentration is higher. The oil absorption speed is also investigated. The presence of PB can speed up absorption. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3309–3314, 2003     

Synthesis of block copolymers via redox polymerization

Polymerization and copolymerization of vinyl monomers such as acrylamide, acrylonitrile, vinyl acetate, and acrylic acid with a redox system of Ce(IV) and organic reducing agents containing hydroxy groups were studied. The reducing compounds were poly(ethylene glycol)s, halogen‐containing polyols, and depolymerization products of poly(ethylene terephthalate). Copolymers of poly(ethylene glycol)s‐b‐polyacrylonitrile, poly(ethylene glycol)s‐b‐poly(acrylonitrile‐co‐vinyl acetate), poly(ethylene glycol)s‐b‐polyacrylamide, poly(ethylene glycol)s‐b‐poly(acrylamide‐co‐vinyl acetate), poly(1‐chloromethyl ethylene glycol)‐bpoly(acrylonitrile‐co‐vinyl acetate), and bis[poly(ethylene glycol terephthalate)]‐b‐poly(acrylonitrile‐co‐vinyl acetate) were produced. The yield of acrylamide polymerization and the molecular weight of the copolymer increased considerably if about 4% vinyl acetate was added into the acrylamide monomer. However, the molecular weight of the copolymer was decreased when 4% vinyl acetate was added into the acrylonitrile monomer. Physical properties such as solubility, water absorption, resistance to UV light, and viscosities of the copolymers were studied and their possible uses are discussed. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 1385–1395, 1999     

Interpenetrating polymer networks composed of castor oil‐based polyurethane and 2‐hydroxy‐4‐methacryloyloxy acetophenone

2‐Hydroxy‐4‐methacryloyloxy acetophenone, a vinyl monomer, was prepared by reacting 2,4‐dihydroxy acetophenone with methacryloyl chloride in presence of triethylamine in methyl ethyl ketone. The vinyl monomer was characterized by Fourier transform infrared spectra and Proton magnetic resonance spectra to confirm the various functional groups in the monomer. The liquid prepolyurethanes obtained from castor oil, toluene‐2,4‐diisocyanate, and hexamethylene diisocyanate, varying the NCO/OH ratio, were interpenetrated with the above vinyl monomer containing ethylene glycol dimethacrylate, using radical polymerization initiated by benzoyl peroxide. The interpenetrating polymer networks were obtained as transparent tough films by transfer moulding. They were characterized for thermal behavior with evaluation of kinetic parameters. From the kinetic data, it is clear that the degradation process of the interpenetrating networks is slower in the temperature range of 270–390°C and faster in the range of 390–510°C. Thermal stability also varies with the change in diisocyanates. The morphology was examined by scanning electron microscopy (SEM). The resulting two‐phase morphology was found to be sensitive to change in monomer concentration. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 1487–1492, 2000     

Compressive Properties and Curing Behaviour of Unsaturated Polyester Resins in the Presence of Vinyl Ester Resins Derived from Recycled Poly(ethylene terephthalate)

Poly(ethylene terephthalate) waste was depolymerised in the presence of tetraethylene glycol and manganese acetate as a catalyst, so as to produce oligomers. An epoxy resin was then prepared by the reaction of these oligomers with epichlorohydrin in presence of NaOH as a catalyst. New diacrylate and dimethacrylate vinylester resins were then synthesized by reaction of the terminal epoxy groups with acrylic and methacrylic acid in the presence of triphenyl phosphite as a catalyst. The chemical structures of the resulting vinyl ester resins were confirmed by ¹HNMR. The vinyl ester resins were used as crosslinking agents for unsaturated polyester resin diluted with styrene, using free radical initiator and accelerator. The curing behaviour of the unsaturated polyester resin, vinyl ester resins and styrene was evaluated at temperatures from 25 to 55 ^○C. The compression properties of the cured resins, having different vinyl ester contents and different cure temperatures, were evaluated. Increasing the cure temperature and the vinyl ester content led to a pronounced improvement in the compression strength and Young’s modulus.     

Effect of the crosslinking agent on porous networks formation of hema-based copolymers

New copolymers of ethylene glycol dimethacrylate/2-hydroxyethyl methacrylate [poly(EGDMA-co-HEMA)],2,2′,2″-nitrilotriethyl triacrylate/2-hydroxyethyl methacrylate [poly(NTETA-co-HEMA)] and pentaerythritol tetraacrylate/2-hydroxyethyl methacrylate [poly(PETA-co-HEMA)] were obtained by suspension polymerization at 70 or 85 °C, using cyclohexane (Cyc) as porogen. In this work, the influence of the crosslinking agent (di, tri, or tetravinyl monomer) on the morphology of the polymeric networks was investigated. Swelling studies, Fourier Transform Infrared (FTIR) and mercury intrusion porosimetry, demonstrated that when both the vinyl groups number and molecular chain length between double bonds of the crosslinking agent decreased, networks with high porosity and crosslinking degree were generated.     

2‐Hydroxypropylmethacrylate based mono‐ and bifunctional gel beads prepared by suspension polymerization

Spherical and swellable gel beads in the size range 35–200 µm were prepared by suspension polymerization of 2‐hydroxypropylmethacrylate (HPMA). In the proposed method, a mixture of cyclohexanol and octanol was used as a diluent phase dispersed in an aqueous medium including poly(vinyl pyrrolidone) (PVP) as the stabilizer. The polymerization was initiated within the organic phase including the monomer and the crosslinker (ethylene glycol dimethacrylate) by an oil soluble initiator benzoyl peroxide. Spherical and swellable gel beads carrying both hydroxyl and carboxyl functional groups were also prepared by suspension copolymerization of HPMA and a water soluble comonomer (methacrylic acid). For this purpose, the suspension polymerization method proposed for HPMA was modified by using poly(vinyl alcohol) as a stabilizer instead of PVP. The effect of initiator concentration, polymerization temperature, monomer/diluent ratio, crosslinker concentration, stirring rate on yield, average size, size distribution, and carboxyl content of the HPMA based gel beads, were investigated. The swelling characteristics of the gel beads were defined. © 2000 Society of Chemical Industry     

Physicochemical properties of irradiated and loaded LDPE films with polyfunctional monomers

Polyfunctional monomers (PFMs), namely, trimethylol propane trimethacrylate (TMPTMA), trimethylol propane triacrylate, ethylene glycol dimethacrylate, and diethylene glycol diacrylate were blended with low‐density polyethylene (LDPE) and exposed to different doses of EB irradiation. Fourier transform infrared and ultraviolet and UV–vis spectroscopy of the unirradiated, irradiated, unloaded, and PFMs‐loaded LDPE films were studied under various irradiation doses up to 300 kGy. The degree of crosslinking and oxidative degradation, as measured by the spectroscopic parameters, were dependent on both the irradiation dose and the type of loaded PFMs. For all of the loaded monomers, the extent of crosslinking increased at different rates as a function of irradiation dose. TMPTMA monomer was the most efficient in enhancing the crosslinking of LDPE films compared to the other loaded monomers. However, the unloaded LDPE film showed the least extent of crosslinking. In addition, the EB‐radiation‐induced changes, such as trans‐vinylene formation, a decrease in vinyl and vinylidene unsaturation; and carbonyl double‐bond formation and change in crystallinity were correlated. The importance of these results on the prediction of the role of polyfunctional monomers in the production of crosslinked polymers is discussed. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2025–2035, 2003     

PVC modification through polymerization of a monomer absorbed in porous suspension‐type PVC particles

In‐situ polymerization is the polymerization of one monomer in the presence of another polymer. It can be performed by sequential emulsion polymerization, or by reactions in the melt, in the solid phase, or in solution. The current report describes two methods to obtain poly(vinyl chloride) (PVC) modification through polymerization of a monomer absorbed in commercial porous suspension‐type PVC particles. The generated modified PVC products differ significantly in their structure and properties. The first approach includes absorption of a monomer/peroxide solution within porous suspension‐type PVC particles, followed by polymerization/crosslinking in the solid state at 80°C in an aqueous stabilizer‐free dispersion. The monomer/crosslinker pairs selected are styrene/DVB (divinyl benzene), methylmethacrylate/EGDMA (ethylene glycol dimethacrylate), butyl acrylate/EGDMA, and ethylhexyl acrylate/EGDMA. The influence of composition and nature of the polymerizing/crosslinking constituents on the modified PVC particle structure was studied by microscopy methods, porosity measurements, and dynamic mechanical behavior (DMTA). The level of molecular grafting between PVC and the modifying polymer was determined by solvent extraction experiments. This work shows that the different monomers used represent distinct courses of monomer transport through the PVC particles. The characteristics of the modified PVC particle indicate that the polymerization/crosslinking process occurs in both the PVC bulk, i.e., within the walls constituting a particle, and in the PVC pores. No indication of chemical intermolecular interaction within the modified PVC particles was found. In the second approach, a solution of monomer, initiator, and a crosslinking agent is absorbed in commercial suspension‐type porous PVC particles, thus forming a dry blend. This dry blend is subsequently reactively polymerized in a twin‐screw extruder at an elevated temperature, 180°C, in the molten state. The properties of the reactively extruded PVC/PMMA blends are compared with those of physical blends at similar compositions. Owing to the high polymerization temperature, short‐chain polymers are formed in the reactive polymerization process. Reactively extruded PVC/PMMA blends are transparent, form single‐phase morphology, have a single T_g, and show mechanical properties comparable with those of the neat PVC. The resulting reactively extruded PVC/PMMA blends have high compatibility. J. Vinyl Addit. Technol. 10:109–120, 2004. © 2004 Society of Plastics Engineers.     

Polymerization of monomers initiated by silyl centers in SiO deposits prepared by pulsed laser ablation

Deposits from silicon monoxide prepared by pulsed laser ablation were allowed to react with acrylic and vinyl monomers—styrene, methyl methacrylate and 1,2 ethylene glycol dimethacrylate. It was revealed by means of FTIR, electron paramagnetic resonance (EPR), and NMR spectroscopies that silyl ?Si· reacts with monomer molecules and initiates the consecutive polymerization. Crosslinking is proved by the occurrence of bending δ(? CH₂) absorption peak at about 750 cm^?1 in FTIR spectra. Because of very low concentration of the propagating radical for styrene we used a radical scavenger N‐phenyl‐t‐butylnitrone for trapping. The measured EPR parameters were compared with the calculated ones. In case of styrene, NMR analysis manifested the presence of Si? C bonds in SiC_xO_y (x + y = 2) units, which can be taken as direct evidence of the reaction between silyl centers and monomer molecules. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4488–4492, 2006     

交联剂对合成高吸油性树脂的影响

采用水分散相悬浮聚合法，以甲基丙烯酸长链烷基酯为单体，二甲基丙烯酸乙二醇酯为交联剂合成高吸油性树脂；并且探讨了交联剂对聚合过程和树脂吸油性能的影响。实验证明，交联剂用量越大，体系凝胶化现象到来得越早，转化率随反应时间增长得较快，但是最终转化率相差不大。交联剂用量越大，树脂对各种油品的吸油倍率越小；交联剂的用量大于0.4mL时，吸油倍率变化不明显。     

Anionic ring‐opening polymerization of adipic anhydride initiated by potassium poly(ethylene glycol)ate

Poly(adipic anhydride) (PAA) was prepared by the ring‐opening polymerization of adipic anhydride (AA) initiated by potassium poly(ethylene glycol)ate. The effects of various factors, such as the amount of initiator, concentration of the monomer, reaction time and temperature, and polarity of the solvent on the polymerization were investigated. The crude polymerized product was a mixture of PAA homopolymer and poly(ethylene glycol)–poly(adipic anhydride) block copolymer, as confirmed by ¹H‐NMR and gel permeation chromatography. Chain‐transfer reactions occurred intensively for the AA polymerization in both the nonpolar solvent toluene and the polar solvents CHCl₃ and tetrahydrofuran, which predominantly determined the molecular weight and the monomer conversion for the polymerized product. The lower monomer conversion in toluene was ascribed to a lower livingness for the initiator in the nonpolar solvent when compared with other two, polar solvents. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2194–2201, 2003     

Analysis by mass spectrometry of the hydrolysis/condensation reaction of a trialkoxysilane in various dental monomer solutions

3‐Methacryloxypropyltrimethoxysilane (MPTMS) was converted to silsesquioxane oligomers by hydrolysis/condensation in three dental monomer solutions. The molecular mass distribution and molecular structures of these oligomers was studied by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry. Each dental monomer imparted distinct characteristics on the oligomeric silsesquioxane produced. Ethoxylated bisphenol A dimethacrylate (EBPADMA) produced low‐mass oligomer silsesquioxanes that showed complete hydrolysis and a very high degree of intramolecular condensation (i.e., there were no methoxy and few silanol groups remaining on the oligomers). 1,6‐Bis(methacryloxy‐2‐ethoxycarbonylamino) 2,4,4‐trimethylhexane also produced fully hydrolyzed oligomeric silsesquioxanes but with twice the average molecular mass as the EBPADMA. Finally, triethylene glycol dimethacrylate produced higher mass oligomeric silsesquioxanes than EBPADMA even though it showed incomplete hydrolysis. The degree of hydrolysis increased with increasing mass, as did the degree of intramolecular condensation. Oligomers with degrees of polymerization below 8 were poorly hydrolyzed and showed little if any intramolecular condensation. Those with degrees of polymerization of 9 or greater were almost completely hydrolyzed with a high level of intramolecular condensation. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1842–1847, 2006     

Processing and mechanical properties of bio‐derived vinyl ester resin‐based composites

A “green” vinyl ester resin (GVER) is investigated for use in structural applications. The GVER was formulated using a monodisperse vinyl ester created via a novel synthetic route capable of using bio‐waste material from paper and biodiesel industries. The GVER was used either as a neat resin or as blended with a commercial vinyl ester resin. The processing viscosity and gel times are investigated. The GVER reaches a similar viscosity as the commercial resin with only half the styrene monomer content, thereby reducing the volatile organic compounds associated with manufacturing. Composites of the GVER matrix reinforced by carbon fabric were tested for their tensile and flexural properties. The mechanical performance of the GVER compares favorably with commercial resin and provide a route for composites manufacturing from sustainably sourced vinyl ester matrix. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44642.     

Optical material having high refractive index,low specific gravity,and excellent impact resistance prepared by unsaturated nitrile-polyfunctional methacrylate-styrenic monomer copolymerization

A resin having a low specific gravity, an excellent impact resistance, and a high refractive index was produced by radical polymerization of a mixture of difunctional methacrylate, such as tetraethylene glycol dimethacrylate or triethylene glycol dimethacrylate, styrenic monomer such as styrene or α-methyl styrene, and acrylonitrile. We provide a totally balanced optical material composed of the said resin, especially a lens. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65: 2247–2255, 1997