Design of novel poly(methyl vinyl ether) containing AB and ABC block copolymers by the dual initiator strategy

A new set of block copolymers containing poly(methyl vinyl ether) (PMVE) on one hand and poly(tert-butyl acrylate), poly(acrylic acid), poly(methyl acrylate) or polystyrene on the other hand, have been prepared by the use of a novel dual initiator 2-bromo-(3,3-diethoxy-propyl)-2-methylpropanoate. The dual initiator has been applied in a sequential process to prepare well-defined block copolymers of poly(methyl vinyl ether) (PMVE) and hydrolizable poly(tert-butyl acrylate) (PtBA), poly(methyl acrylate) (PMA) or polystyrene (PS) by living cationic polymerization and atom transfer radical polymerization (ATRP), respectively. In a first step, the Br and acetal end groups of the dual initiator have been used to generate well-defined homopolymers by ATRP (resulting in polymers with remaining acetal function) and living cationic polymerization (PMVE with pendant Br end group), respectively. In a second step, those acetal functionalized polymers and PMVE-Br homopolymers have been used as macroinitiators for the preparation of PMVE-containing block copolymers. After hydrolysis of the tert-butyl groups in the PMVE-b-ptBA block copolymer, PMVE-b-poly(acrylic acid) (PMVE-b-PAA) is obtained. Chain extension of the AB diblock copolymers by ATRP gives rise to ABC triblock copolymers. The polymers have been characterized by MALDI-TOF, GPC and ¹H NMR.     

Miscibility of poly(vinyl chloride) with ethylene-ethyl acrylate-carbon monoxide terpolyrners

Ethylene/ethyl acrylate/carbon monoxide ter polymers (E/ EA/CO) can exhibit a very high degree of miscibility with poly(vinyl chloride) as determined from dynamic mechanical measurements. The blends yield transparent films and show a large amorphous phase which exhibits only one major glass transition. However, some crystallinity can be detected and has been measured by differential, scanning calorimetry. Residual crystallinity is at least partially due to the somewhat non-uniform nature of the terpolymerization. The acrylate monomer exhibits faster polymerization rates than the other two constituents. By contrast, ethylene/ethyl acrylat copolymers are not miscible with poly(vinyl chloride). The addition of carbon monoxide to the termpolymer structure is believed to yield miscibility with poly(vinyl chloride) via specific interaction of the ketone carbonyl of the terpolymer (proton acceptor) and the tertiary hydrogen of poly(vinyl chloride) (proton donor). This specific interaction allows for a broad range of terpolymer compositions which retain miscibility with polyvinyl chloride. Similar results are also observed with ethylene/vinyl acetate/carbon monoxide (E/VA/CO) as well as ethylene/2-ethylhexyl acrylate/carbon monoxide termpojymers. The vinyl acetate terpolymers (and their blends) display a lower degree of crystallinity than the E/EA/ CO. This is consistent with the more uniform nature of the E/VAJCO terpolymerization.     

Blends of imidized acrylic polymers with SAN copolymers and with PVC

A series of imidized acrylic polymers of varying structural composition generated by reaction of methylamine with poly(methyl methacrylate) were blended with a range of styrene/acrylonitrile or SAN copolymers (0–33% AN) and with poly(vinyl chloride). On the basis of glass transition behavior determined by differential scanning calorimetry, some but not all imidized acrylic structures were found to be miscible with PVC and with SAN copolymers within a limited window of AN levels. Acid functionality in the imidized acrylics appears to hinder their miscibility with SAN rather significantly and with PVC to a lesser extent. Miscible SAN blends showed lower critical solution temperature behavior whereas miscible blends with PVC did not up to the highest attainable temperatures. The composition factors that influence the phase behavior are described and interpreted in terms of possible mechanisms.     

Blends of ethylene–methyl acrylate–acrylic acid terpolymers with ethylene–acrylic acid copolymers: Mechanical and thermomechanical properties

The effect of methyl acrylate content in ethylene–methyl acrylate–acrylic acid (E–MA–AA) terpolymers and acrylic acid content in ethylene–acrylic acid (E–AA) copolymers was investigated in blends of these two materials. The E–MA–AA terpolymer with 8 mol % methyl acrylate was not miscible with any E–AA material no matter what the AA content, whereas the terpolymer with only about 2 mol % methyl acrylate was miscible, at least to some extent, with the E–AA copolymer at high acrylic acid contents. Evidence supporting this conclusion derived from gloss, differential scanning calorimetry testing, and dynamic mechanical measurements. For the E–AA polymer material with the highest acid content, there was a synergistic effect for some properties at low added amounts of E–MA–AA copolymer; the tensile strength and hardness were 10% higher than values for the E–AA copolymer, even though the E–AA copolymer was much stiffer. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2216–2222, 2004     

Synthesis of acrylate modified vinyl chloride and vinyl isobutyl ether copolymers and their properties

With acrylic acid, butyl acrylate and methyl methacrylate as the monomers, acrylate modified vinyl chloride and vinyl isobutyl ether copolymers were prepared by solution polymerization. Firstly, vinyl chloride and vinyl isobutyl ether copolymers were grafted with acrylic monomers to obtain a product containing acrylate grafted vinyl chloride and vinyl isobutyl ether copolymers and polyacrylate, which was then neutralized by triethylamine and dispersed into water to get a self-emulsified emulsion. The acrylate modified vinyl chloride and vinyl isobutyl ether copolymers were characterized by Fourier transform infrared spectroscopy. The mean molecular weight of grafted polymer was determined by gel permeation chromatography, and the particle sizes and their distributions of the dispersions were measured by laser light scattering. The influences of initiator concentration, acrylate content, acrylic acid content and neutralization degree upon the properties of the modified copolymers were discussed. The results show that the emulsion will be with good storage stability, and the modified polymer will be with high water resistance, impact resistance and excellent adhesion when initiator concentration is 1.5%, acrylate content is 50%, acrylic acid content ranges from 9% to 11%, and neutralization degree is between 80% and 100%.     

丙烯酸改性聚醋酸乙烯酯乳液聚合的研究

通过丙烯酸与聚乙二醇共聚合成了具有反应活性的丙烯酸聚氧乙烯酯（简称大单体）,将大单体作为表面活性剂对醋酸乙烯酯乳液聚合的动力学进行了研究;同时在性能上与普通的乳液聚合体系进行了比较。实验结果表明聚合速率随亲水链长度、乳化剂浓度、引发剂浓度、温度的增大而增大,pH值的减小而加快,乳液性能也有了很大的改善．     

Porous crosslinked copolymers of octadecyl acrylate with acrylic acid as sorbers for crude petroleum spills

Bulk and suspension polymerization were used to prepare octadecyl acrylate/acrylic acid (ODA/AA) copolymers. AA content ranged from 0 to 90 mol%. Divinyl benzene was used as a crosslinker at several concentrations (1, 4 and 10 wt%). Isopropyl alcohol or dioctyl phthalate and methyl benzoate were used as the reaction solvents in the presence of poly(vinyl alcohol) as a dispersing agent and 2,2‐azobis isobutyronitrile as the initiator. The polymers so prepared were coated onto poly(ethylene terephthalate) nonwoven (NWPET) fibers. The effects of copolymerization, feed composition, crosslinker concentration and reaction medium or solvent on morphology including porosity and the dynamic mechanical and swelling properties of the crosslinked polymers were determined. Swelling tests were performed in toluene and in 10% crude petroleum diluted with toluene. Bulk polymerization does not result in the formation of a continuous liquid absorbing material while suspension polymerization enables sorbers to be obtained with desired properties. Coating ODA/AA copolymers onto NWPET increases liquid absorption. © 2013 Society of Chemical Industry     

Fourier transform infrared studies of poly(vinyl chloride) blends with ethylene Co- and terpolymers

The miscibility of poly(vinyl chloride) (PVC) with various ethylene copolymers and terpolymers were investigated using FT-IR spectroscopy. All blends reported were 50/50 by weight. In blends of PVC with ethylene/dimethyl acrylamide copolymer (E/DMA), frequency shifts were observed in the amide carbonyl (proton acceptor) and the α-hydrogen of PVC (proton donor) characteristic bands. In blends of PVC with ethylene/ethyl acrylate/carbon monoxide terpolymer (E/EA/CO), both the ester carbonyl and the ketone carbonyl characteristic frequencies showed mutual shifts and appeared as if they merged together. Small frequency shifts were also observed in the α-hydrogen of PVC characteristic bands. In blends of PVC with ethylene/vinyl acetate/carbon monoxide terpolymer (E/VA/CO), the ester carbonyl frequency showed a shift while that of the ketone carbonyl was essentially unchanged. On the other hand, in PVC blends with ethylene/vinyl acetate copolymer (E/VA), the ester CO frequency did not show any shift, which is consistent with their observed immiscibility. Thus, it is clear that incorporating a ketone ? C?O in ethylene/ester copolymers to form the corresponding terpolymers enhances their miscibility with PVC as earlier proposed on the basis of dynamic mechanical studies. Similar results were shown for blends of PVC with ethylene/2 ethyl hexyl acrylate/carbon monoxide terpolymer (E/2EHA/CO). Frequency shifts imply specific interactions which suggest polymer-polyer miscibility on a molecular scale.     

Alkaline hydrolysis of aqueous polymer dispersions,particularly vinyl acetate copolymers

The influence of comonomer species and concentration on the ease of alkaline hydrolysis of vinyl acetate copolymers in the aqueous dispersion form is reported. The comonomers studied include higher vinyl esters, acrylic esters, a fumaric diester, and ethylene. The significance of the emulsion polymerization formulation has also been considered. The rate of hydrolysis is reduced with increasing proportions of comonomers and with increasing length and branching of the alkyl side chain originating from such comonomers. Branched long-chain tertiary vinyl esters reduce not only the rate but also the extent of hydrolysis, being resistant to hydrolysis themselves and also protecting part of the more susceptible vinyl acetate; inhomogeneous copolymers, specially prepared, were less resistant than the more homogeneous copolymer of the same overall composition. The inclusion of quite small amounts, such as 1% by weight, of acid comonomers has a relatively large effect, increasing ease of hydrolysis. For comparison, the behavior of higher vinyl ester homopolymers and methyl methacrylate copolymers with acrylic esters is included. It is concluded that the major factors influencing ease of hydrolysis are steric and other environmental effects arising from the copolymer microstructure.     

Relating the heat-of-mixing of analog mixtures to the miscibility of hydrogen-bonding polymers

The prediction of polymer/polymer miscibility is addressed using analog calorimetry and molecular modeling. For each polymer, an analog compound representing one or two repeat units was chosen. Heat-of-mixing was measured for liquid mixtures of analog compounds and then used in a binary interaction model to predict polymer miscibility. Specifically, we have measured exothermic heats-of-mixing for 4-ethyl phenol, an analog of poly(vinly phenol), with several analogs containing ether, ester, or ketone functional groups. The exothermic heat-of-mixing results are consistent with the observed miscibility of poly(vinyl phenol) with polymers containing these functional groups. Using interaction parametes derived from the analog calorimetry in the binary interaction model or using premixes of 4-ethyl phenol in ethyl benzene, we correctly predict the magnitude and relative order of the fraction of vinyl phenol units in copolymers with styrene required for miscibility with poly(methyl methacrylate), polyacetal, and a polyketone. the miscibility trends for poly(vinyl phenol) blends predicted from analog calorimetry and the binary interaction model are in reasonable agreement with those predicted from the association model of Painter and Coleman, despite the different bases of the two approaches. We have used molecular modeling to complement the analog calorimetry and to assess steric effects on hydrogen-bonding ability for models of poly(n-butyl acrylate) and poly(t-butyl acrylate) with phenol. The modeling results suggest that, in some cases, steric effects and the three-dimensional structure of the polymer can significantly influence the hydrogen-bonding ability of polymers relative to their analogs.     

叔碳酸乙烯酯改性醋丙乳液的制备与性能研究

采用半连续种子乳液聚合,以丙烯酸丁酯(BA)、甲基丙烯酸甲酯(MMA)、乙酸乙烯酯(VAc)为主单体,丙烯酸(AA)为功能单体,叔碳酸乙烯酯(VeoVa10)为改性单体,合成了核壳型丙烯酸酯乳液。探讨了聚合温度、乳化剂、引发剂及功能单体与乳液性能的关系。通过单因素实验探讨了乳化剂用量、配比,改性单体用量等与乳液性能的关系。FT-IR和DSC测试结果表明,各单体之间发生了自由基共聚反应,乳液粒子为核壳结构。     

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     

Concerning the miscibility of poly(vinyl phenol) blends — FTi.r. study

The results of a Fourier transform infrared study of poly(vinyl phenol) (PVPh) blends containing a number of chemically and structurally dissimilar polymers are presented. These polymers include the polyesters poly(ε-caprolactone) and poly(?-propiolactone); poly(vinyl alkyl ethers) where the alkyl groups are methyl, ethyl and isobutyl respectively; poly(ethylene oxide) and poly(vinyl pyrrolidone). All of these PVPh blends, with the exception of that containing poly(vinyl isobutyl ether), exhibit infrared spectral features consistent with a significant degree of mixing. Intermolecular hydrogen bonding interactions involving the PVPh hydroxyl group and either the carbonyl or ether oxygen moieties of the other polymers in the blend are identified. The relative strengths of these intermolecular interactions are discussed together with ramifications pertinent to the overall subject of polymer miscibility.     

Synthesis and photopolymerization of acrylic acrylate copolymers

Acrylate‐functionalized copolymers were synthesized by the modification of poly(butyl acrylate‐co‐glycidyl methacrylate) (BA/GMA) and poly(butyl acrylate‐co‐methyl methacrylate‐co‐glycidyl methacrylate). ¹³C‐NMR analyses showed that no glycidyl methacrylate block longer than three monomer units was formed in the BA/GMA copolymer if the glycidyl methacrylate concentration was kept below 20 mol %. We chemically modified the copolymers by reacting the epoxy group with acrylic acid to yield polymers with various glass‐transition temperatures and functionalities. We studied the crosslinking reactions of these copolymers by differential scanning calorimetry to point out the effect of chain functionality on double‐bond reactivity. Films formed from acrylic acrylate copolymer precursors were finally cured under ultraviolet radiation. Network heterogeneities such as pendant chains and highly crosslinked microgel‐like regions greatly influenced the network structure and, therefore, its viscoelastic properties. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 753–763, 2002     

Preparation and characterization of poly(vinyl alcohol-co-methyl methacrylate) copolymers

Summary An investigation is presented of the preparation and characterization of poly(vinyl alcohol-co-methyl methacrylate) copolymers which can be used for the preparation of novel membranes. These polymers were prepared by copolymerization of vinyl acetate and methyl methacrylate by -irradiation, followed by methanolysis of the produced copolymers. IR and ¹H-NMR studies established the structure of the copolymers.On sabbatical leave from the Department of Chemical Engineering, Sung Kyun Kwan University, Suwon 170-00, Republic of Korea.     

Physical properties of some vinyl tetrahydroabietate and vinyl maleopimarate acid anhydride copolymers

The stress–strain and torsional characteristics of some experimental copolymers of vinyl tetrahydroabietate and vinyl maleopimarate acid anhydride with vinyl chloride and vinyl acetate have been determined. Similar studies were also undertaken on peroxide-cured compositions of a vinyl chloride-vinyl tetrahydroabietate copolymer. Elastie moduli for the uncured copolymers range from 80,200 to 338,000 psi. Cured compositions of vinyl chloride–vinyl tetrahydroabietate copolymer exhibited both lower and higher moduli than that of the uncured copolymer. Some of the cured compositions appear to have an improved impact resistance over that of the uncured polymers.     

Interpolymer complexes of novel linear and crosslinked acrylic acid–Schiff base copolymers

Novel linear and crosslinked copolymers of acrylic acid and Schiff base, containing the amine groups in the main chain and the carboxylic groups in the side chain, have been synthesized by the Michael addition reaction followed by radical copolymerization. The copolymers that exhibited poly(ampholyte–electrolyte) behaviour were used to prepare complexes by reaction with anionic (poly(acrylic acid), poly(styrene sodium sulfonate)), cationic (polyethyleneimine, poly(hexamethylene guanidine)) and non‐ionic (poly(N‐vinylpyrrolidone), poly(ethylene glycol), poly(vinyl alcohol)) polymers. The influence of external factors, such as solvent quality, temperature, pH and ionic strength, on phase (coil–globule) and volume (swelling–collapse) transitions has been studied. © 2003 Society of Chemical Industry     

Novel ionomers based on blends of ethylene-acrylic acid copolymers with poly(vinyl amine)

The polymerization of N-vinyl formamide followed by hydrolysis yields a linear, water-soluble poly(vinyl amine). The high concentration of pendant primary amine groups leads to a polymer with an interesting set of properties. Complexation with water-soluble anionic polyelectrolytes in water solutions leads to a highly water-insoluble material. The study described herein investigated the phase behavior/properties of melt blends of poly(vinyl amine) with ethylene-acrylic acid (EAA) copolymers of less than 10 wt % acrylic acid. The calorimetric and dynamic mechanical analyses of the resultant blends show that the vinyl amine groups are accessible to the acrylic acid groups of the copolymers and the major property changes occur up to the stoichiometric addition of vinyl amine/acrylic acid. At higher levels of vinyl amine (vinyl amine/acrylic acid mol ratio > 4), additional poly(vinyl amine) forms a separate phase. The mechanical, dynamic mechanical, and calorimetric properties of these blends below the stoichiometric ratio show analogous trends as with typical alkali/alkaline metal neutralization. These characteristics relative to the base EAA include improved transparency, lower melting and crystallization temperature, lower level of crystallinity, and increased modulus and strength. The emergence of the β transition in dynamic mechanical testing is pronounced with these blends (as with alkali/alkaline metal neutralization), indicative of microphase separation of the amorphous phase into ionic-rich and ionic-depleted regions. A rubbery modulus plateau for the blends exists above the polyethylene melting point, demonstrating ionic crosslinking. Above 150°C exposure, further modulus increases occur presumably due to amide formation. This study demonstrates that the highly polar poly(vinyl amine) can interact with acrylic acid units in an EAA copolymer comprised predominately of polyethylene (>90 wt %). The thermodynamic driving force favoring ionic association overrides the highly unfavorable difference in composition. © 1996 John Wiley & Sons, Inc.     

Nitric acid digestion and crystallinity of ethylene–vinyl acetate copolymers

Nitric acid digestion studies of ethylene–vinyl acetate copolymers indicated that copolymers containing identical amounts of vinyl acetate but varying in melt index differed in crystallinity. These results were confirmed by x-ray analysis. The differences in crystallinity were interpreted as showing a variation in the degree of short-chain branching in the polyethylene segments of the copolymer chain. This variation was correlated with the conditions of synthesis.     

Miscible blends of styrene-acrylic acid copolymers with aliphatic,crystalline polyamides

Styrene-acrylic acid copolymers exhibit miscibility with various aliphatic, crystalline polyamides (e.g., nylon 6, 11, and 12) at 20% acrylic acid content in the copolymer. At 8% acrylic acid, phase separation is observed with the crystalline polyamides. At 14% acrylic acid, partial miscibility is observed with each polyamide, resulting in the T_g's of the constituents shifted toward the other constituent. The miscibility of the styrene-acrylic acid copolymers ( > 14 wt % AA) can be ascribed to hydrogen bonding interactions with the polyamides. Styrene-acrylic acid (20% AA) copolymers are miscible with other nylons with alternating amide orientation along the chain (e.g., nylon 6,6 and nylon 6,9). These samples tend to crosslink upon exposure to temperatures above the polyamide melting point unlike the nylon 6, 11, and 12 blends in which branching may only occur. Nylon 11/styrene-acrylic acid blends were chosen for crystallization rate studies. A melting point depression of nylon 11 occurs with addition of the styrene-acrylic acid (20% AA). The Flory-Huggins interaction parameter from the melting point depression is calculated to be -0.27. The crystallization rate of nylon 11 is significantly reduced with the addition of the miscible SAA copolymers (20% AA). The spherulitic growth rate equation predicts this behavior based on a T_g increase with SAA addition.