Acrylic Content Research Articles

The effect of varied monomer composition on adhesive performance and peeling master curves for acrylic pressure‐sensitive adhesives

AbstractA group of pressure‐sensitive adhesives were prepared with constant glass transition temperature, using emulsion polymerization. The monomers chosen were butyl acrylate, 2‐ethylhexyl acrylate, and methyl methacrylate, along with a small amount of acrylic acid. The proportion of acrylic acid monomer was held constant for each polymer preparation but acrylic ester monomer levels were varied. The glass transition temperatures of the acrylate copolymers were measured by using differential scanning calorimetry. Drying and weighing the tetrahydrofuran‐insoluble polymer fractions were used to determine the polymer gel fractions. Films of constant coating thickness were applied to poly(ethylene terephthalate) film and adhesive properties (tack and shear) were examined. Peel was examined through the construction of master curves derived from peel tests conducted over a range of temperatures and peel rates. As the 2‐ethylhexyl acrylate content increased, the latex gel fractions were found to increase. With increasing EHA and gel fraction, peel shear was found to increase. When peel force master curves were compared, divergence in peel master curves occurred as peel rates increased where polymers with higher butyl acrylate contents reached greater peel stress values. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2909–2917, 2004

Solubility in the binary and ternary system for poly(alkyl acrylate)-supercritical solvent mixtures

Experimental cloud-point data to 210 ‡C and 2,200 bar are presented for binary and ternary mixtures of poly(methyl acrylate)-CO2-methy acrylate and poly(ethyl acrylate)-CO2, propylene, and 1-butene-ethyl aerylate systems. The accuracy of the experimental apparatus was tested by comparing the measured pressure-temperature phase behavior data of the poly(ethyl acrylate)-CO2 system obtained in this study with those of Rindfleisch et al. [1995]. The phase behaviors for the system poly(methyl acrylate)-CO2-methyl acrylate were measured in changes of pressure-temperature slope, and with cosolvent concentrations of 0, 5.0, 13.7, 25.3, and 43.3 wt%, respectively. With 48.3 wt% methyl acrylate to the poly(methyl acrylate)-CO2 solution significantly changes, the phase behavior curve takes on the appearance of a typical lower critical solution temperature (LCST) boundary. The impact of ethyl acrylate on the cloud-point for the poly(ethyl acrylate)-CO2 system shows the change of slope of the phase behavior curves from negative to positive with ethyl acrylate concentration of 0, 8.2, and 25.0 wt%. The cloud-point behavior for the poly(ethyl acrylate)-CO2-39.5 wt% ethyl acrylate system shows an LCST curve. The solubility curve to ∼150 ‡C and 1,650 bar for poly(ethyl acrylate)-propylene-ethyl acrylate system shows the change of pressure-temperature diagram and with ethyl acrylate concentration of 0, 7.2 and 21.0 wt%. Also, when 41.1 wt% ethyl acrylate was added to the poly(ethyl acrylate)-propylene solution, the phase behavior curve showed the LCST region. The high pressure phase behavior of poly(ethyl acrylate)-1-butene-0, 3.1, 8.1, 18.5 and 30.7 wt% ethyl acrylate system presented the change of pressure-temperature curve from the UCST region to U-LCST region as the ethyl acrylate concentration increased.

Aggregation States and Surface Wettability in Films of Poly(styrene-block-2-perfluorooctyl ethyl acrylate) Diblock Copolymers Synthesized by Atom Transfer Radical Polymerization

Well-defined poly(styrene-block-2-perfluorooctyl ethyl acrylate) [P(St-b-PFA)] copolymers with various chemical compositions were synthesized by atom transfer radical polymerization. Films of P(St-b-PFA) were structurally characterized, from bulk to surface, on the basis of transmittance electron microscopic observation and small-angle X-ray scattering, X-ray photoelectron spectroscopic, and contact angle measurements. For a comparison, poly(styrene-random-2-perfluorooctyl ethyl acrylate) [P(St-ran-PFA)] copolymers were also synthesized by conventional free radical polymerization. While P(St-b-PFA) with the 2-perfluorooctyl ethyl acrylate (PFA) content higher than 18.7 mol % formed a typical phase-separated cylinder structure, P(St-b-PFA) with a lower PFA content and P(St-ran-PFA) were in a miscible state. Since the perfluoroalkyl groups possess extremely low surface energy, they were preferentially segregated at the film surface, resulting in the formation of the PFA surface layer. This was the case for all P(St-b-PFA) films examined, although the aggregation state at the surface was strongly dependent on the PFA content. In the case of the P(St-b-PFA) with the PFA content higher than 18.7 mol %, both advancing and receding contact angles for water were 120 degrees and even larger with almost no hysteresis. In addition, extremely excellent oil-repellent surface properties such as advancing and receding contact angles for dodecane of 76 degrees and 75 degrees were also observed. However, these intriguing liquid-repellent properties were not observed for the films of miscible P(St-b-PFA) and P(St-ran-PFA). Therefore, it can be concluded that the internal structure beneath the surface as well as the surface itself should be deeply considered to design excellent and stable liquid-repellent materials.

Control Crystallization of Calcium Carbonate in Aqueous Solution with In-Situ Radical Polymerization of Sodium Acrylate as a Latent Inductor for Crystal Nucleation and Growth

Abstract Crystallization of CaCO3 with in-situ radical polymerization of sodium acrylate in aqueous solution was carried out by a double jet method to prevent heterogeneous nucleation at glass walls. The concentration of sodium acrylate was 1.71 mM and the feed ratio of sodium acrylate to calcium ions was 0.62. After addition of the calcium reactants into the aqueous solution of sodium acrylate was completed, an aqueous solution of potassium peroxodisulfate as a water-soluble radical initiator was added to the reaction mixture after incubation at 30 °C for several minutes (1, 3, or 20 min). Three different crystal polymorphs of CaCO3 (aragonite, vaterite, and calcite) were selectively induced by changing the time for adding the radical initiator to a calcium carbonate solution with sodium acrylate. Formation of crystalline CaCO3 in the presence of sodium acrylate with the radical initiator at different feed ratio of sodium acrylate to calcium ions was also studied. The higher concentration of sodium acrylate increased sizes of vaterite spherical particles. The present results indicate that the final crystalline phases are highly sensitive to the presence of the active additives at the very initial nucleation stage (within several minutes).

Palladium Nanoparticles by Electrospinning from Poly(acrylonitrile-co-acrylic acid)−PdCl2 Solutions. Relations between Preparation Conditions, Particle Size, and Catalytic Activity

Catalytic palladium (Pd) nanoparticles on electrospun copolymers of acrylonitrile and acrylic acid (PAN-AA) mats were produced via reduction of PdCl2 with hydrazine. Fiber mats were electrospun from homogeneous solutions of PAN-AA and PdCl2 in dimethylformamide (DMF). Pd cations were reduced to Pd metals when fiber mats were treated in an aqueous hydrazine solution at room temperature. Pd atoms nucleate and form small crystallites whose sizes were estimated from the peak broadening of X-ray diffraction peaks. Two to four crystallites adhere together and form agglomerates. Agglomerate sizes and fiber diameters were determined by scanning and transmission electron microscopy. Spherical Pd nanoparticles were dispersed homogeneously on the electrospun nanofibers. The effects of copolymer composition and amount of PdCl2 on particle size were investigated. Pd particle size mainly depends on the amount of acrylic acid functional groups and PdCl2 concentration in the spinning solution. Increasing acrylic acid concentration on polymer chains leads to larger Pd nanoparticles. In addition, Pd particle size becomes larger with increasing PdCl2 concentration in the spinning solution. Hence, it is possible to tune the number density and the size of metal nanoparticles. The catalytic activity of the Pd nanoparticles in electrospun mats was determined by selective hydrogenation of dehydrolinalool (3,7-dimethyloct-6-ene-1-yne-3-ol, DHL) in toluene at 90 °C. Electrospun fibers with Pd particles have 4.5 times higher catalytic activity than the current Pd/Al2O3 catalyst.

Phase behavior on the binary and ternary mixtures of poly(cyclohexyl acrylate) and poly(cyclohexyl methacrylate) in supercritical CO2

High-pressure phase behavior was measured for the CO2–cyclohexyl acrylate and CO2–cyclohexyl methacrylate system at 40, 60, 80, 100, and 120°C and pressure up to 206 bar. This system exhibits type I phase behavior with a continuous mixture-critical curve. The experimental results for the CO2–cyclohexyl acrylate and CO2–cyclohexyl methacrylate system were modeled using the Peng–Robinson equation of state. Experimental cloud-point data, at a temperature of 250°C and pressure of 2800 bar, were presented for ternary mixtures of poly(cyclohexyl acrylate)–CO2–cyclohexyl acrylate and poly(cyclohexyl methacrylate)–CO2–cyclohexyl methacrylate systems. Cloud-point pressures of poly(cyclohexyl acrylate)–CO2–cyclohexyl acrylate system were measured in the temperature range of 40 to 180°C and at pressures as high as 2200 bar with cyclohexyl acrylate concentrations of 22.5, 27.4, 33.2, and 39.2 wt %. Results showed that adding 45.6 wt % cyclohexyl acrylate to the poly(cyclohexyl acrylate)–CO2 mixture significantly changes the phase behavior. This system changed the pressure–temperature slope of the phase behavior curves from the upper critical solution temperature (UCST) region to the lower critical solution temperature (LCST) region with increasing cyclohexyl acrylate concentration. Poly(cyclohexyl acrylate) did not dissolve in pure CO2 at a temperature of 250°C and pressure of 2800 bar. Also, the ternary poly(cyclohexyl methacrylate)–CO2–cyclohexyl methacrylate system was measured below 187°C and 2230 bar, and with cosolvent of 27.4–46.7 wt %. Poly(cyclohexyl methacrylate) did not dissolve in pure CO2 at 240°C and 2500 bar. Also, when 53.5 wt % cyclohexyl methacrylate was added to the poly(cyclohexyl methacrylate)–CO2 solution, the cloud-point curve showed the typical appearance of the LCST boundary. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1117–1125, 2004

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

AbstractThe 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

The influence of silicon-containing acrylate as active diluent on the properties of UV-cured epoxydiacrylate films

A new silicon-containing acrylate, which can be a good active diluent for UV-curable epoxydiacrylate systems, was prepared by reacting N-cyclohexyl-γ-aminopropylmethyldimethoxysilane (CAMS) with trimethylolpropane triacrylate (TMPTA) by Michael-type addition reaction. The reactivity of –NH groups of CAMS with the acrylic groups of TMPTA was characterized by FTIR. The contents of the new active diluent in the UV-cured polymeric films were varied between 5% and 15% by weight. Mechanical, physical, and thermal characterizations of the UV-cured films were investigated: An increase in silicon-containing acrylate content caused a dramatic change of the surface properties of the films, and a decrease in mechanical properties besides the relative elongation. Thermogravimetric analysis of silicon-containing acrylate revealed that incorporating silicon into the structure resulted in a high char yield at 700 °C. Water absorption values of UV-cured films were also affected by the amount of silicon-containing acrylate.

In situ EPR investigation of the addition of persistent benzyl radicals to acrylates on ZSM-5 zeolites. Direct spectroscopic detection of the initial steps in a supramolecular photopolymerization.

Photolysis of dibenzyl ketone derivatives adsorbed on ZSM-5 zeolites produces persistent benzyl radicals (initiator radicals), which add to methyl acrylates (monomers) to generate persistent adduct radicals. Both initiator and adduct radicals are readily observable by conventional steady-state EPR spectroscopy at room temperature and are persistent for time periods ranging from seconds to many days. The rate of the formation and the amount of the adduct persistent radical formed depends on the structure of the initiator radical (benzyl radical derivative) and the structure of the monomer (acrylate derivative). The lifetimes of the initiator and adduct radicals depend on the supramolecular structure of the radical@zeolite complex and the diffusion and reaction dynamics of the radicals in the complex. The most intense signal and highest addition rate to methyl acrylate were observed for the smallest initiator radical, the benzyl radical, because of its high mobility and relatively rapid diffusion within the internal zeolite surface. With increasing length of an alkyl chain (methyl, ethyl, and pentyl) on either the initiator (alpha position of the radical) or monomer (alkyl group of acrylate ester), the rate of radical addition to the monomer decreased, a result that is consistent with the decreased mobility and diffusion of the initiator radical or monomer. Deuterium isotope experiments and variation of the methyl acrylate concentration demonstrated that the initial adduct radical from methyl acrylate adds to another methyl acrylate to generate a secondary adduct radical, which, in turn, can continue to propagate to form a polymer that is cross-linked to the zeolite crystals. The results demonstrate that EPR can be a powerful tool for the direct in situ analysis of supramolecular photochemistry involving radicals rendered persistent by supramolecular steric effects. The latter eliminate the need for sophisticated flash photolysis equipment to investigate the structure and dynamics of reactive radicals and require only the use of simpler steady-state lamps.

Hydrophobic association and temperature and pH sensitivity of hydrophobically modified poly(N‐isopropylacrylamide/acrylic acid) gels

AbstractHydrophobically modified poly(acrylic acid/N‐isopropylacrylamide) gels were synthesized by the radical copolymerization of acrylic acid/N‐isopropylacrylamide with a small amount of the hydrophobic comonomer 2‐(N‐ethylperfluorooctanesulfoamido)ethyl acrylate, stearyl acrylate, or lauryl acrylate in tert‐butanol with ethylene glycol dimethacrylate as a crosslinker. Swelling kinetics and fluorescence measurements showed that the hydrophobic association ability of fluorocarbon groups was stronger than that of hydrocarbon analogues in modified hydrogels that contained both physical and chemical crosslinking networks. The effects of the fractions and the species of the hydrophobe on the gel swelling and pH and temperature sensitivity were studied. The results indicated that the swelling behavior and pH and temperature sensitivity of the gels were affected by the degree of hydrophobic modification. A hydrogel with a suitable 2‐(N‐ethylperfluorooctanesulfoamido)ethyl acrylate content (0.349 mol %) showed good pH and temperature sensitivity. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 2406–2413, 2003

Gas-chromatographic determination of butanol and butyl acrylate in aqueous solutions with the use of headspace analysis

A procedure has been developed for the determination of the concentration of butanol and butyl acrylate in aqueous solutions in the range of 0.5–20 MPC. The procedure is based on static headspace gas-chromatographic analysis on a column filled with the Chromaton N-AW-HMDS sorbent containing 15 wt % of polyethylene glycol adipate with detection by a flame-ionization detector.

Fortschritte im Bonding - Neuentwicklungen von Klebern und Polymerisationslampen

In this study bond strengths (after 1 h and 24 hrs) of a light-curing resin (Enlight) and of a light-curing glass ionomer cement (Fuji Ortho LC) employing various polymerization lamps for the direct bonding of brackets were compared by shear testing. The shear bond strength of brackets bonded with a self-curing resin (Concise) were used as standard of comparison.The minimum bond strength could be achieved with all the polymerization lamps using the applied adhesives. In this study bond strengths of resin modified glass ionomer cement are comparable to the light-curing composite resin, or are actually somewhat higher when using lamps with short polymerization times, but compared to the self-curing composite adhesive bond strengths are significantly lower.24 hours after bonding all three adhesives showed a significant increase of bond strengths: Enlight by 19 %, Fuji Ortho LC by 6.6 % and Concise by 16 %.In the second part of the study a comparison of polymerization lamps of various technologies was carried out by determining the degree of polymerization of composite samples using Fourier-Transform Infrared Spectroscopy (FTIR).Results showed that the various lamps using selected curing times were adequate for a successful polymerization of this composite (residual acrylate content approx. 40 %). Even after very long curing times, post-curing of the composite is to be expected. ATR-FT- IR spectroscopy showed that, uncured areas could be detected in the center of the lowest layer of the adhesive (1-7 µ m) when bonding brackets with light-curing materials were used.

Structure of Water Sorbed into Poly(MEA-co-HEMA) Films As Examined by ATR−IR Spectroscopy

The structure of water sorbed into poly(2-methoxyethyl acrylate) (PMEA), poly(2-hydroxyethyl methacrylate) (PHEMA), and their copolymers (p(MEA/HEMA)) was investigated by attenuated total reflection infrared (ATR−IR) spectroscopy. The extinction coefficient of the OH stretching band of sorbed water (εOH) was calculated from the band area obtained by IR measurement and the amount of sorbed water obtained by thermogravimetric analysis. When the polymers contacted with water vapor (relative humidity = ∼55%), the εOH values were quite similar in all polymers. On the other hand, when the polymers contacted with liquid water, the εOH values were drastically changed by the content of 2-methoxyethyl acrylate (MEA). When the MEA content of the polymers was low (<60 mol %), the εOH value of the water sorbed into polymers in contact with liquid water was equal to that in contact with water vapor. In the higher MEA content (70−100 mol %), on the other hand, the εOH values of the water sorbed into polymers in contact with liquid water were 5−8 times larger than that in contact with water vapor. These results seemed to indicate that the interaction between the primary hydration water around the MEA-containing polymer chain and water molecules surrounding the primarily hydrating water is very weak. Such water with a large εOH value seemed to correspond to “cold-crystallizable” water, which has been observed by DSC as anomalous water other than intermediate and nonfreezable waters. Taking both the experimental results obtained in this work and those thermodynamically obtained previously into consideration, it was strongly suggested that the cold crystallization of water is generated by caging water molecules in a small space by the polymer chains with a small hydration region. The correlation between the εOH value and the blood compatibility of the copolymer was also discussed.

Graft copolymerization of ethyl acrylate onto cellulose using ceric ammonium nitrate as initiator in aqueous medium.

Ceric ammonium nitrate (CAN) in the presence of nitric acid has been used as efficient initiator for graft copolymerization of the ethyl acrylate onto cellulose at 35.0 +/- 0.1 degrees C. Graft copolymerization of ethyl acrylate onto cellulose has taken place through the radical initiation process. The graft yield and other grafting parameters have been evaluated by varying concentration of ethyl acrylate from 2.5 x 10(-1) to 15.0 x 10(-1) mol dm(-3) and ceric ammonium nitrate from 5.0 x 10(-3) to 25.0 x 10(-3) mol dm(-3) at constant concentration of the nitric acid (8.0 x 10(-2) mol dm(-3)). The rate of graft copolymerization has shown 1.5 order with respect to the concentration of the ceric ammonium nitrate. The graft copolymerization data obtained at different temperatures were used to calculate the energy of activation, which has been found to be 28.9 kJ mol(-1) within the temperature range from 20 to 50 degrees C. The effect of addition of cationic and anionic surfactants on graft copolymerization has also been studied. On the basis of the experimental observations, reaction steps have been proposed and a suitable rate expression for graft copolymerization has been derived.

Calorimetric study of block-copolymers of poly( n-butyl acrylate) and gradient poly( n-butyl acrylate- co-methyl methacrylate)

The nanophase separation in diblock and triblock copolymers consisting of immiscible poly( n-butyl acrylate) (block A) and gradient copolymers of methyl methacrylate (MMA) and n-butyl acrylate ( nBA) (block M/ A) were investigated by means of their heat capacity, C p, as a function of the composition of the blocks M/ A and temperature. In all copolymers studied, both blocks are represented by their C p and glass transition temperature, T g, as well as the broadening of the transition-temperature range. The low-temperature transition of the blocks A is always close to that of the pure poly( n-butyl acrylate) and is independent of the analyzed compositions of the block copolymer, but broadened asymmetrically relative to the homopolymer due to the small phase size. The higher transition is related to the glass transition of the copolymer block of composition M/ A. Besides the asymmetric broadening of the transition due to the phase separation, it decreases in T g and broadens, in addition, symmetrically with increasing acrylate content. The concentration gradient is not able to introduce a further phase separation with a third glass transition inside the M/ A block.

Effect of the octadecyl acrylate concentration on the phase behavior of poly(octadecyl acrylate)/supercritical CO2 and C2H4 at high pressures

Pressure–composition isotherms were measured for the CO2/octadecyl acrylate system at 45.0, 80.0, and 100.0°C and at pressures up to 307 bar. This system exhibited type I phase behavior with a continuous mixture-critical curve. The solubility of octadecyl acrylate for the CO2/octadecyl acrylate system increased as the temperature increased at a constant pressure. The experimental results for the CO2/octadecyl acrylate system were modeled with the Peng–Robinson equation of state. A good fit of the data was obtained with the Peng–Robinson equation of state with one adjustable parameter for the CO2/octadecyl acrylate system. Experimental cloud-point data for the poly(octadecyl acrylate)/CO2/octadecyl acrylate system were measured from 36 to 193°C and at pressures up to 2100 bar, and the added octadecyl acrylate concentrations were 11.9, 25.9, 28.0, 35.0, and 40.0 wt %. Poly(octadecyl acrylate) dissolved in pure CO2 up to 250°C and 2100 bar. Also, adding 45.0 wt % octadecyl acrylate to the poly(octadecyl acrylate)/CO2 solution significantly changed the phase behavior. This system changed the pressure–temperature slope of the phase-behavior curves from an upper critical solution temperature (UCST) region to a lower critical solution temperature region as the octadecyl acrylate concentration increased. Cloud-point data to 150°C and 750 bar were examined for poly(octadecyl acrylate)/C2H4/octadecyl acrylate mixtures at octadecyl acrylate concentrations of 0.0, 15.0, and 45.0 wt %. The cloud-point curve of the poly(octadecyl acrylate)/C2H4 system was relatively flat at 730 bar between 41 and 150°C. The cloud-point curves of 15.0 and 45.0 wt % octadecyl acrylate exhibited positive slopes extending to 35°C and approximately 180 bar. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 372–380, 2002

Reaction of different α-sulfonyl acetamides with methyl acrylate

The base-induced tandem-coupling/cyclization reactions of various α-sulfonyl acetamide derivatives A with methyl acrylate differentiated between two different pathways to form α-sulfonyl analogs of glutarimides B and 2-hydroxycyclohexenecarboxylic acid derivatives C in different ratios. The reaction of α-sulfonyl acetamide dianion with methyl acrylate depended on three factors: the stability of the dianion, concentration of methyl acrylate and the structure of sufonyl and amide substituents. By changing the reaction conditions, we efficiently controlled the cycloaddition reaction to synthesize the desired product, each of which has potential biological activities. A ring closure mechanism is proposed for the reactions.

On the study of polyurethane ionomer — Part II

AbstractPhotosensitive‐fluorescein polyurethane (PU) ionomer was successfully synthesized at our laboratory. The reaction of toluene diisocyanate with polyester, fluorescein, hydroxypropyl acrylate and other major additives to form the structures of these ionomers has been proven by FT‐IR spectroscopy. For a dilute concentration of photosensitive‐fluorescein PU ionomer molecule in aqueous solution, the fluorescence studied exhibits fluorescence at around 508 nm. In aqueous solution, the number average particle size appears to increase with increasing concentration of epoxy, fluorescein and hydroxypropyl acrylate used to prepare the photosensitive‐fluorescein PU ionomer molecules. The reason for the free volume of photosensitive‐fluorescein PU ionomer molecules is due to strong intermolecular interactions between hydrophilic groups of these ionomer molecules increasing. Therefore, the number average particle sizes of these ionomer molecules increases. Furthermore, the addition of benzoin as a photoinitiator to photosensitive‐fluorescein PU ionomer molecule results in an increase is the average particle size of this ionomer molecule. This is due to increased free volume resulting from strong intermolecular interaction between hydrophilic groups of ionomer molecules. For self‐cured films made by photosensitive‐fluorescein PU ionomer, the tensile strength is seen to increase with increasing concentration of epoxy, fluorescein and hydroxypropyl acrylate, respectively. This may be attributed to increased crosslinking due to strong intermolecular interaction between photosensitive‐fluorescein PU ionomer molecules themselves. However, the addition of benzoin as a photoinitiator to photosensitive‐fluorescein PU ionomers results in an increase in the tensile strength of these ionomers as well. Copyright © 2002 John Wiley &amp; Sons, Ltd.

Interpolymer specific interaction in blends of poly(styrene- co-alkyl acrylate- co-4-vinylpyridine) and poly(styrene- co-alkyl acrylate- co-acrylic acid)

The interpolymer specific interaction of proton donating polymer (PDP) and proton accepting polymer (PAP) in toluene was studied by viscometry coupled with light scattering. The viscometric experiment results show that the stronger the interpolymer interaction is, the higher the viscosity of PDP/PAP blend solution than the weight-average of both components at high concentration, in contrast to lower viscosity at low concentration. Based on the relationship of viscosity enhancement factor with polymer level in solution, a new polymer–polymer interaction parameter k a to estimate interpolymer interaction was developed. The effects of functional groups content and acrylate unit on interpolymer interaction were studied with this parameter combined with light scattering. The results show that interpolymer interaction ability increases with the functional group and long chain alkyl acrylate content. With the increase in side chain length of acrylate unit, enhancement in the interpolymer specific interaction can be realized.

Preparation of a self‐compatibility alloy via a seed‐graft concentrated‐emulsion pathway

AbstractA novel polymerization procedure, the concentrated‐emulsion graft polymerization of styrene monomer with poly(butyl acrylate) seed, was proposed for the production of a self‐compatibility macromolecule alloy. The effects of the butyl acrylate content, sodium dodecyl sulfate concentration, and polymerization temperature on the graft ratio were investigated. Scanning electron microscopy, transmission electron microscopy, and impact strength were used to characterize the microstructure and mechanical performance of the self‐compatibility macromolecule alloy. The results showed that increasing the butyl acrylate content, reducing the sodium dodecyl sulfate concentration, and improving the polymerization temperature all favored an increased graft ratio, which resulted in increased impact strength of the self‐compatibility macromolecule alloy. Therefore, the concentrated‐emulsion polymerization method is particularly suitable for seed‐graft polymerization. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2915–2920, 2002; DOI 10.1002/app.10288