Research articles

Functional non-woven fiber mats were prepared by combining the electrospinning method and surface-initiated atom transfer radical polymerization (ATRP). The surface-initiated ATRP of 3-(N-2-methacryloyloxyethyl-N,N-dimethyl) ammonatopropanesulfonate), 2-hydroxyethyl methacrylate and 2-(perfluorooctyl)ethyl acrylate proceeded successfully from the fiber surface of poly(methyl methacrylate)-co-poly(2-(2-bromoisobutyryloxy)ethyl methacrylate) without any structural changes. A grafted layer after the surface-initiated ATRP was observed by atomic force microscopy. Static contact angles against water were also evaluated to discuss the relationship between the roughness of the electrospun non-woven fiber mats and wettability.

A novel fluorinated diamine monomer, 1,1′-thiobis-[(2-trifluoromethyl)4-aminophenoxy) naphthyl ether], was successfully synthesized in two steps route, including the Williamson etherification reaction, followed by catalytic reduction. A series of fluorine-containing poly(ether amide)s were synthesized from such diamine with various aromatic dicarboxylic diacids. These polymers were amorphous in nature, readily soluble in various organic solvents and exhibited high thermal stability and low refractive indexes.

We have synthesized novel Mussel-mimetic adhesive resin from biomass monomers. Because the adhesive resin contains catechol group at their chain ends, which is similar chemical structure of 3,4-dihydroxyphenyl-L-alanine (DOPA) produced by Mussel, it demonstrated strong adhesive characteristics onto organic and/or inorganic surfaces beyond the conventional instant superglue as shown in figures (X, conventional instant superglue; Y, poly(DHCA-co-4HCA) resin). The origin of this strong adhesive characteristic was discussed by strong type of hydrogen bond interaction between our new resins and oxidized and/or OH group on the substrates.

A new kinetic model of styrene-free radical bulk polymerization was developed. Experimental data of styrene conversion dependence on reaction time were well described by estimated kinetic model. It was determined that the first-order reaction followed by autoacceleration of styrene-free radical bulk polymerization is taking place simultaneously between 41.7 and 110.5 °C.

Isotactic-poly(1-butene) shows superior mechanical property after crystal–crystal transitions. Very recently, Miyoshi. revealed molecular dynamics of the crystalline stems in metastable tetragonal form. In this study, molecular dynamics in stable trigonal crystal is investigated by ¹³C center bands only detection of exchange nuclear magnetic resonance. The experimental results indicate that overall motions and side-chain dynamics in slow dynamic range are frozen up to melting temperatures. On the basis of molecular dynamics, roles of (i) unique crystallization and (ii) solid–solid transitions for superior mechanical property are discussed.

A pentamethylcyclopentadienyl (Cp*)-based ruthenium complex with phenolic phosphine ligands 4-(hydroxyphenyl)diphenylphosphine ([PPh₂(pPhOH)]) showed a high catalytic activity for aqueous living radical polymerizations of hydrophilic methacrylates (for example, poly(ethylene glycol) methacrylate (PEGMA), 2-hydroxyethyl methacrylate (HEMA) and so on). Importantly, the activity was high enough to control the aqueous polymerizations even with just catalytic amount. Such an advanced catalysis would be caused not only by a simple hydrophilicity of the ligand but also by a water-assisted dynamic transformation from the original saturated form [Cp*RuCl(PR₃)₂; 18e; PR₃=phosphine] into an unsaturated but active one [Cp*RuCl(PR₃); 16e] upon which water molecule(s) may additionally coordinate for further stabilization.

The colloidal polyion complex formed from sodium polyacrylate (NaPA) and poly(vinyl ammonium) chloride (PVACl) is almost stoichiometric but slightly charged by the adsorption of the excess polyelectrolyte component onto the neutral complex. The charge stabilizes the colloidal polyacrylate–poly(vinyl ammonium) complex in aqueous solution of a non-stoichiometric mixture of NaPA and PVACl, and the aggregation number of the colloidal complex increases with approaching the stoichiometric composition. On the basis of the experimental results obtained, we propose a simple model for the colloidal polyion complex formation.

Reversible inclusion complexation between size-mismatched components, poly(ethylene glycol) (PEG) and β-cyclodextrin (β-CD), is described. A PEG chain with proper end groups allowed β-CD to be trapped onto the chain, and multitopic β-CD derivatives to crosslink the chain supramolecularly. The supramolecular crosslinking formed only when the system was heated, and dissociated by dilution and shaking without reheating.

Impact modification of poly(ethylene terephthalate)–poly(butylene terephthalate) blend using different impact modifiers was carried out in this research work and the results were co-related using various analytical techniques.

The addition of methanol to dilute THF solutions of chiral-achiral random copolymers of fluorene derivatives and the chiral homopolymer showed thermo-reversible circular dichroism (CD) induction in the main-chain fluorene absorption region, demonstrating the uneven population of the right- and left-handed helical conformation in the polymer chains. From the sign of the induced CD, we found two helical screw-sense inversions by changing the chiral monomer content. The Ising model for chirally interacting chiral-achiral random copolymers can explain the double screw-sense inversions.

The polyaniline (PANi)/MnFe₂O₄ nanocomposite containing hollow ferromagnetic nanoparticles has been synthesized. This report is a helpful method to improve mixability of inorganic particles with an organic phase. The results of atomic force microscopy image indicate the even distribution of MnFe₂O₄ in the PANi base, and this proves the effectiveness of dodecyl benzene sulfonic acid and ultrasonic devices in mixing two non-homogenous phases.

Interactions between brush-like segments were calculated both in perturbation and smoothed-density scheme. The figure schematically illustrates the considered interactions between two brush-like segments, where the thick and thin solid lines represent the main and side chains, respectively, whereas the dashed lines connect interacting segments. The calculated results were compared with experimental values for polystyrene polymacromonomers.

Would the chain-scission mechanism of the polymer depolymerizations be changed by the non-thermal effects of microwave irradiation? and how are the chain-scission mechanism and its kinetic behaviors? In this paper, the kinetic processes and mechanisms of poly(ethylene terephthalate) (PET) hydrolytic depolymerization of microwave were investigated, and the chain-scission mechanism was further discussed to give effective support to the non-thermal effects of microwave irradiation for which chemical reactions of small molecules could not give effective evidences.

The aligned nanofiber assemblies showed anisotropic wettability based on the high alignment degree of the nanofibers. The poly(3,4-ethylenedioxythiophene)/poly(4-styrene sulfonate) (PEDOT/PSS) composite film containing aligned nanofibers displayed an anisotropic actuation response when a voltage was applied in air. The orientation of the embedded nanofibers within the PEDOT/PSS matrix leads to the control of actuation direction because of the difference of anisotropic mechanical properties in the composite films.

At the end of the copolymerization procedure in supercritical carbon dioxide, biodegradable/biocompatible triblock stabilizer remained in the product. The presence of the stabilizer provided the copolymer product with higher yield and molecular weight in random highly porous shapes.

The three type water-soluble monocyclic aromatic (MA) polymers were synthesized; MA polymer has same molecular weight (MW), sulfonated phenol–formaldehyde (SPF) polymer with more –SO₃ and less –OH functional groups, has high water-reduction percentage and high slump loss and poor workability preservation properties, the aminosulfonate–phenol–formaldehyde polymer (AS) and aminosulfonate–phenol–salicylic acid-formaldehyde (AH) polymer bonded –SO₃ and –COOH as dispersion groups, −OH and –NH₂ as fluidity preservation groups have better water-reducing capacity, workability preservation properties, setting time retardation of cement paste and higher compressive strengths of concrete.

Atomic force microscopy (AFM) phase images for the ridge and valley regions of the water-etched poly(ethylene oxide)/poly(L-lactic acid) (50/50) blend crystallized at crystallization temperature (T_c)=110 °C. The AFM graph (5 μm×5 μm) of the ridge region b shows a texture different from that of the valley region c. The surface patterns of the lamellae in the valley and ridge in these two regions appeared as flat-on and edge-on lamellae, respectively. The anisotropicity of the platelet crystals in these two regions was also apparently different. The orientation of the crystal lamellae in the valley (region c) was circumferential, whereas that of the lamellae in the ridge (region b) was radial. The difference in orientation in the ridge and valley regions may account for the cracks in the ridge regions but not in the valley region.

Using off-lattice Monte Carlo simulation, the critical value of Flory–Huggins parameter, χ, for flexible–semiflexible (isotropic–isotropic) polymer systems as a function of stiffness of semiflexible components has been estimated. The simulation data were compared with that of mean field and it was found that both agree very well. Interfacial tension and width of flexible–semiflexible polymer systems had been studied for strong segregation and weak segregation limits.

An investigation has been undertaken to find out the effect of different polyfunctional monomers (PFMs) on the properties of chlorinated polyethylene (CPE) crosslinked by electron beam (EB). Physico-mechanical properties of EB-irradiated samples were compared with the dibenzoyl peroxide-cured samples. Dependence of properties on irradiation dose was determined from a dose range of 0–20 Mrad. The results showed an increase in physico-mechanical properties as a result of introducing PFMs, the most efficient being triallyl cyanurate (TAC) and triallyl isocyanurate (TAIC).

pH-responsive poly(6-(acrylamido)hexanoic acid)-grafted silica particles (PAaH-SiO₂) were prepared via reversible addition-fragmentation chain transfer (RAFT)-controlled radical polymerization using the chain transfer agent immobilized silica particles. Millimeter-sized ‘liquid marbles’ can be prepared using the pH-responsive PAaH-SiO₂ particles. The ‘liquid marble’ can be transferred intact onto the surface of neutral or acidic water pool, which exhibited long-term stability. When pH of the water pool was changed to alkaline, ‘liquid marble’ burst immediately on the surface of the water pool.