Research articles

Our study explored microstructures at skin, sub-skin and core zones of injection-molded carbon black particles/polypropylene composite. Figure 3 in the paper showed the schematic map on definition of each zone. We found that strong oriented microstructure was formed at core instead of at sub-skin, especially under lower packing pressure. A band with non-continuous conductive path was found under the action of higher injection process, and it will expand with lowering packing pressure.

The concept of controlling supramacromolecular self-assembly and disassembly of two building blocks (of polymers) with end-functional groups is displayed. By self-assembling two building blocks that carry non-covalent bonding moieties, a block copolymer-type supramacromolecule is formed via non-covalent bonding, resulting in a nanophase-separated structure with the length scale of the building blocks. By contrast, macrophase separation with a much larger length scale than the building blocks themselves can be observed if the two blocks are pulled apart under external stimuli such as heat or applied stress.

Polyrotaxane networks were synthesized by exploiting a Pd-templated bis-macrocycle as a topological cross-linker during radical polymerization. Radical polymerization of 4-vinylpyridine with the topological cross-linker in the presence of a catalytic amount of AIBN gave the network polymer as a gel. The addition of 4-tert-butylstyrene as a vinyl co-monomer to the polymerization system afforded a sufficiently stable gel as the polyrotaxane network, enabling the introduction of stopper moieties into the trunk polymer.

Bio-based thermosetting resins, biseugenyl succinate (BEUS) and bis(4-maleimidephenyl) succinate (BMIS) were synthesized from succinic acid and eugenol. The BEUS/BMIS cured at 230 °C for 1 h showed a higher glass transition temperature and a greater tensile strength than 2,2′-diallyl bisphenol A (DABA)/4,4′-bismaleimidediphenylmethane (BMIM) cured under the same condition. The Fourier Transform Infrared (FTIR) analysis of the cured materials revealed that chain polymerization of allyl and maleimide groups occurred to produce BEUS/BMIS, whereas a stepwise ene reaction and subsequent chain polymerization in addition to an etherification reaction occurred to produce DABA/BMIM.

This paper discusses an effective route in the graft copolymerization of methyl methacrylate monomer onto syndiotactic polystyrene (sPS) using free-radical polymerization, and the effect of an organophilic montmorillonite (O-MMT) on the final properties of the graft copolymer sample. The structure of vinyl-terminated sPS multicenter macromonomer and the graft copolymer were characterized by means of Fourier transform infrared and ¹H nuclear magnetic resonance spectroscopy. The exfoliated sPS-graft-poly(methyl methacrylate)/MMT nanocomposite was characterized by means of X-ray diffraction, transmission electron microscopy, thermogravimetric analysis and differential scanning calorimetry.

Photo-stimulated luminescence spectra (PSLS) emission from alumina-filled epoxy nanocomposites consisting of varying volume fractions of alumina nanoparticles was collected and analyzed to characterize dispersion within the sample through intensity maps. The measurements are based on integrated intensity data from the R1 curve of α-alumina throughout each specimen. This novel method has potential as a quality control method to determine the location of voids, inclusions and/or agglomerations, while in addition predicting the volume percentage of particles within a specimen.

Two different strategies have been successfully used to modulate the swelling capacity of thermo-responsive hydrogels based on 2-(2-methoxyethoxy)ethyl methacrylate: (1) controlling the crosslinking degree from varying the crosslinker type and amount, and (2) using N-isopropylacrylamide as comonomer, which in addition allows to modulate the volume and glass transition temperatures.

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.

Aromatic-ring-layered polymers were synthesized by Sonogashira–Hagihara coupling reaction using xanthene as a scaffold. The polymers were characterized by various spectroscopic and electrochemical methods. The polymers emit brightly without excimer formation, despite the layered structure.

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.