Note in 2015

A facile synthesis of ABA triblock copolymers composed of aliphatic polyesters and aromatic polyimides was performed by ring-opening polymerization ɛ-caprolactone and L-lactide initiated by hydroxy-terminated polyimide.

This study explores the relationship between the mechanical properties and composite structure of a bacterial cellulose/polyethylene glycol (BC/PEG) gel with a peripheral region that is crosslinked by polyethylene glycol diacrylate (PEGDA). The results indicated that the mechanical strength of the gels was dependent not only on the amount of crosslinked PEGDA, but also on the extent to which the composite structure extends below the surface. As retention of the fiber phase is vital to reducing the brittleness of the material, the concentration gradient of the PEGDA polymer is a critical factor.

A 0.3-nm-high step pattern was formed on a poly(methyl methacrylate) (PMMA) polymer surface by thermal nanoimprinting a sapphire template. Large-area transcription was attained under the condition of ~0.2 MPa load for 300 s at 120 °C. We also observed the thermal deformation of the atomically stepped pattern formed on a PMMA surface by in situ atomic force microscopy at high temperature and found the atomic step pattern was stable near the imprinting temperature of 120 °C and also at about 20 °C higher than the bulk glass transition temperature of PMMA (105 °C).

Poly(l-3-hydroxybutanoic acid) [P(l-3HB)] and poly(d-3-hydroxybutanoic acid) [P(d-3HB)] in their equimolar blend crystallized synchronously and separately into each homo-crystallites but not stereocomplex crystallites. In the case of the blend, the orientation and periodical rotation of lamellae in the spherulites disappeared at a relatively low crystallization temperature (T_c); the nucleation for the spherulite growth was prolonged, and the size of homo-crystallites and the radial growth rate of spherulites were decreased, owing to the synchronous and separate homo-crystallization and the coexistence of P(l-3HB) and P(d-3HB) homo-crystallites in spherulites.

The impact strength of polyamide 11 (PA11) was improved by dispersing 10–30 wt% poly(butylene succinate) (PBS) without adding a compatibilizer, and no deterioration of the flexural modulus was occurred. The impact strength was controlled by the difference in shrinkage ratios between PA11 and PBS, and was three times that of neat PA11 (an increase from 13 to 40 kJ m⁻²). The mechanism of impact strength enhancement is discussed in terms of the formation of the dilational stress fields.

A facile method of preparing cyclodextrin-grafted chitosan (CyD-g-CS) by means of the carboxymethlation of cyclodextrins and the dehydration-condensation reaction to chitosan was developed. In this method, crude product containing ~10% of the carboxymethylated-cyclodextrin was subjected to the grafting reaction without further purification. The product (CyD-g-CS) was finally purified by dialysis. Furthermore, doxorubicin-capturing nanoparticles composed of CyD-g-CS and sodium triphosphate were prepared.

The incorporated star-shaped four-armed stereo diblock poly(lactide) (4-LD) with poly(l-lactide) (PLLA) core and poly(d-lactide) (PDLA) shell and equimolar l- and d-lactide units formed stereocomplex (SC) crystallites and facilitated and accelerated the homo-crystallization of linear one-armed PLLA during heating and slow cooling and of linear one-armed PDLA during heating. The accelerating effect was higher for PLLA/4-LD with the opposite configurations of one-armed PLLA and the PDLA shell of 4-LD than for PDLA/4-LD with the identical configurations of one-armed PDLA and the PDLA shell of 4-LD.

Procedures for implementing molecular dynamic simulations in preproduction evaluation and optimization of miniemulsion systems in polymeric material design has been investigated and evaluated in the production of ligand-selective synthetic receptor mimic-containing polymeric particles targeting the ligand bisphenol A. The graphical abstract, from left to right, presents the ligand bisphenol A, snapshot from simulation overlaid with molecular density distribution plot for components, indicating the stability of simulated emulsions, and finally a graphical representation of a theoretical binding site extracted from simulated systems presenting a cavity with bisphenol A and two interacting polymer monomers.

We developed a facile and efficient material for mercury based on a polymer combining metal-complexation and acidic aqueous solution-soluble groups. Because the polymer is soluble in acidic aqueous solution, the metal-complexation proceeds homogeneously and efficiently. As metal complexation progresses, cross-linking takes place between the metal-complexation groups and the metal ions, precipitating the polymer complex, which can be easily separated by filtration.

In this work, we newly prepared the multi-walled carbon nanotube (MCNT)-grafted poly(N-isopropylacrylamide) (PNIPAM) on their termini. After grafting PNIPAM, MCNTs dispersed well into water. In addition, the synthesized PNIPAM-terminated MCNTs (PNIPAM-MCNTs) were blended with poly(vinylalcohol) (PVA), and a hybrid film was prepared. The hybrid film showed bending actuation in response to infrared laser due to the heat generated by MCNTs.

Polyhydroxyalkanoates (PHAs) are eco-friendly plastics that are synthesized by bacteria as an intracellular storage material. Ethanol is a key compound in molecular weight regulation of PHA during biosynthesis. In this study, three strains of Escherichia coli expressing PHA synthase (PhaC_Re, PhaC_Ac or PhaC_He) were cultured to compare the effect of ethanol level on PHA molecular weight. As a result, it was revealed that PhaC_Ac tends to produce low molecular weight PHA due to its high ethanol sensitivity whereas PhaC_He produces high molecular weight PHA even in the presence of ethanol.

Spherulitic morphology of the phase-separated blend of two crystalline polyesters, poly(butylene succinate) (PBS) and poly(ethylene succinate) (PES), was investigated using polarized optical and atomic force microscopes. The thin crystalline layers of PBS were exhibited on the PES-rich phases in the blend melt-crystallized at the crystallization temperature of PBS then at that of PES successively. The PBS–PES copolyesters that form through transesterification between PBS and PES in the melt, preferentially localize at the interface and can stabilize the layered structure.

An effective method for the synthesis of the rotaxane cross-linked polymers (RCPs) was developed using a metal-containing supramolecular cross-linker (MSC). Radical polymerization of several vinyl monomers and bulky end-capped comonomer afforded RCPs in high yields. The obtained RCPs exhibited thermal properties corresponding to their respective polymer skeletons. Swelling ratio gradually increased with the decreasing amount of the steric comonomer units, indicating that the sliding ability of the movable cross-linker is strongly related to the swelling ability.

Molecular parameters and chain stiffness of polyethylene glycol/α-cyclodextrin inclusion complex: polyrotaxane were determined by use of synchrotron small angle X-ray scattering combined with light scattering and viscometry coupled with SEC.

The emulsion formation and the subsequent phase-separation process of water/toluene mixtures has been investigated by employing a pair of block copolymer surfactants having a linear A-B-A and its cyclized A-B topologies. The linear surfactant was found to be more effective to keep the emulsion layer in the water phase, attributable to the folding/extending motion of the hydrophobic A segments specifically in the linear surfactant.