Original Article in 2018

MMA-BnMA copolymers with various monomer sequences (blocky, random, alternating tendency) were prepared by partial modifications of atactic poly(BnMA) or by direct copolymerization of MMA and BnMA. ¹³C NMR spectra of the copolymers were subjected to principal component analysis, one of the standard procedures of multivariate analysis. The analysis showed clearly the formation of highly blocky copolymers by hydrogenolysis as well as the formation of copolymers with somewhat alternating tendency by the acidic debenzylation, saponification, and transesterification at late processes of the reactions.

Water-in-oil (W/O) gel-emulsions consisting of water and a monomer were successfully prepared using N-3-hydroxypropylcarbonyl-L-isoleucyl-aminooctadecane as a gelator. Low-temperature polymerization of the gel-emulsions with a redox initiator was performed to obtain the corresponding porous polymers. Polymerization of gel-emulsions containing bifunctional monomers gave crosslinked porous polymers, which were found to be mechanically robust and solvent resistant. The adsorption capacities of the polymers toward several liquids were assessed and rationalized in terms of the surface microstructures of the polymers. The time courses of the adsorptions were investigated, revealing a two-step adsorption process comprising rapid permeation into the cavities of the porous polymers followed by a slow swelling step.

Random copolymers (P(M_100-m/T _m )) composed of 2-methacryloyloxyethyl phosphorylcholine, which suppresses protein fouling, and 3-(triethoxysilyl)propyl methacrylate, which can react covalently to the glass surface, were prepared via photoinitiated radical polymerization. Coating of the glass with P(M_100-m/T _m ) was confirmed by red fluorescence from Rhodamine 6G. The protein antifouling properties of the P(M_100-m/T _m ) coating on glass were confirmed using fluorescence-labeled proteins.

The origin of the reaction rate acceleration in the microwave-assisted synthesis of poly(butylene succinate) (PBS) was investigated by measuring the rate of removal of the water by-product from the reaction solution under equivalent reaction conditions using both microwave and conventional heating methods. Microwave heating selectively activated and removed the water from the reaction solution more rapidly and to a greater extent than oil bath heating. These results indicate that the principal effect of microwave irradiation in the synthesis of PBS was the accelerated removal of the water by-product.

The interphase structure of isotactic poly(methyl methacrylate) (it-PMMA)/aluminananoparticle mixtures obtained from tetrahydrofuran (THF) solution was discussed. The it-PMMA in the mixtures forms two amorphous phases (crystallizable and incrystallizable phases) depending on casting conditions from THF. The polymer interphase on Al2O3 particles changes into a crystallizable structure with a trans-gauche rich conformation and amorphous. The interphase shows a lower Tg than the melt-cast one and is easy to crystallize at low temperature. The novel structure was formed by the conformation freezing of the polymer at Al2O3 surface.

Amphiphilic incompletely condensed polyhedral oligomeric silsesquioxanes possessing various substituents and poly(ethylene glycol)s of different chain lengths have been developed. It has been elucidated that their self-association behaviors in water are dependent on the substituents and chain lengths of poly(ethylene glycol)s. Precise molecular design, excellent thermal stability, and good dispersibility have been realized at once.

Polydiacetylene (PDA) derivatives exhibit color change with application of external stimuli, such as heating and mechanical stress. The original layered PDA shows the irreversible color transition from blue to red with heating at the threshold temperature. Here we found that the alkyldiamine-intercalated PDA induced the different color-change properties, such as the raise of the color-transition temperature, the temperature-dependent color-change, and the reversible color change. The intercalated diamines have the stabilization effect of the layered polymer. The stimuli-responsive color-change properties can be tuned by the intercalated organic guests.

Reverse osmosis membranes have been playing a main role for the desalination of water in the world. Hydration structure of polyamide functional layer of the membrane was studied via neutron scattering and atomistic molecular dynamics simulations. Experimental and computational structure factors, S(Q), of the polyamide/water system showed good agreement. Water clusters in water-rich system were well connected to each other and formed channel-like structure. Polyamide–water interactions and polyamide-polyamide interactions, which are thought to be important to enhance the performance of the membranes, were examined in detail.

Molecularly imprinted hydrogel layer SPR sensor chips with lectin-recognition sites, which were prepared via surface-initiated atom transfer radical polymerization (SI-ATRP) combined with molecular imprinting, exhibited not only large SPR signal change in response to a target lectin but also inhibited nonspecific protein adsorption.

The effects of long-term storage of poly(3-hydroxbutyrate-co-3-hydroxyvalerate) were evaluated over a range of temperatures. As the storage temperatures were increased towards 100 °C, secondary crystallisation resulted increasing the melting point, Tg, modulus and strength. At 125 and 150 °C secondary crystallisation and degradation occurred simultaneously; the effects of degradation masked by secondary crystallisation. The significant observation is that the degradation process remains active at storage temperatures well below the melting point and long-term stability of P(3HB-co-3HV) is not only affected by secondary crystallisation, but also sub-melting point degradation.

The alternating conjugated polymer was synthesized with thiophene-substituted aza-boron dipyrromethene. The synthesized polymer had the near-infrared light-absorbing ability (molar extinct coefficient: 48,000 M⁻¹cm⁻¹) in the region over 1300 nm with the peak at 864 nm. From the electrochemical data, it was found that the polymer had the deep lowest unoccupied molecular orbital (LUMO) level. This result means that only the highest occupied molecular orbital level was influenced and the LUMO can be preserved by extension of π-conjugation through the polymer main-chain.

An immiscible blend of isotactic polypropylene (PP) and ethylene-butene-1 copolymer (EB) containing a small amount of N,N'-dicyclohexyl-2,6-naphthalene dicarboxamide as a nucleating agent to generate β-form crystals was prepared by T-die extrusion. We successfully prepared an extruded sheet in which the orientation of the PP molecules is perpendicular to the deformation of the EB particles. It is suggested that EB barely affects the crystalline form and orientation of PP. Since this sheet containing a large amount of β-form crystals exhibits an extraordinary structure, unique mechanical anisotropy is obtained.

To synthesize CO₂-derived polycarbonates with high T_g values, epoxides having rigid and bulky 2-norbornyl or 1-adamantyl substituents were selected as comonomers. The alternating copolymer obtained from 1-adamantylethylene oxide showed a T_g above 150 °C. This is the highest T_g among those observed for alternating copolymers obtained from CO₂ and a terminal epoxide.

By simply coating a thin layer of 4,4’-diphenylmethane diisocyanate, polyacrylic acid and borax on the surface of PET film, a transparent PET film with extremely low gas vapor barrier value can be obtained. The oxygen transmission rate can be dramatically decreased to the detection limit of commercial instrumentation (<0.005 cc/m²/day).

Synthesis and properties of borafluorene-containing conjugated polymers with various comonomers are presented. From the comparison with the gallafluorene copolymers, higher luminescent quantum yields were obtained from the borafluorene copolymers. Additionally, from the electrochemical measurements, it was shown that the electron-withdrawing property of the boron atoms led to the stabilization of LUMOs of the borafluorene copolymers. In the X-ray diffraction profiles, the significant peaks originated from π−π stacking and assembly of the side chains were observed. The borafluorene copolymers were more crystalline materials relative to the gallafluorene polymers.

The thermoresponsive copolymer P(MEO₂MA-co-OEGMA₅₀₀) was successfully prepared using a novel photopolymerization procedure. The synthesis was carried out using a user-friendly method with a few ppm of a photoredox iridium-based catalyst. Monomer conversions higher than 50% were achieved in less than 1 h of synthesis showing a faster polymerization rate when compared to the traditional Cu-based ATRP synthesis. The photochemically controlled method here described provides true control over polymer structure, architecture, and properties. Furthermore, the polymer showed no toxicity on four mammalian cell lines at the highest concentration tested (0.4 mg/ml).