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This new polyphosphazene is a hybrid organic–inorganic polymer that possesses a backbone of alternating phosphorus and nitrogen atoms and two side-chain-tethered POSS pendant units as inorganic parts. The incorporation of POSS units into the side chain of polyphosphazene improves the thermal stability of polyphosphazene-POSS because of the filler effect, and removes the crystallinity of polyphosphazene-POSS because of the bulk and large volume of the POSS units. Polyphosphazene-POSS shows high storage stability against gelation compared with polyphosphazene-Cl.
We establish the 13C nuclear magnetic resonance (NMR) method as the best available method for the evaluation of carbon black (CB) distribution in rubber blend. We find that the line widths of NMR peaks increase as CB contents increase. Using this phenomenon it is found that, in polyisobutyrene rubber (IIR)/polyisoprene rubber (IR)/CB composites, CB more easily distributes in IR than in IIR. And we can estimate that more than 70% of CB is distributed in to the IR phase, irrespective of CB content.
The curing behavior of a novolac resin (NV) cured with hexamethylenetetramine (HMTA) under a two-roll mixing mill process, as well as the influence of an excess amount of HMTA on the curing reaction, were investigated by dynamic light scattering and gel permeation chromatography. The relationships between the number of mixing times, the weight-average molecular weight, hydrodynamic radius and the HMTA amount suggests that structural differences governing the mechanical properties of NV are initiated in the pregel stage.
Three non-charged π-conjugative polymeric fluorophores, that is, poly(di-n-octylfluorene; PF8), poly[(9,9-dioctylfluorenyl-2,7-diyl)-alt-bithiophene] and poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene], spontaneously physisorbed onto the neutral surface of 0.5-μm-sized spherical silica and four other ceramics in common nonpolar organic solvents within several hrs at room temperature. This process was observed via photoluminescence and excitation spectra. Attractive van der Waals interactions between the polymers and ceramics are responsible for the solution-phase physisorption. Surprisingly, the highest fraction (51–56%) of β-phase PF8 was found to deposit at the surface without thermal treatment.
Crosslinking DM-β-CD with various types of diisocyanates realizes urethane-crosslinked DM-β-CD polymers. The 4,4′-methylenebis(phenyl isocyanate) (MDI) and 1,4-phenylene diisocyanate (PDI)-crosslinked DM-β-CD polymers show high adsorption capabilities toward PCBs (TeCBs, PeCBs and HeCBs) in isooctane. Similarly, the MDI-crosslinked DM-β-CD polymer shows a high adsorption capability toward 2,2′,3,3′,5,5′-HeCB in insulating oil.
Porous thin-film polymethylsiloxane microparticles have been prepared successfully from octyltrichlorosilane and methyltrichlorosilane in W/O emulsion system by using several oil phases and changing the amount of the silanes or a surfactant Span 60.
Band patterns for N. clavata spider silk protein and for three different markers in 3% SDS-PAGE. M: marker, A: spider silk solution under a reduced state, B: spider silk solution under an unreduced state. The reduction due to a reductant cleaves the disulfide bonds and decreases the molecular weight from ca. 600 to ca. 270 kDa. Spider silk protein with ca. 600 kDa is suggested to be crosslinked by disulfide bonding between the two proteins.
In this study, we prepared a novel oil gel composed of poly(L-lactide) and a poly(trimethylene carbonate) derivative. We investigated the release of testosterone, an inexpensive therapeutic drug for the segmental defect of bones, from the gel. Dimethyl sulfoxide and dimethyl carbonate, which are organic solvents with relatively low toxicities, were used as dispersion media. The oil gel in dimethyl sulfoxide released testosterone faster than that in dimethyl carbonate. In addition, the dimethyl carbonate oil gel was vacuum-dried to reduce the gel porosity and resulted in slow testosterone release.
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.
