Volume 44 Issue 7, July 2012

Antifreeze proteins (AFPs) function as inhibitors of ice growth. Computer simulation studies have contributed to the understanding of the molecular-scale mechanism of ice growth inhibition by AFPs. For example, molecular dynamics simulations of a growing ice–water interface to which a winter flounder AFP for a {20\(\overline{2}\)1} pyramidal plane is bound have indicated that the growth rate of ice surrounding the AFP decreases drastically, owing to depression of the ice melting point through the Gibbs–Thomson effect.

Chemical synthesis of a new type polyphenol was achieved by oxidative polycondensation of 4-((2-phenylhydrazono)methyl)phenol (4-PHMP). According to spectral analysis, the obtained polymer from 4-PHMP is composed of a mixture of phenylene and oxyphenylene units. 4-PHMP and poly(4-PHMP) are soluble in highly polar solvents, such as dimethyl sulfoxide and dimethylformamide. Thermal analysis shows that poly(4-PHMP) has relatively high thermal stability. Also, the polymer has a low band gap (E_g′=1.52 eV) and appears to be interesting candidates for solar-cell applications.

Temperature-dependent curves of T₁^H for the SBR with and without end-chain modification in the SBR/Si composites showed the increment of the T₁^H values as the MAS rate increases and the considerable change at the fast MAS rate of 25 kHz. The increase of T₁^H values is represented by the factor f that decides the observed T₁^H minimum value. The plot of centrifugal pressure caused by MAS as a function of 1/f exhibited the similar trend to that of the stress–strain curve. The differences in the T₁^H between the end-chain-modified and normal SBR under fast MAS was attributed to the Payne effect.

Nanocomposite gels containing chitosan as a network polymer and chitin nanowhiskers as reinforcing fillers were successfully prepared by cross-linking with the blocked isocyanate, HDS. Young’s modulus and stress at break of the nanocomposite gels increased to maximum values of 169 and 135 kPa, respectively, with increase in whisker content up to 13.3%, whereas the degree of swelling decreased from 357 to 33.0.

A series of semi-alicyclic PIs have been synthesized from an alicyclic dianhydride MTDA and various aromatic diamines by a one-step high temperature polycondensation procedure. Flexible and tough PI films have been cast from their solution in common solvents. The PI films exhibited good thermal stability and good transparency in the ultraviolet-visible (UV-vis) light region.

A network polymer with photoinduced mending ability is prepared from a cinnamoyl-telechelic prepolymer and a tetra-cinnamoyl linker by photodimerization. Though the trans–cis isomerization competes with the dimerization of cinnamates, the dimerization primarily proceeds at a temperature higher than the melting point of the prepolymer. When a film of the network polymer is damaged, cinnamate dimers in the polymer are dissociated to form cinnamate monomers. These monomers can be dimerized again by photoirradiation to recover the network structure.

We have prepared silver nanoparticles from a solution of AgNO₃ and copolymers containing acryloylmorpholine and n-isopropylacrylamide (NIPAM) blocks by stirring the solution, and have examined the thermoresponsive properties of the associated plasmon peaks. The hydrosols prepared from the copolymer caused a red shift of the plasmon absorption with an increase in the temperature because the degree of nanoparticle protection was reduced owing to the shrinkage of the NIPAM blocks at 40 °C.