The structure and adsorption kinetics of poly (ethylene oxide) end-capped with perfluorodecanoyl groups either at one or both ends have been characterized. These nearly monodisperse polymers with molecular weights in the range of 400-l6Kg/mol are efiective nonionic surfactants with very high surface activity. For aqueous solutions with concentrations in the range of 2-8 mg/ml. surface tensions detennined by the drop-volume method are as low as 13.6-18.0 mN/m at 20℃. At high surface coverage. close. packed PEO chains with one end capped forin a brush-like structure at the interface. Polarized infrared reflectance spectroscopy showed that perfluoroalkyl groups were nearly perpendicular tO the air-water interface. The molecular area per chain was 30-32 Å2 for poly(ethylene oxide)capped only at one end and 36-40 Å2 for poly (ethylene oxide) with both ends capped. Only 22% of poly (ethylene oxide) chains with both ends capped form loops at the interface, while the remaining chains form an extended Structure at high surface coverage.

We have extended the definition of the Manhattan lattice from two-dimensional to three-dirnensuional (3D) spaces. The number of self-square end-to-end distances, (R2n), were counted exactly up to 31 and 30 steps, respectively. Analyisis using the method of the Dlog padé approximant gave the exponents γ=1.1615±0.0002 and ν=0.5870±0.0025, which are in good agreement with corresponding values for self-avoidng walks on the ordinary 3D lattice. This result suggests that self-avoiding walks on the 3D Manhattan lattice belong to the smae universality calss as self-avoiding walks on the ordinary 3D lattice.

A comprehensive model for solid-state polymerization of poly (ethylene terephthalate) was developed from analyzing the similarities and the differences between solid-state and melt polymerization. Considering the end groups diffusion limitation and the modification of concentrations of end groups and byproducts in the amorphous phase, a system of mass transfer and balance equations suitable for the solid-state polymerization of PET were obtained, based on simplifying the reaction kinetics of melt polymerization of PET. The degradation and other side reactions neglected in the earlier models for the solid-state polymerization of PET were included in the model. This simulation gave a quantitative prediction in the effect of temperature, particle size, starting molecular weight, and ratio of end groups on the degree of polymerization of products during the solid-state polymerization of poly (ethylene terephthalate). These simulation results were in agreement with experiments.

The effect of self-nucleation on the nonisothermal and isothermal crystallization behaviors of the segmented copolymer poly(ether ester), based on poly(ethylene glycol) as the soft segment and poly(ethylene terephthalate) as the hard segment was investigated by means of differential scanning calorimetry (DSC) and depolarization polarized light (DPL) techniques, respectively. The results demonstrated that selfnucleation could enhance the crystallization rate in both cases. The experimental conditions of the self-nucleation procedure studied by DSCwere discussed in detail. The isothermal crystallization was analyzed by the Avrami equation, and the Avrami parameters were dependent on the melting temperature.

For improved surface properties, nonwoven fabrics of polypropylene and poly(ethylene terephthalate) were treated with several kinds of surfactants, including anionic, cationic, and nonionic types. The adsorption isotherms of the anionic, cationic, and nonionic surfactants on the nonwoven fabrics were different. The adsorption isotherm of the cationic surfactant (dodecyl dimethylbenzyl/ammonium chloride) exhibited a maximum. The adsorption isotherm of the anionic surfactant (sodium dodecylbenzene sulfonate) was in the shape of the fifth Brunauer adsorption isotherm, and that of the nonionic surfactant (alkylphenol/ethylene oxide condensate) was similar to the fourth Brunauer adsorption isotherm. The time of the adsorption equilibrium was constant for the same types of adsorbate and adsorbent, and it was not related to the initial concentration. The specific surface resistance of the nonwoven fabrics decreased substantially after the adsorption of ionic surfactants. The nonwoven fabrics with the surfactants were characterized with scanning electron microscopy and X-ray photoelectron spectroscopy.

The mean square end-to end distances〈h2(c)〉of confined radom walks (R W) and confined self-avoiding walks (S A W) have been obtained by means of Monce Carlo simulation on a simple cubic lattice. The geometry of confinement considered includes: a cubic box'or a sphere. an infinice tube of square ofr circular cross section, and a gap between two parallel infinite plates, corresponding to confincements in three, two and one dimertsions respectively. The〈h-(c)〉value of a confined R W chain decreased monotonically with decreasing confinement size and approached to a value of 0, 1/3 and 3/2 of 〈h2(o)〉is the mean square end-to-end distance of a R W chain without any confinenent. A S A W chain confined in a cubic box also showed a continuous decreise of 〈h2(O)〉with decreasing coafiement size. However. a S A W chain confined in two and one dimcasionsshowed a minimum value of 〈h2(c)〉/〈h2(O)〉with deerteasing confinement size.

Supramolecular assemblies of lycopene in aqueous tetrahydrofuran and chitosan matrix were studied by using ultravioletevisible absorption spectroscopy and transmission electron microscopy. It was found that lycopene in aqueous tetrahydrofuran could form H-type molecular aggregates, as manifested by the fact that the main absorption band of lycopene was blue-shifted to 354 nm. Similar results were obtained when lycopeneechitosan complexes were dissolved in water with 1% acetic acid. The main absorption band of the solution, however, was further blue-shifted to 349 nm. The exciton model was used to interpret the spectral shifts of the aggregates. TEM images showed the dentritic, cubic or triangular shapes of the supramolecular assemblies of lycopene in chitosan matrix. A structural model for the supramolecular aggregates was proposed according to the experimental results. It is considered that the supramolecular assemblies form liquid crystals of the nematic type and contain both H-aggregation (more) and J-aggregation (little). The changes in the proportion of H-or J-type aggregation cause the hypsochromic or bathochromic shift of absorption spectrum.

We calculated the effective mass of ring-torsion (RT) and bond-order (BO) defect states in a pernigraniline-base polymer, on the basis of an extended Ginder-Epstein model. The calculated effective mass is sensitive to electron-RT coupling. In the case of medium coupling, the effective mass for an RT-BO soliton is≈650me and that for an RT-BO polaron is≈178me. RT relaxation dominates the defect mass. The large effective masses imply that linear translation of the defects is not likely to be a dominant mechanism of charge transport in the polymer.

The flow behavior and the effect of the spinning conditions on the fiber properties and structure of the copolyesters, i.e., samples of copoly(p-hydroxybenzoate-bisphenol A terephthalate), were investigated. The experimental results indicated that the apparent viscosity was affected significantly by shear rate, melt temperature, and p-hydroxybenzoate unit content; and the copolyester melts exhibit highly shear thinning behavior. The fiber modulus increase with the increase in extrusion temperature and draw-down ratio, and the tensile properties could be improved when a high spin draw ratio was used. High birefringence, indicating the presence of mesophase, was observed on a hot-stage polarizing microscope. Scanning electron microscopy revealed that the fibers spun at relatively high temperature had a well-developed, highly oriented fibrillar structure. The fibers spun at low temperatures, however, were poorly oriented and nonfibrillar in character.

The mesophase transition and its kinetics of chitosan in the solutions of chitosan/dichloroacetic acid (DCA) were investigated by means of DSC and depolarized light intensity technique, respectively. The mesophase formation of chitosan in DCA involves nucleation and growth. The isothermal kinetics of mesophase formation from isotropic phase were described by Avrami using the equation with an exponent n close to 1, which suggests that the formation of chitosan mesophase is a process of instantaneous nucleation and one-dimensional rod-like growth in the temperature range investigated. This was confirmed by small angle light scattering Hv patterns of the mesophase.