We have been searching a new ion exchange material in the form of a fiber which could get large advantages over the conventional bead type. In this approach, an effective chelating fiber is prepared by the coupling of polyacrylonitrile (PAN) and ethylenediamine. A synthesized ion exchange fiber (poly(acrylo-amidino ethylene amine), PAEA) achieved 7.8 mequiv/g of adsorption capacity in a batch test. The coupling process and capacity were confirmed through FT-IR, acid−base neutralization titration, ICP, IC, and AAS. By means of verifying the bonding peaks (hydrogen and ionic bonding) under several pHs, molecular bonding between PAEA and ions (Cu2+ and CrO4 2-) was certified. Surface morphologies of chelating fibers and also after metal ion adsorption were examined by AFM. Compared with a batch test, the adsorption ability was low due to the diffusion path of ions in the dynamic test.

ABSTRACT:Rigid polyurethane foams (PUFs) were prepared from polymeric 4,4-diphenylmethane diisocyanate (PMDI) and polyether polyol with amine catalyst. Water was used as the chemical blowing agent and, cyclopentane and hydrofluorocarbon (HFC) were used as the physical blowing agents. The kinetic rate of forming the PUF increased with the catalyst and water content. The cell size of the PUF sample decreased with increasing amount of the blowing and gelling catalysts. In the case of the PUF sample blown by water only, the amount of the blowing catalyst had no significant influence on the density and the compressive strength of the PUF sample. In the case of the PUF sample prepared with using HFC or cyclopentane as the blowing agent, however, as the amount of the blowing catalyst increased, the density and the compressive strength of the PUF sample increased. The PUF sample blown by the physical blowing agent had smaller cell size than the PUF sample blown by the chemical blowing agent, if compared at same density. The PUF sample blown by mixed blowing agent (cyclopentane/water = 7/3, mole ratio) had lower thermal conductivity than the PUF samples blown by cyclopentane or water only, at the equal mole content of the blowing agents. This result suggests that the low thermal conductivity of the PUF sample blown by mixed blowing agent is due to the increase in the structural stability of the PUF foams. [DOI 10.1295/polymj.36.368] KEY WORDS Kinetic Rate / Morphology / Chemical Blowing Agent / Physical Blowing Agent / Polyurethane foams (PUFs) have been commercially used in wide variety of applications since the 1940s. These foams surround us in today's society, playing an important role in many industries and our daily lives. Especially rigid polyurethane foam is one of the most important thermal insulating materials used today for construction and for sole insulation in electric appliances like refrigerators, and freezers. 1 Polyurethane foams generally consist of a solid polymer matrix and a gaseous phase formed by blowing agents. In some cases, more than one solid components are added in the solid phase as fillers or extenders. Foaming of polymeric materials is carried out by mechanical, chemical, or physical means. The most widely used method involves dispersing a gas throughout a fluid polymer phase and stabilizing the resultant foam. In most systems, foams are allowed to expand before stabilizing the system. 2,3The kinetic rate of forming PUF is increased by a catalyst or by raising temperature.2 The kinetic rate affects the cell morphology of PUF samples. In addition, the kinetic rate is the important factor in the manufacture of PUF.1,4 For design of a PUF, information of the kinetic rate and its effect on the properties of the PUF are necessary.Thermal conductivity is the most important property for thermal insulating materials. The thermal conductivity of closed-cell foams depends mainly on the total gas content and the thermal conductivity of entrapped blowing gas inside the closed cells. In addition, the ...

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The effects of maleic anhydride-grafted polypropylene (PP-g-MAH) addition on polypropylene (PP) and poly(acrylonitrile-butadiene-styrene) (ABS) blends were studied. Blends of PP/ABS (70/30, wt%) with PP-g-MAH were prepared by a twin-screw extruder. From the results of mechanical testing, the impact, tensile and flexural strengths of the blends were maximized at a PP-g-MAH content 3 phr. The increased mechanical strength of the blends with the PP-g-MAH addition was attributed to the compatibilizing effect of the PP and ABS blends. In the morphological studies, the droplet size of ABS was minimized (6.6 μm) at a PP-g-MAH content of 3 phr. From the rheological examination, the complex viscosity was maximized at a PP-g-MAH content of 3 phr. These mechanical, morphological and rheological results indicated that the compatibility of the PP/ABS (70/30) blends is increased with PP-g-MAH addition to an optimum blend at a PP-g-MAH content of 3 phr.