Volume 44 Issue 5, May 2012

Miniemulsion polymerization of styrene based on the in situ surfactant-generation technique has been investigated for a range of carboxylic acids and counterions. Miniemulsion polymerizations have been conducted successfully using the carboxylic acids lauric acid, palmitic acid and oleic acid, respectively. Coagulation/phase separation was not observed and the number-average particle diameters were <100 nm. The counterions K⁺, Na⁺ and Li⁺ were investigated in combination with five different carboxylic acids (all permutations), revealing that satisfactory miniemulsion formation/stability could only be obtained with K⁺.

Irganox-1035 has a positive effect on damping performance of PAE/Irganox-1035 hybrids. When the Irganox-1035 amount in PAE/Irganox-1035 hybrids increases from 0 to 70 phr, the tanδ values increase from 2.2 to 4.2, demonstrating PAE/Irganox-1035 hybrids are promising damping materials. Meanwhile, the single loss factor also indicates Irganox-1035 has a good compatiblity with PAE.

This figure reveals the relationship between the area of the conducting parts and the volume resistivity changed with CPP–SO₃H content. The PP/CPP–SO₃H/PANI composites’ area of the conducting parts is much higher than the PP/CPP/PANI 0 composite’s area, and volume resistivity of the PP/CPP–SO₃H/PANI composites is much lower than that of the PP/CPP/PANI 0 composite. These may elucidate that the introduction of the –SO₃H on CPP can increase the area of the conducting parts of the composite, improve the compatibility between PP and PANI-DBSA and decrease volume resistivity of the composite.

Poly(acrylic acid) (PAAc) gel particles with DNA–ethidium bromide (EtBr) was synthesized and pH-sensitivity and fluorescence property were evaluated for applying to optical micro-pH sensor. Swelling ratio of PAAc gel particles with DNA–EtBr complexes were regularly changed with pH and the gel particle responded to pH for about 60 s. Furthermore, fluorescence intensity of PAAc gel particles with DNA–EtBr complexes were detected with high-sensitivity and changed in response to pH as shown in figure (The left shows the gel particles in pH 2.1 and the right shows in pH 11).

Eight homopolycyanurates have been synthesized by interfacial polycondensation of 2-carbazol-4,6-dichloro-s-triazine [CDCT] with 1,7-dihydroxynaphthalene [DHN,-1,7], 1,4-dihydroxyanthraquinone [DHA-1,4], ethylene glycol [EG], diethylene glycol [DEG], triethylene glycol [TEG], 1,2-propane diol [Pr-1,2], 1,4-butane diol [Bu-1,4] and 1,8-dihydroxyanthraquinone [DHA-1,8]. All the homopolycyanurates thus synthesized were characterized for their solubility, density, viscosity, infrared spectra, nuclear magnetic resonance spectra and thermo gravimetric analysis.

Photomobile polymer fiber was prepared from a mixture of commercially available compounds. The fiber was bent toward the light source upon exposure to UV light. Addition of a low-molecular weight liquid-crystalline compound enhanced the photomechanical properties and photoreactivity.

An anhydrous proton conductor was prepared by mixing with double-stranded DNA (dsDNA), the most important genetic material of living organisms, and the imidazole (Im) molecule, one of the heterocyclic molecules. This DNA–Im showed an anhydrous proton conduction of 5.2×10⁻³ S cm⁻¹ at the intermediate temperature. On the other hand, the single-stranded DNA–Im composite material did not show the high anhydrous proton conduction. Therefore, the high anhydrous proton conduction in dsDNA–Im composite material was due to the arrangement of phosphate groups along the one-dimensional molecular chain.

The two-extrusion method has a positive effect on the OIT value of the recycled HDPE in comparison with the traditional one-step extrusion method. It can avoid the antagonism between the cross-linking agent and the antioxidant, and to improve the oxidation inducing time (OIT) value of the samples. Even for the different antioxidants (Irganox1035 and Irganox300), the positive effect is the same.

The effect of the viscosity of polycarbonate (PC) matrix on the thermal conductivity of PC/vapor-grown carbon fiber (VGCF) composite was investigated in terms of the rheological properties of PC/VGCF. Thermal conductivity of low viscosity PC increased with contents of VGCF in spite of adding the same amount of VGCF. From the result of the rheological properties which were originated in the network structure, we clarified that the dense network of VGCF could be formed in lower viscosity matrix.

As a new approach, the location of nano-filler was monitored in the polypropylene/ethylene propylene diene monomer (PP/EPDM) blend using atomic force microscopy (AFM), dynamic mechanical thermal analysis (DMTA) and surface parameters and then the effect of nanoclay distribution on the final foam morphology was discussed. The results revealed that the organoclays have more affinity with PP and foaming is mainly occurred in PP phase. It seems the location of nanoparticles in this phase facilitated the nucleation via heterogeneous nucleation mechanism.

EIReP of ethylene propylene diene monomer (EPDM)/polypropylene (PP) blends presents a novel approach where the EPDM phase is cross-linked and grafted to PP by high-energy electrons without any coagent during melt mixing with PP. In the present work, the effect of absorbed dose, absorbed dose per rotation, and of different blend ratios on the properties and morphology of PP-EPDM TPVs is discussed in detail. The effect of premixing time is also discussed to observe its influence on the morphology and final properties of the TPVs prepared.