Walaiporn Prissanaroon-Ouajai

Electrical Conductivity Response of Poly(Phenylene-vinylene)/Zeolite Composites Exposed to Ammonium Nitrate

Poly(p-phenylenevinylene) (PPV) was chemically synthesized via the polymerization of p-xylene-bis(tetrahydrothiophenium chloride) monomer and doped with H2SO4. To improve the electrical conductivity sensitivity of the conductive polymer, Zeolites Y (Si/Al = 5.1, 30, 60, 80) were added into the conductive polymer matrix. All composite samples show definite positive responses towards NH4NO3. The electrical conductivity sensitivities of the composite sensors increase linearly with increasing Si/Al ratio: with values of 0.201, 1.37, 2.80 and 3.18, respectively. The interactions between NH4NO3 molecules and the PPV/zeolite composites with respect to the electrical conductivity sensitivity were investigated through the infrared spectroscopy.

Thermoplastic Vulcanizates/Recycled Polypropylene Blend for Automotive OEM

An original equipment market (OEM) in Thailand mainly imports thermoplastic vulcanizates (TPV) from abroad that leads to a high manufacturing cost. To reduce the cost and to create value-added products from a plastic scrap, therefore, this research aim is to observe a possibility of using TPV and recycled polypropylene (rPP) blends as a raw material for OEM. The blends with various rPP loadings were successfully prepared through a traditional twin-screw extruder. Proportions between TPV and rPP were adjusted to determine the optimal flow and mechanical properties for productions of different auto parts. The blends were tested for studying rheology and mechanical properties: tensile; hardness; flexural; and creep behavior. All tests resulted in discussions about the feasibility of using TPV/rPP blends with respect to auto part specifications in real applications. Test results suggested that the TPV/rPP blends meet the requirements of specific automotive applications. Thermal property and morphological analysis were also carried out to have more understanding about changes in mechanical properties.

All-Solid-State pH Sensor Based on Conducting Polymer

A solid-state (free of internal electrolyte solution) reference electrode based on metallic silver is simply fabricated via a simple electrodeposition from AgNO3. Potentiometry is carried out to study the performance of the solid-state reference electrode in comparison with the commercial Ag/AgCl reference electrode. In addition, the proposed solid-state reference electrode has been integrated with the PPy-modified pH electrode to form an all-solid-state pH sensor, showing the capability of pH measurement. Absence of the internal solution leads to the pH sensor that is convenient to use and maintenance. In addition, the proposed pH sensor is possibly applied to biochemical and medical processes as well as flow infection analysis.

Preparation and properties of low density polyethylene-activated carbon composite foams

Low density polyethylene (LDPE) containing activated carbon (AC) was foamed with azodicarbonamide (ADC), an exothermic chemical foaming agent, through an extrusion process. The effects of ADC and AC contents on the cellular structure, density, void fraction, and mechanical properties of LDPE-AC composite foams were investigated. The density of composite foams decreased but the void fraction increased as the content of ADC increased due to higher gas liberation. Moreover, the large cell size was also observed in composite foams with high amount of ADC. At low AC dosages (5-10 wt%), the density of composite foams decreased with increasing the void fraction compared to the composite foam without AC because more foaming nucleation centers was induced by adding AC in the composite foam leading to more gas bubble generation. However, the addition of AC up to 15-20 wt% decreased the cell formation and the average cell size tended to decrease with increasing AC content. This attributed to AC particles that assist...

Electroless Copper Deposition on PET Sheets

This paper describes metallization of PET surface by Sn-free electroless deposition (ELD) of thin copper layer. Prior to introduction to ELD process, the PET surface was plasma-pretreated in argon atmosphere. ELD is a multi-step process involving silanization with TMS, activation with PdCl2 and copper deposition. Contact angle measurement and XPS analysis were carried out at each stage in order to confirm the chemical change of the PET surface after modification. XPS analysis revealed that the copper surface consisted mainly of Cu2O, combined with Cu0, making Cu-coated PET sheet suitable for the use as substrate for electropolymerization of pyrrole. This study offers an alternative to preparing flexible sensors. This process could be further applied to micro-contact printing technique to fabricate flexible patterned electrodes.