Dong Jin Kang

Synergistic Effects of Zirconia-Coated Carbon Nanotube on Crystalline Structure of Polyvinylidene Fluoride Nanocomposites: Electrical Properties and Flame-Retardant Behavior

Pristine multiwalled carbon nanotubes (MWNTs) and zirconia-coated multiwalled carbon nanotubes (ZrO(2)/MWNTs) by isothermal hydrolysis and the traditional chemical precipitation method have been dispersed into polyvinylidene fluoride (PVDF) copolymer by solution mixing in N,N-dimethylformamide (DMF). The effect of ZrO(2)-coated MWNTs on morphological properties, electrical properties, and flame-retardant behavior has been studied in comparison with virgin PVDF and PVDF/MWNTs nanocomposites. Due to the improved dispersion of the coated nanotubes, the incorporation of 3 wt % of ZrO(2)-coated MWNTs leads to an increase of the thermal stability and dielectric properties and a decrease of the peak heat-release rate.

Microcellular Structure of PP/Waste Rubber Powder Blends with Supercritical CO2 by Foam Extrusion Process

A new approach towards the recycling of waste ground rubber tire (WGRT) powder was demonstrated in this study by introducing the polypropylene/ waste ground rubber tire (PP/WGRT) foaming method by using CO2 as the foaming agent in an extrusion foaming process. The regression models were constructed to study the relationships between the foam structure (i.e., void fraction, average cell size, and cell density) of foamed PP/WGRT blends, the processing parameters (extruder’s die temperature and CO2 concentration), and WGRT content by applying a three-factor central composite design (CCD) statistical approach. The response surface plots generated using the regression models allow the rapid selection of the proper process parameters to obtain microcellular PP/WGRT blends with the desired density and morphology.

Effect of Filler and Urethane Rubber on NR/BR with Nanosilica: Morphology and Wear

The blends of butadiene rubber (BR), urethane rubber (EU) and natural rubber (NR) was prepared using a blending technique in presence of different types of carbon black. The effect of filler on morphological and wear characteristics was studied. ISAF type of carbon black showed a significant effect on optimum cure time, cure rate index and mechanical properties by reacting at the interface between BR, EU and NR matrix. All the samples show only one melting peak on the DSC curve; this is attributed to the same backbone structure of the matrix and the carbon black reinforcement. Blends containing ISAF type of carbon black showed high abrasion resistant properties against Du-Pont abrader, DIN abrader and different mining rock surfaces and also is found to be the toughest rubber against all types of rock.

Effect of fillers on morphological properties in NR/SBR blends for OTR tyres

Abstract The blends of styrene butadiene rubber (SBR) and natural rubber (NR) are prepared using a two-roll mixing mill in the presence of different types of carbon blacks as reinforcing filler. The effects of fillers on cure characteristics and thermal, dynamic–mechanical, morphological properties of the blends are studied. The ISAF N231 type of carbon black shows a significant effect on tensile, tear and modulus properties by reacting at the interface between SBR/NR matrixes. The dynamic characteristics and storage modulus of SBR/NR with SAF N110 and SRF N774 types of carbon black show distinct characteristics in respect to all other blends in this system. The thermal stability of the rubber vulcanizates containing SAF N110 and SRF N774 types of carbon blacks is higher than other blend types. With the increasing percentage of SBR to NR, the thermal stability of the blend is increased. However, the heat buildup of the blends increases with the increase in SBR percentage.