Microwave Study of Recycled ABS Resins

This article provides a review of the research unde rt aken in order to determine the suitability of utilizing microwave technology in the production of Recycled ABS Acrylonitrile Butadiene Styrene resin for mouldin gs. The experimental investigation determined the suitability of the existing re cycled ABS material, the mould material used with respect to performance and lon gevity, potential commercial plant and equipment, end mould compression. Introduction Frequency Characterization of ABS The first step in microwave processing of any material is to locate a frequency band suitable for the mateiial, where it absorbs microwave energy readily. To lo cate this band width, the ABS material was characterized in Variable Frequency M icrowave Ovens operating between the frequenc’y ranges of 2.5 GHz to 6.5 GHz an d 6 GHz to 18 GHz. The variable frequency microwave oven records forward and ref lected powers over regular intervals in the swept frequency range and enables ca lculation of Re flec tan ce=Re fla tan ce forwrd PowerForward Power (1) A low reflectance indicates that the material Forward Power absorbs rela tively higher amount of incident microwave energy. Characterization of the PBS material showed clearly that a frequancy Fig.1 Lower frequency range vs. reflectance of ABS at room te mperatureFig.2 Lower frequency range vs. reflectance of AB S at 80 ℃ 2.5 to 3.5 GHz is the most suitable frequency fo r heating the material. Other alternate frequencies are 12.25 GHz and 15 GHz. Fi g.1. Hazards When ABS is melted a dark fume is omitted, exhaust system was applied, in order to mechanically ventilate and control exposure levels below air borne exposures. The product contains a trace quantity of acrylonitrile, a substance classified by Worksafe Australia as a Category 2 Carcinogen. [TPP115B,+28mm95mm,Y,PZ#] Fig.3 Polypropylene mouldMould design For holding the ABS granules in a single mode cavity, an unfilled p olypropylene mould was designed. A polypropylene lid with a loading arrangement built in the microwave cavity provided pressure to the materinl in the die, duri ng microwave heating. The pressure can be varied with changing weights on the lo ading device and calculating the pressure. Materials Polypropylene has excellent microwave heating properties, a mould was machine to cater for the experimental requirements. Other materials suitable for mould des ign for long term use are quartz and alumina. Quartz being transparent to both m icrowaves and light provides advantages in noncontact optical temperature measur ements. Conclusion The application of microwave heating for the manufacturing of ABS die casts stru ctures has been developed. An experimental results based on the dielectric behav iour illustrate dopent is required to engage dielectric heating. Chemical Compos ition of ABS, Acrylonitrile Butadiene Styrene, the percentage of each compound a s it would have a direct relationship on the dielectric properties of the ABS.

Design and Synthesis of Transparent Poly(acrylonitrile-butadiene-styrene) and Relationship Between Its Phase Construction and Transparency

A series of transparent ABS（T-ABS） resins were prepared by emulsion in situ suspension polymerization. The influences of the particle size and the content of rubber particles on the transparency of T-ABS resins were studied by varying the size and content of rubber particles in a single model system（rubber particles with a uniform size）. The optical properties of T-ABS resins were investigated in a mixed system of SBR/PB particles and a hi-modal particle system（rubber particles with two different sizes, 70 and 400 nm in diameter） of SBR particles. It was found that when the size of the smaller particles （ 70 nm） in the mixed system of SBR/PB particles was in the range of 50-100 nm in diameter, the T-ABS resins showed a better transparency. These results provide a flexible and practical process for the preparation of T-ABS resins with good optical and mechanical properties.

Optimization of top polymer gratings to improve GaN LEDs light transmission

We present a grating model of two-dimensional （2D） rigorous coupled wave analysis （RCWA） to study top diffraction gratings on light-emitting diodes （LEDs）. We compare the integrated-transmission of the non-grating, rectangular-grating, and triangular-grating cases for the same grating period of 6 μm, and show that the triangular grating has the best performance. For the triangular grating with 6-μm period, the LED achieves the highest light transmission at 6-μm grating bottom width and 2.9-μm grating depth. Compared with the non-grating case, the optimized light transmission improvement is about 74.6%. The simulation agrees with the experimental data of the thin polymer grating encapsulated flip-chip （FC） GaN-based LEDs for the light extraction improvement.

Dissolved oxygen sensor by using Ru-fluorescence indicator and a U-shaped plastic optical fiber

A dissolved oxygen （DO） sensor based on U-shape plastic optical fiber （POF） and dichlorotris （1, 10- phenanthroline） ruthenium （[Ru（dpp）^3]^2＋） as an oxygen indicator was described. Fluorescence intensity and lifetime were measured when the sensor was soaked into a water bath blasted with air with varied O2/N2 ratios. The influence of Ru concentration, annealing time and U-shaped POF curve radius on the system sensitivity was also studied. A two-layer model was proposed to analyze the deviation from linear relation described by Stern-Volmer equation, and to explain the deviation and the dependence of the fluorescence on curvature of U-shape POF. By fitting the experimentally measured sub-linear relation of τ0/τ ratio versus oxygen concentration, the proportion of effectively sensitive layer and the Stern-Volmer coefficient can be evaluated to be f = 0.59 and Ksv = 0.61 typically.

FINITE ELEMENT SIMULATION FOR YIELD STRESS OF HARD POLY(VINYL CHLORIDE)/ACRYLONITRILE-BUTADIENE-STYRENE BLENDS AT DIFFERENT CROSSHEAD SPEEDS

Hard poly（vinyl chloride） （PVC）/acrylonitrile-butadiene-styrene （ABS） blends were prepared using injection- molding and influence of crosshead speed on mechanical properties was examined. Based on morphology parameters obtained from transmission electron microscopy photography and the material parameters from true stress-strain curves of neat PVC and ABS, yield stresses of the blends at different crosshead speeds were simulated employing a two-dimensional nine-particle model based on the finite element analysis （FEA）. The FEA results were compared with the experimental yielding stress and the good agreement validated the simulation approach. The FEA approach allowed establishing a yielding criterion related to local yielding of the interstitial matrix between ABS particles.