M. Trada

Young's Modulus of Vinyl Ester Composites Cured by Microwave Irradiation: Preliminary Results

The shrinkage of vinyl ester particulate composites has been reduced by curing the resins under microwave conditions. The reduction in the shrinkage of the resins by microwaves will enable the manufacture of large vinyl ester composite items possible [1–4]. The difference in impact strength between microwave cured vinyl ester particulate composites and those cured under ambient conditions had been investigated [5]. In addition, a previous study found that the difference in fracture toughness obtained by short bar method between selected microwave-condition cured vinyl ester particulate composites and those cured under ambient conditions was only 0.5% [6]. This project is to investigate the difference in Youngs modulus, ultimate tensile strength and yield strength between microwave cured vinyl ester particulate composites and those cured under ambient conditions. The results show that the difference in the Youngs modulus is minimal.

Fracture Toughness of Phenol Formaldehyde Composites Reinforced with E-spheres

A commercial phenol formaldehyde-based resole thermosetting resin supplied by Borden Chemical Australia Pty., was reinforced with ceramic-based fillers (SLG) to increase its fracture toughness. This is the second study of the same series. By testing fracture toughness and viscosity at a range of filler addition levels, the optimal addition of SLG was determined in terms of workability, cost, and performance. The composites obtained were post-cured in a conventional oven as in the previous study. The original contributions of this article include lowering the cost of the composite (35wt% of SLG) by 50% but at the same time the fracture toughness was reduced only by 20% (compared to the neat resin), and increasing the fire resistance of the resins tremendously. It was also found that the values of fracture toughness of the samples in this study were higher than those obtained in the previous study when the percentage by weight of SLG varies from 0 to 35%. The shapes of the plots of fracture toughness against percentage by weight of SLG were also different. The possible reasons for the differences were explained.

Yield and tensile strength of vinyl ester composites cured by microwaves

In the previous investigation, it was found that the difference in Youngs modulus, ultimate tensile strength and yield strength between microwave cured vinyl ester particulate composites and those cured under ambient conditions is minimal provided low power microwaves are combined with short duration of exposure. The results also show that microwave cured composite samples will result in smaller shrinkage with the similar values of mechanical properties mentioned above than those samples cured under ambient conditions [1]. The reduction in the shrinkage of the resins by microwaves will enable the manufacture of large vinyl ester composite items possible. This research with more data collected is to confirm the earlier results. The values of mechanical properties considered in the two studies are very near and reliable.

Relationship Between Electrical and Mechanical Loss Tangents of SLG Reinforced Phenolic Composites: Pilot Study

The mechanical properties of ceramic microspheres (SLG) reinforced phenolic resin composites have been measured and evaluated in earlier studies. This basic but critical and important data has created interest in the relevant industry in Australia. This study is therefore carried out to measure and evaluate the dielectric and mechanical properties of the composites with a view to benefit the relevant industry. The relationship between the two properties will also be studied. The original contributions of this article are that samples post-cured in conventional ovens have higher electrical loss as well as mechanical loss than their counterparts post-cured in microwaves. The storage modulus of all samples post-cured conventionally is higher than its counterpart. This is in line with the fact that it is a softer material with lower glass transition temperature. They also have higher mechanical loss tangent as well as loss modulus. For all percentages by weight of SLG, the glass transition temperature for the microwave cured sample was higher and the composite was stiffer; the opposite was true for the conventionally cured sample.

Tensile tests of phenol formaldehyde SLG reinforced composites: pilot study

Phenol formaldehyde was filled with Envirospheres SLG to increase the strength and impact toughness of the composite for structural applications by the Centre of Excellence in Engineered Fiber Composites (CEEFC), University of Southern Queensland (USQ). In order to reduce costs, the Centre wishes to fill as much SLG as possible subject to maintaining sufficient strength and impact toughness of the composites in structural applications. This project varies the percentages by weight of the SLG in the composites which are then subjected to tensile tests. The results show that composite with 10% by weight of the SLG produces the highest yield, tensile strengths and Youngs modulus combined with a reasonable fluidity for casting.

Mechanical Properties of Vinyl Ester Composites Cured by Microwave Irradiation: Pilot Study

Composite components made from vinyl ester resins by Centre of Excellence in Engineered Fiber Composites (CEEFC), University of Southern Queensland (USQ) suffer considerable shrinkage during hardening. Currently, CEEFC solves the shrinkage problem by breaking a large composite component into smaller composite parts because smaller parts tend to have less shrinkage. These smaller parts are then joined together to form the overall structure. The shrinkage of vinyl ester particulate composites has been reduced by curing the resins under microwave conditions. The reduction in the shrinkage of the resins by microwaves will enable the manufacture of large vinyl ester composite items possible. This project investigates the difference in impact strength, tensile strength and Young’s modulus of 33 percent by weight of fly-ash particulate reinforced vinyl ester composite, VE/FLY-ASH (33%) cured under microwave and ambient conditions. Drop weight impact tests were used to find out the impact strength of the composite, while tensile tests were used to find out the tensile strength and Young’s modulus of the composite. The power levels of microwaves used were 180 and 360 W; the duration of exposure of the composite samples to microwave irradiation varied from 20 to 50 seconds. The difference in impact strength and Young’s modulus between microwave cured vinyl ester particulate composites and those cured under ambient conditions had been found to be minimal. However, the tensile strength of the composite samples cured under microwave conditions can be higher than those cured under ambient conditions.

Tensile properties of nanoclay reinforced epoxy composites

Kinetic epoxy resin was filled with nanoclay to increase tensile properties of the composite for civil and structural. This project manufactured samples with different percentages by weight of nanoclay in the composites in steps of 1 wt %, which were then post-cured in an oven. The samples were then subjected to tensile tests. The results showed that the composite with 3 wt % of nanoclay produced the highest yield and tensile strengths. However, the Young’s modulus increased with increasing nanoparticulate loading. It is hoped that the discussion and results in this work would not only contribute towards the further development of nanoclay reinforced epoxy composites with enhanced material properties, but also provide useful information for the studies of fracture toughness, tensile properties and flexural properties of other composites.

Flexural Properties of Epoxy Composites Filled with Glass Powder: Preliminary Results

Epoxy resin was filled with glass powder with a view to increasing strength of the composite for structural applications by a research Centre on composites, University of Southern Queensland (USQ). In order to reduce costs, the Centre wishes to fill as much glass powder as possible subject to maintaining sufficient strength of the composites in structural applications. This project varies the percentage by weight of the glass powder in the composites which are then subjected to flexural tests. The results show that composite with 25 % by weight of the glass powder produces the highest flexural strength and Young’s modulus combined with a reasonable fluidity for casting; the highest flexural strain was achieved when the percentage by weight of glass powder is 10 %.

Flexural Tests of Phenol Formaldehyde and Slg Composites: Pilot Study

Phenol formaldehyde was filled with Envirospheres slg to increase the strength of the composite for structural applications by a research center on composites, University of Southern Queensland (USQ). In order to reduce costs, the center wished to fill with as much slg as possible, subject to maintaining sufficient strength of the composites in structural applications. This project varied the wt% of the slg in the composites which were then subjected to flexural tests. The results showed that composite with 25 wt% of the slg produced the highest flexural strength and Young’s modulus combined with a reasonable fluidity for casting; the highest flexural strain was achieved when the slg was 10 wt%.

Dielectric properties of sawdust reinforced epoxy composites post-cured in microwaves:

This study focuses on the measurement and evaluation of dielectric properties of composite materials with a view to benefiting these relevant industries. Previously published have been the mechanical and thermal properties of sawdust reinforced epoxy composites. The properties of a dielectric material can be controlled through the introduction of various fillers. This study was primarily undertaken to determine the effect of sawdust on the dielectric properties of the composites. The original contribution of this paper states that samples post-cured in microwaves have higher dielectric constant values but lower loss tangent values than their counterparts post-cured in an oven. For all percentages by weight of sawdust, the glass transition temperature for the microwave-cured samples was lower and the composite was softer; the opposite was true for the oven-cured sample. In addition, the storage modulus of all samples post-cured in microwaves is also lower than their counterparts. This is in line with the fact that it is a softer material and has lower storage modulus and lower glass transition temperature.