Optimization of Flexural Strength of Recycled Polyethylene-terephthalate (PET) Eco-Composite using Response Surface Methodology

Recycling and reuse of plastic waste by blending with virgin polymer has been affirmed to be the best way of managing the waste. Equally, agro-waste are best recycled than being burnt off. In the development of stronger and cheaper ecoefficient recycled PET composite for food packaging, this study focused on reinforcement of the blend of 20 wt. % recycled PET (rPET) and 80 wt. % virgin PET (vPET) with snail shell particulate and kenaf fiber via compression moulding process. The process parameters are fiber dosage, particulate dosage, moulding pressure and temperature. Box-Behnken design was engaged in the design of experiment and the samples were produced according to the experimental runs. Result of analysis of variance pinpointed the process factors as significant contributors to the flexural strength response. The model developed was validated to be significant and statistically fit. Interactions between the process variables as revealed by the response surface plots indicated the response was dependent on the interactive pattern between the variables. Response surface optimization showed an optimum flexural strength of 57.16 MPa was attainable at process parameters of 27.27 wt. %, 4.18 wt. %, 3.95 MPa, and 160 ˚C for fiber proportion, particulate proportion, moulding pressure and temperature respectively yielding 34.2 % improvement over the reference 80/20-vPET/rPET matrix. Model validation experiment undergone with the combined parameters and deviation of +0.036 was noted. Since the deviation is insignificant, the model is concluded to be statistically fit for predicting the flexural strength of the developed eco-composite.

The effect of moulding process parameters on interlaminar properties of CF/PEEK composite laminates

Interlaminar properties are one of the most important indicators of thermoplastic composite quality. A series of laminates with different moulding process parameters were prepared by unidirectional carbon fibre-reinforced polyether ether ketone (CF/PEEK) prepreg to explore the influence of moulding process parameters on the interlaminar properties of CF/PEEK composite laminates. The influence of the three process parameters, moulding pressure, moulding temperature, and holding time on the interlaminar shear strength (ILSS) of [0/90]8 laminates was studied. The interlaminar shear failure modes of specimens under different moulding process parameters were compared, and the correlation between the ILSS and interlaminar shear failure modes was analysed. The results showed that the appropriate moulding pressure was 2 MPa, the proper moulding temperature range was 400–420°C and the holding time should not be less than 20 min. The main failure modes were tensile or compression when the laminates were moulded using proper process parameters; interlaminar shear failure might also appear in those moulded by non-optimised process parameters.

Effect of Moulding Pressure on Brake Lining Produced from Industrial Waste Material: Sawdust

In this study, asbestos-free brake lining was developed with sawdust. Sawdust was considered an alternative to asbestos, whose dust is carcinogenic. The sawdust from hard wood (mahogany and iroko trees) and other components such as abrasive, reinforcer, lubricant, were sieved into grade of 100 µm and used in production of brake linings. The percentages of sawdust for the samples are 40, 45, 50, 55, and 60. The percentages of abrasives (silicon carbides) were 27, 22, 17, 12 and 7, while binder (resins) lubricant (steel dust) and carbon black (reinforcer) were constant at 13%, 15% and 5% respectively on each sample. The molding pressure load was varied at 10 Mg, 20 Mg, 40 Mg, 60 Mg and 80 Mg during compression process. The brake lining properties examined are hardness, compressive strength and density. Also, the effects of molding pressure on these properties were evaluated. The results obtained show that the higher the molding pressure, the better the physical and mechanical properties. Furthermore, at high molding pressure, the properties reached a limiting point which they tend to be constant. The brake linings based on sawdust were then compared with commercial (asbestos-based) brake lining and the results are in close agreement. Hence, sawdust can be effectively used as filler for replacement of asbestos in brake linings.

Process modelling of discontinuous long fibre carbon/polyether ether ketone composites: Defect prediction

A numerical model was developed to predict the defect formation during processing of compression moulded discontinuous long fibre carbon/polyether ether ketone composites. The model inputs are the material's temperature-dependant properties (through-thickness modulus and thermal shrinkage), the temperature distribution of the part during cooling and the applied moulding pressure. The material properties of carbon/polyether ether ketone prepreg were measured during cooling from melt using thermal analyses. The model was employed to identify regions on manufactured panels where pressure could be lost during cooling, which are prone to defect formation. Validation was performed by comparing the predicted defect areas against those found on flat panels moulded at pressures ranging from 10 to 110 bar. The model was then employed in a case study to show the importance of the cooling strategy in order to prevent defects on complex-shape components.

Preparation of Siliconized Graphite by Liquid Silicon Infiltration of Porous Carbon Materials

Siliconized graphite was prepared by liquid silicon infiltration (LSI) of carbon preforms composed of mesocarbon microbeads (MCMBs), petroleum coke and graphite powder as the carbon source with binder of phenolic resin. Effects of the carbon source, binder contents, ball-milling time and moulding pressure on the properties of the porous carbon preforms and the siliconized graphite were investigated. The results showed that the moulding pressure was the main factor influencing the open porosity of the carbon preforms. The carbon preforms with porosity of above 45% could be infiltrated completely with Si, and maximum open porosity of 56% could be reached for the carbon preforms. For the siliconized graphite, high MCMBs contents contributed to high density, while high graphite content led to increased carbon remaining. The densities, open porosities, and the highest bending strength of the siliconized graphite were ranged between 2.90-3.01g·cm-3, less than 1.5%, and 317 MPa, respectively.

Optimization of Moulding Parameters on the Electrical Conductivity of Carbon Black/Graphite/Epoxy Composite for Bipolar Plateusing the Taguchi Method

Optimization of the moulding parameters on the carbon black/graphite/epoxy (CB/G/EP) composite for bipolar plate application using the Taguchi method was carrying out. Moulding parameters of the compression moulding process such as moulding temperature, moulding pressure and moulding time were measured. Analysis of variance (ANOVA) shows that, the most significant moulding parameter is moulding time with percentage contribution of 59.98%.The confirmation experiment using additive model shows that, the electrical conductivity of CB/G/EP composites was 168.50 S/cm. The electrical conductivity of CB/G/EP composite was improved 65.72 % compare with the initial trial. The results show that Taguchi method is an effective approach to obtain the optimal moulding parameters of the CB/G/EP composites.

The Study on the Property and the Microstructure of Pressureless Sintered h-BN Ceramics

Hexagonal boron nitride ceramic（h-BN）has been prepared by pressureless sintering method. The effect of sintering aids, moulding pressure and sintering temperature on the mechanical properties and microstructures of h-BN were investigated. The results show that the densification of as-prepared h-BN ceramic can be contributed to the addition of sintering-aids and the formation of card-house structure. Because of the high densification and card-house microstructure, the obtained h-BN demonstrates higher bending strength and lower porosity when the moulding pressure is 200MPa, sintering temperature is 1850°C and the contents of sintering aids is 10wt%.

Effect of Pressing Pressure on Density and Hardness of Powder Miscanthus Reinforced Brake Pads

The aim of this paper is to develop new natural fibre reinforced for automotive brake pad application. For this purpose, new brake pad sampleswere produced using Miscanthus as reinforcement ingredient. The other ingredients are Cashew, Alumina, Phenolic Resin, and Calcite. Three different laboratory formulations were prepared with varying Miscanthus fibre contents from 10, 25, and 40 (wt) and these formulations were moulded four different moulding pressure values such as 50, 100, 200, and 300 MPa. Sieve analysis, density, apparent density, and hardness properties of brake pad samples produced are examined.

Direct Moulding of Rubber Granules and Powders from Tyre Recycling

SMART project (Sustainable Moulding of Articles from Recycled Tyres) is a research project financed by the European Commission with the aim of developing a new moulding process of granules and powders from tyre recycling without any addition of virgin rubber or linking agent. The so called “direct moulding” is a compression moulding process which is directly applied to rubber particles from tyre grinding. After one year of activities, the new moulding process has been deeply investigated and some results are reported in the current work for the first time. Rubber granules and powders were produced by GumiImpex (partner of the European project) thanks to different technologies: particles from tyre grinding and buffings from tyre machining. Different size distributions of rubber particles and buffings were used to produce rubber sheets with the size of 200x200x5 mm3at the temperature of 160°C and the pressure of 3 MPa by using aluminium moulds. Tensile specimens were extracted from the sheets and tensile tests were performed and related to sample density and particle properties. Rubber densities over 1 g/cm3have been reached for all the samples with ultimate tensile strength and maximum elongation up to 1 MPa and 80%, respectively. These mechanical data are very promising in comparison with properties of polyurethane bound rubber composites. Increasing moulding pressure and temperature would lead to higher mechanical properties, if necessary.