Manufacturing Of Polymer Composites Research Articles

Polymer Composite Manufacturing by FDM 3D Printing Technology

3D printing technology was developed nearly 30 years ago. One of its characteristics is that instead of removing materials, 3D printing creates 3D elements directly from CAD models, adding one layer of material on another. This offers a beneficial capability of making complex elements in terms of shape and materials, impossible to be manufactured by traditional methods. Owing to intensive research in recent years, considerable progress has been achieved in the development and commercialisation of new innovative processes of 3D printing by fused deposition modeling (FDM), including printing of composite materials. The study outlines the main methods of creating polymer composite structures using FDM technology.

Molding of Polymeric Composite Reinforced with Glass Fiber and Ceramic Inserts: Mathematical Modeling and Simulation

This work provides a numerical study of a polymer composite manufacturing by using liquid composite material molding. Simulation of resin flow into a porous media comprising fiber perform (reinforcement) inserted in a mold with preallocated ceramic inserts has been performed, using the Ansys FLUENT® software. Results of resin volumetric fraction, stream lines and pressure distribution inside the mold, and mass flow rate (inlet and outlet gates) of the resin, as a function of filling time, have been presented and discussed. Results show that the number of inserts affects the filling time whereas the distance between them has no influence in a process.

Synthetic Fiber-Reinforced Polymer Composite Manufactured by Resin Transfer Molding Technique: Foundations and Engineering Applications

This chapter focuses on the manufacturing of polymer composites reinforced by synthetic fiber with emphasis to the resin transfer molding technique (RTM). Herein, different related topics to foundations, classification, constituents and technological applications of polymer composites are presented. The problems associated to reinforcement and matrix interface and the manufacturing techniques of polymer composites are discussed. The study confirms RTM technique as a highly efficient process as compared with other manufacturing techniques of polymer composites.

Review of Heat Exchangers Enabled by Polymer and Polymer Composite Additive Manufacturing

ABSTRACTThis paper presents an overview of the most common polymer additive manufacturing processes, including vat photopolymerization, material jetting, sheet lamination, powder bed fusion, and fused filament fabrication. Next, the general strengths and challenges of the common methods are discussed and are followed by discussions on efforts to increase thermal performance of polymers used with the various manufacturing methods. Finally, heat exchangers enabled by polymer additive manufacturing are reviewed to show that novel designs in metal, ceramic, and polymer heat exchangers can be made possible by the unique properties of polymers and the advantages offered by additive manufacturing. By reporting what has been proven possible—and the associated challenges—we hope to stimulate the community and further development in a burgeoning field enabled by polymer additive manufacturing.

Comparative study on chemical composition, physical, tensile, and thermal properties of sugar palm fiber (Arenga pinnata) obtained from different geographical locations

Physical, mechanical, chemical, and thermal properties of sugar palm (Arenga pinnata) fiber were investigated for specimens obtained from three different locations: Kuala Jempol (Peninsular Malaysia), Tawau (West Malaysia), and Tasik Malaya (Indonesia). The morphology of the fiber were observed through scanning electron microscopy (SEM), the thermal properties by thermogravimetric analysis (TGA), tensile properties according to ASTM D3379, and chemical analysis by using neutral detergent fiber (NDF) and acid detergent fiber (ADF). This study confirmed that in sugar palm fiber, the highest chemical content of cellulose resulted in the highest strength and thermal stability of the fiber. Fiber originating from Kuala Jempol had the highest cellulose content of 44.53%, followed by Indonesia (44.47%) and Tawau (43.75%). Kuala Jempol fiber (233.28 MPa) also had the highest tensile strength, followed by Indonesia (211.03 MPa) and Tawau (201.30 MPa), which was affected by the cellulose content in the fiber. Thus, fiber originating from Kuala Jempol had better quality than the others as a reinforcement material in manufacturing of polymer composites.

An integrated approach of quality for polymer composite manufacturing validated and optimized through Taguchi method

Quality problems in the polymer composite products are mainly attributed to design flaws, material inconsistencies, defects in manufacturing process, unquali ed manpower, use of primitive technology, and defective machines. The purpose of this research is to develop a generic framework of quality for polymer composite manufacturing, which is validated and optimized through determining flexure properties by Taguchimethod. To test the proposed framework, 27 polymer composite laminates were produced according to Taguchi L27 orthogonal array by varying thirteen key process parameters including laminates' thickness, weight, ber pattern, matrix, core type, resin and hardener mixing time, viscosity, layup pattern, tooling, cure, temperature, labour and process techniques. Flexure strength was de ned as quality characteristic, and accordingly, e ffects of the selected parameters on exural properties were studied through three-point bendingtest. Results of the study reveal that ber pattern, cure, tooling type, and layup pattern are the most signi cant variables influencing flexure stress, whereas ber pattern, matrix, resin hardening mixing time, and process techniques have signi cant e ffect on flexure strain. The optimized levels of each control parameter for exure stress and strain were obtained, and results were validated through predictive analysis. Findings of this study and the proposed framework are useful for polymer composite application in aviation, mechanical, sports, automobile, and civil industries.

Thermal analysis of additive manufacturing of large-scale thermoplastic polymer composites

The incremental deposition process utilized by most additive manufacturing (AM) technologies presents significant challenges related to residual stresses and warping which arise from repeated deposition of hot material onto cooler material. These issues are magnified at larger scale, where even a small thermal strain can correspond to several millimeters of deformation. In this work we investigate the thermal evolution in thin walls of carbon fiber/acrylonitrile butadiene styrene (CF/ABS) composite materials fabricated via Big Area Additive Manufacturing (BAAM). We measure the thermal evolution of composite parts during the build process using infrared imaging, and develop a simple 1D transient thermal model to describe the build process. The model predictions are in excellent agreement with the observed temperature profiles and from the results we develop criteria to guide deposition parameter selection to minimize the likelihood of cracking during printing.

Effect of Thermal & Alkali Treatment on Pterocarpus Angolensis (Mukwa) Wood Flour

Environmental friendly pre-treatment of fibre has been lately adopted by many researchers worldwide but not fully understood. Although various chemical modifications of fibre through several chemical treatments have been explored, but less has been done on lower sodium hydroxide (NaOH) concentrations. This paper investigated the effect of thermalization at 115 C and lower NaOH of concentrations (1, 3 and 5) effect on mukwa wood flour as a way of minimizing chemical impact on possible manufacturing of eco-friendly wood polymer composites (WPC). Weight loss analysis was carried out to evaluate the effect of thermalization and alkalization modification. X-ray diffraction (XRD), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM) were used to characterize the untreated and treated mukwa wood flour. The results showed significant surface modification thereby improving fibre characteristics as impurities (hemicellulose, lignin and other non-cellulosic substances) were removed.

Characterization of Sorghum Bran/Recycled Low Density Polyethylene for the Manufacturing of Polymer Composites

The objective of the study was to investigate the suitability of using sorghum bran in recycled low density polyethylene (R-LDPE) composites manufacturing. In response to the disposal of environmental problematic agricultural and polymer waste, composite sheets using recycled low density polyethylene and sorghum bran of different loadings (5, 10, 15 and 20 wt%) were prepared by melt compounding and compression molding. The effects of sorghum bran loadings on the mechanical, thermal, water absorption, swelling and crystalline properties of the composites were determined. Characterization of composites was carried out using X-ray diffraction (XRD), differential scanning calorimetry (DSC), thermo gravimetric (TGA/DTG) and mechanical analyses. It was found that increasing fiber loadings resulted to increased moduli and tensile strength while hardness was decreased. XRD indicated that fiber addition to R-LDPE did not change characteristic peak position. DSC results showed that the R-LDPE had significantly larger peak heat flow during cooling run than the blank R-LDPE, showing higher crystallization rates for R-LDPE. The results obtained confirmed that sorghum bran particles showed some potential as a good reinforcement in polymer matrix composites and indicate its thermal stability for possibly future composite applications.

Effect of alkali treatment on interfacial bonding in abaca fiber-reinforced composites

Abaca fibers demonstrate enormous potential as reinforcing agents in composite materials. In this study, abaca fibers were immersed in 5, 10 or 15wt.% NaOH solutions for 2h, and the effects of the alkali treatments on the mechanical characteristics and interfacial adhesion of the fibers in a model abaca fiber/epoxy composite system systematically evaluated. After 5wt.% NaOH treatment, abaca fibers showed increased crystallinity, tensile strength and Young’s modulus compared to untreated fibers, and also improved interfacial shear strength with an epoxy. Stronger alkali treatments negatively impacted fiber stiffness and suitability for composite applications. Results suggest that mild alkali treatments (e.g. 5wt.% NaOH for 2h) are highly beneficial for the manufacture of abaca fiber-reinforced polymer composites.

Investigation on the thermo-oxidative stability of carbon fiber sizings for application in thermoplastic composites

The stability of the surface chemical composition of different polymer sizings on carbon fibers, designed as a reinforcing material for thermoplastic composites, was investigated in detail under conditions closely related to the standard processing ones, i.e. high temperature, short periods of processing time and presence of an oxidative atmosphere. X-ray photoelectron spectroscopy and contact angle measurements were used to characterize the surface properties of the sizings in dependence of treatment time and temperature. The obtained results clearly show a rapid thermo-oxidative altering of the initial surface functionalities, in particular of the polyether based component, which was found to be the major surface constituent of all types of investigated sizing systems. Moreover, the observed degradation of surface functionalities leads to significant changes in the surface free energies of the sizings determined by contact angle measurements. Finally, the surface analysis of single fibers, which were pulled out during fracture of model composite specimens, confirmed that the revealed surface degradation of the sizing also takes place during a standard polymer composite manufacturing process.

Material Characterization of Roselle Fibre ([i]Hibiscus sabdariffa [/i]L.) as Potential Reinforcement Material for Polymer Composites

Recently,in line with rising environmental concerns,n researchers are now replacing synthetic fibres with natural ones as the main component in composites.Natural fibres are preferred to synthetic fibres because of several advantages such as biodegradable,light weight, low cost and good mechanical properties.Roselle is one of the plants found to be suitable to be used to produce natural fibres.In this work,we analysed the physical, thermal and mechanical characteristics of roselle fibre. Roselle fibre has good physical properties which lead to the dimensional stability of the composite product.The result obtained indicated that the moisture content of roselle fibre is 10.9%,while water absorption is 286.5%. Thermal gravimetric analysis (TGA) was conducted to understand the thermal stability of roselle fibre at high temperature.The results show that the initial degradation of roselle fibre starts at 225 °C and completes the decomposition of the lignocellulosic component at 400 4C. A tensile test was conducted to investigate the mechanical properties of roselle fibre.The tensile strength of roselle fibre is 130 - 562 MPa.On the basis of the properties of roselle fibres obtained,we concluded that roselle fibre is one of the good natural fibres that can be used as reinforced material for the manufacturing of polymer composites for different applications,while at the same time saving the cost required to manage the agro waste.

A Study on Chemical Composition, Physical, Tensile, Morphological, and Thermal Properties of Roselle Fibre: Effect of Fibre Maturity

Roselle fibre is a type of natural fibre that can be utilized as a potential reinforcement filler in polymer composites for different applications. This work investigates the chemical, physical, mechanical, morphological, and thermal characteristics of roselle fibre at different levels of maturity (3, 6, and 9 months). The diameter of roselle fibre increases as the plant matures. However in contrast to this, the moisture content and water absorption of roselle fibre decrease as the plant matures. Chemical content of roselle fibres from plants of different ages indicate that as the plant matures, the cellulose content decreases. Tensile strength of roselle fibre decreases from 3 months old to 9 months old. The cross section of roselle fibre shows a typical morphology of bast fibre, where there is a lumen in the central of fibre.Thermal analysis results show that the effect of thermal decomposition of roselle fiber is almost the same for all plant ages. It is concluded that roselle fibres can be used as reinforced material for manufacturing of polymer composites. Based on its excellent properties, roselle fibres are suitable for different applications such as automotive and building components at lower cost.

Characterization of Synthetic Amorphous Silica (SAS) Used in the Ceramics Industry

Silica (SiO2) is one of the most important inputs for the food, pharmaceutics, polymer composite, and ink manufacturing industries. In ceramic materials, fine silica particles are widely used as a packing and sintering aid and to produce other raw materials like mullite (3Al2O3·2SiO2) and silicon carbide (SiC). As most of the silica sources found in nature have relatively low purity and nonhomogeneous properties, use of synthetic grades of silica is necessary in applications such as refractories and technical ceramics that require better control of product composition and microstructure. This paper describes a systematic comparison of four grades of synthetic amorphous silica (SAS) used in technical ceramics. The evaluated SAS materials were formulated by different methods (sodium silicate precipitation, SiCl4 pyrolysis, extraction from rice husks, and physical deposition of silicon vapour). Differences in the physicochemical and thermal and microstructural characterization of each material are related to the principles and techniques involved in their manufacture. The study verified that synthesis conditions strongly influenced the composition and physical properties of the tested SAS samples.

Effects of reinforcement configuration and densification on impact strength of wood veneer/polyester composites

Current energy absorbers in industrial applications are made of metals or fiber-reinforced polymers using glass and carbon fibers. These materials are extremely stiff and strong but exhibit low-energy absorption when subject to the impact load. Other issues in the use of these materials are their high cost (fiber-reinforced polymer) and weight (metal). Wood reinforcements on the other hand are light weight and economic but less stiff. This study investigated the impact resistance and fracture patterns of wood-reinforced polyester composites using a drop-weigh impact test and considers the potential of using wood as a natural reinforcement in the manufacturing of polymer composites. Densified and un-densified Douglas-fir veneers were used to create three different mat configurations: woven, cross, and unwoven (unidirectional) mats. A total of 350 specimens were tested following ASTM D5420, and their impact resistance was calculated using the staircase method. Scanning electron microscopy was used to examine the resin distribution and its penetration into the reinforcement. Additionally, light micrographs of the veneers before and after densification were examined to determine the effect of densification on the cell-wall structure. Glass fiber-reinforced polymer samples had significantly higher impact resistance than the wood composites. Densification of the veneer did not significantly improve the composite performance. The effect of reinforcement configuration on the final performance of the wood–polyester composites, however, was significant with the woven, and cross configurations having notably higher impact energy than unidirectional composites.

Optimal directional nesting of planar profiles on fabric bands for composites manufacturing

The nesting problem of planar (2D) parts into 2D sheets is common among many applications and thus industry branches. This work focuses on manufacturing of polymer composites reinforced by woven fabric where constraints such as part orientation and mirroring apply. A nesting procedure was developed combining a genetic algorithm as an optimization tool for part sequencing and a new Bottom-Left-Fill-Left (BLFL) heuristic for 2D nesting that considers a predetermined part sequence. The BLFL heuristic is a two-step placement method where each part is first roughly placed according to the Bottom Left Fill rules on an appropriately rasterized band and then it is finely moved left so as to eliminate discretization error. This is both a fast and accurate procedure due to a novel shape representation by four equivalent forms, namely vector, raster, simple polygon and high definition polygon. The effectiveness of the proposed approach is tested for nesting orthogonal quadrilateral, orthogonal edged (tetris™-like) and, most importantly, irregular free-form 2D shapes. The approach proved much faster than other known approaches, because of the computationally light evaluation function of the genetic algorithm and more flexible, too, since it allows the user to balance between speed and accuracy, as desired, chiefly by fine-tuning the essential shape representation parameters.

Tooling design and microwave curing technologies for the manufacturing of fiber-reinforced polymer composites in aerospace applications

The increasing demand for high-performance and quality polymer composite materials has led to international research effort on pursuing advanced tooling design and new processing technologies to satisfy the highly specialized requirements of composite components used in the aerospace industry. This paper reports the problems in the fabrication of advanced composite materials identified through literature survey, and an investigation carried out by the authors about the composite manufacturing status in China’s aerospace industry. Current tooling design technologies use tooling materials which cannot match the thermal expansion coefficient of composite parts, and hardly consider the calibration of tooling surface. Current autoclave curing technologies cannot ensure high accuracy of large composite materials because of the wide range of temperature gradients and long curing cycles. It has been identified that microwave curing has the potential to solve those problems. The proposed technologies for the manufacturing of fiber-reinforced polymer composite materials include the design of tooling using anisotropy composite materials with characteristics for compensating part deformation during forming process, and vacuum-pressure microwave curing technology. Those technologies are mainly for ensuring the high accuracy of anisotropic composite parts in aerospace applications with large size (both in length and thickness) and complex shapes. Experiments have been carried out in this on-going research project and the results have been verified with engineering applications in one of the project collaborating companies.

Preparation and bending properties of three dimensional braided single poly (lactic acid) composite

New three dimensional (3D) braided single poly (lactic acid) composites (PLA–SPCs) were obtained by combining 3D and five (5)-direction braiding technique and hot-compression technical process. 3D and 5-direction braided preforms with different braiding angles, thicknesses and fiber volume fractions were prepared. Preforms were preheated in the specially designed die system in order to make all of the fibers partially melted. In the next stage, the preforms were consolidated under a certain pressure (from 7.8 to 10MPa) at temperatures ranging from 130 up to 150°C. Under the controlled processing conditions, one part of fiber body formed matrix while the other part retained its fibrous form.At the same consolidation temperature, the maximum bending stress values resulted to be substantially dependent on the fiber volume fraction of PLA–SPCs, while the bending modulus values were largely subjected to the fiber content in the length direction. The increases of consolidation pressure gave rise to better fusion of neighboring fibers with the result that the maximum stress and modulus were increased. As the consolidation temperature increases, the fusion bonding was improved, the bending failure feature was converted from plastic to brittle, both maximum bending stress and modulus values were increased. It is expected that this study could provide a new approach for the manufacture of high-performance single polymer composites (SPCs) by using thermoplastic polymer fibers.

RECYCLE OF PLASTIC WASTE AND AGRICULTURAL WASTE

Manufacturing of polymer composites using plastic waste is one of the solutions to solve the environmental pollution problems caused by non-biodegradable polymer. In this study, Rice husk fiber Reinforced Polyethylene composites (RhRP) have been fabricated with rice husk fiber and plastic waste (recycle low density polyethylene) by compression molding method. Effect of fiber volume fraction, pressure and temperature on the properties of the composite samples was studied. In addition, mechanical properties, thermal properties and durability of RhRP composites were measured. Moreover, chemical modification of rice husk fiber was done through acid and aqueous alkaline solution. The modified fiber samples exhibit the higher strength as well as the lower water absorption rate compared with the unmodified fiber composite samples. Therefore, the resistance to aging of the composites in aqueous environment improved significantly for the modified composite samples. Furthermore, Scanning Electron Microscope (SEM) was also used to characterize the surface feature and the interfacial adhesion between fiber and matrix polymer. The modified composite samples reveal better interfacial adhesion than the unmodified composite ones. Thermo Gravimetric Analysis (TG/DTA) was employed to determine thermal stability of the composite samples. The modified fiber samples have higher thermal stability than the unmodified composite ones.

English

Oil palm ash (OPA) is available in abundance, is renewable, can be obtained at no cost and shows good performance at high thermal conditions. Combinations of the unsaturated polyester with natural fillers have been reported to improve the mechanical and thermal properties of composites. Utilisation of oil palm ash as a filler in the manufacture of polymer composites can significantly reduce the requirement for other binders or matrixes of composite materials. This research uses oil palm ash as a filler to form composites through the investigation of the effect of different contents of filler on the properties of OPA-filled unsaturated polyester (UP/OPA) composites. The effect of different volume fractions, i.e., 0, 10, 20 and 30 vol.% of oil palm ash introduced into 100, 90, 80 and 70 vol.% of an unsaturated polyester matrix on the composite mechanical properties, i.e., tensile and flexural, has been studied, together with thermal gravimetric analysis (TGA) and differential scanning calorimetric (DSC). Specimens were prepared using compression moulding techniques based on the ASTM D790 and D5083 standards for flexural and tensile tests, respectively. The tensile and flexural mechanical properties of UP/OPA composites were improved in modulus by increasing the filler content. Thermal stability of the composites increased as the OPA filler content was increased, which was a logical consequence because of the high thermal stability of the silica compound of the OPA filler compared with that of the UP matrix. The results from the surface electron microscope (SEM) analysis were the extension of mechanical and thermal tests.