Twin Extruder Research Articles

Parameter Optimization in FDM Filament Fabrication via Single Screw Extruder

The presence of polymer material filaments plays a crucial role in the realm of 3D printing. These filaments are utilized in 3D printing to create prototype products efficiently and cost-effectively. However, ensuring the production of high-quality prototype products necessitates the use of superior filaments characterized by consistent diameter and a round cross-section. Filaments are typically manufactured through an extrusion process using either a single screw extruder or a twin extruder. In this research, a DIY single-screw extruder was developed specifically for filament production. The main objective of this study is to generate quality filaments by optimizing the extruder parameters for various polymer materials. Three different polymers; Ethylene-vinyl Acetate (EVA), Polypropylene (PP), and Acrylonitrile Butadiene Styrene (ABS) were employed in this study. The research aimed to assess the melt flow index (MFI) to demonstrate viscous behavior and establish the ideal parameters for each material in the extrusion process. A total of 27 EVA material filament samples, 26 PP filament samples, and 26 ABS filament samples were successfully produced. Through analysis, optimal settings were identified for EVA, PP, and ABS filaments, resulting in high-quality production. The recommended parameters for producing quality EVA filaments included a temperature of 160°C, screw speed of 400 rpm, and take-up speed of 400 rpm. For PP filaments, the optimal settings comprised a temperature of 230°C, screw speed of 700 rpm, and take-up speed of 250 rpm. Lastly, ABS filament production was optimized with a temperature of 210°C, screw speed of 300 rpm, and take-up speed of 100 rpm. This project's outcomes are anticipated to have significant implications for future advancements in filament manufacturing processes.

Effect of synthesized copper oxide nanorods on electrical and thermal properties of compatibilized high‐density polyethylene/carbon nanofiber nanocomposite films

AbstractHigh‐density polyethylene (HDPE) nanocomposites containing different optimized fractions of carbon nanofiber (CNF) at 6 wt.%, polyethylene glycol (PEG) at 4 wt.%, and copper oxide (CuO) nanorods in concentration ranges of 0.15, 0.5, and 2 wt.% were successfully melt processed using corotating twin extrusion and compression molding technique. The effect of PEG and CuO nanofiller on the HDPE matrix were studied, particularly for the percolation threshold for electrical conductivity, structural morphology, and other properties including thermal stability, thermal conductivity (TC), dielectric, and UV protection properties. It is observed that PEG acts as a good compatibilizer, facilitating better interfacial connection between CNF and HDPE matrix. The optimized composite with 0.15 wt.% CuO nanorods (H/C6/P4/Cu0.15) shows a fine morphology and strong interfacial connections between fillers and the matrix, as observed in FE‐SEM micrographs. This optimized composite exhibits improved thermal stability, higher thermal conductivity (0.0404 W.K−1.m−1), increased dielectric constant, reduced electrical volume resistivity (from 2.1 × 1015 to 2.1 × 106 Ω.cm), and lower optical band gap value (2.74 eV). Additionally, all prepared nanocomposites offer approximately 100% Ultraviolet Protection Factor (UPF) rating for UV protection.Highlights The transformation of insulating HDPE into conducting HDPE composites. The effect of CuO nanorods was investigated in compatibilized HDPE composites. A percolation is achieved in the HDPE composite at 0.15 wt.% of CuO nanorods. PEG and CuO nanorods improved the multifunctional properties of the composite.

Investigation of the mechanical, thermal and wear properties of eggshell/PLA composites

Abstract The current study investigated the potential application of agricultural waste chicken eggshell (CES) as a reinforcement in composites made of poly (lactic acid) (PLA). With the use of twin extruder and injection molding machine, polymer composites have been developed. The performance of the composites was assessed with respect to its mechanical, thermal, and wear properties. It was shown that the increase in eggshell content led to the increase in void content and water absorption. Despite the increase in void content, the mechanical properties, in particular, micro-hardness, tensile strength and flexural strength were significantly improved. Conversely, when the eggshell content increased from 0 to 30 wt%, the impact strength was decreased. A slight decrease in fracture toughness was observed. Thermal properties, such as thermal stability and thermal degradation temperature, were improved with an increase in eggshell content. PLA, PLA-CES-10, PLA-CES-20, and PLA-CES-30 composites exhibited increase in erosion rate by 13.8 %, 10 %, 9 %, and 6 %, respectively, when the impact velocity was increased from 30 m/s to 50 m/s. Data were analyzed statistically with one-way ANOVA and post hoc Tukey’s HSD test (α < 0.05). Overall, PLA/eggshell based polymer composites performed exceptionally well, in addition to their environmental benefits, pollution control, waste utilization, and reduced production cost.

A Study on the Role of Clay Nanoparticles and Temperature on the Creep Behavior of Polyethylene Matrix Nanocomposite

Objective: In the current research, the creep behavior of polyethylene (PE) matrix nanocomposites reinforced with different content of clay nano particles (i.e., 0, 1, 3, 5, 10wt%) at different temperatures (25 and 50℃) has been investigated. Methods: In order to produce composite samples of pure PE reinforced with different percentages of clay (0, 1, 3, 5 and 10% by weight), a twin extruder was used in the temperature range of 200-230℃. Also, to produce the standard samples, an injection machine was used using in the temperature range of 220-230℃. The samples were subjected to a constant load, typically around 0.7 to 0.8 times the yield strength, at 25 and 50℃ , and at constant strain rate of 0.1min-1. Results: The creep investigations showed that for PE and its nanocomposites the creep trend could be divided into primary, secondary, and tertiary stages. The length of each stage depended strongly on both temperature and the stress level at which the samples tested as well as the clay content. It was observed that adding nano particles in small amounts (1wt%) led to an increase in the length of the creep life of PE and it also improved this property in both temperatures. Conclusion: It was observed that increasing test temperature from causes to decrease the creep strength as well as a rapid onset of plastic deformation for all materials including PE and its nanocomposites. PE nanocomposites with higher than 1wt% clay exhibited a noticeable drop in creep strength particularly at 50℃.

A Multifunctional Composites Membrane Aiming at Flexible Sensor and Ultrabroadband Electromagnetic Wave Absorption

A study was conducted on SEBS-based composites granules containing different volume fractions of carbon nanotubes (CNTs) using a twin extruder and hot pressing procedure to produce a SEBS/CNTs membrane. SEM was used to study the membrane s morphology, revealing a 3-D network of CNTs. TGA was utilized to measure the degradation temperature of SEBS polymer and determine the actual volume fraction of CNTs. The mechanical properties, electrical conductivity, and cyclic strain sensing behavior of the SEBS/CNTs were investigated using a tensile testing machine and pico-ammeter. Mathematical models were used to fit the measured data, demonstrating the strain sensing potential of the composites. The composite membrane with 2 wt.% of CNTs exhibited superior electromagnetic wave absorption performance with a minimum reflection loss (RLmin) value. This study provides promising opportunities for the development of advanced materials.

Development and Process Optimization of a Ready-to-Eat Snack from Rice-Cowpea Composite by a Twin Extruder

A central composite rotatable design with four independent variables viz. blend ratio (broken rice flour and cowpea flour): 90:10–70:30, moisture content (10–18% wet basis), barrel temperature (110–150 °C), and screw speed (280–360 rpm) were varied in the development of ready-to-eat snacks using a twin extruder for a broken rice–cowpea product. The effects of the independent variables on specific mechanical energy, water absorption index, water solubility index, total color, hardness, bulk density, expansion ratio, and overall acceptability of the extruded snack were investigated using regression analysis. The results showed that the physical qualities of the ready-to-eat snacks were significantly affected by the extrusion parameters (i.e., blend ratio, barrel temperature, moisture content, and screw speed). From the findings, it was observed that screw speed and moisture contents affected hardness, while water absorption index was affected by all the extrusion parameters. However, the water solubility index and overall acceptance were majorly affected by the moisture content; extrudate produced with barrel ratio of 85:15, 12% moisture content, barrel temperature of 140 °C, and screw speed of 300 rpm was the most acceptable, at 6.73 on a 9 point hedonic scales. The blend ratio and barrel temperature influenced the expansion. Furthermore, the combination of cowpea and broken rice to produce nutritious ready-to-eat snacks has high acceptability and is a promising panacea for food security.

Incorporation of Argan Shell Flour in a Biobased Polypropylene Matrix for the Development of High Environmentally Friendly Composites by Injection Molding.

In this study, a new composite material is developed using a semi bio-based polypropylene (bioPP) and micronized argan shell (MAS) byproducts. To improve the interaction between the filler and the polymer matrix, a compatibilizer, PP-g-MA, is used. The samples are prepared using a co-rotating twin extruder followed by an injection molding process. The addition of the MAS filler improves the mechanical properties of the bioPP, as evidenced by an increase in tensile strength from 18.2 MPa to 20.8 MPa. The reinforcement is also observed in the thermomechanical properties, with an increased storage modulus. The thermal characterization and X-ray diffraction indicate that the addition of the filler leads to the formation of α structure crystals in the polymer matrix. However, the addition of a lignocellulosic filler also leads to an increased affinity for water. As a result, the water uptake of the composites increases, although it remains relatively low even after 14 weeks. The water contact angle is also reduced. The color of the composites changes to a color similar to wood. Overall, this study demonstrates the potential of using MAS byproducts to improve their mechanical properties. However, the increased affinity with water should be taken into account in potential applications.

Effect of dibutyl itaconate on plasticization efficiency of a REX processed polylactide with peroxides

This work reports the effect of a reactive extrusion (REX) process on polylactide (PLA) based formulations plasticized with dibutyl itaconate (DBI). As DBI contains a carbon-carbon double bond, it is suitable for reactive extrusion. REX was carried out in a co-rotating twin extruder with the addition of two different organic peroxides. The main aim of using REX during the blending of the DBI plasticizer with PLA is to improve the interaction between them so the obtained final properties of the formulations could be improved. Plasticization process allowed to improve the ductile properties of PLA, by using REX, an improvement on the tensile strength was obtained with a no remarkable change in ductility. The thermal characterization also revealed that the glass transition temperature Tg was reduced for all formulations including DBI. REX with DBI provided a slight increase in Tg and this effect was also evident in thermomechanical properties. Regarding the thermal degradation behaviour, the plasticizer reduced the onset degradation and the maximum degradation rate, while a slight improvement on thermal stability was observed by using REX with organic peroxides. Finally, plasticizer migration in water was observed in conventional extruded PLA/DBI formulations, while REX provided improved behaviour against migration.

Processing Biodegradable Fused Filament Fabrication Waste with Micro-Silica Particles

Microparticles of sand silica have been mixed with biodegradable waste (polylactic acid) from the fused filament fabrication process to investigate the impact on the mechanical properties. The composite mixtures were prepared using different compositions via a twin extrusion machine. Mechanical characterization using the Tensile Testing Machine was performed. The peak strength values indicated that increasing silica composition increased the tensile strength from 62.8 MPa at 0 wt% to 121.03 MPa at 10 wt%. However, a drop was observed beyond this point. It was concluded that for the yield strength, toughness, and failure strain, a similar trend was observed, and the values of the material increased up to 10 wt%, which corresponds to the increased mechanical property of the mixtures with reinforcement of silica microparticles. It is demonstrated that the mechanical properties have been improved for the processed material attributing to the impact of the recycling process of the polylactic acid from leftover 3D printing waste and promoting its potential reuse in the same application.

Characterization of cellulose nanofibril reinforced polybutylene succinate biocomposite

The environment friendly cellulose nanofibrils obtained from natural cellulose presents unique opportunity for developing a sustainable end product. The beneficial characteristics of cellulose nanofibrils are biocompatibility, low toxicity, suitable surface chemistry and useful physical properties. In the current study, the polybutylene succinate (PBS) with five levels of cellulose nanofibril (NFC) is being developed by using twin extruder. The differential scanning calorimeter results demonstrate that the addition of NFC has insignificant effect on the thermal behavior but it improves the tensile mechanical properties of thermoplastic PBS. The tensile strength reaches upto 30.81 MPA and elastic modulus increases upto 1.5 GPa with the addition of 10% cellulose nanofibril in polybutylene succinate. The rheological analysis shows that the complex viscosity η* of NFC/PBS presents the shear thinning behavior. The decrease in contact angle upto 70.7o with the addition of NFC in PBS matrix is related to its hydrophilic behavior which is also proved by the higher diffusion coefficient. Dynamic mechanical analysis was employed to characterize storage modulus G’ which increased by 1470 MPa due to the rise in PBS stiffness when 10% NFC was added. Finally, the interaction of cellulose nanofibrils in the polybutylene succinate matrix is evaluated by using fracture surface and X-ray photoelectron spectroscopy.

Effect of the Mg<sub>3</sub>N<sub>2</sub> Sub-Micron Particle on the Grain Refinement of AZ80 Alloy

AZ80 alloy has been widely used to produce high performance Mg casting and wrought parts for high-end applications due to its high mechanical properties and deformation ability. However, at least two important issues still need to be solved in order to further improve its mechanical properties and deformation ability. Firstly, the grain size of α-Mg in AZ80 alloy is relatively large (more than 1000 µm) due to a lack of efficient grain refinement methodologies. Secondly, the size of the eutectic Mg17Al12 phase is also large and the distribution of the eutectic Mg17Al12 phase is continuous, which is very harmful for the mechanical properties, in particular to elongation. In this paper, these two important issues are investigated by adding Mg3N2 sub-micron particle into AZ80 alloy and thereby refining the α-Mg and the eutectic Mg17Al12 phase. Firstly, the Mg3N2 sub-micron particle was directly added into AZ80 alloy by using mechanically stirring in the semi-solid state, subsequently the melting temperature was increased above the liquidous temperature, and finally the melting was casted in the liquid state. It was found that the grain size of α-Mg can be refined from 883.8 µm to 169.9 µm. More importantly, the eutectic Mg17Al12 phase was also refined and the distribution became discontinuous. It should be noted that directly adding the Mg3N2 sub-micron particle into AZ80 alloy leads to a great loss of the Mg3N2 sub-micron particle due to the weak wetting behavior between the Mg3N2 sub-micron particle and Mg melt. The second methodology through mixing Mg3N2 sub-micron particles with AZ91 chips using a twin extruder was also used to prepare AZ91 master alloy with 3wt.% Mg3N2 sub-micron particle, which was subsequently added into AZ80 alloy in the liquid state. In this way, a significant grain refinement of α-Mg and a simultaneous refinement of the eutectic Mg17Al12 phase in AZ80 alloy was also achieved. The grain size of α-Mg can be refined from 883.8 µm to 325.9 µm. However, no significant grain refinement by using UST was observed. Instead, the grain size increases from 325.9 µm to 448.6 µm, indicating that the Mg3N2 sub-micron particle may lose its grain refinement potency due to possible aggregation and clustering. This paper provides an efficient and simple methodology for the grain refinement of α-Mg and the simultaneous refinement of the eutectic Mg17Al12 phase in AZ80 alloy.

Characteristic of low-density polyethylene reinforcement with nano/micro particles of carbon black: a comparative study

Purpose: Low density polyethylene is commonly used polymer in the industry because of its unique structure and excellent overall performance. LDPE, is relatively low mechanical properties and thermal stability can sometimes limit its application in industry. Therefore, the development of particulate reinforced polymer composites is one of the highly promising methodologies in the area of next generation engineering products. Design/methodology/approach: Nano and Micro composite from low density polyethylene LDPE reinforced with different weight fraction of carbon black particles (CB) (2, 4 and 8)% prepared by first dispersion Nano and Micro carbon black particles CB in solvent and then mixing manually with low density polyethylene LDPE pellet and blended by twin-screw extruder, the current research study the mechanical properties (tensile strength, elastic modulus,and hardness), FTIR, DSC,and thermal conductivity of prepared nano and micro composites using two methodes and the morphological properties of nano-micro composites. Findings: The tensile strength of the LDPE/CB nano and micro composites improved at 2% and 4%, respectively, and decreasing at 8%, addition of carbon black nanoparticles led to increase the tensile strength of pure low-density polyethylene from 13.536 MPa to 19.71 MPa, and then dropping to 11.03 MPa at 8% percent,while the elastic modulus of LDPE/ CB nano and miro composites shows an improvement with all percentages of CB. The results show that the mechanical properties were improved by the addition carbon black nanoparticles more than addition micro- carbon black . FTIR show that physical interaction between LDPE and carbon black. The thermal conductivity improvement from 0.33 w/m.k for pur LDPE to 0.62234 w/m.k at 2% CB microparticle content and the reduced to 0.18645 w/m.k and 0.34063 w/m.k at (4 and 8)% micro-CB respectively , The thermal conductivity of LDPE-CB nano-composites is low in general than that the LDPE-CB microcomposite. DSC result show improvement in crystallization temperature Tc, melting temperature and degree of crystallization with addition nano and micro carbon black. Morever, SEM images revealed to uniform distribution and good bonding between LDPE and CB at low percentages and the precence of some agglomeration at high CB content.Research limitations/implications: This research studied the characteristics of both nano and micro composite materials prepared by two steps: mixing CB particles with solvent and then prepared by twin extruder which can be used packaging material, but the main limitation was the uniform distribution of nano and micro CB particles within the LDPE matrix. In a further study, prepare a blend from LDPE with other materials and improve the degradation of the blend that used in packaging application. Originality/value: LDPE with nanocomposites are of great interest because of their thermal stability, increased mechanical strength, stiffness, and low gas permeability, among other properties that have made them ideal for applications in the packaging and automotive industries. LDPE reinforcements nano-sized carbon black can have better mechanical and thermal properties than micron, resulting in less material being needed for a given application at a lower cost.

Comprehensive Characterization of Polymeric Composites Reinforced with Silica Microparticles Using Leftover Materials of Fused Filament Fabrication 3D Printing.

Silica exhibits properties such that its addition into polymeric materials can result in an enhanced overall quality and improved characteristics and as a result silica has been widely used as a filler material for improving the rheological properties of polymeric materials. The usage of polymers in three-dimensional printing technology has grown exponentially, which has increased the amount of waste produced during this process. Several polymers, such as polypropylene (PP), polyvinyl alcohol (PVA), polylactic acid (PLA), and nylon, are applied in this emerging technology. In this study, the effect of the addition of silica as a filler on the mechanical, thermal, and bulk density properties of the composites prepared from the aforementioned polymeric waste was studied. In addition, the morphology of the composite materials was characterized via scanning electron microscopy. The composite samples were prepared with various silica concentrations using a twin extruder followed by hot compression. Generally, the addition of silica increased the tensile strength of the polymers. For instance, the tensile strength of PVA with 5 wt% filler increased by 76 MPa, whereas those of PP and PLA with 10 wt% filler increased by 7.15 and 121.03 MPa, respectively. The crystallinity of the prepared composite samples ranged from 14% to 35%, which is expected in a composite system. Morphological analysis revealed the random dispersion of silica particles and agglomerate formation at high silica concentrations. The bulk density of the samples decreased with increased amount of filler addition. The addition of silica influenced the changes in the characteristics of the polymeric materials. Furthermore, the properties presented in this study can be used to further study the engineering design, transportation, and production processes, promoting the recycling and reuse of such waste in the same technology with the desired properties.

Cellulose‐Reinforced Starch Biocomposite: Optimization of the Effects of Filler and Various Plasticizers using Design–Expert Method

AbstractIn this study, the effect of cellulose as a reinforcement agent and different ratio of glycerol/sorbitol as plasticizers to improve properties in starch biocomposite are optimized with Design–Expert method for the first time. Thermoplastic starch granule is produced with plasticized and cellulose‐reinforced starch by a twin extruder. After conditioning, the starch granule, is molded into sheet using a hot press with thick plates. Dynamic mechanical thermal analysis show that cellulose increases the glass transition temperature to 120 °C. Optimum point of the starch composite obtained by Design–Expert software 7.1.5, is run with 5 wt% cellulose, 17.5 wt% glycerol and 17.5wt% sorbitol that has water vapor permeability value equally of 7.81E‐10g s−1 m−1 Pa−1, tensile strength of 0.85 MPa, Young´s modulus equally of 377.65 MPa, and elongation at break of 7.08%. Field emission scanning electron microscopy of the optimized biocomposite shows uniform distribution of cellulose in the matrix. Hydroxyl stretching vibrations at 3286 cm−1 is a result of new hydrogen bonding between cellulose and starch molecules and peaks at 3366 and 1702 cm−1 are attributed to glycerol and sorbitol, respectively in the Fourier transform infrared spectra.

Morphology and properties of polybutylene succinic and cassava starch blend: Effect of esterification catalysts on graft copolymer formation

AbstractThe purpose of this research is to produce of esterified thermoplastic starch (ETPS) for reactive extrusion melt‐blending with polybutylene succinate (PBS) in film blowing application. Esterification TPS named M‐TPS and T‐TPS were prepared from cassava starch, glycerol (plasticizer), and maleic anhydride (MA), tartaric acid (TA) as reactive compatibilizers in a twin extruder, respectively. FTIR results showed that esterification reactions were successfully formed between both MA and TA with cassava starch. The esterified TPSs was then melt blended with PBS in the presence of four kinds of esterification catalysts. The effect of compatibilizer contents on the blend properties was studied in terms of tensile properties, melt flow index (MFI), and electron scanning microscopy (SEM). The results show that TA induced better compatibilization effect than MA did, as evidenced by the PBS/T‐TPS blend possessing higher strength than these of PBS/M‐TPS, although SEM images showed structural morphology of both blends is similar. The effect of the esterification catalyst type and contents on properties of the PBS/T‐TPS blend was also studied. The results from the Molau test confirmed the formation of graft‐copolymer (PBSgT‐TPS) at the interface of two phases of the blend when compatibilizers were added in the presence of an organotin compound catalyst.

High‐temperature stabilization of polypropylene using hindered phenol–thioester stabilizer combinations, Part 1: Optimization and efficacy via nondust blends

AbstractThe thermal degradation of unstabilized polypropylene has been investigated under long‐term processing (twin extruder) and thermal aging at 150°C, with additive concentration studies on combinations of an established hindered phenolic antioxidant (pentaerythritol tetrakis (3‐(3,5‐di‐tert‐butyl‐4‐hydroxyphenyl) propionate) [S1010] and two popular thioesters (distearyl‐3,3′‐thiodipropionate [DSTDP] and didodecyl‐3,3′‐thiodipropionate [DLTDP]) using melt flow rate, carbonyl index and powder diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) (FTIR), and differential scanning calorimetry (DSC) (oxidation induction time [OIT]) and ultimate embrittlement time (Fracture) on injection‐molded test pieces. It was found that 20:80 phenol:thioester ratios provided the best long‐term thermal stability (LTTS); however, this was the reverse for processing stabilization (80:20), underlining the antioxidant nature of the two stabilizers (long term vs. melt). Melt preblending of the stabilizers (to form a no‐dust blend) gave rise to improved LTTS. DRIFTS FTIR indicated that there was an improvement in preblending the additives, which removed any volatile impurities. Increased additive dispersion and localized potential efficacy in the stabilization cycle is important, as well as possible improved addition of the additives to the extruder rather than fine powder. The data are discussed in relation to the long‐term stabilization of polypropylene in high‐temperature applications such as under the bonnet of automobiles where minimizing stabilizer losses and maximizing synergy are important.

Characteristic of polypropylene nanocomposite material reinforcement with hydroxyapatite for bone replacement

Purpose: Human bone suffered some degeneration due to age and accidents; therefore, there are many interests in the prepared synthetic bone with properties nearer to natural bone. The present study prepared a nanocomposite of polypropylene reinforced with different weight fraction of Nano hydroxyapatite (HAp) to be used as a bone replacement with good biological properties that enhanced the growth of osteoplastic cells and enhance the prevention of clots and coagulates creation. Design/methodology/approach: Nanocomposite from polypropylene reinforced with different weight fraction of Hydroxyapatite (HAp) (1,2 and 3) % prepared by first dispersion Nano hydroxyapatite insolvent and then mixing with a pellet of polypropylene by the twinscrew extrusion process, the current research study the surface properties ( atomic force microscopy (AFM), contact angle test) Moreover, it studied the characteristics of prepared nanocomposite materials (Differential Scanning Calorimetry (DSC), Field Emission-Scanning Electron Microscopy (FE-SEM) and Fourier Transform Infrared (FTIR)). Findings: The AFM results show the surface roughness decreased with increasing content of HAp, which diminished the chance of creation clots and coagulates on it. The contact angle results referred to polypropylene behaviour transformed from hydrophobic to hydrophilic with addition HAp that permission to grow the osteoplastic cell on it, so the healing process is accelerated. Moreover, the FE-SEM images revealed uniform distribution and good bonding between polypropylene and Hydroxyapatite. The thermal properties were measured by the DSC test showed the melting temperature, and the enthalpy of melting (indicated to increase the crystalline structure per cent) are increased with increasing the percentage of Hydroxyapatite. Research limitations/implications: This research studied the characteristics of nanocomposite materials prepared by three steps (dispersion by ultrasonic device, manually mixed and melting and mixing by twin extruder) which can be used as a bone replacement. However, the main limitation was the uniform distribution of nano-hydroxyapatite within the matrix. In a further study, the cytotoxic test can be tested to study the effect of prepared nanocomposite on living cells’ growth. Practical implications: The interest object is how to connect among different properties to prepared bone replacement with good properties and biocompatibility that made able to stimulate the growth and healing process. Originality/value: The nano-hydroxyapatite is a biomaterial that has a composition similar to the natural mineral phase of the bone and does not have any negative effect, which enhanced the growth of osteoplastic cells and decreased the clots and coagulates creation; therefore, nano-hydroxyapatite is used to decrease the surface roughness which decreased the chance of coagulation creation and to enhance the hydrophilic properties.

3D Printing PLA Waste to Produce Ceramic Based Particulate Reinforced Composite Using Abundant Silica-Sand: Mechanical Properties Characterization.

Due to the significant properties of silica, thermostatics can be enhanced using silica-additives to maximize the quality of polymer compounds and transform plastics into tailored properties. The silica additives can enhance the handling and quality performance of composites and thermoplastic polymers due to their diverse potential. Besides, using silica as an additive in different characteristics can allow granulates and powders to flow easily, minimize caking, and control rheology. On the other hand, the eruption of 3D printing technology has led to a massive new waste source of plastics, especially the polylactic acid (PLA) that is associated with the fused deposition modeling (FDM) process. In this paper, the impact on the mechanical properties when silica is mixed with waste PLA from 3D printing was studied. The PLA/silica mixtures were prepared using different blends through twin extruders and a Universal Testing Machine was used for the mechanical characterization. The result indicated that increasing silica composition resulted in the increase of the tensile strength to 121.03 MPa at 10 wt%. Similar trends were also observed for the toughness, ductility, and the yield stress values of the PLA/silica blends at 10 wt%, which corresponds to the increased mechanical property of the composite material reinforced by the silica particles. Improvement in the mechanical properties of the developed composite material promotes the effective recycling of PLA from applications such as 3D printing and the potential of reusing it in the same application.

Enhancement of tribological properties and characteristic of polymer matrix composite (UHMWPE reinforced with short fibres of polyester) for Total Disc Replacement (TDR)

Purpose: The number of people suffering from Degenerative Disc Disease (DDD) is increasing. The disease causes heavy pain and restrict a number of day-to-day life activities. In extreme cases, the degraded disc is removed under total disc replacement which is usually made up of Ultra-High Molecular Weight Polyethylene (UHMWPE). The material has astounding biocompatible characteristics mechanical properties and wear resistance. However, these characteristics are insufficient in arthroplasty application. Therefore, research investigations are ongoing to improve tribological properties through reinforcement that may result in a composite material of UHMWPE. Thus the current study is aimed at reinforcing UHMWPE with short fibres of polyesters to enhance the tribological properties and surface characteristic so as to improve wear resistance and nourish the fibroblast cells on synthetic disc. Design/methodology/approach: The researcher prepared UHMWPE composite material, reinforced with different weight fractions of short polyester fibres (2, 4, 6, 8 and 10% following hot press method. Further pin-on-disc device was used to study the tribological properties (coefficient of friction and volume of wear). The study tested surface roughness and surface characteristics by atomic force microscopy (AFM) device, hardness by shore D device, contact angle to study the effect of polyester short fibres on wettability of UHMWPE surface and tested the thermal properties and crystalline degree using Differential Scanning Calorimetry measurement (DSC) device. Findings: The results infer that the wear resistance got improved when using 2% w.t polyester though it got decreased initially. However, the value was still more than neat UHMWPE. There was a decrease observed in coefficient of friction, but after 4 w.t% polyester, the coefficient of friction got increased due to increasing percentage of fibres which make it harder and stiff compared to UHMWPE. There was a decline observed in surface roughness due to alignment of the fibres with smooth surface. The contact angle got increased in a moderate range while the roughness enhanced the growth of fibroblast cell. The hardness of composite material got increased, because the fibres turned stiffer and harder than the matrix. DSC results infer the improvements in thermal stability due to high thermal properties of polyester fibres compared to UHMWPE. The degree of crystallinity got increased which in turn enhanced wear resistance, especially at 6 w.t % polyester fibres. There was a mild increase observed in density since the density of polyester is higher than polymer. Research limitations/implications: The major challenge was the dispersion of fibres. Uniform distribution of fibres within the matrix (UHMWPE) was achieved through two steps of mixing processes such as mechanical mixture and twin extruder. In future studies, fatigue tests must be conducted to study the behaviour of prepared composite materials under fatigue cycle. Practical implications: A significant objective is how to connect among different properties to obtain good improvement in tribological and surface properties so as to enhance wear resistance and growth of fibrolase cells. Originality/value: In this study, polymeric short fibres were used as reinforcement with polymeric matrix to enhance the wettability of fibres with matrix. In this way, the bonding among them got increased which supports the tribological, surface, and crystalline behaviour.

Tensile Mechanical Behavior and Bioactivity of PLA/PCL Biopolyester Threads for Suture

AbstractIn this paper the mechanical tensile static test of threads both in o‐knot of blends made by two biopolyesters, polylactic acid (PLA) and poly(ɛ‐caprolactone) (PCL), compatibilized with a triisocyanate (T) in a low amount (1 phr, per hundred resin), and high amount, 5 phr, is performed. The highest mechanical strength of the PLA/PCL/T threads is of about 30 MPa. PLA, PCL, and T are mixed in a twin extruder and the resulting blend is spinnable by a melt spinning process in order to produce thin threads of about 0.3 mm diameter. Compatibilizing filler improves the mechanical performance of the PLA/PCL blend for the chemical branching and/or cross‐linking reactions induced among the two typically immiscible biopolyesters. Chemical reactions link PLA with PCL, whose macromolecular structure complexity grows with the filler load. Blended biopolymers can be considered promising biomaterials because they seem to be bioactive and able to inhibit bacterial growth.