Impact Strength Values Research Articles

Pengaruh Media Pendingin Proses Laku Panas Terhadap Persebaran Butir Ferrite dan ketangguhan Mild Steel AISI 1020

This research aims to determine the toughness properties and microstructure of AISI 1020 steel material which was previously treated by using a variety of cooling media including air cooling, oil cooling and grease cooling. After being cooled by using several cooling media, it was continued with impact and microstructure testing. The results showed that AISI 1020 steel specimens using air cooling media, had the average impact strength value of 19.1 joules/mm, while those using oil cooling media had an average impact strength of 35.2 joules/mm, and those using grease cooling media had an impact strength of 45 joules/mm. From this data, the one with the highest impact strength value was the grease cooling media at 45 joules/mm and the one with the lowest impact strength was the air cooling media, namely 19.1 joules/mm. The results of metallographic observations were obtained when the grease media was used, the distribution of ferrite was reduced and did not have time to form, whereas in steel that was cooled with oil, the distribution of ferrite was almost the same as the untreated material and for air media, the shape of the ferrite structure spread and formed evenly.

Evaluation of flexural strength, impact strength, and surface microhardness of self-cured acrylic resin reinforced with silver-doped carbon nanotubes

BackgroundPoly-methyl methacrylate (PMMA) is a type of polymer mostly used to make denture bases. Self-cured acrylic resin (PMMA) can be used to repair a fractured acrylic denture base; however, even after repair, this area remains vulnerable. Carbon nanotubes (CNTs) could be used as a filler for polymer reinforcement. Furthermore, silver nanoparticles are efficient agents for the prevention of dental biofilm and improving their mechanical properties. The doping of CNTs with silver nanoparticles may lead to a synergistic interaction that is predicted to enhance the mechanical characteristics of the fillers.ObjectivesThe aim of the study was to assess the influnce of manual incorporation of 0.5% weight percent (%wt.) of silver doped carbon nanotubes (Ag-doped CNTs) into commercial self-cured PMMA on its flexural strength, impact strength, and surface microhardness.MethodsIn this investigation, a total of 60 specimens comprised of acrylic resin were employed. They are divided into two main groups: (a) the control group, which was made by using liquid monomer and commercial self-cured PMMA powder; and (b) the modified group, prepared by hand mixing the purchased silver-doped CNTs powder (0.5% wt.) to self-cured PMMA powder (99.5%wt.), and then the blended powder was incorporated into the liquid monomer. Flexural strength, flexural modulus, impact strength, and surface microhardness were evaluated. Independent sample t-tests were used to statistically analyze the data and compare the mean values of flexural strength, flexural modulus, impact strength, and surface microhardness (p-value ≤ 0.05).ResultsThe flexural strength of the modified groups with Ag-doped CNTs (132.4 MPa) was significantly greater than that of the unmodified (control) groups (63.2 MPa). Moreover, the flexural modulus of the modified groups with Ag-doped CNTs (3.067 GPa) was significantly greater than that of the control groups (1.47 GPa). Furthermore, the impact strength of the modified groups with Ag-doped CNTs (11.2 kJ/mm2) was significantly greater than that of the control groups (2.3 kJ/mm2). Furthermore, the microhardness of the modified groups with Ag-doped CNTs (29.7 VHN) was significantly greater than that of the control groups (16.4 VHN), (p-value = 0.0001).ConclusionThe incorporation of 0.5% wt. silver doped CNTs fillers to the self-cured acrylic resin enhanced its flexural strength, flexural modulus, impact strength, and surface microhardness.

Effect of Incorporation of Poly Vinyl Pyrrolidone on Transverse Strength, Impact Strength and Surface Roughness of Autopolymerizing Acrylic Resin

Autopolymerizing acrylic resin is one of the most frequently used materials in dentistry, but it has relatively poor mechanical properties This study investigated the effect of the addition of poly vinyl pyrrolidone on transverse strength, impact strength and surface roughness of autopolymerzing acrylic resin. A total of 60 specimens were prepared, 30 specimens of each conventional and modified autoplymerizing acrylic.20 specimens of each groups were fabricated with dimensions of (64×10×2.5) mm to conduct the transverse strength and surface roughness tests, while the remaining 10 specimens of each group were fabricated with dimensions of (80×10×4) mm to perform the impact strength test. The results of this study showed that the modified autopolytmerized acrylic had significantly higher transverse strength, and significantly lower surface roughness values while there was no significant differences in impact strength value. It can be concluded that addition of Polyvinylpyrrolidone can improve transverse strength and surface roughness of autopolymerizing acrylic resin.

Study of antibacterial and mechanical properties of poly(methyl methacrylate‐co‐acrylic acid)/hydroxyapatite biocomposite by using artificial neural network approach

AbstractA novel, promising biocomposite was synthesized through the free radical polymerization method using methyl methacrylate (MMA), acrylic acid (AA), and hydroxyapatite derived from oyster shells (Os‐HA). Fourier transform infrared spectroscopy (FTIR) peaks indicate the conjugation of Os‐HA in the biocomposite. From the TGA analysis, it was observed that a weight loss of nearly 2% is achieved at 210°C, up to 15% at 210 to 420°C, and up to 95% at 420 to 580°C. The SEM image shows the uniform dispersion of the Os‐HA particles and strong interaction with the copolymer matrix. The broad spectrum at 2θ = 14.6° in XRD analysis indicates the amorphous nature of poly(MMA‐co‐AA)/Os‐HA. The higher inhibition zone of the biocomposite is observed at 125 μL against E. coli bacteria. The maximum water absorption is observed at 15 wt% of Os‐HA. The young's modulus gradually increases, while the impact strength decreases up to 20 wt% of Os‐HA. The artificial neural network (ANN) model has been used to assess the optimum values of impact strength, tensile strength, and Young's modulus of the biocomposite material. The correlation factor (R = 0.998) of the ANN model data indicates greater accuracy of the experimental result.

Effect of Nystatin Coated Copper Oxide (CuO) Particles on Mechanical, Thermal, and Antifungal Properties of Polymethyl Methacrylate (PMMA)–Based Denture Materials

Polymethyl methacrylate (PMMA) has garnered significant attention in the field of dentistry due to its wide applications. This paper proposes the incorporation of the nystatin coated copper oxide (CuO) particles having desirable conductivity and antifungal properties, as a filler in the PMMA denture to address their low thermal conductivity, low impact strength, low fatigue resistance, and microbial adhesion. The prepared nystatin coated CuO particles were characterized with several analytical techniques. The nystatin coated CuO particles were mixed in different ratios (0%, 1%, 2%, and 4%) in PMMA corresponding to groups C, E1, E2, and E3, respectively. The prepared samples of composite PMMA with nystatin coated CuO were evaluated to determine their transverse strength, impact strength, Vickers hardness (HV), and thermal conductivity. Furthermore, antifungal properties of CuO particles, nystatin coated CuO particles, and their acrylic composites were evaluated against Candida albicans. Scanning electron microscopy (SEM) analysis confirmed the particles’ spherical and irregular shapes. The particle sizes range from nano to micron level. Fourier‐transform infrared spectroscopy (FTIR) and energy dispersive X‐ray spectroscopy (EDX) analysis confirmed the coating of nystatin on CuO. X‐ray diffraction (XRD) analysis showed the diffraction patterns and planes of CuO monoclinic shape structure. The composite prepared to have higher values of HV (19.53 ± 0.65, 20.16 ± 0.37, and 21.11 ± 0.75, respectively) as compared to the control. The impact strength values were measured high at 14.12 ± 5.55 kJ/m2 for 2% containing nystatin coated CuO acrylic resins compared to control and other groups. The conductivity increased linearly with the addition of CuO particles. The addition of CuO particles causes a reduction in flexural strength as compared to the control group. As the concentration of nystatin coated CuO (1%, 2%, and 4%) in acrylic samples increased, the antifungal properties were improved. Thus, the incorporation of optimized concentrations of nystatin coated CuO particles in acrylic resin resulted in the improved mechanical, thermal, and antifungal properties.

Исследование превращений переохлажденного аустенита при ступенчатой закалке стали 20Cr2Mn2SiNiMo

Currently, step quenching of steels in the temperature range of martensitic transformation, including quenching – partitioning, has found wide application in the automotive industry. Step quenching technology is successfully used to increase a set of properties, which most often include temporary tensile strength and relative elongation. The authors carried out a dilatometric study of the supercooled austenite transformations occurring in the 20Cr2Mn2SiNiMo steel, when implementing various options of step quenching with holding in the martensitic region. It was found that after single-stage quenching, single-stage quenching followed by tempering, and two-stage quenching, primary martensite, isothermal bainite, and secondary martensite are formed in various quantitative ratios. Using X-ray diffraction phase analysis, the amount of residual austenite was determined during step quenching. It has been shown that two-stage quenching makes it possible to stabilise up to 14 % of residual austenite, in the structure of the studied steel, at room temperature. Research has revealed that 20Cr2Mn2SiNiMo steel is characterised by a decrease in the crystal lattice parameter of the residual austenite, with an increase in its content in the steel structure. Uniaxial tensile and impact bending tests were carried out, and the values of the mechanical properties were determined. It has been found that during two-stage quenching, higher strength and elongation values, with lower values of relative contraction and impact strength are achieved compared to oil quenching and low-temperature tempering. The study showed that, with regard to the structural reliability of machine-building parts, step quenching is not the optimal heat treatment mode for the steel under study. The best combination of strength, ductility and impact hardness is achieved after quenching and low-temperature tempering.

Fabrication of animal shell and sugarcane bagasse particulate hybrid reinforced epoxy composites for structural applications

This study investigated the effects of using egg and snail shells, along with sugarcane bagasse, on various properties of hybrid reinforced epoxy composites for structural applications. The particulate shells and sugarcane bagasse serve as reinforcements while the matrix consists of epoxy resin and hardener. The composites were produced using the hand lay-up technique, and the mechanical, wear and physical properties of the prepared samples were evaluated. The fractured surfaces of the samples were examined using a scanning electron microscope. The results revealed that the source of the shell had an impact on the properties of the composites as eggshell-sugarcane bagasse particulate reinforced epoxy composites exhibited improved strengths, while snail shell-sugarcane bagasse particulate reinforced epoxy composites showed improved moduli. Optimal values were obtained for flexural and tensile strengths at 15 and 18 wt%, respectively, while flexural and tensile moduli were optimal at 12 and 15 wt%, respectively. Eggshell-sugarcane bagasse particulate reinforced epoxy composites demonstrated an optimal impact strength value of 21.81 J/m2, while snail shell-sugarcane bagasse particulate reinforced epoxy composites showed optimal results in all other properties mostly at 20 wt%. Conclusively, the use of snail shell-sugarcane bagasse particles was found to be more effective than eggshell-sugarcane bagasse particles for enhancing the properties of epoxy-based composites for structural applications while particulate reinforcement content within the range of 12–20 wt% are responsible for optimum performances.

Experimental Investigation of Effects of Manganese IV Oxide on the Mechanical Properties of Aluminium Alloy.

Aluminium and its alloys have proven to be highly valuable for a variety of technical applications due to its superior strength-to-weight ratio and exceptional corrosion resistance. As a result, there are numerous financial and environmental advantages to recycling it. The goal of this work is to significantly expand the engineering uses of recycled aluminium alloy by improving its mechanical characteristics by treatment with of MnO2. 30 kg of recyclable scrap aluminium alloy was initially acquired for the investigation in the form of ingots. Then, 5 kg of each was re-melted in three distinct samples. The first sample was re-melted and then left to cool naturally without any further intervention. 24g of dark powder from a dry cell thrown away was applied to the second sample, and 24g of MnO2 was applied to the third. Every sample underwent standard cooling procedures. The samples were then subjected to impact, tensile, and hardness testing by ASTM E8M-91 standard test protocols. The three samples were also subjected to XRD analysis. The sample treated with MnO2 had the highest hardness value, measuring 124 HV; the sample treated with powder from a discarded battery came in second, with 108.33 HV. With 99.30 HV, the control sample had the lowest value. The control sample had the highest UTS value of 92.74 MPa, the MnO2-treated sample had a UTS value of 68.23 MPa, and the sample treated with discarded battery powder had the lowest UTS value of 30.71 MPa. The control sample had the maximum impact strength value of 12.20 Joules, the discarded battery powder treated sample had an impact strength value of 11.96 Joules, and the MnO2-treated sample had an impact strength value of 11.32 Joules. The results of the study show that the recycled aluminium alloy becomes harder when MnO2 is added. Nevertheless, the inclusion of MnO2 shows a notable decline in the UTS of recycled aluminium alloy as well as a minor decrease in its impact strength.

НАПОЛНЕННЫЕ ПОЛИМЕР-ОЛИГОМЕРНЫЕ МАТЕРИАЛЫ С ПОВЫШЕННЫМ СОПРОТИВЛЕНИЕМ УДАРНЫМ НАГРУЗКАМ. ЧАСТЬ 1

The effect of dissolved PVC in ED-20 epoxy resin is shown, containing magnesium hydroxosilicate as a filler, as a form of formation of a curable material. The values of impact strength, strength and elastic modulus are estimated depending on the amount of dissolved polymer. Microwave radiation is used to intensify the dissolution of PVC. The possibility of dissolving PVC in epoxy is shown. It is clear that a solution of PVC in the mass of epoxide is able to form a spatially cross-linked polymer structure that changes the final properties of the material.

Preparation of rigidity toughness balance and stable poly(glycolic acid) based on chain extension reaction

AbstractAs a completely degradable material, poly(glycolic acid) (PGA) has excellent rigidity, barrier properties, degradability and biocompatibility. However, the inherent brittleness and easily hydrolysable characteristics limit its widespread application. Herein, we introduced chain extension ADR to modify PGA to ameliorate these defects. The results showed that ADR could react with PGA to form “comb‐like” and “cross‐linked” chain extension structures resulting in the improvement of complex viscosity and formation of gel. Because of the chain entanglement of chain extension structures, the toughness of modified PGA was improved (which was verified by the impact strength value of 4.3 kJ/m2 that was about 126% of virgin PGA) without sacrificing its rigidity. Furthermore, the hydrolysis results indicated that the representative PGA/1.0ADR had better hydrolysis stability, it had more complete morphology and slower degradation rate than virgin PGA in the 17‐day hydrolysis experiment. Apart from better toughness and hydrolysis stability, there was also improvements in crystallization performance, the sample PGA/1.0ADR endowed with higher crystallization peak temperature (2.3°C higher than virgin PGA) and lower crystallization activation energy. In short, this work prepared a kind of modified PGA with rigidity toughness balance and better hydrolysis stability, which could expand the application range of PGA‐based materials.

Improved Mechanical Properties of Basalt and Glass Fibre Reinforced Polymer Composite by Incorporating Nano Silica

Granite waste that increasingly accumulates yearly is significant with granite industry growth. This research aims to use nano silica extracted from granite dust to identify the effect of nano silica on the mechanical properties of Basalt and Glass Fibre Reinforced Polymer Composite. The approach encompassed three distinct weight percentages of nano silica, specifically 1 wt%, 3 wt%, and 5 wt%, seamlessly blended into a polyester resin matrix. The evaluation of composite mechanical attributes was conducted through compression and Izod impact tests by following ASTM D3410 and ASTM D256. Remarkably, the pinnacle of this enhancement materialises at the 1 wt% threshold,signifying the impact strength and compression strength values. Beyond this point, a decline was observed, underscoring the critical importance of judicious weight percentage selection. This novel composite configuration holds promising implications, particularly for components within container trucks, where the fusion of exceptional impact and compression strength is paramount.

Evaluation of Impact Strength and Flexural Strength of Polyether Ether Ketone vs. Computer-Aided Design/Computer-Aided Manufacturing Polymethyl Methacrylate Denture Base Materials: An In-Vitro Study.

The objective is to comparatively assess the impact strength and flexural strength of polyether ether ketone (PEEK) vs. computer-aided design/computer-aided manufacturing (CAD/CAM) polymethyl methacrylate denture base material. A total of 90 samples were fabricated with traditional heat cure PMMA, PEEK, and CAD/CAM PMMA and divided into three groups of 30 samples each.The impact strength of all the samples was measured using an Izod impact tester with a pendulum in the air at 23±2°C. A three-point bending test was used in a Universal Testing Machine to assess the flexural strength of all the samples. The impact strength and flexural strength mean values were computed using a one-way ANOVA test. Impact strength and flexural strength of PEEK (IS=10.22±1.25 kJ/m2 and FS=120±8.0 MPa) is almost identical to CAD/CAM PMMA sample (IS=9.595±3.313 kJ/m2 and FS=118.11±5.00 MPa) whereas for conventional heat cure PMMA (IS=4.00±.011 kJ/m2 and FS=75.4±4.50 MPa) the values are least among the three. PEEK or CAD/CAM PMMA share almost identical and superior mechanical properties, and both can be used as better alternatives for complete denture fabrication rather than using conventional heat cure PMMA.

Study of Tensile and Impact Properties for 0<sup>0</sup> and 45<sup>0</sup> Fiber Directional Orientation of Polyester Resin Composites with Woven Ramie Reinforced

The current technological need is the use of eco-friendly and biodegradable composites. It seeks to increase the use of natural resources to engineer composite materials to be better than before. This study aims to analyze the effect of ramie fiber orientation for ramie composites (in this study 450 and 00) on tensile strength and impact strength and find the best orientation angle with higher power and impact value than the other fiber angles on ramie composite. The fiber used in this study was ramie fiber, and the matrix used was Yukalac 157 BQTN-EX polyester resin. This research method uses the experimental process of conducting experiments and testing. The results showed that the 00 angle direction composite achieved the highest average tensile strength value of 54.3 N/mm2, and the impact strength showed the highest average impact strength value of 0.0168 J/mm2, performed by the 00 composites.

An In Vitro Study Comparing the Impact and Flexural Strength of Leucitone 199 Denture Base Resin and Conventional Denture Base Resin Enhanced With Glass Fibre Mesh and Polyethylene Fibre Mesh.

Purpose The purpose of this in vitro study was to compare and evaluate the impact and flexural strength of conventional denture base resin reinforced with glass fiber mesh and polyethylene fiber mesh with Leucitone 199 denture base resin (Dentsply Sirona, Charlotte, USA). Leucitone is an expensive denture base material. To come up with a cheaper solution for reinforced denture base resin with superior impactand flexural strength was the goal of this study Material and methods The specimens (maxillary denture bases) were fabricated using a standard polyvinylsiloxane mold with conventional heat-cured polymethyl methacrylate resin (ISO 1567:1999). The specimens were divided into three groups (n = 10). Group I specimens, or the control group, were pre-reinforced Leucitone 199. Group II and Group IIIspecimens were reinforced with 3% by weight of glass fibers and polyethylene fibers in weave form, respectively. All the specimens were immersed in water for 1 week before testing. The impact strength was measured with a falling weight impact testing machine. One-way analysis of variance and Tukey's post hoc test were used for statistical analysis. The flexural strength was measured with the three-point bending test in a universal testing machine. Results The highest impact strength values were exhibited by the Leucitone 199 group, followed by the polyethylene fiber mesh group, followed by the glass fibers mesh group. The highest flexural strength was seen in the Leucitone 199 group, followed by the glass fiber mesh group. The least flexural strength was seen in the polyethylene fiber mesh-reinforced group. Conclusion Reinforcement of maxillary complete dentures showed a significant increase in impact strength and flexural strength, but not in comparison to pre-reinforced Leucitone 199 dentures. By using pre-impregnated glass and polyethylene fibers in woven form (prepregs), the impact strength of the denture bases can be increased effectively.

High‐Impact PLA in Compatibilized PLA/PCL Blends: Optimization of Blend Composition and Type and Content of Compatibilizer

AbstractIn this work, the effectiveness of seven commercial compatibilizers is tested in polylactide (PLA)/poly(ε‐caprolactone) (PCL) blends with different compositions to obtain a high‐impact PLA. None of the compatibilizers is effective for 90/10 and 80/20 PLA/PCL compositions, as no improvement of the impact strength is observed. For the 70/30 composition, compatibilizers having glycidyl methacrylate (GMA) and acrylate groups in their structure are proved the most effective, as the morphological change towards co‐continuity induced by them leads to significant impact strength improvements (of ≈345% and 90% with respect to the neat PLA and the noncompatibilized PLA/PCL 70/30 blend, respectively). The 70/30 PLA/PCL composition, as it shows the best balance of properties, and the best compatibilizer (ElvaloyPTW) are chosen to carry out the optimization of the compatibilizer content. It is found that adding 6 phr to the blend results in highly toughened and ductile blends while maintaining a high modulus and yield strength values. Larger compatibilizer contents lead to even higher impact strength values, but the low‐strain mechanical properties are notably reduced. Thus, in this work, a simple and easily scalable method to produce high‐impact PLA is shown, as it implies the compounding of three commercially available components without involving any toxic solvents.

Comparative Study of Mechanical and Physical Properties of Rice Husk Filled Polyethylene Waste Composites

Polyethylene (PE), a type of plastic, is utilized extensively in many different applications and has become a significant part of our daily life. However, numerous plastic product manufactures have a significant environmental impact. As a result, several approaches have been investigated in order to reduce waste disposal issues. Rice husk (RH), on the other hand, is a form of agricultural waste that contains lignocellulosic fiber that can be used as a filler in polymer composites. As a result, combining both PE waste and RH fiber could be a viable option for saving our world. The objective of this study was to ascertain the impact of different RH fiber loadings, including 5, 10, 15, 20, and 25 %, on the mechanical and physical characteristics of composites manufactured from used HDPE and LDPE materials. Due to inadequate bonding between the hydrophilic fiber and the hydrophobic polymer matrix, it was discovered that increasing the filler loading lowered the tensile strength, elongation at break, and impact strength of the composites. In comparison to RH/HDPE, the tensile strength of RH/LDPE composites showed a greater decline at 45 % at the highest loading of 25 % RH fiber. Both composites showed a 98–99 % decrease in elongation at break as a result of constrained chain elongation and mobility. Additionally, the impact strength value of RH/HDPE waste composites decreased by 43 % compared to 31 % for RH/LDPE waste composites. In contrast, the inclusion of fillers improved the modulus and density of the composites substantially. While the trends for RH/HDPE and RH/LDPE composites are similar, RH/HDPE waste composites demonstrated superior mechanical characteristics than RH/LDPE waste composites.

Feasibility of utilization of recycled HDPE in manhole covers for urban traffic areas and industrial zones

The consumption of plastic raw materials has been exponentially growing throughout the world in the last decade and so has, in the same proportion, their associated waste. Recycling through the mechanical treatment of the heavy fraction of these plastics is the most economic and the safest alternative to use this waste and to recirculate it for reuse within the same industry or for other related industries located near the place where the waste is generated. In this paper, a study of characterization and post-processing of recycled high density polyethylene received by a hazardous waste manager in southern Spain is presented, an area in which containers, Intermediate Bulk Containers, and drums, originally used for oil products from refineries and petrochemical industries nearby, are employed. These high density polyethylene materials are validated to meet the requirements of the harmonized standards to be used as self-supply in the production of manhole covers. EN 124–6:2015 standard allows the use of plastic materials such as PE or PP, even using material externally reprocessed, such as material derived from thermoplastic products that have not been previously used as lids or manhole covers. Class A-15 and B-125 of the standard are oriented for the construction of these types of elements to cover or close in certain urban spaces such as pedestrian areas, parking areas or multi-story car parks for vehicles. The study shows that the recycled material fully complies with the density; it keeps unalterable during fire test after application of the coating, there are no adverse effects on artificial ageing; the decrease of the average value of the tensile impact strength by 21.84%; and achieves 6 mm of maximum deflection against the test load Fp (45.3 MPa). Therefore, it can be considered a valid scenario for the effective use of solid plastic waste in products that make up part of the urban or industrial areas, as an example of complete circularity material and offers a valid alternative to the end-of-waste condition.

Mechanical and thermal properties of recycled polypropylene bamboo fibre-reinforced composites

<span lang="EN-US">In this article, a kind of green composite was prepared from recycled polypropylene (r-PP) which was further reinforced with various loadings of chemically modified bamboo fibres. Effects of bamboo fibre loading on the mechanical and thermal properties of r-PP/bamboo composites were studied. Those properties were characterized by tensile testing, impact testing, thermogravimetric analysis (TGA), and differential scanning calorimeter (DSC). Standardized test specimens with 0%, 10%, 20%, and 30% mass fractions of bamboo fibre were obtained by an extrusion process which was then finalized on injection molding. The experiment revealed the tensile strength and strain of the composite become greater with the increase of bamboo fraction in the ultimate value of 20% mass fraction. The composite with 10% bamboo fibre loading recorded the highest value of impact strength. Meanwhile, it was evident that the presence of bamboo fibre decreased the thermal stability of recycled polypropylene materials. Therefore, this composite material may find good potential for semi-structural loading applications in relatively low-exposure working.</span>

Improving the flame retardancy properties of PLA/PC blends

Polylactic acid/Polycarbonate (PLA/PC) blend was prepared via twin screw extruder by taking the bio-based content as much as possible and the better mechanical, thermal, and impact properties into consideration. Flame retardant (FR) performance of the PLA/PC blend was improved by using the mixture of ammonium polyphosphate, triphenyl phosphate, and zinc borate. FR properties of PLA/PC blend was evaluated according to the UL 94 test standard. The variations in tensile and flexural strength, and Izod-notched impact strength values were determined. In order to reduce the total amount of flame retardant additive, instead of using a mixture of TPP and APP (weight ratio of 2/1) at 21 wt% weight fraction, 1 wt% Zinc borate together with 18 wt% TPP-APP mixture was used and obtained V0 rating for the thickness of 1.5 mm. It was reported that weight fraction of flame retardant additives (APP and TPP) was successfully reduced by using a mixture of APP, TPP and ZnB without degrading the mechanical properties such as tensile and flexural strengths. Using less total FR additive weight (19 wt%) led to 15 and 24% higher tensile and flexural strength values, respectively, compared to higher FR additive weight (21 wt%).

The Characterization of Mechanical and Chemical Properties of Recycled Styrofoam Waste Employing Extrusion Process

<p><em>Styrofoam waste is a polystyrene plastic-based waste in the form of foam with low density. Scavengers or recyclers are not interested in receiving styrofoam waste because of its light density which makes it ineffective in transportation and storage. Styrofoam waste can actually be converted into solid polystyrene products through a thermal-extrusion process but data regarding the optimum operating temperature and the characteristics of the resulting solid polystyrene products are not yet available. The purpose of this study was to investigate the properties of solid polystyrene products resulting from recycled styrofoam waste and determine the optimum temperature of the thermal-extrusion treatment process to be compared with the characteristics of the original polystyrene based on the results of tensile and impact tests. In this study, the processing was carried out using the thermal-extrusion method; Styrofoam is melted and extruded into a mold to produce polystyrene solids. The research was carried out with variations in extrusion temperature at 180°C, 200°C, and 220°C. The polystyrene solids are then molded into tensile and impact test specimens by injection molding. The results showed that the optimal extrusion temperature was 200°C with tensile and impact strength values of 27.55 MPa and 1,069 j/m2, respectively. Compared to the original polystyrene, the tensile strength value is 25.3% lower and the impact strength value is 29.5% lower. The decrease in the tensile and impact strength values is due to the shortening of the molecular bonds in the recycled polystyrene during the thermal-extrusion treatment process. Even though the tensile strength and impact are still lower, the use of styrofoam waste using the thermal-extrusion method has the potential to be developed at the production and commercialization stage because the resulting product has good economic value and can also reduce the use of original polystyrene and at the same time can solve the problem of styrofoam waste.</em></p>