Izod Impact Resistance Research Articles

Evaluation of Temperature Influence on Tensile Strength and Izod Impact Resistance on Poly Methyl Methacrylate (PMMA)

The increasing use of poly methyl methacrylate (PMMA), often replacing tempered glass, is a consequence of its high rigidity, practicality, lightness and transparency. However, current manufacturing standards in the polymer industry recommend specific tests on these materials. The present study aims to mechanically test the properties of poly methyl methacrylate (PMMA) material under conditions that simulate a much more aggressive environment than usual. Infrared spectroscopy (FTIR), thermogravimetric (TG/DTG) tests, Izod impact tests, and scanning electron microscopy (SEM) analysis were performed. The results showed that poly (methyl methacrylate) (PMMA) maintained its tensile mechanical properties up to 105°C. Regarding the impact tenacity, the temperature negatively influenced the performance of this polymer.

Aluminum-Filled Amorphous-PET, a Composite Showing Simultaneous Increase in Modulus and Impact Resistance.

Metal-plastic composites have the potential to combine enhanced electrical and thermal conductivity with a lower density than a pure metal. The drawback has often been brittleness and low impact resistance caused by weak adhesion between the metal filler and the plastic. Based on our observation that aluminum foil sticks very strongly to poly(ethylene terephthalate) (PET) if it is used as a backing during compression moulding, this work set out to explore PET filled with a micro and a nano aluminum (Al) powder. In line with other composites using filler particles with low aspect-ratio, the tensile modulus increased somewhat with loading. However, unlike most particle composites, the strength did not decrease and most surprisingly, the Izod impact resistance increased, and in fact more than doubled with certain compositions. Thus, the Al particles acted as a toughening agent without decreasing the modulus and strength. This would be the first case where addition of a metal powder to a plastic increased the modulus and impact resistance simultaneously. The Al particles also acted as nucleating agents but it was not sufficient to make PET crystallize as fast as the injection moulding polyester, poly(butylene terephthalate) (PBT).

Impact resistance and failure mechanism of 3D printed continuous fiber-reinforced cellular composites

The present research investigated previously unexplored attributes of 3D printed continuous fiberglass reinforced Nylon composites, Drop-weight and pendulum (Charpy and Izod) impact resistance including their failure mechanisms with a view to assessing their suitability for prospective high-performance applications such as aerospace, automobile and building industries. The composites were printed with different cellular structures (triangular, hexagonal, rectangular and solid) and three distinct fiber orientations (0/0/0/0, 0/90/0/90 and 0/45/90/-45). Results of the impact assessment of the developed composites exhibited substantial performance when compared to traditional 3D orthogonal plain-woven composites indicating 3D printing process as a promising composite fabrication technology. The effect of fiber orientation was very dominant towards dictating mechanical properties; cross-lay samples (0/90/0/90) absorbed the highest Drop-weigh impact energy followed by quasi-isotropic (0/45/90/-45) and unidirectional (0/0/0/0) composites, while the highest pendulum impact energy was showed by unidirectional composites, followed by cross-lay and quasi-isotropic samples. Incorporation of cellular structure had some effect on the properties measured and composite weight reduction; however, relative contribution of different structures was confounding associating a lot of factors that warn further research.

Polyamidoamines based on castor oil‐styrene co‐oligomer/triethylenetetramine as curing agents in high‐performance epoxy coatings

AbstractPolyamidoamines (PAMAMs) based on castor oil‐styrene co‐oligomer and triethylenetetramine (TETA) or benzylated TETA were synthesized and diluted with an amide‐like diluent (EFA). The intermediates and products structures were characterized using FT‐IR, 1H NMR, gel permeation chromatography, and scanning electron microscopy. The diluted PAMAMs types were used as the curing agents of the epoxy resin to produce the modified coatings. The mechanical, chemical, and visual properties of the epoxy coatings obtained by commercial hardeners compared to the modified coatings. The modified coatings were transparent, and had humidity resistance higher than the commercial coatings, at 15°C and 80% relative humidity. The modified coatings were obtained with the lowest surface defects and improved mechanical properties such as Izod impact resistance, tensile strength, and the pull‐off adhesion (3.3–4.8 kJ m−2, 42.2–54.5 MPa and 3.0–3.5 MPa) relative to the commercial coatings (1.1–3.0 kJ m−2, 28.7–39.9 MPa and 1.4–2.1 MPa), respectively. Moreover, in spite of the commercial coatings, the modified coatings were cost‐effective and showed the behaviors of appropriate self‐healing and chemical resistance.

Izod impact energy study of re-forced polisher matrix compounds with curaous fibers aligned and epoxy matrix reinforced with piassava fibers

Polymer matrix composites have been applied in components such as helmets and shielding for which tough-ness is a major requirement. Natural fiber presents interfacial characteristics with polymeric matrices that favor a high impact energy absorption by the composite structure. The objective of this work was then to assess the Izod impact resistance of polymeric composites reinforced with different amounts, up to 30% in volume, of a promising high strength natural fiber from the Amazon region known as curaua. Among these, the piassava fiber extracted from a palm tree native of South America stands as one of the most rigid with a potential to be used as composite reinforcement. Therefore, the present work investigates the notch toughness behavior, by Izod impact tests, of epoxy composites reinforced with up to 40 % in volume of continuous and aligned piassava fibers.The results showed a remarkable increase in the notch toughness with the amount of incorporated curaua fibers. This can be attributed to a preferential debonding of the fiber/matrix interface, which contributes to an elevated absorbed energy. . It was found that the incorporation of piassava fibers results in significant increase in the impact energy of the composite. Scanning electron microscopy analysis showed that the nature of the piassava fiber interface with the epoxy matrix is the major responsible for the superior toughness of the composite. Keywords:Piassava, curaua, polymer matrix, epoxy matriz, Izod

Preparation and characterization of antistatic packaging for electronic components based on poly(lactic acid)/carbon black composites

ABSTRACTPoly(lactic acid) (PLA) is a biodegradable aliphatic polymer obtained from renewable sources; its main application is in the packaging sector. Electronic components require the use of antistatic packaging that prevents damage and electric shock. As PLA has no conductive characteristics, it requires the addition of allotropic carbon forms such as conductive carbon black to make the polymer less resistive as the dissipative material and making it suitable for the manufacture of antistatic packaging. In this study, PLA was melt blended with 5, 10, and 15 wt % of carbon black. The composites were prepared using a high‐speed mixer. Samples were characterized by Izod impact resistance tests, scanning electron microscopy, thermal properties, electrical characterization, and biodegradation tests in garden soil. The addition of carbon black in the PLA matrix increases the temperature of degradation and decreases the crystallinity degree and the impact resistance of the composites. However, carbon black is a great option to increase the electrical conductivity of PLA. The addition of carbon black in PLA makes the composite less resistive and suitable for use as antistatic packaging for the transportation and storage of electronic components. Furthermore, this composite does not cause damage to the environment as the carbon black does not interfere in the degradation mechanism of PLA. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47273.

Processing of a Green Fiber-Reinforced Composite of High-Performance Curaua Fiber in Polyester

Lignocellulosic fibers extracted from the curaua plant are among the strongest natural fibers used as polymer composite reinforcements for engineering applications. However, to date, such composites have been limited in terms of their mechanical strength and impact energy. The objective of the present work is to investigate the possibility of improving the tensile strength as well as impact energy of curaua fiber-reinforced polyester composites by varying the process parameters, i.e., the amount of fibers with thinner diameter and the pressure applied during composite preparation. Using 60 vol.% of thinner, continuous, and aligned curaua fibers, it was possible to obtain tensile strength above 200 MPa. Moreover, by applying pressure of 30 MPa during curing, composites with tensile strength above 270 MPa were obtained. Regarding the Izod impact resistance, toughness of over 340 J/m was obtained for notched specimens machined perpendicular to the fiber alignment direction.

The Weathering Study of PC/ASA Alloy For Automotive Exterior Applications

Polycarbonates (PC) are used in automotive industry due to high physical and mechanical properties like high impact resistance and ductility. Polycarbonates are blended with ABS (Acrylonitrile-Butadiene-Styrene) and ASA (Acrylonitrile-Styrene-Acrylate) terpolymers for interior and exterior applications of automotive components to achieve good physical and mechanical properties. Other reason for choosing such alloys for interior applications is the IZOD impact resistance requirement higher than 40kJ/m 2 . Recently, grades of PC/ASA with UV stabilized are developed for non-painted exterior applications. The aim of our study is to investigate whether new developed PC/ASA could be chosen for exterior applications of automotive industry. In this study, the samples are prepared from injection molding and the weathering performance of PC/ASA was tested by a weather-o-meter for 1500h at a total of 1890 kJ/m 2 at 340nm with a cut-off filter at λ<290nm. The results are evaluated by FT-IR, DSC, TGA and SEM. It has been observed that UV degradation of PC/ASA leads to several major changes in its IR spectrum like broad bands occurred in the hydroxyl region around 3300cm -1 , and carbonyl stretching region increased around 1728 cm -1 . The main degradations were based on photo-oxidation and photo-Fries rearrangement of PC. In our study, the photo-oxidation was followed by the color shift to yellowing of the polymer.

Wear resistance and friction coefficient of nano-SiO2 and ash-filled HDPE/lignocellulosic fiber composites

This work comparatively evaluates the effect of nano-SiO2 (at 2 and 3 wt%), rice husk and bagasse ash (at 5 and 10 wt%) on the wear resistance and friction coefficient of HDPE (high-density polyethylene)/lignocellulosic fiber composites. Rice husk and bagasse fibers at 50% by weight contents were mixed with HDPE and 2% maleic anhydride-grafted polyethylene as compatibilizer. SEM images showed a fairly appropriate connection between the polymer matrix and fillers. We found that the fillers improve the wear resistance, and the effect of nano-SiO2 is more pronounced. The rice husk ash showed a better performance compared to the bagasse ash, probably due to greater SiO2 content measured by X-ray fluorescence spectrometry. In contrast to nano-SiO2, both ashes had a reducing effect on other mechanical strengths (Izod impact resistance, modulus of elasticity and modulus of rupture). All fillers remarkably increased the water absorption and thickness swelling. The water uptake of composites increased after wear.

Crystallinity and mechanical properties of polylactide/ether‐amide copolymer blends

ABSTRACTThe present study focuses on the improvement of impact properties and particularly on the interaction between crystallinity development and mechanical properties of impact modified polylactide (PLA). The PLA was toughened by the addition of a random linear ether‐amide copolymer (PEBAX 3533™). A random copolymer of ethylene, methyl‐acrylate, and glycidyl‐methacrylate (LOTADER AX8900™) was also used to reactively compatibilize the ether‐amide copolymer with the PLA matrix. Melt rheology of the blends was investigated in small amplitude oscillatory shear and showed that the impact modifier could significantly influence the viscoelastic response of the material. The Izod impact resistance and tensile properties were measured using standard testing protocols. The blend morphology was also examined using scanning electron microscopy on cryofractured and microtomed surfaces, while the crystalline morphology was assessed by optical microscopy. A sub‐micron dispersion of the impact modifier was achieved in the presence of the reactive compatibilizer. Significantly improved impact strength was found with 10 wt % impact modifier. High crystallinity samples showed the highest impact strength with values reaching 68 kJ/m2, hence a 20‐fold improvement with respect to the neat PLA. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44677.

Curaua fiber reinforced high-density polyethylene composites: effect of impact modifier and fiber loading

Short fibers are used in thermoplastic composites to increase their tensile and flexural resistance; however, it often decreases impact resistance. Composites with short vegetal fibers are not an exception to this behavior. The purpose of this work is to produce a vegetal fiber reinforced composite with improved tensile and impact resistance in relation to the polymer matrix. We used poly(ethylene-co-vinyl acetate), EVA, to recover the impact resistance of high density polyethylene, HDPE, reinforced with Curaua fibers, CF. Blends and composites were processed in a corotating twin screw extruder. The pure polymers, blends and composites were characterized by differential scanning calorimetry, thermogravimetry, infrared spectroscopy, scanning electron microscopy, tensile mechanical properties and Izod impact resistance. EVA used as impact modifier in the HDPE matrix exhibited a co-continuous phase and in the composites the fibers were homogeneously dispersed. The best combination of mechanical properties, tensile, flexural and impact, were obtained for the formulations of composites with 20 wt. % of CF and 20 to 40 wt. % of EVA. The composite prepared with 20 wt. % EVA and containing 30 wt. % of CF showed impact resistance comparable to pure HDPE and improved tensile and flexural mechanical properties.

High-speed impact and mechanical strength of ZrO2/polycarbonate nanocomposite

This study empirically investigates the mechanical strength and high-speed impact resistance of polycarbonate matrix reinforced with different amounts of nano-ZrO2. In order to enhance the mechanical strength of polycarbonate, especially the impact resistance, the nanoparticles were added to polycarbonate matrix as filler with the ratios of 1, 2, 3 and 5% of the composite’s total weight. Transmission electron microscope was utilized for the observation of microscopic structure of the composites, and it revealed an exceptional homogeneous mixture of ZrO2 particles in the polycarbonate matrix. From the results of the tests, it was figured out that adding 1–3 wt% of nano-ZrO2 into polycarbonate remarkably increased the impact resistance of the composite. The results also showed that adding 1 and 2 wt% of nano-ZrO2 to polycarbonate had the most desirable effects on the enhancement of tensile, bending and buckling strength; however, the composites with 3 wt% of nano-ZrO2 had the greatest Izod impact and high-velocity impact resistance. Finally for the impact tests, it was revealed that adding large amounts of nano-ZrO2 (more than 3 wt%) would decrease the mechanical strength of ZrO2/polycarbonate nanocomposite specimens; thus, the fracture occurred, while less energy was absorbed compared with the neat polymer.

Fabrication of adduct filled glass fiber/epoxy resin laminate composites and their physical characteristics

Adducts were synthesized from thiokol and epoxy resin using triethylamine as a catalyst, and their structure and molecular weights were determined. The synthesized adducts, which possessed an epoxide group on their chain as a modifier to enhance the toughness of the epoxy resin, were well dispersed in the epoxy matrix, resulting in the successful manufacture of laminate composites made from glass fiber/epoxy resin (GF/EP). The microstructure and mechanical properties, such as the tensile strength, impact resistance and mode I interlaminar fracture toughness, were investigated and compared with those of the GF/EP system. The addition of the adduct to the epoxy matrix led to an increase in both the mode I interlaminar fracture toughness and IZOD impact resistance of the GF/EP.

Comparative study of the mechanical properties of polyester resin with and without reinforcement with fiber-glass and furcraea cabuya fibers

A commercially available polyester resin was reinforced with cabuya fibers. The experimental variables were the fiber loading and the length of the fiber. Tensile strength, flexural strength, and the Izod impact resistance were measured for the samples and compared to the polyester resin performance without reinforcement. Mechanical properties of the cabuya fiber reinforced material were also compared with the same resin but reinforced with glass fibers. An increase in fiber load decreases the tensile strength for the cabuya reinforced composite, where a value of 52.6 MPa corresponded to the tensile stress of the resin without reinforcement and a value of 34.5 MPa for the best reinforcement achieved with cabuya. An increase in both fiber load and length increases the Young’s modulus of the cabuya reinforced material, and a maximum value of 2885 MPa was obtained. The Young’s modulus and impact resistance values for the cabuya composite (2885 MPa and 100.87 J/m, respectively) reached higher values than those obtained for non-reinforced polyester material (2639 MPa and 5.82 J/m, respectively), and lower than the glass fiber composite (5526 MPa and 207.46 J/m, respectively); while the tensile and flexural strength obtained for the cabuya composite (34.5 MPa and 32.6 MPa, respectively) were lower than the unreinforced (52.6 MPa and 62.9 MPa, respectively) and glass fiber reinforced polyester (87.3 MPa and 155 MPa, respectively).

Failure behaviour of self-reinforced polypropylene at and below room temperature

Self-reinforced polypropylene is a very tough material. It is even thought that its impact resistance increases with decreasing temperature. This was investigated by examining the constituent tapes and matrix. Tensile tests on both drawn polypropylene tapes and self-reinforced polypropylene were similar: the stiffness increased and the failure strain slightly decreased at low temperatures. The matrix, however, embrittled below room temperature due to the glass transition. In contrast with literature data on Izod impact resistance, the penetration impact resistance did not increase at low temperatures. At lower temperatures, the damaged area after non-penetration impact was significantly reduced. This was caused by a change in the damage mode from tape–matrix debonding to matrix cracking, as the matrix went through its glass transition. These conclusions provide the first understanding of the failure behaviour of self-reinforced polypropylene below room temperature, and can be exploited to further optimise the excellent impact resistance of self-reinforced polymers.

Izod Impact Tests in Polyester Matrix Composites Reinforced with Banana Fibers

Polymer matrix composites have been applied in components such as helmets and shielding for which toughness is a major requirement. A natural fiber presents interfacial characteristics with polymeric matrices that favor a high impact energy absorption by the composite structure. The objective of this work was then to assess the Izod impact resistance of polymeric composites reinforced with different amounts, up to 30% in volume, of a promising high strength natural fiber, the banana fiber. The results showed a remarkable increase in the notch toughness with the amount of incorporated banana fibers. This can be attributed to a preferential debonding of the fiber/matrix interface, which contributes to an elevated absorbed energy.

Flame retardant high density polyethylene optimized by on-line ultrasound extrusion

The effect of on-line ultrasound application by a special static mixer die which promotes extensional flow simultaneously during the single screw extrusion process was thoroughly studied. The proportion of aluminum trihydroxide (ATH) used as flame retardant on high density polyethylene (HDPE) was optimized. The morphological, thermal, flammability, combustion, mechanical and rheological properties of the materials were investigated. The morphological study pointed out that this process is able to strongly reduce the size of ATH particles and improve their dispersion and distribution within the polymer matrix. The addition of zinc borate (ZB) at low concentration (namely 3 phr) showed its well-known synergistic effect in the thermal, oxygen index and fire combustion behavior. According to the UL94 standard, the rating for all materials tested changed from HB to V2, with respect to materials prepared without ultrasound; furthermore a rating V0 was achieved only with the addition of 2 phr organo-clay. Rheological results under simple and small amplitude oscillatory shear flow confirmed the enhanced particle dispersion and finer particle morphology evidenced by larger values of the moduli and by deviations from the semicircular shape observed in the Cole–Cole diagram. Mechanical properties such as Izod impact resistance, tensile strength, strain at break and tenacity were also improved by the on-line ultrasound process. In this work, the appropriate on-line ultrasound extrusion conditions to use the lowest ATH content (30 phr or 21.5 in wt%) were found, rendering HDPE optimized flame retardant materials with improved processability and mechanical properties.

NOVEL POTENTIALLY BIODEGRADABLE POLYURETHANES FROM BIO-BASED POLYOLS

Completely bio-based polyols, suitable for the preparation of rigid polyurethanes were synthesized from polyglycerol, lactic acid and fatty acids. Lactic units were introduced into the polyol structure by the ring opening addition of L-lactide to hydroxyl groups, in the presence of the titanium(IV) isopropoxide catalyst. To address the incompatibility issue of simple lactide–(poly)glycerol polyols with isocyanates, vegetable oil-based fatty acids were introduced into the polyol structure. Cast thermosetting polyurethane resins were prepared by reacting polyols with diphenylmethane diisocyanate. Polyurethanes were crosslinked glassy amorphous materials with tensile strength of ~ 60 MPa, flexural modulus of 0.9 - 2.3 GPa and notched Izod impact resistance of 30 - 80 J/m. These polyurethanes are potentially biodegradable.

Design of Experimental Design as a Tool for the Processing and Characterization of HDPE Composites with Sponge-Gourds (Luffa-Cylindrica) Agrofiber Residue

Sponge-gourd (Luffa-Cylindrica) agrofiber residue (LC)-HDPE composites were manufactured by extrusion and injection moulding. The effects of fiber content, fiber size, screw speed and barrel zones temperatures on tensile strength at yield (TS) point, modulus of elasticity (MOE), flexure stress (FS) and Izod pendulum impact resistance were evaluated by using a design of experiments (DOE)-2 4 Factorial with centerpoint. Furthermore, a model was also determined for each response variable as well as to generate foreknowledge for additional combinations of the experimental factors. The design analysis showed that the LC-fiber content is the most important experimental factor, since it significantly affected three out of the four mechanical properties studied, specifically MOE, FS and Izod Impact resistance. The second most important parameter is the LC-fiber size. Additionally, the design analysis showed that screw speed and temperature of barrel zones did not present any influence on the properties investigated. Finally, the models were validated by comparing the results from additional experimental runs with the predicted values obtained from the respective model.

NOVEL POTENTIALLY BIODEGRADABLE POLYURETHANES FROM BIO-BASED POLYOLS

Completely bio-based polyols, suitable for the preparation of rigid polyurethanes were synthesized from polyglycerol, lactic acid and fatty acids. Lactic units were introduced into the polyol structure by the ring opening addition of L-lactide to hydroxyl groups, in the presence of the titanium(IV) isopropoxide catalyst. To address the incompatibility issue of simple lactide–(poly)glycerol polyols with isocyanates, vegetable oil-based fatty acids were introduced into the polyol structure. Cast thermosetting polyurethane resins were prepared by reacting polyols with diphenylmethane diisocyanate. Polyurethanes were crosslinked glassy amorphous materials with tensile strength of ~ 60 MPa, flexural modulus of 0.9 - 2.3 GPa and notched Izod impact resistance of 30 - 80 J/m. These polyurethanes are potentially biodegradable.