Determinação de temperatura de transição dúctil-frágil de plásticos através de testes de impacto instrumentado

Correa, Carlos Alexánder Grajales; Yamakawa, Roberto S.; Hage, Elias

doi:10.1590/s0104-14281999000100010

Cited by 8 publications

(9 citation statements)

References 7 publications

(10 reference statements)

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“…At room temperature, the fracture surface morphology has typical ductile characteristics with the presence of regions of shear flow due to “whitening” under tension . Figure shows the photos of the fracture surface of the samples obtained by optical microscopy, in which the direction of crack propagation can be verified.…”

Section: Resultsmentioning

confidence: 96%

Effect of Graphite Content on The Mechanical Properties of Acrylonitrile‐Butadiene‐Styrene (ABS)

Braga

Passador

Saito

et al. 2019

Macromolecular Symposia

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Composites based on graphite‐reinforced acrylonitrile‐butadiene‐styrene (ABS) polymer matrix are prepared in compositions of 1 and 2 wt% of graphite and the mechanical properties are compared to the neat ABS. The specimens are prepared by melt mechanical mixing through an intensive homogenizer/mixer followed by the hydropneumatic press. The materials are characterized by Charpy impact strength, Shore D hardness, and optical microscopy. Results shows that the ABS impact strength decreased (reduction of 33% with only 1 wt% of graphite) with the increase of the graphite content in the compositions, the addition of highly rigid graphite in the ABS matrix altered the tenacity mechanism. In addition, there was a 12% increase in the hardness of the composites in relation to the neat ABS. Microscopic analysis shows the presence of small graphite particles well distributed in the polymer matrix.

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Section: Resultsmentioning

confidence: 96%

Effect of Graphite Content on The Mechanical Properties of Acrylonitrile‐Butadiene‐Styrene (ABS)

Braga

Passador

Saito

et al. 2019

Macromolecular Symposia

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“…The sample > 2002 presents encrusted particles can be pigmented or load, since this sample has a monitor with a gray frame. The observation of the fracture surface by SEM also allows one to verify the correlation between the type of fracture and the characteristics shown in the images [22]. In the case of the images shown in Figure 6, it can be seen that the fracture is of ductile type.…”

Section: Flexion Testmentioning

confidence: 83%

Evaluation of Recycled Polymers from Crt Monitor Frames of Different Years of Manufacture

Gabriel

Santana

Veit

2014

Progress in Rubber, Plastics and Recycling Technology

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The recycling of polymeric waste has attracted considerable interest and many efforts have been made to facilitate large scale recycling. The rapid evolution of technology has generated large volumes of obsolete and unusable polymeric products. One example is the CRT (cathode ray tubes) monitor that are rapidly being replaced by monitor types such as LCD, LED and Plasma. The present materials and routes for recycling this waste is not well known, which encourages studies in this area. The main objective of this work is to identify the type of polymer present in the CRT monitor frames and evaluate if the quality of the recycled polymer is changed according to the monitor age (year of manufacture). Monitors of different years of manufacture but the same brand were collected and disassembled. Frames were separated into two groups (older and younger). After, the frames were comminuted and samples were injected, according to ASTM D638-08. The samples were characterized by infrared, density, mechanical, MEV and TGA tests. The results obtained by infrared (FTIR) showed that regardless of the year of manufacture the monitor frames are produced with the same polymeric material, which was identified as copolymer ABS (acrylonitrile butadiene styrene). The results of mechanical and thermal tests showed that, in general, the recycled ABS polymers regardless of the year of manufacture showed no significant losses in their properties. However, it was found, by the TGA test, that there was a small variation in polymer composition.

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“…40,41 One of the most used standard impact test is defined as Izod impact test, which provides a comparison of different toughness levels for polymer samples, which are fractured under standard conditions. 39…”

Section: Resultsmentioning

confidence: 99%

Chemical modification of sugarcane bagasse and sisal fibers using hydroxymethylated lignin: Influence on impact strength and water absorption of phenolic composites

Tita

Medeiros

Tarpani

et al. 2018

Journal of Composite Materials

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Chemical modification of fiber surfaces can increase wettability of composites reinforced by vegetal fibers and, consequently, the dispersion of the fiber in the matrix and mechanical properties can be improved. Although there are some studies about agents for chemical modifications of vegetal fiber surfaces, there are few data and discussion about the usage of lignin. In the present work, chemical modifications of sugarcane bagasse and sisal fibers using lignin (previously hydroxymethylated) were carried out under different reaction times (15, 30, and 60 min). The composition (holocellulose, hemicelluloses, cellulose, and lignin contents) of the treated and untreated fibers was evaluated. Phenolic composites were prepared using unmodified and modified fibers via compression molding process under temperature. Izod impact, water absorption tests, and scanning electron microscopy were performed to evaluate composite properties. The resin and lignin were characterized by size exclusion chromatography. Results showed that there was a tendency of reducing water absorption for composites prepared from modified fibers. Impact strengths of composites reinforced with sugarcane bagasse with modified fibers were similar to the ones with unmodified fibers (around 20 J/m). However, impact strengths for composites reinforced with modified sisal fibers (around 104 J/m for 15 min of reaction time) were higher than the ones with unmodified fibers (around 95 J/m). Therefore, the usage of lignin as a modifier agent of vegetal fiber surfaces to increase fiber–matrix adhesion for phenolic composites is a strategic alternative for improving products through simple, eco-friendly, and low-cost procedures.

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Determinação de temperatura de transição dúctil-frágil de plásticos através de testes de impacto instrumentado

Cited by 8 publications

References 7 publications

Effect of Graphite Content on The Mechanical Properties of Acrylonitrile‐Butadiene‐Styrene (ABS)

Effect of Graphite Content on The Mechanical Properties of Acrylonitrile‐Butadiene‐Styrene (ABS)

Evaluation of Recycled Polymers from Crt Monitor Frames of Different Years of Manufacture

Chemical modification of sugarcane bagasse and sisal fibers using hydroxymethylated lignin: Influence on impact strength and water absorption of phenolic composites

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