Observation of “Black” and “White” Crazes in High-Impact Polystyrene under Transmission Electron Microscopy

Kuboki, Takashi; Jar, P.‐Y. Ben; Toko, Kiyoshi; Shinmura, T.

doi:10.1021/ma0001234

Cited by 4 publications

(5 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As suggested by Brown et al, the black crazes may result from the staining of unsaturated rubber molecules that diffused into the crazes during the craze growth. Without the presence of the rubber molecules, the color of the crazes should remain white and should not be affected by the staining process . Therefore, the observation of white crazes in 0.84S and 0.45S in specimens tested at the high strain rates, especially in regions of 30 μm away from the fracture surface, as shown in Figure , parts c and d, for 0.84S and Figure b for 0.45S, is an indication of the low mobility of the unsaturated polybutadiene molecules in the rubber particles.…”

Section: Discussionmentioning

confidence: 94%

“…Compared with those in Figure b, the micrographs in Figure c show a slight increase in craze number but a decrease in craze opening width. The crazes in Figure c include white crazes of which the low contrast with the matrix came from the insufficient OsO 4 staining . Figure d shows TEM micrographs for specimens fractured at the highest strain rate, 1.8 × 10 s -1 .…”

Section: Resultsmentioning

confidence: 99%

“…Without the presence of the rubber molecules, the color of the crazes should remain white and should not be affected by the staining process. 16 Therefore, the observation of white crazes in 0.84S and 0.45S in specimens tested at the high strain rates, especially in regions of 30 µm away from the fracture surface, as shown in Figure 8, parts c and d, for 0.84S and Figure 9b for 0.45S, is an indication of the low mobility of the unsaturated polybutadiene molecules in the rubber particles. Piorkowska et al 41 suggested that the mobility of the polybutadiene molecules depends on the strain rate, and when the strain rate reaches a critical value, the mobility of the polybutadiene molecules could not keep up with the craze growth rate, resulting in a craze that does not contain rubber molecules in its full length.…”

Section: Deformation Of Craze Fibrilsmentioning

confidence: 88%

“…The crazes in Figure 8c include white crazes of which the low contrast with the matrix came from the insufficient OsO 4 staining. 16 Figure 8d shows TEM micrographs for specimens fractured at the highest strain rate, 1.8 × 10 s -1 . Crazes in Figure 8d have similar opening width with those in Figure 8c, but the number of crazes initiated from each rubber particle in Figure 8d has been much increased.…”

Section: Optical Microscopymentioning

confidence: 99%

See 3 more Smart Citations

Mechanical Deformation of High-Impact Polystyrene under Uniaxial Tension at Various Strain Rates

et al. 2002

Self Cite

View full text Add to dashboard Cite

Tensile properties of two high-impact polystyrenes (HIPS), named 0.84S and 0.45S, were evaluated at four strain rates, from 2.7 × 10-3 to 1.8 × 10 s-1, using un-notched dumbbell specimens. Under the strain rates up to 1.6 × 10-1 s-1, 0.84S showed slightly higher fracture energy than 0.45S, where the fracture energy is defined as the total area under the force−displacement curve. However, when the strain rate was further increased to 1.8 × 10 s-1, the difference was remarkably increased, due to a dramatic increase of the fracture energy for 0.84S at the highest strain rate, 1.8 × 10 s-1. The high fracture energy for 0.84S was found to come mainly from the fracture strain. The microscopic examination, using optical microscopy and transmission electron microscopy (TEM), shows the trend of deformation behavior, which supports the tensile test results, and suggests that the adiabatic deformation process, which has long been known to cause the fracture energy increase at high strain rates for many polymers, does not provide a satisfactory explanation for the results presented here. Instead, it is believed that at the highest strain rate the molecular stretch, instead of the molecular flow, dominated the craze fibril deformation and resulted in the craze proliferation around the rubber particle. Such a craze proliferation mechanism did not occur in 0.45S, because unlike 0.84S, the displacement misfit between particle and matrix was insufficient to initiate crazes. As a result, the fracture strain and the fracture energy were limited. We conclude from the study that the different capability to initiate crazes is a dominant factor for the significantly different fracture energy of the two HIPS at the highest strain rate.

show abstract

Section: Discussionmentioning

confidence: 94%

Section: Resultsmentioning

confidence: 99%

Section: Deformation Of Craze Fibrilsmentioning

confidence: 88%

Section: Optical Microscopymentioning

confidence: 99%

See 2 more Smart Citations

Mechanical Deformation of High-Impact Polystyrene under Uniaxial Tension at Various Strain Rates

et al. 2002

Self Cite

View full text Add to dashboard Cite

show abstract

“…The micrograph shows very little short black or bright lines in the matrix. There was no doubt that the lines were crazing, which was adjacent to the rubber particles 17. As indicated in parts of Figure 5(b) by an arrow, the minute crazing generated from the rubber particle surface had the typical microstructures and the same internal details of draw fibrils; also, some of the crazing fibrils were broken down.…”

Section: Resultsmentioning

confidence: 93%

Impact behavior and fracture morphology of acrylonitrile–butadiene–styrene resins toughened by linear random styrene–isoprene–butadiene rubber

Yang

Wang

et al. 2011

J of Applied Polymer Sci

View full text Add to dashboard Cite

A novel toughening modifier, styrene-isoprene-butadiene rubber (SIBR), was used to improve the impact resistance and toughness of acrylonitrile-butadienestyrene (ABS) resin via bulk polymerization. For comparison, two kinds of ABS samples were prepared: ABS-1 was toughened by a conventional modifier (a low-cis polybutadiene rubber/styrene-butadiene block copolymer), and ABS-2 was toughened by SIBR. The mechanical properties, microstructures of the as-prepared materials, and fracture surface morphology of the specimens after impact were studied by instrumented notched Izod impact tests and tensile tests, transmission electron microscopy, and scanning electron microscopy, respectively. The mechanical test results show that ABS-2 had a much higher impact strength and elongation at break than ABS-1. The microscopic results suggested that fracture resistance of ABS-1 only depended on voids, shear yielding, and few crazing, which resulted in less ductile fracture behavior. Compared with ABS-1, ABS toughened by linear random SIBR (ABS-2) displayed the synergistic toughening effect of crazing and shear yielding, which could absorb and dissipate massive energy, and presented high ductile fracture behavior. These results were also confirmed by instrumented impact tests.

show abstract

Synthesis of styrene–butadiene rubber latex via miniemulsion copolymerization

2009

View full text Add to dashboard Cite

Observation of “Black” and “White” Crazes in High-Impact Polystyrene under Transmission Electron Microscopy

Cited by 4 publications

References 10 publications

Mechanical Deformation of High-Impact Polystyrene under Uniaxial Tension at Various Strain Rates

Mechanical Deformation of High-Impact Polystyrene under Uniaxial Tension at Various Strain Rates

Impact behavior and fracture morphology of acrylonitrile–butadiene–styrene resins toughened by linear random styrene–isoprene–butadiene rubber

Synthesis of styrene–butadiene rubber latex via miniemulsion copolymerization

Contact Info

Product

Resources

About