Development of crazes in polycarbonate, investigated by ultra small angle X-ray scattering of synchrotron radiation

Lode, U.; Pomper, T.; Karl, Andreas; Krosigk, G. von; Cunis, S.; Wilke, W.; Gehrke, Rainer

doi:10.1002/marc.1998.030190109

Cited by 7 publications

(10 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The ultra‐small angle X‐ray scattering (USAXS) setup is regarded as one of the most appropriate apparatuses to detect these large‐scale structures. Because the strong difference in electron density between the polymer matrix and the cavities in the relevant angular range is accessible by this technique . Moreover, such whitening clearly influences the aesthetics and properties of industrial goods made of polymers since cavitation can be potentially triggered during processing or service.…”

Section: Introductionmentioning

confidence: 99%

Cavitation‐Induced Stress Whitening in Semi‐Crystalline Polymers

Men

2018

Macro Materials & Eng

View full text Add to dashboard Cite

Cavitation‐induced stress whitening in semi‐crystalline polymers during stretching significantly influences the physical properties of the materials. This review summarizes studies focusing on two different cavitation processes triggered at small and large strain regimes. The corresponding mechanisms of these two cavitation processes are discussed. For cavitation activated at small strain, there are two basic but distinctly different models with the initiation of cavities either in the amorphous phase or in the crystalline skeleton. For the cavitation triggered at a large strain regime, there are also two different arguments being either due to the defects located in the ends of micro‐fibrils or as a consequence of the fragmentation of load‐bearing inter‐fibril/micro‐fibril tie chains in highly oriented amorphous networks. A unified understanding of the cavitation processes during stretching semi‐crystalline polymers based on interpenetrated network model is proposed. Finally, this review outlooks future research topics for better understanding the cavitation mechanism to meet the industrial need.

show abstract

Section: Introductionmentioning

confidence: 99%

Cavitation‐Induced Stress Whitening in Semi‐Crystalline Polymers

Men

2018

Macro Materials & Eng

View full text Add to dashboard Cite

show abstract

“…It is obvious that these large scale structures are not accessible with a conventional small angle X‐ray scattering setup. But at least the beginning of this process should be well‐detectable by X‐ray scattering due to the strong difference in electron density between the polymer and the voids in the relevant angular range accessible by USAXS (see Lode et al,11 Gehrke et al,12 and Roth et al13).…”

Section: Introductionmentioning

confidence: 99%

Investigation of structural changes in semi‐crystalline polymers during deformation by synchrotron X‐ray scattering

Schneider

2010

J Polym Sci B Polym Phys

View full text Add to dashboard Cite

The mechanical behavior of polymer materials is strongly dependent on polymer structure and morphology of the material. The latter is determined mainly by processing and thermal history. Temperature-dependent on-line X-ray scattering during deformation enables the investigation of deformation processes, fatigue and failure of polymers. As an example, investigations on polypropylene are presented. By on-line X-ray scattering with synchrotron radiation, a time resolution in the order of seconds and a spatial resolution in the order of microns can be achieved. The characterization of the crystalline and amorphous phases as well as the study of cavitation processes were performed by simultaneous SAXS and WAXS. The results of scattering experiments are complemented by DSC measurements and SEM investigations. KEYWORDS: mechanical properties; on-line X-ray scattering; polypropylene; SAXS; strain-induced crystallization; structural characterization; WAXS INTRODUCTION The stress-strain curves of semicrystalline materials generally show three characteristic regions. Although the initial region before the yield point apparently behaves elastically, stress relaxation due to rearrangements in the amorphous phase can be observed. The mobility in the amorphous phase depends on the difference between the ambient temperature and the temperature characteristic of the glass transition, which is the dominant relaxation process in the temperature range under investigation. After the yield point, typically local necking occurs with high local strain, whereas the overall strain remains moderate. In the case of dog-bone specimens then the neck propagates over the whole specimen during constant load. In the true stressstrain diagram necking is a fast local deformation from the yield strain to the strain of the fully yielded specimen. In the third step during further elongation strain hardening occurs, until finally the specimen fails.

show abstract

“…Moreover, due to the absence of modulations in the vertical intensity streaks, a spherical object shape can be excluded, although energetic considerations might favor spheres. Thus the cylindrical nanobubbles give rise to a form factor contribution27 with a log‐normal distribution for the radius r with a mean value ξ 1 and a width σ r 28 …”

Section: Resultsmentioning

confidence: 99%

Pressure‐Sensitive Adhesive Blend Films for Low‐Tack Applications

Müller‐Buschbaum

Ittner

Maurer

et al. 2007

Macro Materials & Eng

View full text Add to dashboard Cite

Polymer blend films consisting of a tacky and a non-adhesive component are promising candidates for low tack applications. Immiscibility of both components results in a phase separation process yielding a tacky matrix with glassy objects embedded. The influence of the blending ratio of the components poly-n-butylacrylate (PnBA) and polystyrene (PS) is addressed. The mechanical information resulting from the tack test shows the possibility to vary the bonding strength of the PSA blend over a wide range. The macroscopic and microscopic structural characterization with optical microscopy and ultra small angle X-ray scattering shows that the blend PnBA:PS exhibits similarities to common filler systems as well as deviates regarding installed structures. Due to the large domain size on a microscopic level, only the tacky component, PnBA, defines the adhesive behavior. The non-adhesive component limits the contact area between the adhesive and the substrate.

show abstract

Development of crazes in polycarbonate, investigated by ultra small angle X-ray scattering of synchrotron radiation

Cited by 7 publications

References 0 publications

Cavitation‐Induced Stress Whitening in Semi‐Crystalline Polymers

Cavitation‐Induced Stress Whitening in Semi‐Crystalline Polymers

Investigation of structural changes in semi‐crystalline polymers during deformation by synchrotron X‐ray scattering

Pressure‐Sensitive Adhesive Blend Films for Low‐Tack Applications

Contact Info

Product

Resources

About