Nanostructure evolution

Automated Extraction of Interference Functions. For the classical synthetic polymer materials it is, in general, possible to strip the interference function from the scattering data by an algorithm that does not require user intervention. Quantitative information on the non-topological parameters is lost (Stribeck [26,153]). The method is particularly useful if extensive data sets from time-resolved experiments of nanostructure evolution must be processed. Background ideas and references are presented in the sequel. 

Figure 3.13 (Top) TEM micrographs of (a-i) silver nanocoils prepared by backfilling, (j-k) helical mesoporous silica grown inside nanochannels of different sizes (indicated below each micrograph). (Bottom) Schematic of differing confined nanostructural evolution with decreasing diameter of the nanochannels [56],...

Nashner MS, Somerville DM, Lane PD, Adler DL, Shapley JR, Nuzzo RG (1996) BimetaUic catalyst particle nanostructure. Evolution from molecular cluster precursors. J Am Chem Soc 118 12964... 

Stribedc et al. (Stiibeck, 2008) described nanostructure evolution in Polypropylene during online mechanical testing with simultaneous SAXS and refined details of the interaction between the different phases including cavitation. 

Stribeck, N. et al. (2008). Nanostructure Evolution in Polypropylene During Mechanical Testing, Macromol. Chem. Phys. Vol. 209 (2008), pp.1992-2002 Vonk, C.G. (1979). A small angle X-ray scattering study of polyethylene fibres, using the two-dimensional correlation function. Colloid Polym. Sci. Vol. 257 (1979), pp.l021-1032... 

T. Toyama, Y. Nagai, Z. Tang, M. Hasegawa, A. Almazouzi, E. van Walle and R. Gerard, Nanostructural evolution in surveillance test specimens of a commercial nuclear reactor pressure vessel studied by three-dimensional atom probe and positron annihilation , Acta Mater, 2007,55, 6852-6860. 

Stribeck N, Nbchel U, Funari S S, Schubert T and Timmann A (2008) Nanostructure evolution in polypropylene during mechanical testing, Macromol Chem Phys 209 1992-2002. 

Rena-Alonso, R., Mariotto, G., Gervais, C., Babonneau, F., and Soraru, G.D. New insights on the high-temperature nanostructure evolution of SiOC and B-doped SiBOC polymer-derived glasses. Chem. Mater. 2007 19 5694-5702. 

Title Multiphase polymer systems micro- to nanostructural evolution in advanced technologies / edited by Andreea Irina Barzic and Silvia loan. 

Studies of deformation by X-ray scattering are presently experiencing a change from the so-called stretch-hold technique [1] to an in situ study of nanostructure evolution during dynamical tensile tests. Thus, here the new perspectives, their technical foundations, and first results are discussed in com-... 

Enhancement of the strain rate. Only recently scientists have been able to record good SAXS patterns with a cycle time of 30 s even fi om thin samples at synchiotron beamlines that are easily accessible. Exploiting such short cycle times at slow strain rates (e w 10 s ) makes it possible to monitor a dynamic mechanical test by SAXS measurements, which are sufficiently accurate to study the nanostructure evolution inside the material. Admittedly, such strain rates... 

Throughout the years, quasi-dynamical studies employing the stretch-hold principle [1] represent the predominant part of all the investigations on the nanostructure evolution of composite materials [6,16-35]. Since this technique means that the sample is held at a constant elongation until a low-noise scattering pattern has been exposed, the data can, in principle, be analyzed by quantitative evaluation, although most of the published papers do not proceed far beyond a presentation and interpretation of the accumulated images. 

One of the most important goals of the method is the elucidation of the mechanisms of nanostructure evolution during application of mechanical load. In the previous section it has been demonstrated that for this purpose not the... 

Stribeck N, Buzdugan E, Ghioca P, Serban S and Gehrke R (2002) Nanostructure evolution of SIS thermoplastic elastomers during straining as revealed by USAXS and multi-dimensional chord distribution analysis, Macromol Chem Phys 203 636-644. 

Stribeck N, Androsch R and Funari S S (2003) Nanostructure Evolution of Homogeneous Poly(ethylene-co-l-octene) as a Function of Strain, Macromol Chem Phys 204 1202-1216. 

Stribeck N and Funari S S (2003) Nanostructure Evolution in a Poly(ether ester) Elastomer during Drawing and the Displacement of Hard Domains from Lamellae, J Polym Sci Part B Polym Phys 41 1947-1954. 

Nanostructure Evolution During Chemical Processing of Gels A High-Resolution Electron Microscope Study. 1. Rare Earth Oxide and Hydroxycarbonate Colloids, Z.C. Kang and L. Eyring, J. Solid State Chem., 88, 303-323 (1990). 

Nanostructure Evolution During the Transition of Ti02, PbTiOs and PZT from Gels to Crystalline Thin Films, Z.C. Kang, A. Gupta, M.J. McKelvy, L. Eyring and S.K. Dey, Mater. Res. Soc., Symp. Proc., 230,301-306 (1992). 

Nanostructure evolution and calcium distribution in sol-gel derived bioactive glass./. Mater. Chem, 19, 1276-1282. 

Stribeck, N. Nanostructure evolution studies of bulk polymer materials with synchrotron radiation. Progress in method development. Anal. Bioanal. Chem. 376,608-617 (2003)... 

Tensile testing is done in a home-made [1] stretching-machine. The machine performs symmetric drawing in order to maintain the position of the beam on the sample. Signals from load cell and transducer are recorded during the experiment. The macroscopic deformation is determined close to the beam position to ensure accurate comparison of the mechanical data with the nanostructure evolution. For this reason a precise method has been developed [2]. In this method a pattern of fiducial marks is stamped on the sample. The sample is monitored by a TV-camera. Using the fiducial marks the local strain s = - o)/ o is computed automatically... 

Figure4.10 presents the nanostructure evolution during the mechanical test for the material injection molded from the hottest melt (235 °C). A plain microfibrillar pattern is observed from the beginning. During the test the microfibrils narrow (vertical bar-shaped reflections move closer to the meridian), and the intensity in the central meridional streak is changing. An ordinary nanostructure and its response to strain is not observed. An ordinary nanostructure would exhibit distinct peaks along the meridian that clearly move outward with increasing strain instead of a meridional streak. In other materials that are studied in straining tests (cf. Chaps. 5 and 6) we have observed such distinct peaks moving. They indicate a well-defined preferential distance between hard domains instead of an extremely broad distribution of distances. Nevertheless, let us relate the position of the peak maximum on the meridian...

As the last step in nanostructure evolution analysis we are searching for hints concerning the formation, transformation and destruction of domains. Initial strain may arrange hard segments in such a way that they form new hard domains. Further straining may break intermediate hard domains, resulting either in a transformation of thin-layer sandwiches into thick-layer sandwiches or in a complete loss that decreases the number of sandwiches. 

Fig. 4.19 Nanostructure evolution mechanisms of the TPU injection-molded samples as a function of processing temperature and strain...

Fig. 5.9 Nanostructure evolution during tensile testing of PP nanocomposites determined from the CDF long period peak. Most-frequently long period L e)...

By comparing the extracted nanostructure evolution information to the mechanical data it has been found that missing improvement of mechanical properties appears to result predominantly from the inhibition of a load-bearing semicrystalline morphology inside the PP by the MMT. 

Stribeck, N., Androsch, R., Funari, S.S. Nanostructure evolution of homogeneous poly(ethylene-co-l-octene) as a function of strain. MacromoL Chem. Phys. 204, 1202-1216 (2003)... 

General Nanostructure Evolution in Load-Cycling Tests... 

---