Polypropylene isotactic microscopy

Snetivy D and Vancso G J 1994 Atomic force microscopy of polymer crystals 7. Chain packing, disorder and imaging of methyl groups in oriented isotactic polypropylene Po/yme/ 35 461... 

AFM Atomic force microscopy aPP Atactic polypropylene DSC Differential scanning calorimetry HDPE High-density polyethylene iPP Isotactic polypropylene LLDPE Linear low-density polyethylene MD Microdomain ODT Order-disorder transition PB Poly(butadiene)... 

Dehydrated calcium pimelate is added (between 0.01 and 0.5 wt %) as the nucleating agent to isotactic polypropylene to produce the (3 modification of iPP [63]. Following molding between two glass plates at 220°C thin films of the polymer are isothermally crystallized at 140°C-143°C in a microscopy hot stage. After the hedritic structures develop, the samples are quenched to room temperature. Prior to AFM examination, the specimens are etched with a 1% solution of potassium permanganate in a mixture of sulfuric and orthophosphoric acid [64, 65]. This procedure is described in detail in the literature Caution consult the literature for safety precautions ) and helps to remove preferentially amorphous phase of PP [64]. Thus, unlike in the many other examples discussed in Sect. 3.2, here the interior of a specimen is analyzed after its exposure. 

IPP-EPM blends were generally considered to be immiscible (92-95). Chen et al. (96) have reported miscibility and a LCST in blends of isotactic polypropylene and an ethylene-propylene terpolymer (EPDM). Seki et al. (97) reported that iPP was miscible with EPM with both 19 and 47 mol% of ethylene based on both transmission electron microscopy (TEM) and SANS. However, the molecular weight of the iPP was below 10, OOOgmoP. More recently both Nitta et al. (98) and Kamdar et al. (99) reported that the miscibility between iPP and EPM, whose molecular weight is higher than 100,000 g moP, is strongly dependent on ethylene content in EPM. The miscibility increases with decrease of ethylene content. IPP was miscible with EPM with ethylene content lower than around 17 mol% based on both dynamic mechanical analysis (DMA) and TEM. The EPM domain sizes decrease with decrease of ethylene content as shown in Fig. 2.3. 

In this section, we present the morphology development of neat elastomeric polypropylene as well as its blend with POE by means of optical microscopy and atomic force microscopy. ePP is essentially atactic polypropylene, which is amorphous in character, but contains some level of isotacticity (26). The incorporation of crystal-lizable iPP blocks provides the physical junctions to these amorphous ePP to possess elastomeric properties like a network in the solid state, but these crystal junctions can be removed upon melting, and thus affords melt processability like thermoplastics. 

Menyhard et al. [9] reported the generation of polymer blends based on the P-modification of polypropylene. The authors studied the melting and crystallization characteristics as well as the structure and polymorphic composition of the blends by polarized light microscopy (PLM) and differential scaiming calorimetry (DSC). It was observed that the most important factor of the formation of the blend with P-crystalline phase when semicrystalline polymers were added to isotactic polypropylene (iPP) was the a-nucleation... 

Polarized light microscopy micrographs of a P-nucleated isotactic polypropylene/polyamide-6 (iPP/PA-6) blend containing 5 wt% PA-6. Isothermal crystallization was carried out at = 135X for (a) t = 0 min, (b) = 21 min, (c) f = 45 min, and (d) = 60 min. (Reproduced from Menyhard, A., Varga, J., Liber, A., and Belina, G. 2005. Polymer blends based on the P-modification of polypropylene. European Polymer Journal 41 669-677 with permission from Elsevier.)... 

Presence of TCL changes the properties of crystalline matrix. Transcrystallization of isotactic polypropylene in the presence of different fibers has been thoroughly analyzed. Gray as the first one provided detailed description of isotactic polypropylene behavior in the presence of wood fibers using polarized light microscopy. He observed that when melted polymer is cooled down, it crystallizes in spherulite forms in nonisothermal and isothermal conditions, creating additionally a TCL. 

More recently, the same strategy was attempted to prepare isotactic/syndiotactic stereoblock polypropylene by using mixtures of rac-dimethylsilyl-bis(2-methyl-benz[e]-l-indenyl)ZrCl2 and diphenylcarbenyl(Cp)(9-fluorenyl)ZrCl2 in combination with MAO. Morphological studies by means of atomic force microscopy on such materials documented exclusive microphase separation between the isotactic and syndiotactic domains. This behavior is at odds with physical blends of isotactic and syndiotactic polypropylene, for which macrophase separation was observed. ... 

Thomann, R. Kressler, J. Setz, S. Wang, C. Miilhaupt, R. Morphology and phase behavior of blends of syndiotactic and isotactic polypropylene 1. X-ray scattering, light microscopy, atomic force microscopy, and scaiming electron microscopy. Polymer 1996, 37, 2627-2634. 

Schdnherr, H. Snetivy, D. Vancso, G J. A nanoscopic view at the spherulitic morphology of isotactic polypropylene by atomic force microscopy. Polym. Bull. (Berlin) 1993, 30, 567-574. 

Haeringen, D. T.-V Varga, J. Ehrenstein, G W. Vancso, G J. Eeatures of the hedritic morphology of fS-isotactic polypropylene studied by atomic force microscopy. J. Polym. Sci., Part B Polym. Phys. 2000, 38, 672-681. 

Stocker, W Magonov, S. N. Cantow, H. J. Wittmann, J. C. Lotz, B. Contact faces of epitaxially crystallized a- and y-phase isotactic polypropylene observed by atomic force microscopy. Macromolecules 1993, 26, 5915-5923. 

Snetivy, D. GuiUet, J. E. Vancso, G J. Atomic force microscopy of polymer crystals. 4. Imaging of oriented isotactic polypropylene with molecular resolution. Polymer 1993, 34, 429-431. 

Machado G, Denardin E L G, Kinast E J, Gongalves M C, de Luca M A, Teixeira S R and Samios D (2005) Grystalline properties and morphological changes in plastically deformed isotactic polypropylene evaluated by X-ray diffraction and transmission electron microscopy, Eur Polym J 41 129-138. 

Machado G, Kinast E J, Scholten J D, Thompson A, Vargas T D, Teixeira S R and Samios D (2009) Morphological and crystalline studies of isotactic polypropylene plastically deformed and evaluated by small-angle X-ray scattering, scanning electron microscopy and X-ray diffraction, Eur Polym J 45 700-713. 

The catalytic effect of various metals, metal oxides, and metal stearates on the thermo-oxidative degradation has been examined in the solid phase and in solution. In the latter case activity decreased in the order Cu, Mn, Fe, Cr, Co, Ni, Ti, Al, Zn, and V. The chemiluminiscence observed during thermo-oxidation has been interpreted as arising from the decomposition of ctketone hydroperoxides followed by oxidation of the polymer chain by secondary peroxy radicals. U.v. and fluorescence microscopy together with energy-dispersive. Y-ray analysis have been used to develop a model for the distribution of partially degraded polymer in isotactic polypropylene. ... 

Somani RH, Yang L, Zhu L, Hsiao BS (2005) Flow-induced shish-kebab precursor structures in entangled polymer melts. Polymer 46 8587-8623 Sorrentino A, De Santis F, Titomanlio G (2007) Polymer crystallization under high cooling rate and pressure a step towards polymer processing conditions. Lect Notes Phys 714 329-344 Stocker W, Magonov SN, Cantow HI, Wittmann JC, Lotz B (1993) Contact faces of epitaxially crystallized a- and y-phase isotactic polypropylene observed by atomic force microscopy. Macromolecules 26 5915-5923... 

Young RJ (1974) Dislocation model for yield in polyethylene. Philos Mag 30 85 Zhou J-J, Liu J-G, Yan S-K, Dong J-Y, Li L, Oian C-M, Schultz JM (2005) Atomic force microscopy study of the lamellar growth of isotactic polypropylene. Polymer 46 4077-4087 Zia Q, Radusch HI, Androsch R (2009) Deformation behavior of isotactic polypropylene crystallized via a mesophase. Polym Bull 63 755... 

---