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  • 1
    Electronic Resource
    Electronic Resource
    Diamagnetism and structure of nitric acid-treated bulk polyethylene (1982)
    Springer
    Polymer bulletin 7 (1982), S. 317-321 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary An alternative procedure to examine the nature of the end product of nitric-acid-treated bulk polyethylene involving the measurement of the diamagnetic susceptibility is reported. This simple non-destructive method complements previous results obtained by means of IR spectroscopy. Thus after selectively removing the surface layer of the polyethylene lamellae with nitric acid (t 〉 50h) the diamagnetic susceptibility substantially decreases to values which are consistent with tilted paraffinic chains terminated by carboxyl groups including -NO2 groups in a 4∶1 ratio.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00256799
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  • 2
    Electronic Resource
    Electronic Resource
    X-ray diffraction study of poly-p-phenylene doped with SbF5 and SbCl5 (1989)
    Springer
    Polymer bulletin 21 (1989), S. 635-639 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract X-ray diffraction experiments have been performed on SbF5 and SbCl5 doped PPP prepared by the Kovacic method. Results are discussed in terms of two structural models which account for the regular intercalation of dopants within the polymer crystal lattice.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00264146
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  • 3
    Electronic Resource
    Electronic Resource
    Hardness of nitric acid treated polyethylene followed by recrystallization (1987)
    Springer
    Colloid & polymer science 265 (1987), S. 37-41 
    Details
    ISSN: 1435-1536
    Keywords: Microhardness ; polyethylene ; fuming nitric acid ; dicarboxylic acids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The hardness variation of melt crystallized polyethylene as a consequence of controlled fuming nitric exposure has been investigated using the microindentation technique. This study complements previous results obtained using other reagents (H2SO4, ClHSO3). After HNO3 exposure the microhardness of polyethylene decreases very rapidly, instead of increasing after the first hours of treatment. The hardness decrease is correlated to the volume fraction of interlamellar microvoids arising through selective acid digestion. For longer treatment times (t〉40 h) the fragility of the material increases and the sample collapses under the indenter. The hardening of the degraded material after recrystallization from the melt is followed as a function of treatment time. The results are discussed in the light of the molecular mechanisms involved. Comparison of the experimental data with hardness calculations for ideal PE lamellar structures and chain extended dicarboxylic crystals implies that the major contribution to hardening is due to electron dense groups attachment at the surface of a mixed lamellar structure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01422661
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  • 4
    Electronic Resource
    Electronic Resource
    Influence of chlorosulfonation on the surface mechanical properties of lamellar polyethylene (1983)
    Springer
    Polymer bulletin 10 (1983), S. 553-557 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary The hardening of lamellar polyethylene (PE) as a consequence of a controlled chlorosulfonation treatment has been studied using the microindentation technique. The hardness of the polymer turns out to be a linear function of the density of treated PE. The rate of increase is larger for samples with higher crystallinity. This increase is related to the hardening of crystal lamellae due to the surface attachment of electron dense groups. The latter impede the slippage of crystals and substantially reduce the rate of creep of the material under the contact pressure applied.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00285375
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  • 5
    Electronic Resource
    Electronic Resource
    Lamellar structure in melt crystallized low density polyethylene (1984)
    Springer
    Polymer bulletin 12 (1984), S. 269-274 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary A combined X-ray diffraction and DSC investigation of the crystalline phase in lamellar low density polyethylene after conventional chlorosulfonation treatment has been carried out. Our results indicate that the acid attack does not involve any heavy group penetration within the lattice. The location of these groups at the basal crystal surface contributes, however, to an enhancement of the melting temperature of the modified lamellae. It turns out that the destruction level of crystalline material at 45°C, after 15–20 h is of the order of 20% and progressively increases for longer periods of time.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00275978
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  • 6
    Electronic Resource
    Electronic Resource
    Lamellar structure in melt crystallized low density polyethylene (1983)
    Springer
    Colloid & polymer science 261 (1983), S. 412-416 
    Details
    ISSN: 1435-1536
    Keywords: Lamellar structure ; low density polyethylene ; chlorosulfonation ; small angle X-ray diffraction ; electronmicroscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The investigation of representative details in the lamellar microstructure of LDPE observed after controlled chlorosulfonation using both EM and SAXD is reported. For this purpose melt crystallized PE with two branch contents (ε=0.28 and 2.53 branches per 102CH2) has been prepared using Kanig's technique over a range of temperatures and treatment times. During the first treatment hours the selective incorporation of electron-dense atoms at the lamellar surface produces a macroscopic weight increase, swelling of the sample and a concurrent decrease of the SAXS intensity. The main result, however, is that the thickness of the lamellar structure does not vary with treatment time. After long chlorosulfonation times a saturation of electron-dense atoms within the surface layer and a reduction in the lateral dimensions of the lamellae take place. Optimum conditions for revealing the representative morphology are such as to lead to a weight increase of 50% for PE withε=0.28 of branches and only to an increase of 10% for material of branch content represented by anε value of 2.53.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01418215
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  • 7
    Electronic Resource
    Electronic Resource
    Degradation of nitric acid-trbeated bulk polyethylene (1983)
    Springer
    Colloid & polymer science 261 (1983), S. 626-630 
    Details
    ISSN: 1435-1536
    Keywords: Low-density polyethylene ; differential scanning-calorimetry ; long period ; fuming nitric acid ; dicarboxylic acids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract LDPE samples with differing branching content were treated with fuming nitric acid for times up to 180 h at 60°C. The samples were examined by differential scanning calorimetry and small angle X-ray diffraction. While the crystal thickness derived from the X-ray long period remains practically constant throughout treatment timet, a conspicuous sharpening and shifting of the melting curves to higher temperatures witht is observed. It is suggested that the shift in melting peak is caused by the contribution of the dicarboxylic groups attached to the crystal surface after treatment. It is further shown that the shift depends inversely on the crystal thickness. The comparison of melting points for long time nitric acid treated PE samples with data from dicarboxylic acids has permitted the derivation of an expression for the melting temperature of longer molecular diacids.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01415031
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  • 8
    Electronic Resource
    Electronic Resource
    Degradation of nitric acid-treated bulk polyethylene (1980)
    Springer
    Polymer bulletin 3 (1980), S. 305-310 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary The Selective removal of Chain Defects (branches, unsaturations) by nitric acid from melt crystallized polyethylene is examined with reference to the question of the distribution of defects between crystalline and “amorphous” domains. The results obtained using the IR methyl band at 1376 cm−1 together with weight-loss measurements support the view that the majority of defects, which are situated in the non-crystalline regions, are selectively digested by the nitric acid attack. After removal of the non-crystalline phase the small remaining branch content located within the crystal cores confirms the levels of defect inclusion previously derived from unit cell expansion data.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00254879
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  • 9
    Electronic Resource
    Electronic Resource
    X-ray diffraction study of poly(p-phenylene). Part I. Variation of crystallite size with annealing temperature (1990)
    Weinheim : Wiley-Blackwell
    Acta Polymerica 41 (1990), S. 152-155 
    Details
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Eine Linienprofilanalyse der (hk0)-Reflexe von gesintertem Poly(p-phenylen) wird vorgestellt. Die Maxima der Weitwinkelröntgenbeugung wurden analysiert, um die mittlere Größe der kohärent streuenden Bereiche in Abhängigkeit von der Temperatur TA zu untersuchen. Die Ergebnisse zeigen, daß die Querabmessung der kohärent streuenden Bereiche bis TA = 300°C zuerst leicht zunimmt und dann für TA 〉 300°C stark anwächst. Dies hängt mit der Umordnung starrer Ketten aus den ungeordneten in kristalline Bereiche zusammen. Das Fehlen einer Röntgenkleinwinkelstreuung stützt die Annahme einer eingefrorenen nematischen flüssig-kristallinen Struktur, die etwa 40% des Materials umfaßt.
    Notes: A line profile analysis of the (hk0) reflections of sintered poly(p-phenylene) is presented. The wide angle X-ray diffraction maxima were analyzed to study the average size of the coherently diffracting domains as a function of annealing temperature TA. The results show that the lateral size of the coherently diffracting domains increase first slightly for TA 〈 300°C and then rapidly for TA 〉 300°C. This is related to a rearrangement of rigid chains from disordered into the crystalline regions. The absence of SAXS supports the view of a nematic frozen-in liquid crystalline structure contributing to about 40% of the material.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/actp.1990.010410303
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