Study of stretched polypropylene fibres by pulsed and CW NMR spectroscopy

Ševčovič, L.; Mucha, L.

doi:10.1016/j.ssnmr.2009.09.001

Cited by 4 publications

(2 citation statements)

References 23 publications

(41 reference statements)

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“…Besides higher intensities of the lines of the CH 2 and CH carbons in amorphous regions also Deconvolution of the spectra measured for the miPP and ZN-iPP is also shown in Figure 6 and the relative integral intensities of the individual lines determined by this procedure are summarized for both studied samples in Table 3. In spite of the fact that we have used a two-phase model of polymer with crystalline and amorphous regions only, while three-phase model takes into account also interphase regions of the partially crystalline polymer [7,11,17], the relative integral intensities of the lines related to the main chain CH 2 and CH groups in the crystalline regions of both samples are in accordance with the degree of the crystallinity obtained by DSC (cf. Table 1).…”

Section: Resultssupporting

confidence: 62%

“…Alternative explanation that the observed differences might be in connection with the dispersion of chemical shifts seems to be for two highlyisotactic polymers rather improbable. The segmental motion in amorphous regions of iPP is related to the glass transition relaxation (#-relaxation) that was recently studied by wide-line 1 H NMR [17]. To confirm a difference discussed above we also measured 1 H NMR spectra under MAS with the spinning rate of 6 kHz at 71°C.…”

Section: Resultsmentioning

confidence: 82%

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High-resolution solid-state NMR study of isotactic polypropylenes

Fričová¹,

Uhrinova²,

Hronský³

et al. 2012

Express Polym. Lett.

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Since the commercialization of Ziegler-Natta process of polypropylene synthesis, this technology was for decades almost the only source of all grades of polypropylene (PP). Only at the end of the last century a new process was developed, based on metallocene catalysis. This process provides new types of metallocene PP (m-PP) different from previous Ziegler Natta PP types (ZN-PP), the main difference consisting in the production of grades with different stereoregularity (isotactic, syndiotactic, hemi-isotactic, atactic) [1] or narrow polydispersity of the polymer chains, compared to Ziegler-Natta catalysts, which produces only highly polydisperse isotactic polymers. The tacticity of isotactic (i) m-PP and ZN-PP is virtually the same (98% of isotactic diads), though the configurational defects are more frequent in m-iPP [2]; this might be reflected in a lower melting temperature of m-iPP in comparison with ZN-iPP. Comparing to ZN-iPP, m-iPP offers a unique balance of stiffness, transparency, and organoleptic properties which is not achievable with ZN-iPP. On the other hand, m-iPP is usually less rigid than ZNiPP homopolymers. Thus, any additional information on similarity or differences in m-iPP vs. ZNiPP behaviour seems to be of scientific as well as Abstract. The high-resolution solid-state 13 C NMR spectra were recorded for metallocene (m) and Ziegler-Natta (ZN) isotactic polypropylenes (iPP) in pelletized form using cross polarization (CP) and magic angle spinning (MAS) techniques within the temperature range of 20-160°C. Besides the CP MAS experiments also the MAS 13 C NMR spectra (without CP), MAS 1 H NMR spectra and rotating frame spin-lattice relaxation times T 1" ( 13 C) were measured at elevated temperatures. With the rise of temperature the splitting of CH 2 , CH and CH 3 signals into two components was detected in 13 C NMR spectra and assigned to amorphous and crystalline phases. The temperature dependences of chemical shifts and integral intensities obtained from the deconvoluted spectra provided information on the main chain and CH 3 groups motions in amorphous and crystalline regions of studied samples. While T 1" ( 13 C) values show that the rate of segmental motion in amorphous regions in m-iPP and ZN-iPP is virtually the same, larger linewidths in 13 Vol.6, No.3 (2012) 204-212 Available online at www.expresspolymlett.com DOI: 10.3144/expresspolymlett.2012.23 * Corresponding author, e-mail: olga.fricova@tuke.sk © BME-PT commercial importance. NMR investigation is considered to be one of the basic relevant methods. The high-resolution solid-state 13 C NMR studies of iPP reported NMR spectra recorded with combination of magic angle spinning (MAS), cross polarisation (CP) and dipolar decoupling (DD) techniques [3][4][5][6][7][8][9][10][11][12][13][14]. Since iPP can crystallize in several crystalline forms, depending on the crystallization temperature and on the presence of specific nucleating agents, the shape of the spectra was found to depend strongly on the physical treatment of the sa...

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Section: Resultssupporting

confidence: 62%

Section: Resultsmentioning

confidence: 82%

High-resolution solid-state NMR study of isotactic polypropylenes

Fričová¹,

Uhrinova²,

Hronský³

et al. 2012

Express Polym. Lett.

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Solid and melt-state 1H NMR studies of relaxation processes in isotactic polypropylenes

et al. 2013

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Effect of Composition on the Molecular Dynamics of Biodegradable Isotactic Polypropylene/Thermoplastic Starch Blends

Woźniak-Braszak

Knitter

Markiewicz

et al. 2019

ACS Sustainable Chem. Eng.

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Polyolefins such as polypropylene are used in an immensely broad range of commodity products and account for the largest volume of synthetic polymers generated worldwide. For this reason, this family of thermoplastics contributes significantly to solid waste both on land and in the ocean. One viable approach to mitigate this growing problem and simultaneously reduce the cost of and dependence on petroleum-based polymers relies on blends wherein an added biopolymer can promote natural biodegradation. Due to their chemical dissimilarity, however, nonpolar polyolefins and polar biopolymers tend to phase-separate, in which case a fundamental, molecular-level understanding of the role of polymer/polymer interfaces on chain mobility in blends differing in composition is needed. In the present study, the molecular dynamics of blends composed of isotactic polypropylene (iPP) and glycerol-plasticized thermoplastic starch (TPS) are investigated by solid-state proton nuclear magnetic resonance and dielectric relaxation spectroscopies. Blends prepared by twin-screw extrusion range in composition from 10 to 70 wt % TPS, and their morphologies and thermal properties are examined by scanning electron microscopy and differential scanning calorimetry, respectively. This comparative analysis establishes the influence of TPS on the molecular dynamics of biphasic iPP/TPS blends relative to the constituent homopolymers.

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Study of stretched polypropylene fibres by pulsed and CW NMR spectroscopy

Cited by 4 publications

References 23 publications

High-resolution solid-state NMR study of isotactic polypropylenes

High-resolution solid-state NMR study of isotactic polypropylenes

Solid and melt-state 1H NMR studies of relaxation processes in isotactic polypropylenes

Effect of Composition on the Molecular Dynamics of Biodegradable Isotactic Polypropylene/Thermoplastic Starch Blends

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