TY - JOUR

T1 - Structure of the in situ produced polyethylene based composites modified with multi-walled carbon nanotubes

T2 - In situ synchrotron X-ray diffraction and differential scanning calorimetry study

AU - Kazakova, Mariya A.

AU - Selyutin, Alexander G.

AU - Semikolenova, Nina V.

AU - Ishchenko, Arcady V.

AU - Moseenkov, Sergey I.

AU - Matsko, Mikhail A.

AU - Zakharov, Vladimir A.

AU - Kuznetsov, Vladimir L.

PY - 2018/10/20

Y1 - 2018/10/20

N2 - Polyethylene based composites modified with multi-walled carbon nanotubes (MWCNTs) were produced via in situ polymerization of ethylene with the Ti-Ziegler–Natta catalyst preliminarily immobilized on MWCNTs. The composite structure was characterized with transmission and scanning electron microscopy, differential scanning calorimetry (DSC) and in situ synchrotron X-ray Diffraction (in situ XRD). For the first time the Ti-containing catalyst species of the size 2–3 nm were observed on the MWСNTs surface stabilized in the polymer matrix. A comparative study of the melting-crystallization cycles of neat polyethylene (PE) and MWCNT-PE composites with in situ XRD and DSC provide information on the nucleation of PE crystals. For the first time, the in situ XRD technique was used for estimation of the coherent scattering region of PE blocks during the melting-crystallization cycles. These experiments and molecular dynamic modeling showed that MWCNTs act as the template for the PE chain orientation and as the nucleating agent for PE crystallization. However, the nucleation of PE crystals in composites occurs on the nanotube surface and also within the space between nanotubes. Thus, the relative volume of PE nucleated on nanotubes depends on their content in the composite and can be significant only for the composites with high nanotube loading.

AB - Polyethylene based composites modified with multi-walled carbon nanotubes (MWCNTs) were produced via in situ polymerization of ethylene with the Ti-Ziegler–Natta catalyst preliminarily immobilized on MWCNTs. The composite structure was characterized with transmission and scanning electron microscopy, differential scanning calorimetry (DSC) and in situ synchrotron X-ray Diffraction (in situ XRD). For the first time the Ti-containing catalyst species of the size 2–3 nm were observed on the MWСNTs surface stabilized in the polymer matrix. A comparative study of the melting-crystallization cycles of neat polyethylene (PE) and MWCNT-PE composites with in situ XRD and DSC provide information on the nucleation of PE crystals. For the first time, the in situ XRD technique was used for estimation of the coherent scattering region of PE blocks during the melting-crystallization cycles. These experiments and molecular dynamic modeling showed that MWCNTs act as the template for the PE chain orientation and as the nucleating agent for PE crystallization. However, the nucleation of PE crystals in composites occurs on the nanotube surface and also within the space between nanotubes. Thus, the relative volume of PE nucleated on nanotubes depends on their content in the composite and can be significant only for the composites with high nanotube loading.

KW - In situ polymerization

KW - In situ synchrotron X-ray diffraction

KW - Multi-walled carbon nanotubes

KW - Polyethylene composites

KW - Polymer crystallization

KW - FIELD

KW - MECHANICAL-PROPERTIES

KW - GROMACS

KW - SINGLE-WALL

KW - FUNCTIONALIZATION

KW - NANOPARTICLES

KW - NANOCOMPOSITES

KW - CALIBRATION COEFFICIENT

KW - HEAT-FLOW DSC

UR - http://www.scopus.com/inward/record.url?scp=85050891844&partnerID=8YFLogxK

U2 - 10.1016/j.compscitech.2018.07.046

DO - 10.1016/j.compscitech.2018.07.046

M3 - Article

AN - SCOPUS:85050891844

VL - 167

SP - 148

EP - 154

JO - Composites Science and Technology

JF - Composites Science and Technology

SN - 0266-3538

ER -