Electrical conductivity of carbon nanotube/polypropylene composites prepared through microlayer extrusion technology

2017 ◽  
Vol 37 (8) ◽  
pp. 795-804 ◽  
Author(s):  
Changjin Li ◽  
Zhiwei Jiao ◽  
Liangzhao Xiong ◽  
Weimin Yang
Keyword(s):  
Electrical Conductivity ◽  
Polymer Matrix ◽  
Rotation Speed ◽  
Mapping Method ◽  
Degree Of Crystallinity ◽  
Polypropylene Composites ◽  
Multilayered Composites ◽  
Promising Application ◽  
Anisotropic Conducting ◽  
Extrusion Technology

Abstract The morphological distribution of carbon nanotubes (CNTs) in polymer matrix has a crucial impact on the performance of CNT-filled polymer composites. A novel microlayer extrusion technology used in the dispersion and orientation of CNTs was proposed, and polypropylene (PP)/multiwalled CNT (MWCNT) composites with different numbers of layers were prepared with it. The MWCNT dispersion was investigated by scanning electron microscopy and Raman mapping method, and the MWCNT orientation was quantified by Raman spectroscopy. The influences of the dispersion and orientation of MWCNTs on the electrical conductivity and crystallization behavior of the composites were investigated. The results showed that the anisotropic conducting properties of the multilayered composites varied distinguishably with the increase of layer numbers and rotation speed. Furthermore, the degree of crystallinity of PP increased when the layer number increased from 1 to 729. All of these results suggest that with the increase of the layer numbers and the rotation speed, the dispersion and orientation of MWCNTs in PP matrix improve greatly. Overall, we provide an efficient and practical approach to control the dispersion and orientation of CNT in polymer matrix, which has a promising application prospect in the field of plastic processing.

Effects of the Mould Pressure and Mould Pressing Time on the Properties of Graphite/Phenolic Resin Composites

2013 ◽  
Vol 706-708 ◽  
pp. 95-98
Author(s):  
Mi Dan Li ◽  
Dong Mei Liu ◽  
Lu Lu Feng ◽  
Huan Niu ◽  
Yao Lu
Keyword(s):  
Mechanical Properties ◽  
Electrical Conductivity ◽  
Flexural Strength ◽  
Polymer Matrix ◽  
Phenolic Resin ◽  
Polymer Matrix Composites ◽  
Resin Composites ◽  
Matrix Composites ◽  
Natural Graphite ◽  
Pressing Time

Polymer matrix composites made from phenolic resin are filled with natural graphite powders. They are fabricated by compression molding technique. The density, electrical conductivity and flexural strength of composite are analyzed to determine the influences of mould pressure and mould pressing time on the physical, electrical and mechanical properties of composite. It is found that the density, electrical conductivity and flexural strength of composites increased with increasing mould pressure. Under pressure of 40 MPa for 60 min, the density, electrical conductivity and flexural strength of composites were 1.85 g/cm3, 4.35  103 S/cm and 70 MPa, respectively. The decreased gaps could be the main reason for the increasing of density, electrical conductivity and flexural strength as mould pressure increases. The results also show that the density of composites increased with increasing mould pressing time.

scholarly journals Accelerated aging of WPCs Based on Polypropylene and Birch plywood Sanding Dust

2021 ◽  
Vol 11 (1) ◽  
pp. 319-328
Author(s):  
Janis Kajaks ◽  
Karlis Kalnins ◽  
Juris Matvejs
Keyword(s):  
Accelerated Aging ◽  
Degree Of Crystallinity ◽  
Accelerated Weathering ◽  
Recrystallization Process ◽  
Surface Layers ◽  
Uv Aging ◽  
Polypropylene Composites ◽  
Weathering Processes ◽  
Melting Temperatures ◽  
Dsc Measurements

Abstract A lot of researchers are closely related with natural, lignocellulose fibre containing bio-composites production and studies. Various of polymer matrices, mainly polyolefins, combinations with natural fibres as a reinforcement are used. Our studies are focused on polypropylene based bio-composites containing birch plywood production by-product sanding dust (PSD) accelerated weathering processes. The obtained results showed the following sight. After the aging the surface of all samples had faded, the changes of the gloss (decreasing) and of the whiteness degree (increasing) also had taken place, but microhardness of the surface of specimens significantly has decreased. The tensile strength and modulus of the samples after UV aging diminished about 30–35%. That indicates to the changes not only in the surface layers of polymer but also inside of the polymer structure. The FTIR measurements showed that during UV aging process occurs significant changes of chemical structure of the weathered surface of all samples. DSC measurements showed an increase of degree of crystallinity of the weathered polypropylene composites after the first heating due to the recrystallization process in the polypropylene matrix and a small decreasing after second heating. The melting temperatures of all composites after UV aging considerably diminish up to 30°C.

Production of Dispersion-Strengthened Cu-TiB2 Alloys by Ball-Milling and Spark-Plasma Sintering

2007 ◽  
Vol 534-536 ◽  
pp. 1489-1492 ◽  
Author(s):  
Dae Hwan Kwon ◽  
Jong Won Kum ◽  
Thuy Dang Nguyen ◽  
Dina V. Dudina ◽  
Pyuck Pa Choi ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Ball Milling ◽  
Spark Plasma Sintering ◽  
Ball Mill ◽  
Milling Time ◽  
Rotation Speed ◽  
Sintering Temperature ◽  
Milled Powder ◽  
Plasma Sintering ◽  
Spark Plasma

Dispersion-strengthened copper with TiB2 was produced by ball-milling and spark plasma sintering (SPS).Ball-milling was performed at a rotation speed of 300rpm for 30 and 60min in Ar atmosphere by using a planetary ball mill (AGO-2). Spark-plasma sintering was carried out at 650°C for 5min under vacuum after mechanical alloying. The hardness of the specimens sintered using powder ball milled for 60min at 300rpm increased from 16.0 to 61.8 HRB than that of specimen using powder mixed with a turbular mixer, while the electrical conductivity varied from 93.40% to 83.34%IACS. In the case of milled powder, hardness increased as milling time increased, while the electrical conductivity decreased. On the other hand, hardness decreased with increasing sintering temperature, but the electrical conductiviey increased slightly

Heat Build-Up and Fire Performance of Wood-Polypropylene Composites Containing Recycled Mineral Wool

2013 ◽  
Vol 849 ◽  
pp. 269-276
Author(s):  
Olli Väntsi ◽  
Timo Kärki
Keyword(s):  
Heat Release ◽  
Polymer Matrix ◽  
Mineral Wool ◽  
Fire Performance ◽  
Wood Plastic Composites ◽  
Polypropylene Composites ◽  
Plastic Composites ◽  
Wool Fibers ◽  
Residual Masses ◽  
Heat Build Up

The heat build-up and fire performance of wood plastic composites containing recycled mineral wool filler were investigated. Six wood polypropylene composites with recycled mineral wool content between 0 % and 64 % were evaluated. It was found that the heat build-up of the studied composites increased with initial addition of recycled mineral wool, but increasing the content of recycled mineral wool in the composites further did not have a notable effect onthe heat build-up. Fire performance investigation showed that the addition of recycled mineral wool into the composites did not decrease the magnitude of heat release rate peak, but decreased the total heat release of the composites. Investigation of residual masses after the pyrolysis demonstrated a good dispersion of recycled mineral wool fibers in the polymer matrix. It is concluded that fire protection of the polymer matrix is essential when developing the fire performance of wood plastic composites with recycled mineral wool as filler.

scholarly journals Production of conductive bacterial cellulose-polyaniline membranes in the presence of metal salts

2019 ◽  
Vol 90 (13-14) ◽  
pp. 1517-1526
Author(s):  
Hyunjin Kim ◽  
Ji Eun Song ◽  
Carla Silva ◽  
Hye Rim Kim
Keyword(s):  
Electrical Conductivity ◽  
Bacterial Cellulose ◽  
Metal Salt ◽  
Cost Effective ◽  
Chain Structure ◽  
Copper Salt ◽  
Metal Salts ◽  
Degree Of Crystallinity ◽  
Cost Effective Method ◽  
Washing Durability

This study presents a cost-effective method of enhancing the electrical conductivity and washing durability of bacterial cellulose (BC)-polyaniline (PANI) membrane by the addition of metal salt. In this study, two types of metal salts were tested: copper (II) sulfate and iron (II) sulfate. The optimal condition to produce BC-PANI-metal salt membranes was 0.05% (w/v) of copper (II) sulfate (copper salt). X-ray diffraction analysis showed that the crystallinity of BC-PANI increased after adding copper salt. According to the increased degree of crystallinity, the polymer chain structure of BC-PANI-copper salt (BC-PANI-Cu) was more organized than that of BC-PANI, as confirmed by scanning electron microscopy. In addition, this ordered structure of BC-PANI-Cu indicated enhanced electrical conductivity. Moreover, the addition of copper salt improved the electrical conductivity of BC-PANI to a level about 3.8 times higher than that of BC-PANI produced without metal salt, and it retained about 40% of its original electrical conductivity after three washing cycles. From the results, the addition of copper salt improved both the electrical conductivity and washing durability of the BC-PANI membrane.

Effect of modified microcrystalline cellulose on poly(3-hydroxybutyrate) molecular dynamics by proton relaxometry

2020 ◽  
pp. 096739112092607
Author(s):  
Filipe Antonio dos Santos Viegas Ribeiro ◽  
Maxwell de Paula Cavalcante ◽  
Maria Inês Bruno Tavares ◽  
Amanda Ramos Aragão Melo
Keyword(s):  
Molecular Dynamics ◽  
Polymer Matrix ◽  
Degree Of Crystallinity ◽  
Hybrid Films ◽  
Scanning Calorimetry ◽  
Reciprocal Influence ◽  
Proton Relaxometry ◽  
Solution Casting Method ◽  
Cellulose Concentration ◽  
Modified Cellulose

Hybrid films of poly(3-hydroxybutyrate) (PHB) and modified cellulose by solution casting method were prepared, aiming to study the influence of modified cellulose (0.25%, 0.5% and 0.75% w/w) on the structural organization and thermal properties of PHB matrix. The modified cellulose showed good dispersion in polymer matrix, due to the high compatibility between phases explained by similarity of polymer and filler structures. The composites were studied by wide-angle X-ray diffractometry, differential scanning calorimetry, thermogravimetric analysis, and time-domain nuclear magnetic resonance (NMR) spectroscopy. The conjugation of results coming from those techniques allowed to determine the cellulose concentration that had the highest influence on crystalline planes and degree of crystallinity of PHB, that is, the influence in the composite structure. The molecular dynamics obtained by NMR showed a reciprocal influence between polymer matrix and cellulose particles, enhancing the interactions present in the agglomerated particles.

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