Impact of aspect ratio and CNT loading on the dynamic mechanical and flammability properties of polyethylene nanocomposites

e-Polymers ◽  
2014 ◽  
Vol 14 (1) ◽  
pp. 57-63 ◽  
Author(s):  
Selvin P. Thomas ◽  
Mostafizur Rahaman ◽  
Ibnelwaleed A. Hussein
Keyword(s):  
Aspect Ratio ◽  
Heat Release ◽  
Late Onset ◽  
Melt Blending ◽  
Crystallization Peak ◽  
Multiwalled Carbon ◽  
Dynamic Mechanical ◽  
Release Capacity ◽  
Peak Heat Release Rate ◽  
Heat Release Capacity

AbstractIn this study, the effects of aspect ratio and loading of multiwalled carbon nanotubes (MWCNTs) on the dynamic mechanical, thermal, and flammability properties of low-density polyethylene (LDPE)/MWCNT nanocomposites prepared by the melt blending technique were investigated. At low CNT loading, CNT with low aspect ratio acted as a plasticizer in LDPE. The storage modulus of the nanocomposites increased with the increase in aspect ratio and CNT loading. The increase in scan rate for the composites results in the decrease in total crystallinity, crystallization peak temperature, and a late onset of crystallization. The flammability properties like heat release capacity, peak heat release rate, and total heat release decrease with the increase in both aspect ratio and loading of CNTs in the composites.

Evaluation of mechanical and dynamic mechanical properties of multiwalled carbon nanotube-based ethylene–propylene copolymer composites mixed by masterbatch dilution

2016 ◽  
Vol 50 (29) ◽  
pp. 4093-4101 ◽  
Author(s):  
Maija Hoikkanen ◽  
Minna Poikelispää ◽  
Amit Das ◽  
Uta Reuter ◽  
Wilma Dierkes ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Aspect Ratio ◽  
Melt Mixing ◽  
Multiwalled Carbon ◽  
Mixing Processes ◽  
Ethylene Propylene ◽  
Dynamic Mechanical ◽  
Mixing Method

A two-step masterbatch mixing technique was studied for preparation of carbon nanotube-filled ethylene–propylene diene elastomer compounds, and compared to conventional one-step mixing process. In the two-step process, a masterbatch compound with carbon nanotube content of 50 parts per hundred was prepared by melt-mixing ethylene–propylene diene elastomer. This material was then compounded with pristine ethylene–propylene diene elastomer and composites with different carbon nanotube concentrations were compared. The aim of this study is to compare the efficiency of two different mixing processes on the dispersion of carbon nanotubes and to facilitate the handling of carbon nanotubes, as the masterbatch can be prepared in a controlled way and used for further dilution without the problems related to carbon nanotube processing. The compound properties were studied with emphasis on mechanical characterization and dynamic mechanical thermal analysis. Masterbatch mixing resulted in the similar mechanical properties of the composites compared to the direct mixing method. At the relatively low loadings of carbon nanotubes, the considerable improvements of the mechanical properties were observed. The aspect ratio of the carbon nanotubes determined by transmission electron microscope was found to be similar to the one calculated from the Guth equation. It showed a considerable reduction in aspect ratio independent of the used mixing method.

scholarly journals Impact of melamine and its derivatives on the properties of poly(vinyl acetate)-based composite wood adhesive

2020 ◽  
Author(s):  
Zuzanna Góral ◽  
Joanna Mastalska-Popławska ◽  
Piotr Izak ◽  
Paweł Rutkowski ◽  
Joanna Gnyla ◽  
...  
Keyword(s):  
Heat Release ◽  
Vinyl Acetate ◽  
Glass Fibers ◽  
Fire Retardant ◽  
Wood Adhesive ◽  
Melamine Phosphate ◽  
Release Capacity ◽  
Ceramic Fillers ◽  
Heat Release Capacity ◽  
Composite Wood

Abstract A fire retardant composite adhesive for bonding wood and wood-based elements has been developed and characterized. To obtain the enhanced fire-proof properties of the wood adhesive dispersion based on the poly(vinyl acetate) (PVAc), ceramic fillers (17.5 wt% total)—alumina, silica, kaolin and glass fibers were applied. Moreover, fire retardants such as melamine, melamine phosphate and melamine polyphosphate (up to 7 wt%) were also used. Thermal analysis (TG-DSC), strength tests, rheology, pH and flammability measurements (PCFC) were performed. The best properties of the adhesive were achieved for ceramic additives supported by melamine phosphate. A slight improvement of shear strength, shift of the last decomposition step of PVAc (residue degradation) towards higher temperatures by about 50 °C, reduction in mass loss from 100 wt% to less than 70 wt% and about 30–40% improvement of flammability parameters such as heat release capacity, total heat release or peak heat release rate were found compared to the pure poly(vinyl acetate) adhesive.

Numerical study on the heat release capacity of the active-passive phase change wall affected by ventilation velocity

2020 ◽  
Vol 150 ◽  
pp. 1047-1056 ◽  
Author(s):  
Yong Guan ◽  
Tuo Wang ◽  
Rui Tang ◽  
Wanling Hu ◽  
Jianxuan Guo ◽  
...  
Keyword(s):  
Phase Change ◽  
Heat Release ◽  
Numerical Study ◽  
Release Capacity ◽  
Heat Release Capacity ◽  
Passive Phase ◽  
Ventilation Velocity

scholarly journals Nacre-Mimetic Green Flame Retardant: Ultra-High Nanofiller Content, Thin Nanocomposite as an Effective Flame Retardant

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2351
Author(s):  
Irlaine Machado ◽  
Isabel Hsieh ◽  
Veronica Calado ◽  
Thomas Chapin ◽  
Hatsuo Ishida
Keyword(s):  
Heat Release ◽  
Flame Retardant ◽  
Polyurethane Foam ◽  
Proton Nuclear Magnetic Resonance ◽  
Resonance Spectroscopy ◽  
Compression Tests ◽  
Release Capacity ◽  
Cone Calorimeter Test ◽  
Heat Release Capacity ◽  
Nanofiller Content

A nacre-mimetic brick-and-mortar structure was used to develop a new flame-retardant technology. A second biomimetic approach was utilized to develop a non-flammable elastomeric benzoxazine for use as a polymer matrix that effectively adheres to the hydrophilic laponite nanofiller. A combination of laponite and benzoxazine is used to apply an ultra-high nanofiller content, thin nanocomposite coating on a polyurethane foam. The technology used is made environmentally friendly by eliminating the need to add any undesirable flame retardants, such as phosphorus additives or halogenated compounds. The very-thin coating on the polyurethane foam (PUF) is obtained through a single dip-coating. The structure of the polymer has been confirmed by proton nuclear magnetic resonance spectroscopy (1H NMR) and Fourier transform infrared spectroscopy (FTIR). The flammability of the polymer and nanocomposite was evaluated by heat release capacity using microscale combustion calorimetry (MCC). A material with heat release capacity (HRC) lower than 100 J/Kg is considered non-ignitable. The nanocomposite developed exhibits HRC of 22 J/Kg, which is well within the classification of a non-ignitable material. The cone calorimeter test was also used to investigate the flame retardancy of the nanocomposite’s thin film on polyurethane foam. This test confirms that the second peak of the heat release rate (HRR) decreased 62% or completely disappeared for the coated PUF with different loadings. Compression tests show an increase in the modulus of the PUF by 88% for the 4 wt% coating concentration. Upon repeated modulus tests, the rigidity decreases, approaching the modulus of the uncoated PUF. However, the effect of this repeated mechanical loading does not significantly affect the flame retarding performance.

scholarly journals Exploring the Contribution of Two Phosphorus-Based Groups to Polymer Flammability via Pyrolysis–Combustion Flow Calorimetry

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 2961 ◽  
Author(s):  
Rodolphe Sonnier ◽  
Belkacem Otazaghine ◽  
Christelle Vagner ◽  
Frédéric Bier ◽  
Jean-Luc Six ◽  
...  
Keyword(s):  
Heat Release ◽  
Cooperative Interaction ◽  
Flow Calorimetry ◽  
Complete Combustion ◽  
Release Capacity ◽  
Phosphorus Containing ◽  
Combustion Flow ◽  
Heat Release Capacity ◽  
Polymer Flammability ◽  
Good Agreement

From a set of around 100 phosphorus-containing polymers tested in pyrolysis–combustion flow calorimetry, the contributions to flammability of two phosphorus-containing pendant groups (called 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and PO3) were calculated using an advanced method previously proposed and validated. The flammability properties include total heat release (THR) and heat release capacity (HRC) measured in standard conditions, i.e., anaerobic pyrolysis and complete combustion. The calculated contributions are in good agreement with the main modes of action of both phosphorus groups, i.e., flame inhibition for DOPO and char promotion for PO3. Moreover, the results provide first conclusions about the cooperative interaction between phosphorus and nitrogen, as well as the influence of the architecture of tested co-polymers.

Iron-containing, high aspect ratio clay as nanoarmor that imparts substantial thermal/flame protection to polyurethane with a single electrostatically-deposited bilayer

2014 ◽  
Vol 2 (41) ◽  
pp. 17609-17617 ◽  
Author(s):  
A. A. Cain ◽  
M. G. B. Plummer ◽  
S. E. Murray ◽  
L. Bolling ◽  
O. Regev ◽  
...  
Keyword(s):  
Thin Films ◽  
Aspect Ratio ◽  
Heat Release ◽  
Polyurethane Foam ◽  
Heat Release Rate ◽  
Release Rate ◽  
High Aspect Ratio ◽  
Peak Heat Release Rate ◽  
Self Assembled ◽  
Flame Protection

Single bilayer polymer/clay nanobrick wall self-assembled thin films, deposited as a continuous coating on open-celled polyurethane foam, cut peak heat release rate in half with only 3.2 wt% addition.

scholarly journals Influence of fiberglass mesh on flammability of EPS used as insulation of buildings

2018 ◽  
Vol 22 (2) ◽  
pp. 1025-1036
Author(s):  
Qiang Xu ◽  
Cong Jin ◽  
Gregory Griffin ◽  
Jordan Hristov ◽  
Dejan Cvetinovic ◽  
...  
Keyword(s):  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Fire Behavior ◽  
Fire Spread ◽  
Expanded Polystyrene ◽  
Heat Fluxes ◽  
Release Capacity ◽  
Heat Release Capacity ◽  
Combustion Calorimeter

Different scale tests to explore the influence of fiberglass mesh on the fire behavior of expanded polystyrene (EPS) have been conducted. Micro scale combustion calorimeter to measure the heat release rate per unit mass, heat release capacity, and the total heat release of EPS and as well as the fiberglass for milligram specimen mass has been used. Cone colorimeter bench scale burning tests with the EPS specimens and EPS-fiberglass compound specimens have been carried out. The heat release rate per unit area, ignition times, and the derived minimum igniting heat fluxes were determined. Comparative burning tests on the fire spread tendency of EPS and EPS-fiberglass compound specimens have been carried out. It was established that the fiberglass mesh stabilizes the EPS fire as a wick fire due to the adherence of the melting polystyrene adheres to the fiberglass mesh and this causes an upwards fire spread.

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