Synergistic effects of metal hydroxides and fumed nanosilica as fire retardants for polyethylene

AbstractThis work aims to study the synergistic effect of aluminum/magnesium hydroxide microfillers and organomodified fumed silica nanoparticles as flame retardants (FRs) for linear low-density polyethylene (LLDPE), and to select the best composition to produce a fire-resistant polyethylene-based single-polymer composite. The fillers were added to LLDPE at different concentrations, and the prepared composites were characterized to investigate the individual and combined effects of the fillers on the thermo-oxidation resistance and the fire performance, as well as the microstructural, physical, thermal and mechanical properties. Both filler types were homogeneously distributed in the matrix, with the formation of a network of silica nanoparticles at elevated loadings. Melt flow index (MFI) tests revealed that the fluidity of the material was not considerably impaired upon metal hydroxide introduction, while a heavy reduction of the MFI was detected for silica contents higher than 5 wt%. FRs introduction promoted a noticeable enhancement of the thermo-oxidative stability of the materials, as shown by thermogravimetric analysis (TGA) and onset oxidation temperature (OOT) tests, and superior thermal properties were measured on the samples combining micro- and nanofillers, thus evidencing synergistic effects. Tensile tests showed that the stiffening effect due to a high content of metal hydroxide microparticles was accompanied by a decrease in the strain at break, but nanosilica at low concentration contributed to preserve the ultimate mechanical properties of the neat polymer. The fire performance of the samples with optimized compositions, evaluated through limiting oxygen index (LOI) and cone calorimetry tests, was strongly enhanced with respect to that of the neat LLDPE, and also these tests highlighted the synergistic effect between micro- and nanofillers, as well as an interesting correlation between fire parameters and viscosity.

Download Full-text

Flame Retardancy and Mechanical Properties of Chitosan and DOPO with Different Mass Ratios in Epoxy Resin

10.21203/rs.3.rs-1095633/v1 ◽

2021 ◽

Author(s):

Junjie Wang ◽

Xinyu Wang ◽

Chenyu Zhou ◽

Zhiquan Pan ◽

Hong Zhou

Keyword(s):

Mechanical Properties ◽

Heat Release ◽

Epoxy Resin ◽

Flame Retardancy ◽

Synergistic Effects ◽

Resin Matrix ◽

Simultaneous Increase ◽

Combined System ◽

Cone Calorimetry ◽

Limiting Oxygen Index

Abstract This work focused on the effects of chitosan (CS) and 9,10-dihydro-9-oxo-10-phosphaphenanthrene-10-oxide (DOPO) on the flammable propertied of epoxy resin matrix. The EP composites were fabricated by direct mixing method through a general curing method. The influence of CS, DOPO and CS / DOPO on the resin was investigated through cone calorimetry tests (CC), UL-94 vertical burning, limiting oxygen index (LOI), thermal gravimetric analyzer (TGA), differential scanning calorimeter (DSC) and thermogravimetric analyzer-Fourier infrared combined system (TG-FTIR). The char residues of modified EPs after CC tests were investigated by FTIR, EDX and XPS. Under the 10% addition of CS / DOPO in EP, with the mass ratio of CS and DOPO of 1 : 1, 1 : 2, 1 : 3, 2 : 1 and 3 : 1, the flame retardancy properties of EPs all increased, but only if EP/10% CS1/DOPO2 and EP/10% CS2/DOPO1 achieved a V-0 rating and their values of LOI were 33.7% and 32.5%, respectively. Compared with EP, the peak heat release rate, peak smoke produce rate and total heat release of EP/10% CS1/DOPO2 and EP/10% CS2/DOPO1 decreased, especially, total smoke release decreased by 61.9% and 71.0%, the char residuals amount increased by 84.3% and 41.6%, and the average CO2 yield decreased by 55.4% and 55.0%, respectively. It is worth nothing that the mechanical properties increased, especially the flexural strength increased by 36.0% and 38.4%, respectively. The results indicated that DOPO and CS had important synergistic effects for simultaneous increase both the flame retardancy and mechanical properties of EP composites.

Download Full-text

Halloysite Nanotubes and Silane-Treated Alumina Trihydrate Hybrid Flame Retardant System for High-Performance Cable Insulation

Polymers ◽

10.3390/polym13132134 ◽

2021 ◽

Vol 13 (13) ◽

pp. 2134

Author(s):

Sandra Paszkiewicz ◽

Izabela Irska ◽

Iman Taraghi ◽

Elżbieta Piesowicz ◽

Jakub Sieminski ◽

...

Keyword(s):

Mechanical Properties ◽

Polymer Blend ◽

Hybrid System ◽

Reference Sample ◽

Melt Flow Index ◽

Halloysite Nanotubes ◽

Flow Index ◽

Scanning Calorimetry ◽

Limiting Oxygen Index ◽

Alumina Trihydrate

The effect of the presence of halloysite nanotubes (HNTs) and silane-treated alumina trihydrate (ATH-sil) nanofillers on the mechanical, thermal, and flame retardancy properties of ethylene-vinyl acetate (EVA) copolymer/low-density polyethylene (LDPE) blends was investigated. Different weight percentages of HNT and ATH-sil nanoparticles, as well as the hybrid system of those nanofillers, were melt mixed with the polymer blend (reference sample) using a twin-screw extruder. The morphology of the nanoparticles and polymer compositions was studied using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The mechanical properties, hardness, water absorption, and melt flow index (MFI) of the compositions were assessed. The tensile strength increases as a function of the amount of HNT nanofiller; however, the elongation at break decreases. In the case of the hybrid system of nanofillers, the compositions showed superior mechanical properties. The thermal properties of the reference sample and those of the corresponding sample with nanofiller blends were studied using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Two peaks were observed in the melting and crystallization temperatures. This shows that the EVA/LDPE is an immiscible polymer blend. The thermal stability of the blends was improved by the presence of HNTs and ATH-sil nanoparticles. Thermal degradation temperatures were shifted to higher values by the presence of hybrid nanofillers. Finally, the flammability of the compositions was assessed. Flammability as reflected by the limiting oxygen index (OI) was increased by the presence of HNT and ATH-sil nanofiller and a hybrid system of the nanoparticles.

Download Full-text

Novel Bicomponent Functional Fibers with Sheath/Core Configuration Containing Intumescent Flame-Retardants for Textile Applications

Materials ◽

10.3390/ma12193095 ◽

2019 ◽

Vol 12 (19) ◽

pp. 3095 ◽

Cited By ~ 5

Author(s):

Muhammad Maqsood ◽

Gunnar Seide

Keyword(s):

Mechanical Properties ◽

Flame Retardants ◽

Woven Fabric ◽

Core Component ◽

Cone Calorimetry ◽

Limiting Oxygen Index ◽

Bicomponent Fibers ◽

The Core ◽

Melt Spun ◽

Intumescent Flame Retardants

The objective of this study is to examine the effect of intumescent flame-retardants (IFR’s) on the spinnability of sheath/core bicomponent melt-spun fibers, produced from Polylactic acid (PLA) single polymer composites, as IFR’s have not been tested in bicomponent fibers so far. Highly crystalline PLA-containing IFR’s was used in the core component, while an amorphous PLA was tested in the sheath component of melt-spun bicomponent fibers. Ammonium polyphosphate and lignin powder were used as acid, and carbon source, respectively, together with PES as a plasticizing agent in the core component of bicomponent fibers. Multifilament fibers, with sheath/core configurations, were produced on a pilot-scale melt spinning machine, and the changes in fibers mechanical properties and crystallinity were recorded in response to varying process parameters. The crystallinity of the bicomponent fibers was studied by differential scanning calorimetry and thermal stabilities were analyzed by thermogravimetric analysis. Thermally bonded, non-woven fabric samples, from as prepared bicomponent fibers, were produced and their fire properties, such as limiting oxygen index and cone calorimetry values were measured. However, the ignitability of fabric samples was tested by a single-flame source test. Cone calorimetry showed a 46% decline in the heat release rate of nonwovens, produced from FR PLA bicomponent fibers, compared to pure PLA nonwovens. This indicated the development of an intumescent char by leaving a residual mass of 34% relative to the initial mass of the sample. It was found that the IFRs can be melt spun into bicomponent fibers by sheath/core configuration, and the enhanced functionality in the fibers can be achieved with suitable mechanical properties.

Download Full-text

Polyethylene-based single polymer laminates: Synergistic effects of nanosilica and metal hydroxides

Journal of Reinforced Plastics and Composites ◽

10.1177/0731684418802974 ◽

2018 ◽

Vol 38 (2) ◽

pp. 62-73 ◽

Cited By ~ 2

Author(s):

Andrea Dorigato ◽

Giulia Fredi ◽

Luca Fambri ◽

José-Marie Lopez-Cuesta ◽

Alessandro Pegoretti

Keyword(s):

Polymer Composites ◽

Magnesium Hydroxide ◽

Synergistic Effects ◽

Cone Calorimetry ◽

Polyethylene Matrix ◽

Limiting Oxygen Index ◽

Fumed Silica Nanoparticles ◽

Degradation Temperature ◽

Peak Heat Release Rate ◽

Polymer Laminates

This work aims to investigate the fire performance of novel polyethylene-based single polymer composites. Fumed silica nanoparticles and magnesium hydroxide microfiller were added at an optimized concentration to a linear low-density polyethylene matrix, which was then reinforced with ultra-high molecular weight polyethylene fibers. Through the optimization of the production process, it was possible to limit the porosity inside the single polymer composites, thus retaining the pristine mechanical properties of the fibers. The addition of SiO2 and magnesium hydroxide determined an increase in the elastic modulus in both the longitudinal and transversal direction, but it concurrently led to a reduction in ductility, especially in the transversal direction. The fillers were proved to bring interesting improvements of the thermal degradation resistance and of the flame behaviour. Thermogravimetric analysis tests highlighted an increase in the onset degradation temperature and in the temperature associated to the maximum degradation rate. Moreover, both the oxidation onset temperature and limiting oxygen index were considerably improved. Cone calorimetry tests evidenced that filled single polymer composites were characterized by lower peak heat release rate and total heat released with respect to neat single polymer composites.

Download Full-text

Synergistic Effect of Functionalized Silica Nanoparticles and a β-Nucleating Agent for the Improvement of the Mechanical Properties of a Propylene/Ethylene Random Copolymer

Macromolecular Materials and Engineering ◽

10.1002/mame.201300320 ◽

2013 ◽

Vol 299 (6) ◽

pp. 707-721 ◽

Cited By ~ 14

Author(s):

Dimitrios G. Papageorgiou ◽

George Vourlias ◽

Dimitrios N. Bikiaris ◽

Konstantinos Chrissafis

Keyword(s):

Mechanical Properties ◽

Synergistic Effect ◽

Silica Nanoparticles ◽

Random Copolymer ◽

Nucleating Agent ◽

Functionalized Silica ◽

Functionalized Silica Nanoparticles

Download Full-text

Synergistic Effect of APP and TBC Fire-Retardants on the Physico-Mechanical Properties of Strandboard

Materials ◽

10.3390/ma15020435 ◽

2022 ◽

Vol 15 (2) ◽

pp. 435

Author(s):

Feiyu Tian ◽

Deliang Xu ◽

Xinwu Xu

Keyword(s):

Mechanical Properties ◽

Flame Retardants ◽

Oxygen Index ◽

Fire Retardant ◽

Modulus Of Rupture ◽

Fire Retardancy ◽

Thickness Swelling ◽

Cone Calorimetry ◽

Limiting Oxygen Index ◽

Polymeric Diphenylmethane Diisocyanate

This study explored the feasibility of fabricating fire-retardant strandboard with low mechanical properties deterioration to the physico-mechanical properties. A hybrid fire-retardant system of ammonium polyphosphate (APP) and 1,3,5-tris(2,3-dibromopropyl)-1,3,5-triazinane-2,4,6-trione (TBC) was investigated. Thermogravimetric analysis results show that both APP and TBC enhance the thermal stability and incombustibility of wood strands. An infrared spectrum was applied to investigate the effect of flame retardants on the curing behaviors of polymeric diphenylmethane diisocyanate (PMDI) resin. Based on the results of limiting oxygen index (LOI) and Cone calorimetry (CONE), APP and TBC both lead to a higher fire retardancy to strandboard. It is worth mentioning that the two flame retardants lead to evidently differential influences on the modulus of rupture (MOR), modulus of elasticity (MOE), internal bond (IB), and water-soaking thickness swelling (TS) properties of strandboard. Hence, a hybrid flame retardant is prominent in manufacturing strandboard with both good fire retardant and satisfying physico-mechanical properties.

Download Full-text

Development of multifunctional polyurethane elastomer composites containing fullerene: Mechanical, damping, thermal, and flammability behaviors

Journal of Elastomers & Plastics ◽

10.1177/0095244318796616 ◽

2018 ◽

Vol 51 (3) ◽

pp. 262-279 ◽

Cited By ~ 16

Author(s):

Yasin Kanbur ◽

Umit Tayfun

Keyword(s):

Thermoplastic Polyurethane ◽

Melt Flow Index ◽

Flow Index ◽

Polyurethane Elastomer ◽

Matrix Composites ◽

Fire Performance ◽

Adjuvant Effect ◽

Limiting Oxygen Index ◽

Melt Compounding ◽

Index Value

Thermoplastic polyurethane (TPU) composites filled with fullerene in the range from 0.5 wt% to 2 wt% were fabricated using melt-compounding. Fullerene addition levels up to nearly twofold increase in tensile strength, percent elongation, and modulus of TPU. The mechanical properties are improved as modified C60 content decreases. Fullerene loadings also enhance thermal stability of TPU. Glass transition temperature decreases by the inclusion of C60 into TPU matrix. Composites exhibited the improvement for storage modulus and vibration-damping behavior. The UL-94 rating and limiting oxygen index value of TPU are also extended to higher values after C60 loadings. Adjuvant effect is observed on fire performance in which pristine C60 inclusions and higher concentrations of C60 exhibit better fire performance. Additions of C60 give identical melt flow index values with that of TPU. Modified C60 particles disperse more homogeneously than pristine ones into TPU matrix because of the improvement in interfacial interactions between fullerene and polyurethane elastomer.

Download Full-text

Basalt Fiber-Based Flame Retardant Epoxy Composites: Preparation, Thermal Properties, and Flame Retardancy

Materials ◽

10.3390/ma14040902 ◽

2021 ◽

Vol 14 (4) ◽

pp. 902

Author(s):

Yu Guo ◽

Meihui Zhou ◽

Guang-Zhong Yin ◽

Ehsan Kalali ◽

Na Wang ◽

...

Keyword(s):

Mechanical Properties ◽

Thermal Properties ◽

Flame Retardant ◽

Basalt Fiber ◽

Mechanical Analysis ◽

Epoxy Composites ◽

Cone Calorimetry ◽

Limiting Oxygen Index ◽

Pre Treatment ◽

The Impact

We aimed to study the impact of surface modification of basalt fiber (BF) on the mechanical properties of basalt fiber-based epoxy composites. Four different types of pretreatment approaches to BF were used; then a silane coupling agent (KH550) was applied to further modify the pretreated BF, prior to the preparation of epoxy resin (EP)/BF composites. The combination of acetone (pre-treatment) and KH550 (formal surface treatment) for basalt fiber (BT-AT) imparted the EP/BF composite with the best performance in both tensile and impact strengths. Subsequently, such modified BF was introduced into the flame-retardant epoxy composites (EP/AP750) to prepare basalt fiber reinforced flame-retardant epoxy composite (EP/AP750/BF-AT). The fire behaviors of the composites were evaluated by vertical burning test (UL-94), limiting oxygen index (LOI) test and cone calorimetry. In comparison to the flame-retardant properties of EP/AP750, the incorporation of BF-AT slightly reduced LOI value from 26.3% to 25.1%, maintained the good performance in vertical burning test, but increased the peak of the heat release rate. Besides, the thermal properties and mechanical properties of the composites were investigated by thermogravimetric analysis (TGA), universal tensile test, impact test and dynamic mechanical analysis (DMA).

Download Full-text

A New Flame-Retardant Epoxy Composites Based on Silica and Metal Salt of Phosphinate

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.357-360.1461 ◽

2013 ◽

Vol 357-360 ◽

pp. 1461-1464 ◽

Cited By ~ 3

Author(s):

Xue Qing Liu ◽

Heng Zhou ◽

Ji Yan Liu ◽

Hao Wang ◽

Shao Jun Cai

Keyword(s):

Mechanical Properties ◽

Thermal Stability ◽

Rice Husk ◽

Oxygen Index ◽

Metal Salt ◽

Synergistic Effects ◽

Combustion Time ◽

Limiting Oxygen Index ◽

Rice Husk Silica ◽

Thermal Stability Of

The influence of silica on the mechanical properties, thermal stability and the flammability of epoxy (EP) blended with aluminum methylethylphosphinate (Al (MEP) has been studied by the limiting oxygen index (LOI), UL-94 test, thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). Results show that adding silica enhances the mechanical properties of EP/Al (MEP). Synergistic effects between Al (MEP) and silica are obtained leading to the increase of LOI and to the reduction of combustion time. The TGA data demonstrate that silica can enhance the thermal stability of the EP/Al (MEP) and increase the char residue formation at high temperature. When the rice husk silica is substituted for silica, the composite presents lower LOI, lower thermal stability and char formation as well as inferior mechanical strength. The SEM results indicate that rice husk silica based composite shows poorer fillermatrix adhesion, which will be responsible for its inferior mechanical properties, lower thermal stability and flammability.

Download Full-text