Highly effective flame retardant lignin/polyacrylonitrile composite prepared via solution blending and phosphorylation

Published in Polymer Degradation and Stability 19 September 2020

Abstract

Aiming at improving the thermal stability and flame retardancy of polyacrylonitrile (PAN), a novel flame retardant PAN composite was prepared via a facile approach. First, lignin (LIG) and PAN were dissolved in dimethyl sulfoxide (DMSO) to form a uniform blend solution of LIG and PAN, then the solution was poured into the mould to scrape the LIG/PAN composite film. Subsequently, the flame retardant LIG/PAN composite (FR-LIG/PAN) was fabricated via phosphorylation. The structure of pure PAN, LIG, LIG/PAN and FR-LIG/PAN composite was characterized by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The thermal and combustion properties of the samples were evaluated by using thermogravimetric analysis (TGA) and cone calorimeter test (CCT).

In addition, the cross section and char residue of FR-LIG/PAN composite after combustion were observed by scanning electron microscopy (SEM). Furthermore, the elemental compositions and contents of the cross section and char residue of FR-LIG/PAN composite after combustion were tested by energy-dispersive X-ray spectroscopy (EDS). The results indicated that hydroxyl group and benzene skeleton were present in LIG/PAN and the phosphorus element was successfully introduced into FR-LIG/PAN composite via phosphorylation. The amount of char residue for FR-LIG/PAN at 800 °C is more than those of pure PAN and LIG/PAN. SEM photos indicate the expansion characteristics of the char residue, and EDS results prove that the uniform distribution of elements in the cross-section of FR-LIG/PAN composite. Moreover, FR-LIG/PAN exhibits the lowest peak heat release rate (pHRR) and smoke production rate (SPR). These results demonstrated that FR-LIG/PAN had excellent flame retardancy and char forming ability. In addition, the composition of the gases evolved from pyrolysis process of FR-LIG/PAN was analyzed by thermogravimetry coupled with Fourier transform infrared spectroscopy (TG-FTIR). The main pyrolysis products in gas phase are H2O, CO2 and PO•. This work proposes one facile method for preparation of practical flame retardant PAN composite.

EU project on fire safety statistics

Published by Pinfa on 15/09/2020:

Pilot project on fire data launched after European Parliament vote will prepare EU initiatives on fire safety. A consortium with Efectis, IFV, CTIF, NFPA, DBI, VFDB, BAM, the European Fire Safety Alliance, The University of Edinburgh and The University of Lund has been awarded the contract for an EU pilot project on EU fire data, aiming to pave the way for European actions on fire safety. This project is the result of a 2018 vote in the European Parliament (see pinfa Newsletter n°95). The aim is to define how “to provide meaningful data sets to allow legislative decisions on fire safety at Member States and at EU level”.

EU tender details “Closing Data Gaps and Paving the Way for Pan-European Fire Safety Efforts” (19th November 2019) https://etendering.ted.europa.eu/cft/cft-display.html?cftId=5447
Modern Building Alliance (MBA) summary 27th May 2020 “Pilot project on fire Safety” https://www.modernbuildingalliance.eu/pilot-project-on-fire-safety

Fire and Polymers

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Fore more information: click here

 

Post Doctoral position- Fire REsistaNce of External Thermal Insulation Composite Systems”

Place: Institut Pprime (UPR 3346 CNRS), ISAE-ENSMA, Téléport 2, 1 Avenue Clément Ader, BP 40109, 86961 Futuroscope Chasseneuil cedex, France

Dates: 4th january – 30th june 2020 (6 months). Possibly to continue in CORIA Rouen

Context: Due to current thermal regulations (RT 2012 and 2020), external thermal insulation (ETI) has been developed extensively (with two types: ventilated cladding and composite systems of external thermal insulation, ETICS). This potentially translates into an increase in the fuel mass and fire propagation on the facades, with regard to the insulation materials used (PE, EPS, PIR, PUR), generally derived from plastic. The consequence is the emergence of strong external flames, for which the spreading can be enhanced by the combustible load on the facade. In this context, one of our objectives will then be to characterize the ignition as well as the flame propagation processes in the specific case of the facade situation. Considering those different elements, part of the project will be dedicated to the study of ETICS and ventilated systems: -The experimental characterization of the thermal decomposition of materials used, the development of new and performant models of pyrolysis and their validation at increasing scale. -The experimental study of the ignition process of the materials used, and for representative conditions of facades, for the development and the validation of representative key parameters and models. -The experimental investigation of the thermal exchange (radiation and convection) between the flame and the combustible facade, for the development of more realistic radiative models and laws of walls. -The experimental investigation of thermal exchange and flow characteristics in ventilated system when submitted to a fire. In particular, the amount of pyrolysis gases transported in the air layer and their contribution to fire propagation. more information: click here Subject-Post-Doctoral position – ANR FRENETICS

3rd ECOFRAM conference

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The topics of the event will be the following:

Sustainable FR additives

Biobased and biodegradable FR polymers and composites

Global life cycle approaches

Fire safety regulation and ecological issues

For more information: click here

Matrix matters: Hyperbranched flame retardants in aliphatic and aromatic epoxy resins

Published 5 October 2019 in Polymer Degradation and Stability

Abstract

We synthesized a library of phosphorus-based flame retardants (phosphates and phosphoramides of low and high molar mass) and investigated their behavior in two epoxy resins (one aliphatic and one aromatic). The pyrolytic and burning behavior of the two resins (via TGA, TG-FTIR, Hot stage FTIR, Py-GC/MS, PCFC, DSC, LOI, UL-94, Cone calorimeter) are analyzed and compared to the results of flame retardant (FR)-containing composites. A decomposition pathway incorporating the identified modes of action and known chemical mechanisms is proposed. The overlap of decomposition temperature (Tdec) ranges of matrix and FR determines the efficacy of the system. Low molar mass FRs strongly impact material properties like Tg but are very reactive, and high molar mass variants are more thermally stable. Varying P–O and P–N content of the FR affects decomposition, but the chemical structure of the matrix also guides FR behavior. Thus, phosphates afford lower fire load and heat release in aliphatic epoxy resins, and phosphoramides can act as additives in an aromatic matrix or a reactive FRs in aliphatic ones. The chemical structure and the structure-property relationship of both FR and matrix are central to FR performance and must be viewed not as two separate but as one codependent system.

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Thermal Stability and Flammability Behavior of Poly(3-hydroxybutyrate) (PHB) Based Composites

Published: 11 July 2019,  for pdf format: click here

Abstract

A series of samples based on poly(3-hydroxybutyrate) (PHB) containing five different additives were prepared and their thermal stability and flammability were discussed. The samples first underwent flammability screening by using Pyrolysis Combustion Flow Calorimeter (PCFC) analyses. Then, four samples were selected for further investigations. PHB composites containing sepiolite (Sep.) inorganic nanofiller, and also organic ammonium polyphosphate (APP) were examined for flammability and thermal behavior using PCFC, thermogravimetric analysis (TGA), flame test, and Differential Scanning Calorimetry (DSC) analyses. Moreover, burning behavior of samples were captured on a digital camera to give a deeper sense of their flammability character for comparison.

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The results revealed a significant improvement of flammability and thermal stability of composites, particularly in the presence of sepiolite with respect to the value obtained for unfilled PHB. Regarding TGA results, the char residue yield was increased to ca. 20.0 wt.% in the presence of sepiolite, while 0.0 wt.% was observed for PHB. PCFC measurements uncovered higher performance of PHB-Sep. sample as signaled by 40% reduction in the peak of heat release rate with respect to PHB. According to observations, PHB-Sep. sample showed non-dripping behavior with high capacity of charring in the presence of Sep. in a vertical flame test. Read more: click here

 

 

 

Speciale Issue-Flame retardants in Composites Part B: Engineering

FR special issue : please click here

Composites Part B: Engineeringhas recently identified flame retardants and flame-retardant polymer/composites as one of its 20 focused topics for the journal and launched a speciale issue. This Special Issue is purposely organised to announce this decision. We want our flame retardantsresearch community tobeaware that Composites Part B: Engineeringis now dedicated to publishingthe latest progress on flame retardants and flame-retardant polymer composites.

For more information: : please click here

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Wood & Fire Safety 2020 Conference

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The 9th International Scientific Conference Wood & Fire Safety 2020 (WFS 2020) will be held as usual at the Hotel Patria, Strbske Pleso, Slovakia, May 3-6, 2020.

More information: http://wfs2020.sk

 

Biodegradable polyester thin films and coatings in the line of fire: the time of polyhydroxyalkanoate (PHA)?

Published in “Progress in Organic Coatings”

Abstract

From sustainability standpoint, bio-based resins are of crucial importance nowadays rather than fossil-based resins, but the former suffers from low flame retardancy. Bio-based thin films and coatings are in their early stage of development; hence, a long way must be paved to make them resistant against flame/fire. Polylactic acid (PLA)-based biocompatible (timesand some biodegradable) coatings have been in the core of attention, but even among available works one can rarely find a comprehensive report on flame retardancy of PLA thin films and coatings. Attention should also be paid to the fact that first-generation biodegradable polyesters, PLAs, are not fully biodegradable. Moreover, synthesis of PLAs is hooked on crop consumption. On the other hand, polyhydroxyalkanoates (PHAs) with more or less similar structure, but different physical properties due to their lower glass transition temperature compared with PLAs, are known as the second-generation of bio-polyester. Overall, we highlight here that PHAs might be a better candidate for thin film manufacturing thanks to their synthesis by microorganism as well as significant variability of their microstructure that provides a wide range of properties, and notably their full biodegradability compared with PLAs. Though mass production of PHAs is not cost-effective these days and their market just entered into the growth phase, we suggest study on flame retardancy of PHA-based resins, thin films, and coatings for near future. This short communication deals with the current status and future ahead of PHA-based flame retardant thin films and coatings.

Read more: click here

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