scholarly journals Flax/PP and Flax/PLA Thermoplastic Composites: Influence of Fire Retardants on the Individual Components

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2452
Author(s):  
Baljinder K. Kandola ◽  
Wiwat Pornwannachai ◽  
John Russell Ebdon

This study is based on previously reported reaction to fire properties of flax fibre-reinforced polymeric (polypropylene, PP and polylactic acid, PLA) composites, prepared by pre-treating the fabrics with different fire retardants (FRs) prior to composite preparation. It was observed that while all of these treatments were very effective in flax/PLA in terms of achieving a V-0 rating in a UL-94 test, only an organophosphonate FR was capable of achieving a V-0 rating for flax/PP. However, all fire-retardant treatments impaired the mechanical properties of the composites; the reduction was more in flax/PLA compared to flax/PP composites. To understand these effects further, here thermal analysis and pyrolysis combustion flow calorimetry of the composites and each component separately treated with FRs have been conducted and the results analysed in terms of the effect on each component so as to observe any interaction between the different components. The results indicated that in flax/PLA composites, the water released during FR catalysed dehydration-decomposition of flax may hydrolyse PLA, changing decomposition pathway of PLA to produce less flammable volatile, hence resulting in reduced flammability.

Holzforschung ◽  
2020 ◽  
Vol 74 (4) ◽  
pp. 372-381
Author(s):  
Saara Hautamäki ◽  
Michael Altgen ◽  
Daniela Altgen ◽  
Erik Larnøy ◽  
Tuomas Hänninen ◽  
...  

AbstractIn built environments the combustibility of wood is a great concern, which limits the use of wood as a building material due to legislation. The reaction-to-fire properties of wood can be altered with the use of fire-retardant chemicals, and most of the commonly used fire retardants already have a long history of use. However, only limited information is available on the impact of different fire retardants on the adhesion properties of wood. Additionally, comparative studies between chemicals from different groups of fire retardants is scarce. The objective of this study was to investigate and compare the effects of two commonly used fire retardants, sodium silicate (SS) and diammonium phosphate (DAP), on veneer properties, the focus being especially on thermal behavior and adhesion. Thermal properties and combustibility were studied using thermogravimetric analysis (TGA), flame test and calorimetry. Glue bond strength was analyzed with an automated bonding evaluation system (ABES) and the leaching of chemicals was determined according to EN84. Additionally, the surface characteristics of modified veneers were imaged with scanning electron microscopy (SEM). Results revealed notable differences in the thermal properties of SS and DAP, with DAP having better fire-retardant performance in all thermal testing. SS also affected thermal properties and combustibility of modified veneers, but the effect was only moderate compared to DAP. Neither SS or DAP had any significant resistance against leaching but ABES testing showed a notable increase in the glue bond strength of DAP modified veneers.


2021 ◽  
Vol 5 (10) ◽  
pp. 258
Author(s):  
Latha Krishnan ◽  
Baljinder. K. Kandola ◽  
John R. Ebdon

This study investigated the effects of phosphorus fire retardants (FRs) in matrices from co-cured blends of an unsaturated polyester (UP) with inherently fire-retardant phenolic resoles (PH) on the mechanical and flammability properties of resultant glass fibre-reinforced composites. Three different phenolic resoles with UP have been used: (i) an ethanol soluble (PH-S), (ii) an epoxy-functionalised (PH-Ep), and (iii) an allyl-functionalised resin (PH-Al) with two different phosphorus FRs: resorcinol bis (diphenyl phosphate) (RDP) and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO). The flammabilities of the resultant composites were evaluated using cone calorimetry and the UL-94 test. Cone calorimetric results showed reductions in peak heat release rate (PHRR) and total heat released (THR) as expected compared to those of UP and respective UP/PH composite laminates without FRs. UL-94 tests results showed that while all composites had HB rating, FR containing samples self-extinguished after removal of the flame. The mechanical properties of the composites were evaluated using flexural, tensile and impact tests. All FRs reduced the mechanical properties, and the reduction in mechanical properties was more severe in UP/PH-S (least compatible blends) composites with FRs than in UP/PH-Al (most compatible blends) composites with FRs. Amongst the different composites, those from UP/PH-Al with DOPO showed the best fire retardancy with little deterioration of mechanical performance.


2014 ◽  
Vol 11 (2) ◽  
pp. 159-167
Author(s):  
Rasmika Patel ◽  
Amin Hirani ◽  
Hitesh Patel

The urethane polymers of castor oil (COPU) are used in many commercial applications but one of the major limitations of these polymers is their inherent flammability and poor mechanical properties. Polymers containing phosphorous groups belong to the fire retardants, and when blended with castor oil based polyurethane improves the latter’s fire retardant properties. Present work, deals with the synthesis of a monomer bis (m-hydroxy phenyl) phenyl phosphate (BHPPP) and its related polyurethanes. Characterization of the monomer and polyurethanes are discussed. Blending of the polyurethanes with COPU in different proportions improves both the flame retardant and mechanical properties of the COPU.


2014 ◽  
Vol 1048 ◽  
pp. 465-468 ◽  
Author(s):  
Chun Gui Du ◽  
Jian Gang Song ◽  
Yong Xing Chen

This paper presents a study on the different applying methods of (NH4)2HPO4 fire retardant influence on physical and mechanical properties of bamboo scrimber. The results showed: the properties of bamboo scrimber would change with applying methods changing of fire retardant; the method of applying fire retardants before gluing would increase the part of physical and mechanical properties of bamboo scrimber, but it would increase the manufacturing cost of bamboo scrimber; the method of applying fire retardants after gluing would reduce the part of physical and mechanical properties of bamboo scrimber.


Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4581
Author(s):  
Baljinder K. Kandola ◽  
S. Ilker Mistik ◽  
Wiwat Pornwannachai ◽  
A. Richard Horrocks

Biocomposites comprising a combination of natural fibres and bio-based polymers are good alternatives to those produced from synthetic components in terms of sustainability and environmental issues. However, it is well known that water or aqueous chemical solutions affect natural polymers/fibres more than the respective synthetic components. In this study the effects of water, salt water, acidic and alkali solutions ageing on water uptake, mechanical properties and flammability of natural fibre-reinforced polypropylene (PP) and poly(lactic acid) (PLA) composites were compared. Jute, sisal and wool fibre- reinforced PP and PLA composites were prepared using a novel, patented nonwoven technology followed by the hot press method. The prepared composites were aged in water and chemical solutions for up to 3 week periods. Water absorption, flexural properties and the thermal and flammability performances of the composites were investigated before and after ageing each process. The effect of post-ageing drying on the retention of mechanical and flammability properties has also been studied. A linear relationship between irreversible flexural modulus reduction and water adsorption/desorption was observed. The aqueous chemical solutions caused further but minor effects in terms of moisture sorption and flexural modulus changes. PLA composites were affected more than the respective PP composites, because of their hydrolytic sensitivity. From thermal analytical results, these changes in PP composites could be attributed to ageing effects on fibres, whereas in PLA composite changes related to both those of fibres present and of the polymer. Ageing however, had no adverse effect on the flammability of the composites.


2021 ◽  
Vol 216 ◽  
pp. 108859
Author(s):  
Dong-Jun Kwon ◽  
Neul-Sae-Rom Kim ◽  
Yeong-Jin Jang ◽  
Hyun Ho Choi ◽  
Kihyun Kim ◽  
...  

2021 ◽  
Vol 30 ◽  
pp. 263498332110074
Author(s):  
Henry C Obasi ◽  
Uchechi C Mark ◽  
Udochukwu Mark

Conventional inorganic fillers are widely used as fillers for polymer-based composites. Though, their processing difficulties and cost have demanded the quest for credible alternatives of organic origin like coconut shell fillers. Dried shells of coconut were burnt, ground, and sifted to sizes of 63, 150, 300, and 425 µm. The ground coconut shell particles (CSP) were used as a filler to prepare polypropylene (PP) composites at filler contents of 0% to 40% via injection melt blending process to produce PP composite sheets. The effect of the filler particle size on the mechanical properties was investigated. The decrease in the size of filler (CSP) was found to improve the yield strength, tensile strength, tensile modulus, flexural strength, flexural modulus, and hardness of PP by 8.5 MPa, 15.75 MPa, 1.72 GPa, 7.5 MPa, 100 MPa, and 10.5 HR for 63 µm at 40%, respectively. However, the elongation at break and modulus of resilience of the PP composites were seen to increase with increase in the filler size. Scanning electron microscope analysis showed that fillers with 63 µm particle size had the best distribution and interaction with the PP matrix resulting in enhanced properties.


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