scholarly journals Enhancement of Wood Biological Resistance and Fire Retardant Properties after Laccase Assisted Enzymatic Grafting

Forests ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 1102
Author(s):  
Cristian Bolaño ◽  
Sabrina Palanti ◽  
Luigi Benni ◽  
Diego Moldes

Several treatments of wood, based on laccase assisted grafting, were evaluated in this paper. Firstly, the efficacy of lignosulfonate and kraft lignin from Eucalyptus spp. as a wood preservative was assessed. Both ligno products were anchored to wood surfaces via laccase treatment in order to avoid leaching. Moreover, some of these wood preservative treatments were completed with the addition of silver nanoparticles. For comparison, a commercial product was also analyzed in terms of its fungal decay resistance during surface application, in accordance to use class 3, CEN EN 335. Secondly, the anchoring of a flame retardant based on tetrabromobisphenol-A (TBBPA) was attempted, to limit the dispersion of this toxic substance from treated wood. In both cases, kraft lignin and lignosulfonate showed an improvement in wood durability, even after leaching. However, the addition of silver nanoparticles did not improve the efficacy. On the other hand, the efficacy of TBBPA as a flame retardant was not improved by grafting it with laccase treatment or by adding O2, a co-factor of laccase.

Holzforschung ◽  
2017 ◽  
Vol 71 (9) ◽  
pp. 689-695 ◽  
Author(s):  
Carmen Fernández-Costas ◽  
Sabrina Palanti ◽  
María Ángeles Sanromán ◽  
Diego Moldes

Abstract Enzymatic grafting of kraft lignin (KL) on wood surfaces is presented as a non-leachable wood protection treatment. Scots pine and European beech mini-blocks were treated with KL solution in the presence of laccase isolated from Myceliophthora thermophila and the formation of a stable interaction between wood and lignin was observed. Furthermore, the same strategy was employed to graft KL with the simultaneous entrapment of copper in the polymeric net formed. Enzymatic treatment diminished the leachability of the compounds in accordance with the EN 84 standard. The durability of the leached wood blocks was evaluated by accelerated decay tests. Samples with grafted lignin on the surface lost their antifungal activity in long-term exposure at the concentration tested. This observation is in contradiction to the preliminary tests, where KL seemed to have some biocidal activity. On the other hand, KL grafting in combination with copper entrapment improved the decay resistance and the copper leaching was reduced.


2019 ◽  
pp. 365-372
Author(s):  
Bijamal Raimovna Tausarova ◽  
Anastasiya Yur'yevna Stasenko

The article presents studies on the use of a new composition based on sodium silicate, urea and sodium hydrogen phosphate to impart fire-retardant properties to cellulosic textile materials. The influence of the concentration of the starting components, temperature, and heat treatment time on the flame retardant properties was studied. The change in the fire retardant properties of cotton fabric is given for three heat treatment modes: at 80, 90 and 100 °C. Compared to the initial fabric, the samples treated with a flame retardant have indicators of flame retardant properties. Untreated fabric with a size of 220×170 mm when tested for flammability at an ignition time of 15 s completely burns out in 60 s. In samples treated with a flame retardant, at an ignition time of 15 s, the smoldering time is practically reduced to zero. With an increase in the concentration of the flame retardant, and the temperature of the heat treatment, the loss of material strength, breaking load, and the appearance of the fabric change slightly. Using electron scanning microscopy and energy dispersive microanalysis, it was shown that pure cotton fabric contains 68.77% carbon and 31.22% oxygen; after modification, particles of sodium – 0.02%, phosphorus – 0.04% and potassium – 0.05% are formed on the surface of the treated fabric. distributed fairly unevenly. It has been shown that in cellulosic materials modified with compositions based on sodium silicate and urea, sodium hydrogen phosphate, flame retardant properties increase. The proposed composition provides the achievement of higher fire resistance. Processing can be carried out on standard equipment of finishing enterprises without the stage of high-temperature fixation of the drug.


2014 ◽  
Vol 789 ◽  
pp. 174-177 ◽  
Author(s):  
Zhi Hao Wu ◽  
Li Li Li ◽  
Shuai Shuai Jiang ◽  
Ze Xu Hu ◽  
Yu Chen Mao ◽  
...  

Recycled-polyester (RPET) was melt blended with the phosphorus-containing flame retardant (FRP) and α-zirconium phosphate (α-ZrP). The thermal properties of RPET/FRP/α-ZrP composites were analyzed. Modified RPET fibers were prepared through melt spinning of dried RPET nanocomposite chips. The mechanical properties and fire-retardant properties of RPET/FRP/α-ZrP fibers containing different α-ZrP contents were tested. The results show that the synergism of α-ZrP and FRP exerts a positive effect on the mechanical and the flame-retardant property of RPET, leading to nanocomposite fibers of 1.9cN/dtex and 31.6% limiting oxygen index (LOI) value.


Author(s):  
Z. Sirko ◽  
◽  
E. Starysh ◽  
N. Tsireny ◽  
O. Tsapcko ◽  
...  

The article presents the results of research on the creation of flame retardant composition for fire protection of cellulose-containing materials. The analysis was performed of flame retardant compositions for impregnation of cellulose-based materials. Phosphorus-based compounds have been shown to be most effective in providing fire protection in the solid phase and during decomposition. They are able to decompose when heated to form phosphoric acid, which inhibits direct oxidation and greatly reduces the spread of fire. Also, noteworthy are compositions based on salts and acids of phosphorus and nitrogen. The mechanism of action of these compositions is aimed at reducing the amount of heat during combustion and becomes insufficient for self-combustion. It was also found that during ignition fire-retardant compositions interact with the components of cellulose, which forms residual phosphorus and nitrogen, resulting in increased efficiency of fire-retardant action. Fire-retardant impregnating compositions are aqueous solutions of flame retardants. The materials are impregnated in a container with a flame retardant solution or sprayed on the surface of the material with an industrial spray. This method is simple and effective, but the result is short-lived. More effective is the method of introducing flame retardant at the molecular level into the fiber structure. One of the important methods is to restore the fire-retardant properties of materials during their operation and products from them.


Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 237 ◽  
Author(s):  
Yan Xia ◽  
Chengye Ma ◽  
Hanmin Wang ◽  
Shaoni Sun ◽  
Jialong Wen ◽  
...  

In this study, feather was used as the source of protein and combined with copper and boron salts to prepare wood preservatives with nano-hydroxyapatite or nano-graphene oxide as nano-carriers. The treatability of preservative formulations, the changes of chemical structure, micromorphology, crystallinity, thermal properties and chemical composition of wood cell walls during the impregnation and decay experiment were investigated by retention rate of the preservative, Fourier transform infrared spectroscopy (FT-IR), scanning electronic microscopy-energy dispersive spectrometer (SEM-EDS), X-ray diffraction (XRD), thermoanalysis (TG), and confocal Raman microscopy (CRM) techniques. Results revealed that the preservatives (particularly with nano-carrier) successfully penetrated wood blocks, verifying the enhanced effectiveness of protein-based preservative with nano-carrier formulations. Decay experiment demonstrated that the protein-based wood preservative can remarkably improve the decay resistance of the treated wood samples, and it is an effective, environmentally friendly wood preservative. Further analysis of these three preservative groups confirmed the excellent function of nano-hydroxyapatite as a nano-carrier, which can promote the chelation of preservatives with higher content of effective preservatives.


2017 ◽  
Vol 46 (2) ◽  
pp. 131-138 ◽  
Author(s):  
Arezoo Mamani ◽  
Morteza Ebrahimi ◽  
Maryam Ataeefard

Purpose The purpose of this paper is to investigate the effect of expandable graphite (EG) plates’ incorporation on the mechanical, thermal and fire-retardant properties of an epoxy–aliphatic amine system. In addition, the optimum amount of EG in epoxy/EG composites is determined to achieve the best thermal and mechanical properties at the same time. Design/methodology/approach The epoxy/EG composites were prepared by using (1-4) phr of EG. The morphological structure of epoxy/EG composites was studied by using scanning electron microscopy. The thermal, flame-retardant and mechanical properties of epoxy/EG composites were evaluated by using thermogravimetric analysis (TGA), oxygen index test and dynamic mechanical analysis and tensile and impact test, respectively. Findings TGA results showed that the incorporation of EG to the epoxy resin increased the initial decomposition temperature and residue weight of the composites. It was found that, with increasing EG concentration up to 4 phr, the oxygen index, glass transition temperature and Young’s modulus of epoxy/EG composites increased up to 60 per cent, 4.1°C and 50 per cent, respectively. On the other hand, the sample with 2 phr EG provided the maximum values of tensile strength, storage modulus, cross-linking density, ultimate tensile strain and impact strength. Practical implications Prepared epoxy/EG composites can be used as halogen-free flame-retardant composites. The proposed process for the preparation of the composites is simple and can easily be implicated in the industry. Originality/value To the best of the authors’ knowledge, there is no other publication that considers mechanical, thermal and fire-retardant properties of epoxy/EG composites in one paper. In this work, the optimum concentration of EG in epoxy/EG composites was determined, considering all these properties.


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.


2011 ◽  
Vol 317-319 ◽  
pp. 112-115 ◽  
Author(s):  
Yu Hua Guo ◽  
Jian Jun Guo ◽  
Zhen Huang ◽  
Li Jun Teng

Low density polyethylene and linear low density polyethylene (LDPE/LLDPE (60wt.%/40wt.%))as basic materials, intumescent flame retardant ammonium polyphosphate (APP) was added into them to obtain fire retardant systems. The molding parameters, fire retardant properties, mechanical properties and processing properties of samples were examined. It was showed the rotational speed of main screw was 28-34rad/min. when samples were molded, cylinder temperature was 185-195°C, mold temperature was 85-115°C, preheating time was 5-10min and filling time was 8-21s. APP had good fire retardant and smoking suppression functions. Adding 30% (wt.%) APP can obtain grade of FV-0. With APP content increasing, the mechanical and processing properties of materials decreased.


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