Fungal inhibition and chemical characterization of wood treated with novel polystyrene-soybean oil copolymer containing silver nanoparticles

(1)

Contents lists available atScienceDirect

International Biodeterioration & Biodegradation

journal homepage:www.elsevier.com/locate/ibiod

Fungal inhibition and chemical characterization of wood treated with novel

polystyrene-soybean oil copolymer containing silver nanoparticles

Ahmet Can

a,∗

, Hüseyin Sivrikaya

a

, Baki Hazer

b,c

a_{Forest Industry Engineering, Faculty of Forestry, Bartin University, 74100, Bartin, Turkey}

b_{Bülent Ecevit University, Department of Chemistry, Department of Metallurgical and Materials Engineering, Department of Nano Technology Engineering, 67100}

Zonguldak, Turkey

c_{Kapadokya University, Department of Aircraft Airframe Engine Maintenance, 50420 Ürgüp, Nevşehir, Turkey}

A R T I C L E I N F O Keywords:

Antifungal

Autoxidized soybean oil-Ag FTIR

Polystyrene-g-soybean oil Silver nanoparticle

A B S T R A C T

In this study, Scots pine (Pinus sylvestris L.) samples were impregnated with autoxidized soybean oil polymer containing Ag nanoparticles (Agsbox) and polystyrene-soybean oil copolymer (AgPSsb) in order to inhibit white-rot fungus (Trametes versicolor). Chemical changes of the impregnated specimens were characterized by FTIR techniques. The higher concentration of nano preservative resulted in higher weight percent gain (WPG) in the impregnated samples. The samples impregnated with 1.5% of Agsbox, had the highest WPG (2.98%). The silver nanocomposite-impregnated wood specimens improved the anti-fungal properties. In addition, treatment with 0.4% AgPSsb resulted in the lowest moisture content (23.4%) after decay tests. In the samples, the lowest weight loss (0.87%) due to fungal decay was observed with the use of 0.4 wt% of AgPSsb. Mass losses of Agsbox impregnated specimens at 1.5% and 0.04% were 2.86% and 4.61% respectively. The FTIR spectra of the spe-cimens impregnated with the nanocomposites showed the impregnated components at the peaks of 2910 cm−1 and 1714 cm−1in particular.

1. Introduction

In the past and up to the present day, chemical preservatives have been used to protect wood. Copper chromium arsenic (CCA) is a ﬁrst-generation copper-based wood preservative which is highly eﬀective against a broad spectrum of decay fungi (Bahmani et al., 2015), ter-mites (Lin et al., 2009) and wood-boring insects (Schlultz et al., 2008). Copper chromium arsenic has been replaced by second-generation wood preservatives such as alkaline copper quat and copper azole (Humar and Lesar, 2008) due to the banning of CCA in Europe as well as restrictions on its use in the USA and Canada because of the en-vironmental concerns (Ellis et al., 2007;Kartal et al., 2015).

Environmentally friendly methods (ultrasound, magnetic, micro-wave and biological methods) and materials (vitamins, sugars, plant extracts, biodegradable polymers and microorganisms) are used in the production of nanoparticles (NPs). Thanks to these techniques, silver, copper, gold, iron, metal alloys and oxides are produced in nano size (Kharissova et al., 2013). In recent years, because of their wide range of applications in diverseﬁelds, NPs such as gold and silver have attracted the interest of chemists (Hazer and Akyol, 2016). In addition, com-mercial metallic systems either micronized or dispersed as nano

particulates have been studied by several researchers in the last decade (Kartal et al., 2009;Clausen et al., 2010;Mantanis et al., 2014;Huang et al., 2015). For example, nano copper has been used for impregnation of southern pine in the USA and Canada. Nano technological devices have enabled the grinding of metals to sub-micron size and the dis-persion of the particles in water (Berrocal et al., 2014; Moya et al., 2017). Inorganic NPs are distributed evenly on the surface, thus in-creasing their area of inﬂuence. With regard to the relationship be-tween NPs and the anatomical features of wood, Matsunaga et al. (2012) found that copper NPs could be distributed within the par-enchyma cells, whereas the larger-sized copper particles could be de-posited on the wood-cell walls (Matsunaga et al., 2012).

Vegetable oil-based polymers have been attracting the interest of researchers. This interest can be attributed to the biodegradability, low cost and environmentally friendly properties of vegetable oils (Shogren et al., 2004;Xia and Larock, 2010;Lligadas et al., 2013). Earlier works have stated that polyunsaturated plant oils were readily susceptible to autoxidation (Köckritz and Martin, 2008;Soucek et al., 2012;Allı et al., 2016). In order to utilize the free radical polymerization of vinyl monomers, the autoxidation of the double bonds in vegetable oils causes mostly peroxidation and polymerization leading to macro

https://doi.org/10.1016/j.ibiod.2018.06.022

Received 28 November 2017; Received in revised form 27 June 2018; Accepted 28 June 2018 ∗_{Corresponding author.}

E-mail addresses:6116acan@gmail.com(A. Can),hsivrikaya@bartin.edu.tr(H. Sivrikaya),bkhazer@beun.edu.tr(B. Hazer).

Available online 03 August 2018

(2)

peroxide initiators (Allı et al., 2014;Allı et al., 2016;Ince at al., 2016). In this study, macro peroxide soybean oil with silver NPs was ob-tained via the autoxidation of soybean oil in the presence of silver ni-trate. The silver-soybean oil macro peroxide initiated the free radical polymerization of styrene, resulting in the polystyrene-soybean oil co-polymer containing silver NPs.

Therefore, this study aimed to explore the polymerization of silver NPs with soybean oil and polystyrene and to clarify the impact of Ag NPs in the presence of soybean oil on the decay-resistance of treated wood. Fourier transform infrared spectroscopy-attenuated total re ﬂec-tion (FTIR-ATR) was used to determine the chemical changes. The structure of the chemical bonds in the impregnated samples was in-vestigated and scanning electron microscopy (SEM) was employed to display the distribution of the Ag NPs. In addition, the impregnated wood specimens were used to investigate the antifungal eﬀects of the soybean oil-Ag and polystyrene-soybean oil-Ag nanocomposites.

2. Materials and methods

2.1. Materials

Scots Pine (Pinus sylvestris L.) specimens were prepared from sap-wood blocks with the dimensions of 5 × 15 × 30 mm (height × width × length). The oven-dry density of the samples used was 0.42 g cm−3.

The soybean oil was donated by theﬁrm of Çotanak/Altas Yağ Su ve Tarım Ürünleri Gıda Inşaat Otomotiv Nakliyat San ve Tic. A.S.¸ Ordu, Turkey. The oil consisted of palmitic acid (11 wt%), stearic acid (4.9 wt %), oleic acid (34 wt%), linoleic acid (42 wt%) and linolenic acid (3.6 wt%). The AgNO3was purchased from Sigma-Aldrich.

2.2. Synthesis of soybean oil macro peroxide containing silver nanoparticles (Agsbox)

The autoxidized polymeric soybean oil (PSsbox) was prepared ac-cording to the modiﬁed procedure for the synthesis of gold nano-composites reported in our previous work (Hazer and Akyol, 2016).

A mixture of 18 g of soybean oil and 0.52 g of AgNO3was placed in a Petri dish (Φ = 14 cm, oil thickness: 0.7 mm). This solution was ex-posed to daylight and air at room temperature. After a given time of autoxidation (ca. 1 month), a sticky, dark-brown, viscous liquid polymer layer was formed. The synthesis of polymeric soybean oil (PSbox) was repeated 10–12 times in Petri dishes having diﬀerent radii. The resulting nanocomposite contained 2.8 wt% (0.016 mol%) of silver NPs and was designated as Agsbox.

2.3. Synthesis of polystyrene-soybean oil copolymer containing silver nanoparticles (AgPSsb)

Polymerization of styrene was initiated by the oxidized soybean oil polymer with Ag NPs according to the modiﬁed procedure described in the cited literature (Hazer and Kalaycı, 2017).

For a typical polymerization experiment, 0.12 g of Agsbox nano-composite and 4.52 g of styrene were mixed into 5 mL of toluene in a reaction bottle. Argon was introduced through a needle into the tube for about 3 min in order to expel the air. The tightly capped bottle was then put into a water bath at 95 °C for 6 h. The contents of the tube were then coagulated in methanol. The graft copolymer samples were dried under vacuum at 40 °C overnight (Hazer and Kalaycı, 2017). This product was designated as AgPSsb.

2.4. Pretreatment of wood samples

Organic solvent-based solutions including chloroform and toluene were prepared for impregnation of the wood specimens with soybean oil-Ag and polystyrene-soybean oil-Ag NPs. Three diﬀerent solutions

were used for impregnation of the wood. For this purpose (all w/w): 0.04% and 1.5% of Agsbox were dissolved in chloroform, respectively, and 0.4% of AgPSsb in toluene.

Chloroform and toluene were chosen for preparation of the solu-tions. Prior to impregnation, the wood samples were pretreated with chloroform and toluene to overcome the possible eﬀect of chemical degradation by the selected solvents in the wood during impregnation. For this purpose, the samples to be impregnated with Agsbox were stirred in chloroform, whereas the samples to be impregnated with AgPSsb were stirred in toluene for 2 h. Afterwards, 2 h of stirring was carried out again after changing the chloroform and toluene. Following the stirring process, the samples were left in the lab for 2 h and then dried in a vacuum oven at 40 °C for 4 h. The samples were subsequently oven dried at 103 °C. Control samples were also left in chloroform for 2 h for comparison with the treated samples.

2.5. Impregnation of wood

Prior to the impregnation, the wood samples were dried in an oven at 103 °C until reaching constant weight. Air-dried samples were treated with dilute solutions in an impregnation chamber according to the full-cell process. In this process,ﬁrst, samples were left under vacuum at 650 mm/Hg for 30 min, and then followed by atmospheric pressure for 60 min. The weight gain (%) for each compound was calculated based on the initial (Mu) andﬁnal (Mt) weight of each wood sample using Equation(1).

WPG (%) = 100[(Mt-Mu)/Mu] (1)

where Mu and Mt are the oven-dry weights of the untreated and treated wood blocks, respectively.

2.6. Determination of antifungal eﬃciency

The decay test was performed according to EN 113, but the di-mensions of the wood samples were modiﬁed to 5 × 15 × 30 mm (height × width × length). Prior to the experiment, wood specimens were dried in an oven at 103 °C until constant weight was reached. T. versicolor (L.: Fr.) Pilat white rot fungus was selected for the decay test. Five replicate samples were used for each experiment. The control and treated samples were subjected to conditioning in a chamber at 20 °C and 65% relative humidity prior to the decay test. The eight weeks decay test was conducted in a chamber at 22 °C and 65% relative hu-midity. At the end of the experiment, weight loss was determined based on the oven-dry weight of the test samples in order to assess the bio-logical durability.

2.7. Instrumentation

The morphological analysis of the bio composites was conducted via environmental scanning electron microscopy (ESEM) (Tescan MAIA3 XMU-SEM), with an accelerating voltage of 5 kV. The radial surfaces of the samples were measured. For enhanced conductivity, the surface of all samples was sputter-coated with gold using a Denton sputter coater. The FTIR-ATR analysis was carried out with a Shimadzu IRAAffinity-1 spectrometer equipped with a single reflection ATR pike MIRacle sampling accessory. Four accumulated spectra with a resolu-tion of 4 cm−1 were obtained for wavenumbers from 700 cm−1 to 1800 cm−1 with 32 scans for each sample. The measurements were performed in the earlywood section of the wood. Spectra measurements were taken from eight different points.

The Agsbox-toluene solution was dried on a 200-mesh carbon-coated transmission electron microscopy (TEM) grid (Electron Microscopy Sciences, CF200-Cu, USA) for analysis and inspected with a M-2100 (Japan) high-resolution transmission electron microscope (HRTEM) at 200 kV (LaB6 ﬁlament). Images were recorded with a

(3)

Gatan 794 Slow Scan CCD Camera (USA). Gatan Digital Micrograph software was used for noiseﬁltering and fast Fourier transformation purposes.

2.8. Statistical analysis

The results of the decay test were analyzed by one-way variance analysis (ANOVA) using the SPSS 16.0 program. The significance level (P < 0.05) between the variations was compared using Duncan homogeneity groups in which different letters given along with the average values of the tested parameters indicated a significant differ-ence.

3. Results

According to our previous publication (Hazer and Kalaycı, 2017), Ag NPs in the nanocomposites are spherical in shape. TEM images of the Ag NPs in the AgPsbox macroperoxide initiator showed Ag NPs approximately 5 nm in size, while the Ag NPs in the AgPS-g-Psbox co-polymer nano composite were slightly larger than those of macroper-oxide initiator (ca. 15 nm). These larger-size Ag NPs presumably re-sulted from some aggregation in the copolymer matrix.

3.1. Decay test

The weight loss and moisture content of the wood specimens ob-tained in the decay test are displayed inTable 1. In addition, Duncan's homogeneity groups are indicated with the letters (P < 0.05). Ac-cording toTable 1, the control specimens resulted in mass loss at the rate of 29.74% at the end of the 2-month decay test, which was higher than the standard value. The decay test mass loss allowed by the standardEN 113, 2006of 20% for untreated samples. The mass loss for the untreated Scots pine sapwood was 29.74%; however, in the mod-iﬁed samples, the decay resistance improved at the rate of 84.49%, 90.38% and 97.07%, respectively. The results indicate that the decay resistance of the wood modiﬁed by AgNPs against the white rot fungus T. versicolor was remarkably improved compared to that of the un-treated Scots pine.

3.2. SEM analysis

The SEM images of the Scots pine sapwood samples decayed by T. versicolor are presented inFig. 1and show the woodfibers, lumina of empty tracheids and decomposition of the cell walls. The character-ization of the decayed and control samples is displayed in these images. The different formations were clearer in the samples treated with 0.4% AgPSsb. These formations were assumed to be silver particles, but could not be clarified by energy dispersive X-ray spectroscopy (EDX).

The wood cell wall had a rough after treatment with 0.04% Agsbox and 1.5% Agsbox, whereas the roughness was diminished in samples treated with 0.4% AgPSsb. This might be attributed to the chloroform used as a solvent in the experiment. It was also shown that degradation increased in the cell wall when chloroform was used as the solvent.

As shown inFig. 1, physical changes were observed in the wood samples after the impregnation and decay test. Changes in wood color were seen with impregnation. Visual inspection revealed that the wood material had darkened after impregnation, especially when Agsbox was used at 1.5% concentration. In addition,Fig. 1demonstrates that T. versicolor caused more degradation on the control and the samples treated with 0.04% Agsbox than on the others. In addition, greater hyphal development on the surface of these samples was evidence of the degree of the degradation. The wood cell pores were closed by the polystyrene used in the 0.4% AgPSsb, thus inhibiting the hyphal de-velopment and growth.

3.3. FTIR analysis

The FTIR spectra (Fig. 2) were divided into three band areas, 4000–2700 cm−1_, _{2700–1800 cm}−1_, _and _{1800–400 cm}−1_. _The 4000–2700 cm−1_{samples that were treated with 0.04% Agsbox and} 1.5% Agsbox showed an increased O-H stretching vibration at 3422 cm−1. Two new characteristic peaks appeared in the samples treated with the AgPSsb and Agsbox at 2910 cm−1 and 2840 cm−1, which corresponded to the asymmetric and the symmetric stretching vibration for C-H. The intensity of the characteristic peaks at 2919 cm−1and 2849 cm−1increased after impregnation in the samples treated with the AgPSsb and Agsbox. There was no special peak in the range between 2700 and 1800 cm−1. The region of 1800–700 cm−1 included the main functional groups for organic material, which were characterized for cellulose, hemicellulose and lignin (Liu et al., 2018). It was clear that 1.5% Agsbox caused signiﬁcant changes in the wood chemical structure. The band at 1712 cm−1, indicating an un-conjugated C=O stretch in the xylan in hemicellulose, increased sharply due to the modiﬁcation of the acetyl and carbonyl groups. The peak at 1224 cm−1showed the CO and OH groups in hemicellulose and lignin (Faix, 1991). The absorption peaks of the silver-impregnated specimens increased compared to the control samples. The band at 1224 cm−1shifted at 1240 cm−1after 0.04% Agsbox impregnation.

The IR bands at 1016 cm−1represented the presence of cellulose, which changed after impregnation. This peak was increased in the samples impregnated with Agsbox, while decreased in the AgPSsb im-pregnated samples. This demonstrated the modiﬁcation of the cellulose with the AgPSsb polymer.

4. Discussion

Nano silver has signiﬁcant inﬂuence on fungi by destroying their membrane integrity (Kim et al., 2009). This phenomenon makes it important as a potential antifungal agent. At the ratio 0.04% of Agsbox, the mass loss was 4.61%, whereas the mass loss was reduced to 2.86% at the higher ratio of Agsbox (1.5%). The higher mass loss can be ex-plained by the lower amount of the silver NPs used for the decay test. According to a previous report, silver concentration (50 ppm) was used in smaller amounts in a coating, but no impact was obtained against mold, blue stain and algae (Künniger et al., 2014).

Guaiacyl lignin is a component found at around 28% in Scots pine that give rise to the natural durability of this species (Karunasekera et al., 2017). On the other hand, the white rot fungus T. versicolor has the ability to destroy lignin, cellulose and hemicellulose in high pro-portions (Catto et al., 2016). In the present study, after the 2-month decay test, it can be said that the mass loss was low in the control samples, which may have been due to the decomposition of the lignin. In the literature, a higher content of nitrogen decreased the lignin de-gradation, whereas the destruction of polysaccharides was stimulated Table 1

Weight percent gain (WPG), mass loss and moisture content of nano silver-treated and control wood exposed to decay fungi (Trametes versicolor).

WPG (%)

Weight loss (%) Decay resistancea_(%)

Moisture content after decay test (%) Control – 29.74(0.60)ab _– _55.2 0.04% Agsbox 0.57 (0.11) 4.61(0.91)b 84.49 39.6 1.5% Agsbox 2.98 (0.10) 2.86(0.31)b 90.38 35.6 0.4% AgPSsb 0.81 (0.12) 0.87(0.37)c 97.07 23.4

The data in parentheses are standard deviations.

a _{Decay resistance is the comparison of the modi}_{ﬁed Scots pine wood to} untreated Scots pine wood.

(4)

(Kirk et al., 1978;Schubert et al., 2011).

In this study, the resulting mass loss at 2.86% and 0.87% in the modified samples was below the 3% reference value indicated in the standard (EN 113, 2006). It can be concluded that the wood treated with 1.5% of Agsbox demonstrated the ability to resist the white rot fungus Trametes versicolor due to the synergistic effect of the soybean oil and silver NPs because it is known that soybean oil alone cannot pro-vide sufficient resistance to fungi.Tomak et al. (2011)reported that when wood samples were impregnated with soybean oil, weight loss was 11.68% at the end of a 4-month test period. In addition, some authors have demonstrated the resistance of nano silver to T. versicolor by yielding mass loss as low as < 5% (Berrocal et al., 2014;Narayanan and Park, 2014).

The AgPSsb increased the resistance of the modiﬁed samples to decay fungi as it included the polystyrene and nano silver. Polystyrene is a polymer consisting only of long-chain hydrocarbons which in-creases the decay resistance of wood because of the synergistic eﬀect of Fig. 1. SEM analysis: (a) control, (c) impregnated with 0.04% Agsbox, (e) 0.4% AgPSsb, (g) 1.5% Agsbox; and exposed to fungi: (b) control, (d) 0.04% Agsbox, (f) 0.4% AgPSsb, (h) 1.5% Agsbox (100μm, × 500).

(5)

polymer and silver (Raberg and Hafren, 2008). According toRaberg and Hafren (2008), a 46% weight loss occurred in pine control speci-mens, while those impregnated with polystyrene resulted in 18% weight loss. This was evidence that the polystyrene had been able to prevent mass loss in the treated wood samples compared to the control specimens.

When the decay test was performed, fungal hyphae penetrated the wood through the rays and spread into the lumens via pits and thereby, the decay fungi started to modify the wood structure (Goodell et al., 2003). Subsequently, the secondary wall was dispersed by means of fungal enzymes and/or low molecular substances and the carbohydrate disruption products were changed (Schmidt, 2006; Durmaz et al., 2016). As shown inFig. 1(b) and (d), fungi hyphae had contributed to substantial degradation in the wood samples. The wood cell wall had been almost completely destroyed, particularly in the untreated (Fig. 1 -b) samples. However, the increasing ratio of the chemical lowered the degradation in the wood cell wall (Fig. 1-h). The SEM images (Fig. 1) demonstrate that the higher the amount of silver chemical, the less degradation there was in the wood samples. The SEM examination re-vealed that as the degradation progressed,ﬁbrils were lifted and micro cracks formed in the tangential section of the wood (Fig. 1-d and -f). Generally, in relation to the decomposition of carbohydrates, the characteristic properties could pose as a clear indication of the ﬁrst stage of white-rot decay of softwood, as was seen in spruce (Fackler et al., 2010).

Various enzymes are held to be responsible for the decomposition of the cell wall polymers, but if they are to be involved in the decay processes they must gain access to the interior of the cell wall. However, it has been established studies that the cell wall micropores of undecayed wood have diameters no greater that 2 nm (Hill, 2002). This means that it is quite diﬃcult for the enzymes to penetrate the wood cell wall. Yet, fungi have the ability to secrete small agents that enable the enzymes to permeate the cell walls. The secreted agents allow the penetration of the enzymes even if the microspores are blocked by the impregnation process (Thybring, 2013). Enlarged pores are displayed in the wood sample impregnated with 0.04% Agsbox inFig. 1(d).

With the modiﬁcation of the OH groups occurring in the lignin and cell wall, the OH groups required for the growth of the fungi were re-moved and the decay resistance of the wood increased (Li et al., 2011). The band at 2921 cm−1assigned to the CH stretching methyl and me-thylene groups increased and shifted at 2910 cm−1, and the 1.5% Agsbox impregnation resulted in a 57% increase in the intensity of the band (from 0.028444 to 0.065328). This may have been due to the soybean oil and chemical change in the chloroform. The addition of the nano compounds caused diverse changes in the intensities of the spectrum band. The peak value showed an increase when the chemical concentration rate increased (Fig. 2). White rot fungi can degrade wood polymers such as cellulose, hemicellulose and lignin. Since T. versicolor fungus digests the lignin and carbohydrates, this results in high mass loss in wood (Schubert et al., 2011). There is an increase in the 1712 cm−1peak in the samples impregnated with 1.5% Agsbox, which led to a mass loss (2.86%) considered as high in the wood. In addition, this group shows oleﬁn regions in the soybean oil (Goburdhun et al., 2001;Fabiyi et al., 2011).

5. Conclusions

The method applied in this study to produce polymerized soybean oil with Ag NPs is an easy and effective way to supply wood protection when compared to the traditional nanotechnology process, which re-quires advanced technology. In this study, soybean oil and its poly-styrene copolymer-Ag nanocomposites were used for thefirst time for wood protection in terms of their biological resistance to decay. The soybean oil, polystyrene and nano silver played important roles in the synergistic effect of increasing the decay resistance of Scots pine. Significant changes were observed in the wood chemical structure after

1.5 wt% of Agsbox impregnation. The FTIR analysis and decay test showed that the methylene and methyl groups generated by impreg-nation with Agsbox caused changes in the chemical structure of the wood, resulting in decay resistance against T. versicolor. This research demonstrated that polystyrene copolymer-Ag NPs at the concentration of 0.4 g ml−1are eﬀective against T. versicolor with < 3% mass loss. However, further studies are needed to investigate the antifungal, in-secticidal and termiticidal eﬀect of Ag NPs in higher ratios and with other wood species.

Acknowledgments

This research did not receive any speciﬁc grant from funding agencies in the public, commercial, or not-for-proﬁt sectors.

Appendix A. Supplementary data

Supplementary data related to this article can be found athttps:// doi.org/10.1016/j.ibiod.2018.06.022.

References

Allı, A., Allı, S., Becer, C.R., Hazer, B., 2014. One-pot synthesis of poly(linoleic acid)-g-poly(styrene)-g-poly(ε-caprolactone) graft copolymers. JAOCS (J. Am. Oil Chem. Soc.) 91, 849–858.

Allı, A., Allı, S., Becer, C.R., Hazer, B., 2016. Nitroxide mediated copolymerization of styrene and pentaﬂuorostyrene initiated by polymeric linoleic acid. Eur. J. Lipid Sci. Technol. 118, 279–287.

Bahmani, M., Melcher, E., Schmidt, O., Fromm, J., 2015. Inﬂuence of exposure time, wood species and dimension on the remaining copper and chromium content in CC-treated wood afterﬁeld and laboratory leaching tests. Holzforschung 69 (9), 1143–1150.

Berrocal, A., Rodriguez-Zuniga, A., Veja-Baudrit, J., Noguera, S.C., 2014. Eﬀect of silver nanoparticles on white-rot wood decay and some physical properties of three tropical wood species. Wood Fiber Sci. 46, 527–538.

Catto, A.L., Montagna, L.S., Almeida, S.H., Silveira, R.M., Santana, R.M., 2016. Wood plastic composites weathering: eﬀects of compatibilization on biodegradation in soil and fungal decay. Int. Biodeterior. Biodegrad. 109, 11–22.

Clausen, C.A., Green, F., Kartal, S.N., 2010. Weatherability and leach resistance of wood impregnated with nano-zinc oxide. Nanoscale Research Letters 5 (9), 1464–1467.

Durmaz, S., Özgenç, Ö., Boyacı, İ.H., Yıldız, Ü.C., Erişir, E., 2016. Examination of the chemical changes in spruce wood degraded by brown-rot fungi using IR and FT-Raman spectroscopy. Vib. Spectrosc. 85, 202–207.

Ellis, J.R., Jayachandran, K., Nicholas, D., 2007. Silver the Next Generation wood Preservative. IRG/WP 07–30419. The International Research Group on Wood Protection, Wyoming, USA.

EN-113, 2006. European Committee for Standardization EN 113. Wood preservatives. Test Method for Determining the Protective Eﬀectiveness against wood Destroying Basidiomycetes– Determination of the Toxic Values. European Committee for Standardization, Brussels, Belgium 2006.

Fabiyi, J.S., McDonald, A.G., Morrell, J.J., Freitag, C., 2011. Eﬀects of wood species on durability and chemical changes of fungal decayed wood plastic composites. Compos. Appl. Sci. Manuf. 42 (5), 501–510.

Fackler, K., Stevanic, J.S., Ters, T., Hinterstoisser, B., Schwanninger, M., Salmén, L., 2010. Localisation and characterisation of incipient brown-rot decay within spruce wood cell walls using FT-IR imaging microscopy. Enzym. Microb. Technol. 47 (6), 257–267.

Faix, O., 1991. Classiﬁcation of lignins from diﬀerent botanical origins by FT-IR spec-troscopy. Holzforschung 45, 21–28.

Goburdhun, D., Jhaumeer-Laulloo, S.B., Musruck, R., 2001. Evaluation of soybean oil quality during conventional frying by FTIR and some chemical indexes. Int. J. Food Sci. Nutr. 52, 31–42.

Goodell, B., Nicholas, D.D., Schultz, T.P., 2003. Wood deterioration and Preservation. American Chemical Society (ASC), Washington, DC 465pp.

Hazer, B., Akyol, E., 2016. Eﬃciency of gold nano particles on the autoxidized soybean oil polymer. Fractionation and structural analysis. JAOCS (J. Am. Oil Chem. Soc.) 93, 201–213.

Hazer, B., Kalaycı, Ö.A., 2017. High ﬂuorescence emission silver nano particles coated with poly (styrene-g-soybean oil) graft copolymers: antibacterial activity and poly-merization kinetics. Mater. Sci. Eng. C 74, 259–269.

Hill, C.A.S., 2002. How does the chemical modiﬁcation of wood provide protection against decay fungi? In: Proceedings of the COST E22 Finland, June 2002.

Huang, H.L., Lin, C.C., Hsu, K., 2015. Comparison of resistance improvement to fungal growth on green and conventional building materials by nano-metal impregnation. Build. Environ. 93, 119–127.

Humar, M., Lesar, B., 2008. Fungicidal properties of individual components of copper eethanolamine-based wood preservatives. Int. Biodeterior. Biodegrad. 62, 46–50.

Ince, Ö., Akyol, E., Sulu, E.,Şanal, T., Hazer, B., 2016. Synthesis and characterization of novel rod-coil (tadpole) poly(linoleic acid) based graft copolymers. J. Polym. Res. 23 (1), 1–10.

(6)

Kartal, S.N., Green III, F., Clausen, C.A., 2009. Do the unique properties of nanometals aﬀect leachability or eﬃcacy against fungi and termites? Int. Biodeterior. Biodegrad. 63 (4), 490–495.

Kartal, S.N., Terzi, E., Yılmaz, H., Goodell, B., 2015. Bioremediation and decay of wood treated with ACQ, micronized ACQ, nano-CuO and CCA wood preservatives. Int. Biodeterior. Biodegrad. 99, 95–101.

Karunasekera, H., Terziev, N., Daniel, G., 2017. Does copper tolerance provide a com-petitive advantage for degrading copper treated wood by soft rot fungi? Int. Biodeterior. Biodegrad. 117, 105–114.

Kharissova, O.V., Dias, H.V.R., Kharisov, B.I., Pérez, B.O., Pérez, V.M.J., 2013. The greener synthesis of nanoparticles. Trends Biotechnol. 31 (4), 240–248.

Kim, K.J., Sung, W.S., Suh, B.K., Moon, S.K., Choi, J.S., Kim, J.G., Lee, D.G., 2009. Antifungal activity and mode of action of silver nano-particles on Candida albicans. Biometals 22, 235–242.

Kirk, T.K., Schultz, E., Connors, W.J., Lorenz, L.F., Zeikus, J.G., 1978. Inﬂuence of culture parameters on lignin metabolism by Phanerochaete chrysosporium. Arch. Microbiol. 117, 277–285.

Köckritz, A., Martin, A., 2008. Oxidation of unsaturated fatty acid derivatives and ve-getable oils. Eur. J. Lipid Sci. Technol. 110 (9), 812–824.

Künniger, T., Heeb, M., Arnold, M., 2014. Antimicrobial eﬃcacy of silver nanoparticles in transparent wood coatings. European Journal of Wood and Wood Products 72 (2), 285–288.

Li, Y., Dong, X., Liu, Y., Li, J., Wang, F., 2011. Improvement of decay resistance of wood via combination treatment on wood cell wall: swell-bonding with maleic anhydride and graft copolymerization with glycidyl methacrylate and methyl methacrylate. Int. Biodeterior. Biodegrad. 65, 1087–1094.

Lin, L.D., Chen, Y.F., Wang, S.Y., Tsai, M.J., 2009. Leachability, metal corrosion, and termite resistance of wood treated with copper-based preservative. Int. Biodeterior. Biodegrad. 63 (4), 533–538.

Liu, M., Zhong, H., Ma, E., Liu, R., 2018. Resistance to fungal decay of paraﬃn wax emulsion/copper azole compound system treated wood. Int. Biodeterior. Biodegrad. 129, 61–66.

Lligadas, G., Ronda, J.C., Galia, M., Cadiz, V., 2013. Renewable polymeric materials from vegetable oils: a perspective. Mater. Today 16 (9), 337–342.

Mantanis, G., Terzi, E., Kartal, S.N., Papadopoulos, A.N., 2014. Evaluation of mold, decay and termite resistance of pine wood treated with zinc- and copper-based nano-compounds. Int. Biodeterior. Biodegrad. 90, 140–144.

Matsunaga, H., Kataoka, Y., Kigushi, M., Evans, P., 2012. Accessibility of Wood Cell Walls to Well-deﬁned Platinum Nanoparticles. IRG/WP 12–20494. International Research Group on Wood Protection, Stockholm, Sweden.

Moya, R., Rodriguez, Z.A., Berrocal, A., Vega, B.J., 2017. Eﬀect of silver nanoparticles synthesized with NPsAg-ethylene Glycol (C2H6O2) on Brown decay and white decay fungi of nine tropical woods. J. Nanosci. Nanotechnol. 17 (8), 5233–5240.

Narayanan, K.B., Park, H.H., 2014. Antifungal activity of silver nanoparticles synthesized using turnip leaf extract (Brassica rapa L.) against wood rotting pathogens. Eur. J. Plant Pathol. 140, 185–192.

Raberg, U., Hafren, J., 2008. Biodegradation and appearance of plastic treated solid wood. Int. Biodeterior. Biodegrad. 62 (2), 210–213.

Schlultz, T.P., Militz, H., Freeman, M.H., Goodell, B., Nicholas, D.D., 2008. Development of Commercial wood Preservatives. ACS Symposium Series 982. American Chemical Society, Washington, DC, pp. 9–31 2008.

Schmidt, O., 2006. Wood and Tree Fungi. Springer-Verlag, Berlin, Heidelberg 334pp.

Schubert, M., Volkmer, T., Lehringer, C., Schwarze, F.W.M.R., 2011. Resistance of bioincised wood treated with wood preservatives to blue-stain and wood-decay fungi. Int. Biodeterior. Biodegrad. 65 (1), 108–115.

Shogren, R.L., Petrovic, Z., Liu, Z., Erhan, S.Z., 2004. Biodegradation behavior of some vegetable oil-based polymers. J. Polym. Environ. 12 (3), 173–178.

Soucek, M.D., Khattab, T., Wu, J., 2012. Review of autoxidation and driers. Prog. Org. Coating 73 (4), 435–454.

Thybring, E.E., 2013. The decay resistance of modiﬁed wood inﬂuenced by moisture exclusion and swelling reduction. Int. Biodeterior. Biodegrad. 82, 87–95.

Tomak, E.D., Viitanen, H., Yildiz, U.C., Hughes, M., 2011. The combined eﬀects of boron and oil heat treatment on the properties of beech and Scots pine wood. Part 2: water absorption, compression strength, color changes, and decay resistance. J. Mater. Sci. 46, 608–615.

Xia, Y., Larock, R.C., 2010. Vegetable oil-based polymeric materials: synthesis, properties, and applications. Green Chem. 12 (11), 1893–1909.