A New Protocol for Ash Wood Modification: Synthesis of Hydrophobic and Antibacterial Brushes from the Wood Surface.

Angelika Macior,Karol Wolski,Paweł Chmielarz,Izabela Zaborniak,Katarzyna Lecka-Szlachta,Ewa Ciszkowicz,Joanna Smenda

doi:10.3390/molecules27030890

Angelika Macior, Karol Wolski + Show 5 more

Open Access

https://doi.org/10.3390/molecules27030890

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Abstract

The article presents the modification of ash wood via surface initiated activators regenerated by electron transfer atom transfer radical polymerization mediated by elemental silver (Ag0 SI-ARGET ATRP) at a diminished catalyst concentration. Ash wood is functionalized with poly(methyl methacrylate) (PMMA) and poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) to yield wood grafted with PMMA-b-PDMAEMA-Br copolymers with hydrophobic and antibacterial properties. Fourier transform infrared (FT-IR) spectroscopy confirmed the covalent incorporation of functional ATRP initiation sites and polymer chains into the wood structure. The polymerization kinetics was followed by the analysis of the polymer grown in solution from the sacrificial initiator by proton nuclear magnetic resonance (1H NMR) and gel permeation chromatography (GPC). The polymer layer covalently attached to the wood surface was observed by scanning electron microscopy (SEM). The hydrophobic properties of hybrid materials were confirmed by water contact angle measurements. Water and sodium chloride salt aqueous solution uptake tests confirmed a significant improvement in resistance to the absorption of wood samples after modification with polymers. Antibacterial tests revealed that wood-QPDMAEMA-Br, as well as wood-PMMA-b-QPDMAEMA-Br, exhibited higher antibacterial activity against Gram-positive bacteria (Staphylococcus aureus) in comparison with Gram-negative bacteria (Escherichia coli). The paper presents an economic concept with ecological aspects of improving wood properties, which gives great opportunities to use the proposed approach in the production of functional hybrid materials for industry and high quality sports equipment, and in furniture production.

Highlights

To transform a hydrophilic wood surface into a hydrophobic surface, this study focused on the grafting of poly(methyl methacrylate) (PMMA) onto the wood surface, while poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) was used as a precursor to create antibacterial surfaces
Hydroxyl groups located in the wood cell wall, i.e., cellulose, hemicellulose, and lignin, were esterified with α-bromoisobutyryl bromide creating ATRP initiation sites, followed by the polymerization of MMA or DMAEMA via SI-ATRP from brominated wood cubes to prepare hydrophobic and antibacterial polymer grafts in the form of homopolymers or block copolymers (Scheme 1)
The polymerizations of MMA were carried out by the SI-activators regenerated by electron transfer (ARGET) ATRP approach using silver wire (Ag0 ) as a reducing agent (Table 1), while the DMAEMA serves as an internal reducing agent, the syntheses were performed by ARGET ATRP with

Summary

Introduction

Wood is a material with an uneven structure, and its quality properties depend on considering the anatomical direction. Wood is defined as a heterogeneous, multidirectional, i.e., anisotropic, material [1,2,3]. The structure of the wood varies depending on the type. The main division is softwood and hardwood, but shrinkage, sapwood, and heartwood, mature and juvenile are distinguished [1,2,4]. The surface quality of such material plays an important role in their finishing and bonding properties

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