Grafting of amphiphilic block copolymers on lignocellulosic materials via SI‐AGET‐ATRP

Abstract

Functionalizing biosourced materials is a major topic in the field of materials science. In particular, grafting polymerization techniques have been employed to change the surface properties of various substrates. Here, we report on the grafting of amphiphilic block copolymers in lignocellulosic materials using surface‐initiated activators generated by electron transfer atomic transfer radical polymerization (SI‐AGET‐ATRP). With this modification, it is possible to combine the interesting properties (anisotropy and high mechanical stability) of lightweight lignocellulosic materials, such as wood, with the special properties of the grafted block copolymers. Hydroxyl groups on wood cell wall biopolymers were used for the chemical bonding of an alkyl bromide as the initiator for AGET‐SI‐ATRP of a highly hydrophilic monomer ([2‐(methacryloyloxy)ethyl]trimethylammonium chloride) and a highly hydrophobic fluorinated monomer (2,2,3,3,4,4,5,5‐octafluoropentyl methacrylate). The successful grafting of homopolymers and block copolymers onto the wood structure was confirmed through Fourier transform infrared and Raman spectroscopy. The functionalization with the two homopolymers yielded lignocellulosic materials with opposite wettabilities, whereas by the adjustment of the ratio between the two copolymer blocks, it was possible to tune the wettability between these two extremes. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 885–897

Natural weathering of spruce wood chemically modified by re‐used ε‐caprolactone solution

“…Modified samples with the sixth re‐use of monomer showed 18% higher VC than modified samples with the third re‐use of monomer. This may be related to the amount of DMF in 70% monomer solution, where DMF can swell wood cell walls 9,19,29 . Thus, the use of DMF in the first step of the modification is a critical parameter 9 …”

“…This may be related to the amount of DMF in 70% monomer solution, where DMF can swell wood cell walls. 9,19,29 Thus, the use of DMF in the first step of the modification is a critical parameter. 9 The modified samples were found to be more effective than the reference samples during the first 5 months, but the effectiveness started to disappear after a period of 6 months of weathering.…”

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

“…Up to now, ATRP methods have been successfully used for raw wood modification only a few times [16,18,[40][41][42][43][44]. Poplar wood [16,40], spruce wood [41,44], waterlogged archaeological wood [42,43] and fir wood [18] were grafted with polymers to improve their properties, i.e., hydrophobicity [16,18,43], resistance to attack by fungi and termites, and antibacterial characteristics [40], controlled swelling behavior and tunable wettability [41,44], dimensional stability of wood, therefore preventing shrinkage, cracking and deformation [42]. The approaches ranged from both the classical high catalyst concentration ATRP technique [41,44] to the low ppm ATRP concepts, mainly activators regenerated by electron transfer (ARGET) ATRP with ascorbic acid as a reducing agent [16,40,42,43].…”

“…Poplar wood [16,40], spruce wood [41,44], waterlogged archaeological wood [42,43] and fir wood [18] were grafted with polymers to improve their properties, i.e., hydrophobicity [16,18,43], resistance to attack by fungi and termites, and antibacterial characteristics [40], controlled swelling behavior and tunable wettability [41,44], dimensional stability of wood, therefore preventing shrinkage, cracking and deformation [42]. The approaches ranged from both the classical high catalyst concentration ATRP technique [41,44] to the low ppm ATRP concepts, mainly activators regenerated by electron transfer (ARGET) ATRP with ascorbic acid as a reducing agent [16,40,42,43]. Our previous investigation was focused on the modification of fir wood using supplemental activator and reducing agent (SARA) ATRP with copper wire (Cu 0 ) as a reducing agent, polymerizing hydrophobic monomers from wood structure [18].…”