New plasma technique makes wood transparent and stronger than glass
Researchers have developed a solvent-free method to transform ordinary wood into a transparent material that rivals glass in clarity while maintaining superior strength. The breakthrough could disrupt the $100+ billion global glass market by offering a sustainable, easier-to-manufacture alternative that requires no harsh chemicals.
Originaltitel: Enhancing the optical properties of transparent wood by plasma modification
Transparent trä kan ersätta glas inom möbler och byggmaterial, men industrialiseringen bromsas av giftiga kemikalier och dålig bindning mellan fiber och polymer. Forskare vid Slovak University of Technology och Luleå tekniska universitet utvecklade en solventfri plasmametod — Atmospheric Discharge with Runaway Electrons (ADRE) — som aktiverar trätexturen utan kemikalier. Behandlingen skapar syrerika funktionsgrupper som förbättrar polymerinfiltration och eliminerar luftblåsor vid gränsytan. Resultaten visar 91 procent ljustransmittans vid 550 nanometer och 11 procent lägre skimring jämfört med obehandlat trä. Böjhållfastheten steg till 89,6 megapascal — högre än kemiskt behandlat trä. Hårdnessen ökade från 83,3 till 86,7 Shore D. Metoden erbjuder ett skalbart alternativ för träbaserade optiska kompositer utan miljöbelastning från kemisk delignifiering, vilket förkortar vägen till kommersiell produktion av transparent konstruktionsbaserat trä.
<p>Transparent wood is a promising sustainable alternative to glass, yet its large-scale production is often constrained by harsh chemical delignification, poor polymer compatibility, and limited interfacial control. This study introduces a solvent-free strategy for enhancing the optical and mechanical properties of transparent balsa wood through volumetric plasma modification using Atmospheric Discharge with Runaway Electrons (ADRE). The plasma treatment generates fast electrons capable of activating the entire wood volume, forming oxygen-containing functional groups that improve surface energy and polymer affinity. Morphological analyses (optical microscopy and SEM) revealed that plasma-treated samples exhibit homogeneous resin infiltration and the elimination of interfacial voids observed in untreated transparent wood. FTIR spectra confirmed the introduction of polar carbonyl and hydroxy groups, indicating enhanced chemical interaction between cellulose and the acrylic matrix. Consequently, the plasma-treated transparent wood achieved a visible light transmittance of 91% at 550 nm and reduced haze by 11% compared to non-treated samples. Mechanically, the plasma-treated transparent wood exhibited the highest bending strength in three-point bending tests (89.6 MPa), outperforming non-treated transparent wood (84.5 MPa) and raw wood (41.4 MPa), while partially modified wood showed the lowest strength. Hardness also increased from 83.3 to 86.7 Shore D after plasma activation, corroborating the improved interfacial adhesion and structural integrity. This solvent-free plasma activation approach replicates the interfacial benefits of chemical acetylation without toxic reagents or lengthy processing, providing a scalable and environmentally benign route toward high-performance, optically clear, and mechanically robust cellulose-based composites.</p>