Silver nano-coating of liquid wood for nanocomposite manufacturing

The green composites from renewable resources are being increasingly studied because of their potential to provide benefits to the natural environment. Biotechnologies such as liquid wood injection moulding have several merits into account. Liquid wood is a thermoplastic material made from byproducts of the wood pulp industry. The liquid wood is in the form of pellets, which for processing will be melted and injected, just like plastics. This study is set to explore the potential advantages of combining liquid wood with silver nanoparticles. The use of silver-nanoparticles as antimicrobial agent is being evaluated for biomedical devices as well as furniture in many public places. In order to solve manufacturing problems in handling and spreading nano-particles in injection moulding products, an innovative methodology has been used. Plastic pellets are coated by Physical vapor deposition (PVD) with a nanometric layer of metallic silver. This continuous nanofilm produces silver nanoparticles during the plastification stage of the injection moulding process. Nano-coating fragmentation allows to distribute silver nanoplatelets in the polymer matrix with very low contents and incomparable homogeneity. PVD coating has been optimized to take into account the nature of the raw material to process, mainly in terms of high-water content and small pellet size. Differential scanning calorimetry (DSC) on liquid wood granules coated with silver showed that no alteration has been produced in PVD. In fact, DSC scans show that no interaction is present between the polymer structure and the metal coating. These studies allow also a preliminary evaluation of the properties belongs of the new biomaterial, while opening for discussion the potential applications and future use in a wide variety of areas such as: bioengineering, medical and others.