Compression Molding of Polyhydroxybutyrate Nano-Composite Films as Coating on Paper Substrates

After successful preparation of master batch formulations including polyhydroxybutyrate (PHB) and fibrillated cellulose, the compositions of PHB with different types and concentrations of fillers were used for the deposition of a coating on packaging paper grades, by using compression molding technique in a hydraulic press. The resulting paper coatings are demonstrated to provide a green solution for the production of protective barrier layer films with tunable hydrophobicity and oxygen barrier resistance. The processing of the nanocomposites into flat and homogeneous coatings was optimized for different conditions of molding temperature and times, in particular, the flow conditions of the coating under pressing in contact with the paper substrate strongly depends on the presence of fillers. The effects of filler types on adhesion of the coating at the paper/polymer interface were investigated and the poor adhesion of native PHB coatings was improved after hydrophobic surface modification of the nanocellulose fillers. Under compression molding, the unique inclusion styrene-maleimide nanoparticles with encapsulated wax attached to the nanocellulose fiber surface enhanced the flowing properties of the coating by eliminating fiber agglomeration in contact with the paper substrate and reducing the effects of fiber pull outs. Therefore, hydrophobic fiber modification and the role of wax as a lubricant is necessary to obtain a homogenous dispersion during compressing molding of coating materials for papers

Comparative screening of the structural and thermomechanical properties of FDM filaments comprising thermoplastics loaded with cellulose, carbon and glass fibers

| openaire: EC/H2020/788489/EU//BioELCellAdditive manufacturing (AM) has been rapidly growing for a decade in both consumer and industrial products. Fused deposition modeling (FDM), one of the most widely used additive manufacturing methods, owes its popularity to cost effectiveness in material and equipment investment. Current efforts are aimedtowardhighload-bearingcapacityat lowmaterial costs. However, themechanical reliability of end-products derived from these compositions and their dependence on microstructural effects, have remained as major limitations. This is mainly owing to the unknown mechanics of the materials, including the reinforcing or filler components and their interphase/interface compatibility. For this reason, here we investigate the most relevant commercial polymeric materials used in composite filaments, associated phases and the characterization protocols that can guide component selection, screening and troubleshooting. We first present thermal analyses (thermogravimetric, TGAand differential scanning calorimetry, DSC) in relation to the constituent fractions and identify the type of polymer for uses in filaments production. The influence of various fillers is unveiled in terms of the crystallization behavior of derived 3D-printed parts. To understand the microstructural effects on the material strength, we carry out a series of tensile experiments on 3-D printed dog-bone shaped specimens following ISO standards. Simultaneously, real-time thermal energy dissipation and damage analyses are applied by using infraredmeasurements at fast frame rates (200 Hz) and high thermal resolution (50mK). The failure regions of each specimen are examined via optical, scanning and transmission electron microscopies. The results are used to reveal new insights into the size, morphology and distribution of the constituents and interphases of polymer filaments for FDM. The present study represents advancement in the field of composite filament fabrication, with potential impact in the market of additive manufacturing.Peer reviewe