查看更多>>摘要：This study compared the preparation and characterization of polymer blends containing two types of polystyrene (high-impact polystyrene (HIPS) and general-purpose polystyrene (GPPS)) and thermoplastic corn starch (TPS) as a natural resource. Melt extrusion was used to create TPS/polystyrene blends. SEM, XRD, and DMTA analyses were used to determine the compatibility and mechanical properties of GPPS/TPS and HIPS/TPS blends. SEM analysis revealed that TPS particle size was significantly smaller in HIPS blends than in GPPS blends, owing to lower interfacial tension and better compatibility between HIPS and TPS. According to the DMTA results, the storage modulus of both blends increased significantly, particularly at high PS concentrations. All blends had two peaks on the loss factor curve, one for each phase's glass transition. The Tg of the PS-rich phase in blends was nearly equivalent to the Tg of pure PS. On the other hand, Tg of the TPS-rich phase was unexpectedly lower than that of pure TPS. By adding a low volume of polystyrene to TPS (approximately 20 wt%), the ultimate tensile strength of TPS was increased by more than 200%. At high polystyrene concentrations (approximately 80 wt%), the blend exhibited mechanical properties comparable to pure PS.
查看更多>>摘要：Introducing bio-based acid sources into the cellulose lumens is an effective way to enhance the flame retardant of wooden products. The wood was delignified at first and then phytic acid (PA) was adsorbed solely into the vessels of the wood. With only 8.0 wt% addition of PA, the highly flame retardant wood was obtained. The limiting oxygen index (LOI) of the treated sample was reached 37.2%, the sample also passed the V-0 grade in the UL-94 vertical burning test, and in the CONE test, the total heat release was reduced by 71.3% compared to that of the Natural wood sample. The flame retardant mechanism was probed and summarized as capture of the flaming radicals, the synergistic promotion on charring and suppression on heat and smoke release. After hot-pressing, the flame-retardant treated wood sample exhibited much enhanced mechanical properties, its tensile strength went up to 138 MPa and its bending strength reached 213 MPa, which are 6 times and 7.8 times higher than that of the Natural wood, respectively. This work provided a simple and environmental-friendly method to prepare flame retardant wood for furniture applications.
查看更多>>摘要：Bast fibers of many fiber crops are valuable raw material for diverse applications. The isolated from flax stem technical fibers demonstrate numerous defects that are considered to accumulate both during plant growth and various steps of crop processing. We have performed quantitative estimation of dislocations in flax bast fibers within stems of developing plants and at different stages of stem processing, including drying in sheaves, dew retting, scutching and hackling. Scanning electron microscopy revealed no dislocations in fibers within the stem. Numerous defects appeared after scutching in ex-planta fibers and increased in frequency during subsequent technological step. We propose the disturbance of flax stem integrity and the mechanical treatments acting directly on fibers to serve the main factors of fiber deformation emergence.
NSTL
Elsevier