Transcrystalline morphology and mechanical properties in polypropylene composites containing cellulose treated with sodium hydroxide and cellulase

To evaluate the transcrystalline effects caused by various fibers, which were untreated, or treated with sodium hydroxide and cellulase, isothermal crystallization was performed. It was observed that the untreated and cellulase-treated cellulose fibers (cellulose I) had a nucleating ability to transcrystallize at PP matrix. Especially, cellulose fibers treated with Sodium hydroxide (cellulose II) transcystallized at PP matrix. This result was different from other's. Cellulose fibers also transcrystallized at PP/MAH-PP matrix irrespective of the type of cellulose crystalline structure. In PP/MAH-PP/CELL system, MAH-PP was located around the fiber surface at initial crystallization time, but was gradually expelled from that with the increase of crystallization time, and existed at outer boundaries of transcrstalline region at the final crystallization time. These phenomena were confirmed by IR-IRS spectra. The tensile strength of PP/CELL and PP/MAH-PP/CELL composites decreased with the increase of isothermal crystallization time. Therefore, it is thought that transcrystallinity gives rise to negative effect of tensile strength.     

Approach to derive golden paths based on machine sequence patterns in multistage manufacturing process

Journal of Intelligent Manufacturing - A multistage manufacturing process (MMP) consists of several consecutive process stages, each of which has multiple machines performing the same functions in...     

Influence of graphene nanoplatelets content on the structure and properties of macroporous carbon foams prepared by organic colloidal templates

Graphene nanoplatelets (GNPs)-reinforced carbon foams have been fabricated by polycondensation of resorcinol–formaldehyde resin as a carbon precursor and GNPs as a reinforcing material. The pore structure, mechanical properties, and electrical conductivity were investigated in terms of the amount of the GNPs. The results show that the amount of GNPs has a considerable influence on compressive strength, electrical conductivity, and specific capacitance. Although the amount of GNPs added does not influence the pore structure, the mechanical properties, electrical conductivity, and specific capacitance of carbon foams were improved with increasing the GNPs content. With 5 wt% addition of GNPs, the compressive strength, electrical conductivity, and specific capacitance increased by 75.2, 240.26, and 53.36 %, respectively.     

The preparation and characteristics of low-density polyethylene composites containing cellulose treated with cellulase

Low-density polyethylene (LDPE) composites containing untreated cellulose, cellulose treated with cellulase, and cellulose treated with cellulase after pretreating with NaOH were prepared. The purpose of the cellulase treatment of cellulose is to enhance the interfacial adhesion between the cellulose and the matrix. The effect of this treatment was studied by viscometry and X-ray diffraction. Maleic anhydrideg-polythylene (MAH-PE) was also added to the composite to enhance interfacial interactions between the cellulose and the matrix and to increase the dispersibility and the wettability of cellulose. The increased adhesion in composites containing the treated cellulose and MAH-PE was studied by FTIR. In addition, the thermal, dynamic mechanical, and tensile properties of the composites were investigated. When MAH-PE was added to the composite, it was found that the reaction between MAH-PE and treated cellulose occurred more easily.     

Simple model of microsegregation during solidification of steels

A simple analytical model of microsegregation for the solidification of multicomponent steel alloys is presented. This model is based on the Clyne-Kurz model and is extended to take into account the effects of multiple components, a columnar dendrite microstructure, coarsening, and the δ/γ transformation. A new empirical equation to predict secondary dendrite arm spacing as a function of cooling rate and carbon content is presented, based on experimental data measured by several different researchers. The simple microsegregation model is applied to predict phase fractions during solidification, microsegregation of solute elements, and the solidus temperature. The predictions agree well with a range of measured data and the results of a complete finite-difference model. The solidus temperature decreases with either increasing cooling rate or increasing secondary dendrite arm spacing. However, the secondary dendrite arm spacing during solidification decreases with increasing cooling rate. These two opposite effects partly cancel each other, so the solidus temperature does not change much during solidification of a real casting.     

Study on the initiation of a thermite reaction in aluminum coated steel with a high-velocity impact

Both theoretical and experimental studies have been performed in order to investigate the feasibility of thermite sparking and the impact of rusted steel on aluminum coated steel. For dry rust, the exothermic reaction occurred at 900 °C while the wet rust ignited an exothermic reaction at 1000 °C. This delayed ignition was attributed to the consumption of energy by the water while in wet rust for phase transformation. The experimental study used a compressed-gas-powered impact-testing apparatus that showed that the dry rusted steel ignited sparking upon colliding with un-coated steel. It was also found that the presence of an aluminum coat generated a higher susceptibility to sparking than colliding with un-coated steel.