Evaluation of the effects of additives on the properties of starch-based bioplastic film

The adverse environmental effects of petroleum-based packaging plastics have necessitated the need for eco-friendly bioplastics. Most bioplastics are starch-based and are not without drawbacks, hence there is the need for their properties to be improved. In this study, the effect of varying concentrations of dialdehyde starch and silica solutions on the physical, mechanical, biodegradable, surface topology, and thermal properties of the bioplastic films was examined. The additive concentrations were varied from 60 to 100%. The bioplastic films produced with dialdehyde starch solution recorded better moisture content (6.62–11.85%), bioplastic film solubility (4.23–7.90%), and tensile strength (1.63–3.06 MPa), against (11.24–14.26%), (7.77–19.27%) and (0.53–0.73 MPa) respectively for bioplastic films produced with silica solution. The atomic force microscopy analysis; root-mean-square roughness, kurtosis, and skewness revealed better miscibility and compatibility between the starch matrix and the dialdehyde solution than between the starch matrix and the silica solution. Bioplastic with added dialdehyde starch solution has better tensile strength and long biodegradability than that with silica solution. The research has demonstrated that bioplastic film produced with starch and dialdehyde starch solution has better properties than the one produced with starch and silica solution. The properties evaluation results of the bioplastic films thus demonstrated their aptness for food packaging applications. Graphic abstract

Improvement of the Centrifugal Force in Gravity Driven Method for the Fabrication of Highly Ordered and Submillimeter-Thick Colloidal Crystal

In this paper, we propose a modified gravity method by introducing centrifugal force to promote the stacking of silica particles and the order of formed colloidal crystals. In this method, a monodispersed silica colloidal solution is filled into empty cells and placed onto rotation arms that are designed to apply an external centrifugal force to the filled silica solution. When sample fabrication is in progress, silica particles are forced toward the edges of the cells. The number of defects in the colloidal crystal decreases and the structural order increases during this process. The highest reflectivity and structural order of a sample was obtained when the external centrifugal force was 18 G. Compared to the samples prepared using the conventional stacking method, samples fabricated with centrifugal force possess higher reflectivity and structural order. The reflectivity increases from 68% to 90%, with an increase in centrifugal force from 0 to 18 G.

Effect of chemical structure of elastomer on filler dispersion and interactions in silica/solution-polymerized styrene butadiene rubber composites through molecular dynamics simulation

The dynamic properties, filler–rubber interactions, and filler dispersion in silica/SSBR composites with various chemical structures of SSBR were studied using MD. Competing effects led to the existence of an optimum modifier content of 14.2 wt%.

Characterization of Heat-Resistant Geocement Based on Potassium Silica Solution

The aim of this paper is detailed description of synthesis geocement composite material based on K2O-Al2O3-SiO2 system and characterization its thermal properties. The series of analytic tools were used (XRF, XRD, SEM, BET, particle-size distribution) for accurate identification of chemical and physical properties of raw material. Optimum technological prescription was determined and geocement specimens were tested for identification of mechanical and thermal properties. Three series of specimens were heated up to 1000, 1100 and 1230°C and flexural strength was determined. The thermal analysis TMA and DMA were used for characterization of heat-resistant properties. The maximum shrinkage in the range 30-1000°C was for the first run in temperature rate 20°C/min. only 3%. The heating exposure at slower rate (3°C/min.) caused reduction of shrinkage up to 1.5% at 1000°C. Geocement represents attractive thermal properties.