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Polypropylene is increasingly being used for the thermoforming of food packaging. Compared with amorphous materials, such as polystyrene, it is much more difficult to process and within the industry it is generally poorly understood. In the present study the effects of pigments and nucleating agent on the crystallisation, morphology, and mechanical properties of an un-nucleated isotactic polypropylene (iPP) have been investigated. Results were compared with those obtained for a grade of iPP containing a proprietary nucleating agent. Quinacridone red pigment was found to be almost as efficient a nucleating agent as a standard nucleating agent, Millad 3988, and both of these were superior in performance to the iPP containing the proprietary agent. The white pigment (White PE MB) was found to be a nucleating agent for b-crystals. Young's modulus and yield stress increased with increasing crystallinity and increasing a-crystal content. Elongation at break increased with increasing b content.

The aim of the present work is to investigate the effects of nanoclay (NC) on the mechanical properties of polypropylene (PP)/microcrystalline cellulose (MCC) composites modified by maleic anhydride grafted PP (PP-g-MA). Polypropylene/microcrystalline cellulose nanocomposites were prepared using a twin screw Brabender Plasticorder, the weight percent of the MCC was varied at 0, 0.5, 1, 2, 5, 10, 20, and 40 wt%, and the NC content was varied at 0, 0.05, 0.1, 0.5, 1.0, and 2.0 wt%. The results showed that consistent and uniform PP/MCC nanoclay composite can be produced easily with the presence of PP-g-MA. Compression molding technique was used to produce tensile and impact testing samples; all samples were characterized by tensile and impact tests. It is observed that increasing the amount of either the MCC or the NC will decrease the tensile strength, elongation at break, and impact strength; much more reduction in the same properties was obtained in case both MCC and NC exist within PP composites. Compared with neat PP, a loss of over 75% in both elongation and impact strength was obtained for nanoclay composites which contain 60 wt% PP/40 wt% MCC. The most significant enhancement in the mechanical properties of polypropylene/microcrystalline cellulose nanocomposites is in Young’s modulus where an increment of more than twofold can be achieved for 60 wt% PP/40 wt% MCC nanocomposite. Polarized light photomicrographs showed that MCC particles play a nucleating agent rule in terms of intensity of nucleation and crystal growth acceleration.

This work was intended to provide an understanding of the effect of microcrystalline cellulose (MCC) on the mechanical properties of low-density polyethylene (LDPE). The impact resistance and the tensile properties of low-density LDPE/MCC composites were investigated. The weight fraction of MCC was varied at (0, 0.5, 1, 2.5, 5, 10, 20, and 30 wt%). The obtained blends were then used to prepare the required tensile and impact testing samples by hot compression molding technique. It has been found that MCC has a strong influence on the mechanical properties of LDPE. At a low MCC weight fraction, there was a little improvement in the ultimate strength, fracture stress, and elongation at break, but at a high MCC weight fraction, the tensile properties were deteriorated and reduced significantly. The addition of 1 wt% MCC to LDPE enhanced the mentioned properties by 10, 25, and 6%, respectively. While at 30 wt% MCC, these properties were lowered by 36, 25, and 96%. The elastic modulus of LDPE composites was improved on all MCC weight fractions used in the study, at 20 wt% MCC, an increase in the elastic modulus by 12 folds was achieved. On the other hand and compared with the impact strength of pure LDPE, the addition of MCC particles enhanced the impact strength, the highest value obtained was for LDPE composites filled with 10 wt% MCC where the impact strength enhanced by two folds.

Isotactic polypropylene (iPP) and iron oxide (Fe 3 O 4 ) nanocomposites were mixed by masterbatch blending technique in a single screw extruder machine. The concentrations of Fe 3 O 4 in the iPP/Fe 3 O 4 nanocomposites were 0.5, 1, 2, and 5% by weight. The influence of Fe 3 O 4 nanoparticles on the effectiveness of nucleation, morphology, mode of crystallization, and crystallinity of iPP were studied by differential scanning calorimetry (DSC) and polarized light microscopy (PLM). The introduction of Fe 3 O 4 nanoparticles in the iPP matrix inhibited the formation of b crystals, and caused a shift in the melting point to higher values. The magnitude of the shift was up to 20-21 C which indicates that using the masterbatch technique leads to an enhancement of the dispersion process of the Fe 3 O 4 nanoparticle and the formation of less agglomerates in the iPP/Fe 3 O 4 nanocomposites. The percentage crystallinity, X c , increased at the low cooling rates of 1 and 2 C/ min. At higher cooling rates of 5, 10, and 20 C/min, the masterbatch technique produced nanocomposites of X c with nonuniform trends. The overall crystallization rate enhancement for the iPP/Fe 3 O 4 nanocomposites is attributed to the presence of Fe 3 O 4 nanoparticles as a nucleating agent which have no significant effect on the growth rate of iPP crystals.

Leaching of copper from a Jordanian copper ore has been studied using a stirred batch reactor with hydrochloric acid as the main lixiviant, under the following conditions: temperature 25 -45 o C, acid concentration 0.05 -0.2 N, particle size 462 -1850 m, stirring speed of 700 -1000 rpm, and solid/liquid ratio of 1 -4 g/L. It was found that the rate of leaching of copper ore with hydrochloric acid or sulfuric acid, increases with temperature and acid concentration, while it decreases with increasing particle size. At the same operating conditions, leaching with sulfuric acid gave slightly greater conversion than leaching with hydrochloric acid, particularly at operating conditions of high temperature, high acid concentration, and small ore particle sizes. A maximum copper dissolution of about 87 % can be recovered at a leaching temperature of 45 o C, 462 m particle size, 0.2 N hydrochloric acid, 1.0 g/L solid to liquid ratio, and 1000 rpm stirring speed. Keeping all these operating parameters constant while decreasing the hydrochloric acid concentration to 0.05 N will decrease the copper dissolution to 83 %. On the other hand, decreasing the leaching temperature to 25 o C while keeping the other parameters fixed at 0.2 N, 1.0 g/L solid to liquid ratio, 1000 rpm stirring speed, and a particle size of 462 m decreases the copper dissolution to 80 %.

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This article highlights the melt crystallization behavior of different grades of isotactic polypropylene (iPP) using a hot-stage polarizing optical microscopy. iPP samples were heated up at a heating rate of 10 C/min passing the melting temperature and then kept for 3 min at a temperature range of 175-200 C before they cooled rapidly at 40 C/min to crystallize isothermally at a range of 130-145 C. It has been found that the temperature at which the samples were kept has a strong effect on the crystallization mode; for samples heated up and kept at temperatures below 190 C, the crystallization started with thin and long rods or nodules, which grew in the circumferential direction only while their lengths remain unchanged as the time passed. The shape of the nodules can be straight, circular, branched, or entangled, and they can grow parallel to each other or they can be crossed or in a random way. This phenomenon disappeared completely for samples melted and kept at temperatures above 195 C.