Effect of the Prodegradant-Additive Plastics Incorporated on the Polyethylene Recycling

The effect of degraded plastic with prodegradants on the polyethylene properties was studied. First, the mixture of low-density polyethylene (LDPE) with 5 wt.% prodegradant (oxo-degradable) additive was prepared by melt processing using a mixer chamber. Then, the degradation of the mixtures was evaluated by exposing the oxo-degradable LDPE in a Xenon arc chamber for 300 hours. The degraded material was characterized by infrared spectroscopy (FTIR) assessing the carbonyl index and the hydroperoxide band. Then, different percentages of degraded material (1, 5, 10, 20, and 50 wt.%) were incorporated into the neat LDPE. Mechanical and rheological tests were carried out to evaluate the recycling process of these blends. Also, the feasibility of the blends reprocessing was determined by analysing the melt flow index for each heating process and shear stress applied. It was evidenced that the increment of the content of the degraded material in the neat LDPE decreased the mechanical strength and the processability of blends due to the imminent thermal degradation. All the test results showed that the incorporation of degraded material causes a considerable reduction in the matrix properties during the reprocessing. Nevertheless, at low concentrations, the properties of the oxo-degradable LDPE–LDPE blends were found to be similar to the neat LDPE.

Three-Dimensional Temperature Field of Mixer Chamber Analysis

This paper analyzes the three-dimensional temperature field of mixer chamber during the mixing process by using the finite element method. The paper focuses on analyzing the three-dimensional temperature field of mixer chamber, the distribution of heat transferring, and the influence of forced cooling on the mixing temperature, and has verified by experiment the accuracy of finite element simulation of mixer chamber temperature.

The Effect of the Rotor’s Shape for the Mixing about the Mixing-Extruding Machine

The mixing-extruding machine is made up of mixer and unconventional double-cone screw extruder, which has both the excellent mixing capabilities and the continuous extruding characters. In the mixer chamber, the complex mixing motion of the blends is determined by the different kinds of forces acting on the blends. The different structure of the rotor, the distribution of the three direction forces is changed also。From the force analysis about the blends, there are three structure factors about rotor effecting the mixing process, such as the wedge angle θ of the rotor’s cross-section, the helix angle β of the rotor’s wing and the length of the wings. The best value of each structure factor can be gotten from theoretical analysis.

Effect of the Organoclay Preparation on the Extent of the Intercalation/Exfoliation and the Barrier Properties in Polyamide-6/Montmorillonite Nanocomposites

This paper shows the importance of the clay surface chemistry in the preparation of nanocomposite materials. An Argentinean montmorillonite was used for preparing two modified clays. The filosilicate was intercalated with a quaternary ammonium salt derived from ε- caprolactam to obtain an organofilic material. The other modification was introduced by mixing the clay with hexadecyl trimethyl ammonium chloride. Thus, the polyamide 6 ability in dispersing clays was applied to prepare composites with the intercalated clays. The polyamide 6/clay dry composites with 3 wt % of filler were prepared by melt processing in a mixer chamber. Composites of polyamide 6/organoclay were characterized by X-ray diffraction, transmission and scanning electron microscopy and thermogravimetry. The barrier properties were determined by cyclohexane pervaporation. The results show that the dispersion and degree of delamination depend on a proper chemical treatment and the clay content influences the polyamide 6 nanocomposites solvent pervaporation resistance.