SPE Library

The aim of this work was to investigate the effects of the composition on the properties of LDPE-PA6 blends with an emphasis on the addition of EVA, because this material is often used as interlayer in packaging films. Furthermore, also the effects of additional compatibilization on the blend properties should be investigated.
We found, that the addition of EVA alone shows some compatibilizing effects in blend properties, like impact strength and viscosity. Further improvements can be gained by adding prefabricated additives, like maleic anhydride grafted polyethylene and ethylene vinyl acetate, while the in situ production of such additive shows some reduced effects, likely due to some reduced accessibility of the EVA component for the in-situ grafting. Nevertheless all the investigated approaches show some effectiveness in compatibilisation, which will help to reuse such materials in other applications.

Synthetic polymers derived from crude oil are widely used across various industries. However, increased environmental regulations tackling climate change have spurred interest in development of bio-sourced polymers. While promoting the cause of sustainability, biopolymers also possess inferior mechanical properties, limiting their widespread use. A plausible and cost-effective way of enhancing the properties of pure biopolymers is to blend them with other polymers and/or reinforce them with stiff fibers. This study investigates the thermophysical properties of bio-based thermoset blends of epoxidized pine oil (EPO) and acrylated epoxidized soybean oil (AESO). The blends were prepared via casting in five different ratios by volume (EPO/AESO): 100/0, 90/10, 80/20, 70/30, and 0/100. Mechanical properties of blends were studied via tensile testing and scanning electron microscopy, while chemical properties were analyzed using thermo-gravimetric analysis.

Splay is a primary source of fallout when injection molding parts using polycarbonate. Elimination of splay is a difficult proposition, but maintaining acceptable baseline fallout across production is crucial to keeping waste under control and shipment of defects to customer to a minimum. Overall splay was reduced from 1.8 to 0.9 percent on parts running in excess of 1.4 million annually. The analysis provided in this paper shows how the extent of splay waste was identified, root cause analysis conducted, corrective action implemented, and results verified for one source of polycarbonate splay in a production environment.

Among the many environmental problems which mankind faces in the XXI century is the problem of environmental sustainability and management of the tremendous amount of generated polymer waste. Among various polymer wastes, management of crosslinked plastics is a major environmental problem requiring a solution. This study was specifically directed toward the creation of a new, environmentally friendly and science-based technology for the recycling of crosslinked plastics. Uncrosslinked thermoplastics can be easily reprocessed and reused. However, managing crosslinked plastics is a very challenging problem. This is due to the presence of a three-dimensional network, which prevents flow and shaping of crosslinked plastics upon heating and shearing. Our laboratory developed ultrasonic decrosslinking technology for recycling of the crosslinked high density polyethylene (XHDPE) of different levels of crosslink densities and crosslinked LDPE (XLDPE). This is done by using ultrasonically aided single-screw extruder (SSE) operating at a frequency of 20 kHz and twinscrew extruder (TSE) operating at a frequency of 40 kHz at different levels of ultrasonic energy [1]. The experimental studies on the ultrasonic decrosslinking of XHDPE and XLDPE have shown that the ultrasonic extrusion was capable to preferentially break crosslinks rather than main chains in XHDPE. Significant reduction of the extruder torque, die and barrel pressures with the ultrasonic amplitude was observed during decrosslinking of XHDPE and XLDPE. The specific ultrasonic energy decreased with the flow rate and increased with the ultrasonic amplitude, while die pressure increased with the flow rate and decreased with the ultrasonic amplitude [2-5]. Accordingly, application of ultrasonic treatment during extrusion enabled an increase of productivity.

Thin film packaging is used for a wide range of products including packaging of food, medical tools, electronics, and toys. Each of these applications requires a different type of film, from thin and brittle, to composite film including a foil layer, to biodegradable films. These films can be adhesively bonded, heat sealed, impulse welded, and increasingly, ultrasonically welded. Ultrasonic welding offers many benefits to thin film sealing such as faster cycle times, reduction in film usage due to narrower bond widths, elimination of adhesive layers, improved hermeticity for increased shelf life, and less sensitivity to contaminants in the seal area.
However, tool design can have a significant effect on weld strength. Optimum tool design depends not just on the thickness of the material to be welded, but also the type of polymer to be joined, and seal requirements (such as hermeticity and peel strength). In this study, we seek to provide starting guidelines with the goal of lowering the cost and duration of the tooling development process by investigating the achievable peel strength of a wide variety of film types with twenty-five horn and anvil design combinations.

The addition of de-inking paper sludge into recycled high-density polyethylene composites improves their tensile strength and stiffness, but is detrimental to their ductility and toughness.

Cellulose fibers from agricultural waste are used to prepare composites with improved mechanical properties.

Improved mechanical properties of composites produced by melt blending is achieved at low filler loadings.

Rheo-particle image velocimetry and thermal imaging results show that frictional and viscous heating act synergistically to produce significant temperature increases when a melt is extruded under slip conditions.

A novel ternary composite comprising a biopolymer, natural fibers, and an essential oil extract is a promising active material for extending the shelf-life of food products.

Fully biodegradable polylactic acid/microcrystalline cellulose composites, with surface-modified reinforcing cellulose, are suitable for 3D printing applications.

Rheological, optical, mechanical, and thermomechanical investigation of the properties of cellulose-nanofiber-reinforced polylactide demonstrates the solution method for achieving good fiber dispersion.

A fully biobased composite material, composed of bamboo fibers and a nanoparticle-reinforced bio-epoxy matrix, exhibits improved mechanical properties.

Cellulose from sugarcane bagasse can be used to improve the mechanical and barrier properties of bionanocomposites.

Thermal conductivity and mechanical strength measurements indicate that paper waste sludge particles can be used effectively as fillers in eco-polyol-based foams.

A post-molding stage, in which samples are kept at 105°C, is used to produce semi-crystalline samples in much shorter times than through standard injection into a hot mold.

A novel and environmentally friendly pretreatment approach is used for the production of cellulose-rich fibers as reinforcements for thermoplastic-starch-based bioplastics.

A series of tensile loading-unloading and relaxation tests, under stretching and retraction cyclic deformation conditions, were conducted between room temperature and 50°C.

The mechanical, rheological, and foaming properties of melt-blended samples were investigated.