SPE Library

Biodegradable poly(lactic acid) (PLA)-based PLA/Poly(butylenes succinate) (PBS) foams with open cell structure were prepared via batch foaming method using supercritical carbon dioxide as blowing agent. It was found that PLA was immiscible with PBS, and PBS phase was dispersed as tiny spheres or large domains at various concentrations. The addition of PBS reduced the viscosity of the blends. During foaming process, the PLA/PBS interfaces acted as cell nucleation sites and the low melt strength PBS contributed to the formation of cell connection channels, which resulted in open cell structure. The investigation of PBS content found that PLA/PBS (80/20) foamed at 100 °C obtained the highest cell opening rate (96.2%).

Sustainable solutions are being increasingly demanded in the construction product market place. Polystyrene insulation is an increasingly important component of green construction. The benefits of insulation in residential and commercial buildings include lower energy consumptions, improved thermal comfort, reductions in the first costs of the heating and cooling equipment and reductions in CO2 emissions from the burning of fossil fuels across the United States.
As with all foam insulations, polystyrene foam insulation is combustible and must comply with stringent building and fire codes, which have been in place since 1976. The basic requirement in codes is a flame spread index of 75 or less and a smoke developed index of 450 or less when tested in accordance with ASTM E84, in addition to separation of the foam insulation from building occupants through use of a thermal barrier, typically ½” gypsum board. Additional requirements are in place depending upon the particular application.
Like many other building products – from electrical wires to structural and decorative wood products to paint – foam insulation uses flame retardants to protect people and property from the hazards of fire. Flame retardants used in foam insulation meet current regulations and their history of safe use is supported by scientific research.1 Manufacturers are committed to product safety and the effectiveness of flame retardants, and support research and development efforts to continually advance and improve these materials.
A recent announcement by the Design for the Environment program of the U.S. EPA detailed a suitable polymeric flame retardant for use in polystyrene foam insulation. The chemistry is a brominated polymeric flame retardant to replace Hexabromocyclododecane (HBCD)2. HBCD has recently been listed as a persistent organic pollutant (POP) under the UNEP Stockholm convention and is on the Authorisation List (Annex XIV) under the European Union REACH (Regi

The poly(lactic acid)/ethylene methyl acrylate copolymer (PLA/EMA) blends were melt blended with by a twin-screw extruder. The phase morphologies, mechanical, and rheological properties of the PLA/EMA blends with three weight ratios were investigated. The results showed that the addition of EMA improves the toughness of PLA at the expense of the tensile strength to a certain degree. All the PLA/EMA blends display typical droplet-matrix morphology, and different characteristic linear viscoelastic properties in the low frequency region, which were investigated in terms of their complex viscosity, storage modulus, and Cole-Cole plots. The interfacial tension between the PLA and EMA is calculated using the Palierne model conducted on the 80/20 PLA/EMA blend, and the calculated result is 3.3 mN/m.

In this work, we introduce the in situ microfibrillation of poly (lactic acid) (PLA)/polyamide-6 (PA6) blends as an effective approach in improving PLA’s properties as well as its foaming-ability. The in situ microfibrillation of the PLA/PA6 blends was performed using a facile and cost-effective extrusion process followed by hot stretching of the extrudates. The morphological studies proved the successful formation of fully stretched PA6 microfibrils with diameters as low as 200 nm. Inclusion of a small concentration of PA6 microfibrils (3 wt.%) was shown to lead to significant improvements in the crystallization kinetics and mechanical properties of PLA. In addition, formation of a physically entangled network of PA6 microfibrils improved the melt strength and elasticity of PLA which, in turn, improved the microstructure of PLA foams.

Chitin is a well-known biopolymer that can be extracted from crustacean shells and inherently has good mechanical properties. This paper focuses on using chitin nanowhiskers as a filler to improve the properties of neat polypropylene. Melt blended chitin nanowhisker polypropylene composites with chitin nanowhisker loadings ranging from 2 to 10 wt% was used for analysis. A combination of thermal, barrier, and mechanical properties were examined using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), water vapor transmission test, and tensile test respectively. It was observed that the chitin nanowhisker helped improve thermal stability and crystallization. Additionally, an improvement of about 20% and 17% in elastic modulus and ultimate tensile strength respectively was observed at 5 wt% chitin nanowhisker loading. Lastly, a 258% improvement in water vapor resistance was displayed for the 2 wt% chitin nanowhisker loading. Results from the study showed that chitin nanowhisker is a suitable biodegradable filler material for polypropylene to strengthen its thermal, barrier, and mechanical properties.

Blending of plastics used in packaging is an interesting approach for recycling or upcycling. Therefore, this study focused on the effects of processing on the properties of recycled PP and PP/LDPE blends. MFI measurements, Differential Scanning Calorimetry (DSC) and hot-stage polarized optical microscopy techniques were used to investigate the miscibility of PP/LDPE blends based on the thermal properties, degree of crystallinity, crystallization and morphology development in the blends. The MFI indicates, that PP and PP/LDPE blends are marginally sensitive to degradation at common processing conditions. The degree of crystallinity of the blends decreases with an increase of the LDPE content. Furthermore, the spherulite growth rate and crystal size of PP decrease with an increase of LDPE content.
The shifts of crystallization temperatures from the DSC measurement, in conjunction with the crystallization kinetics, indicate that PP/LDPE (25 wt% LDPE) is partially miscible.

Polylactide (PLA) is a promising material, with favorable modulus, renewable sources, and biodegradability. However, its low extension at break (4-7 %) and toughness (notched Izod, 26 J/m) limit its applications [1]. PLA toughening has been the subject of recent reviews [1,2], and is the basis for several commercial products. This work aims to increase PLA toughness using rubbery linear low density polyethylene (LLDPE), glycidyl methacrylate functional PE compatibilizer (EGMA), and novel catalysts that promote copolymer formation at the interface of immiscible blends of PLA and EGMA/LLDPE. Droplet size was reduced from 2.7 ?m to 1.7 ?m with addition of 5 wt% EGMA, and further to 1.0 ?m with the addition of cobalt octoate catalyst. Extension at break of 200 % is achieved with only 5 wt% reactive compatibilizer, 15 wt% LLDPE, and 0.01 M cobalt octoate.

Glycerol-plasticized soy protein isolate (SPI) films with dialdehyde carboxymethyl cellulose (DCMC) as crosslinking agent were solvent casted and tested for their mechanical properties. Results indicate that the addition of DCMC increased tensile strength (TS) up to 218%, suggesting effective crosslinking between SPI and DCMC. The significant improvements in the TS compared to other dialdehyde polysaccharide crosslinking agents such as the dialdehyde starch is due to higher compatibility of DCMC with SPI, which was confirmed by SEM imaging. Furthermore, based on stress-strain features, a hypothetical mechanism was proposed to illustrate the effect of the polymeric cross-linking agent.

The objective of this work is to investigate the degradation mechanisms and property changes of a blend of poly (etheretherketone) (PEEK) with poly [2, 2’-(m-phenylene-5, 5’-bibenzimidazole] (PBI) upon exposure to water at temperatures up to 288 °C. The molecular scale damping behavior of PEEK/PBI blend was probed using dynamic mechanical analysis (DMA). Atomic Force Microscopy based nanomechanical mapping has been used to assess the moduli profile near the interface of PEEK and PBI with various environmental exposure histories. The results demonstrate that the incorporation of water influences the compatibility behavior of PEEK and PBI through enhanced interfacial adhesion. Fracture toughness of the PEEK/PBI blend is significantly reduced by hot water exposure at 288 ºC.

Intumescent and char forming additives are typically blended into certain types of commercial plastics to impart resistance to fire propagation. Intumescent compounds such as ammonium polyphosphate/ melamine/ pentaerythritol, silica gel/potassium carbonate are already used as flame retardant (FR) additives. In this work, a naturally occurring polyphenol, namely tannic acid, is explored as an intumescent and char forming additive for polyamide - Nylon 6. The tannic acid was meltblended into Nylon 6 and the compounded plastic was evaluated for thermal stability, total heat release (THR) and heat release capacity (HRC). It was found that HRC and THR of nylon blended with tannic acid decreased by 50% and 20% respectively.

Corrugated cardboards have truss structure, so these have advantageous in terms of specific strength, workability, price and recycling efficiency. Because of these properties, corrugated cardboards are used as not only packing materials but also furniture etc. When a disaster caused in Japan, refugees sleep directory on the floor with a blanket. It caused the second healthy damage like the economy class syndrome. For prevent refugees from its damage, beds made from corrugated cardboard has been used instead of cots in Japanese shelters. We need to give flameretardancy to the cardboard bed for enhancing safety. In this research, flameretardancy of corrugated cardboards is aimed to using Poly-vinyl alcohol (PVA). PVA is useful for the coat of the cardboard. The coating PVA on the cardboard is possible to be recyclable, because PVA has water solubility. We used 2 kinds of flameretardant in this time. In the result of combustion test, the Halogen, Phosphorous and Nitrogen based compound show great flameretardancy for PVA.

Recently corrugated cardboard is utilized for not only packing materials but also furniture and beds at shelters in Japan. The reason why the cardboard has the characteristics of lightness, high strength, cheapness and recycle ability. Therefore, there is the strong needs to add flameretardancy for cardboard beds in medical facilities for prevention of second disaster. The purpose on this study is to add flameretardancy to the cardboards with keeping the recycle ability. In this paper, the cardboard of combusting behavior was measured by using a calorimeter under the UL-94 standard. So far we have used 6 kinds of flameretardant include 3 kinds of commercial flameretardant. As a result ammonium sulfate has given superior flameretardancy to cardboards. However we considered that it has no practical use, because flameretardancy of cardboards must be safety from chemical toxicity. Therefore we selected 2 kinds of flameretardant. As a result a flameretardant which contain phosphorus and nitrogen gave great flameretardancy to cardboards with small quantity.

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.

Soil burial tests, conducted under natural conditions, were used to investigate the biodegradability of bio-nanocomposites containing silica, silicate, and graphene reinforcements.

Using an industrial waste as an inorganic filler in plastic/wood composites improves the fire and mechanical properties of the material, as well as reducing its financial and environmental cost.