SPE Library

With the rapid increase in the market for recycled polyethylene from various sources, there is an urgent need to quantify the performance of these materials. Blends of recycled high density polyethylene (HDPE) were prepared to obtain specific mechanical properties and MFI. The results show that the MFIs had significant effect on the rheological, mechanical and phase morphology characteristics of the various blends.

This work studied bio-plastics such as polylactic acid (PLA) and protein based plastics form corn and compared to petroleum based plastics such polyethylene (PE) and polystyrene in terms of their ecological as well as economical performance from a 'Cradle to Grave' perspective. This study included energy input, emissions output of green house gases and costs from their life cycle steps of raw material acquisition to the final product disposal. It was found that products manufactured from bio-based feedstocks were relatively higher in cost, they resulted in less green house gas emissions.

In this work the devulcanization of tire rubber crumb was studied by using an industrial scale twin screw extruder. A reasonably high throughput extrusion process has been developed and the effect of processing conditions has been studied. The effects of different screw configurations, screw speed and feed rate on the stability of process have been investigated. Crosslink density and percent of devulcanization of different samples are measured. Curing behavior, tensile strength, and elongation at break of different compounds consisting of blends of virgin rubber with devulcanized crumb have also been evaluated.

In this work the devulcanization of tire rubber crumb was studied by using an industrial scale twin screw extruder. A reasonably high throughput extrusion process has been developed and the effect of processing conditions has been studied. The effects of different screw configurations screw speed and feed rate on the stability of process have been investigated. Crosslink density and percent of devulcanization of different samples are measured. Curing behavior tensile strength and elongation at break of different compounds consisting of blends of virgin rubber with devulcanized crumb have also been evaluated.

Recent earth environmental concern requires easy recycle material system and the use of biodegradable polymer and natural fiber is noticed in composite materials. To apply the natural fiber for the structural parts the use as reinforcement of Sheet Molding Compound (SMC) is desirable because it is expected that SMC can be used in various fields in terms of high productivity and dimensional stability. Considering that fiber reinforced composite is used for structural part the use of long-span must be possible. Therefore the evaluation of the durability such as degradation is very important subject. In this study SMC (Sheet Molding Compound) that reinforcement was jute cloth were prepared. The jute cloth reinforced SMC was immersed in hot water to promote the degradation. And after immersion an increase ratio of water and bending properties were compared with that of jute cloth reinforced SMC without immersion. As a result the fracture mechanism changed from the combination of crack propagation in matrix area and delamination in the interface around the fiber bundle to only crack propagation in matrix area by water immersion.

Recent earth environmental concern requires easy recycle material system, and the use of biodegradable polymer and natural fiber is noticed in composite materials. To apply the natural fiber for the structural parts, the use as reinforcement of Sheet Molding Compound (SMC) is desirable because it is expected that SMC can be used in various fields in terms of high productivity and dimensional stability. Considering that fiber reinforced composite is used for structural part, the use of long-span must be possible. Therefore, the evaluation of the durability such as degradation is very important subject. In this study, SMC (Sheet Molding Compound) that reinforcement was jute cloth were prepared. The jute cloth reinforced SMC was immersed in hot water to promote the degradation. And after immersion, an increase ratio of water and bending properties were compared with that of jute cloth reinforced SMC without immersion. As a result,the fracture mechanism changed from the combination of crack propagation in matrix area and delamination in the interface around the fiber bundle to only crack propagation in matrix area by water immersion.

Melt compounded polymer blends such as PP/HDPE blends from post consumer waste have often been reported to exhibit poor mechanical properties. This work reports on the potential improvement in performance of PP/HDPE blends using polypropylene copolymers as compatibilizers. The properties of the PP/HDPE blends in general progressively varied from that of 100% HDPE to 100% PP. Analysis showed some improvements in mechanical performance of the blends with the addition of PP copolymers, but DMTA results suggest no improvement in compatibility.

One of the most attractive environmentally friendly energy generation methods is wind power. In order for this technology to compete favorably with the cost of traditional energy generation methods, the wingspan needs to be greatly increased from current dimensions. For this to occur, we need to take advantage of new material developments such as nano-composites.In order to manufacture such large parts, we need to understand factors affecting flow. In the case of flow through porous media, the material properties are permeability and viscosity. In this work we present preliminary results on the effect of carbon nano fibers on permeability.

Wind energy is one of the most promising environmentally friendly renewable sources of energy. Epoxy has been the preferred resin used to manufacture wind blades; however with the increased need to lower costs, vinyl ester resin is gaining importance as a alternative material. The curing of vinyl ester resin in the presence of carbon nanofibers (CNFs) was studied by differential scanning calorimetry (DSC). It was found that the carbon nanofibers have a catalytic effect on the curing kinetics of vinyl ester. However there is a percolation threshold and increasing the amount of CNFs beyond this threshold hinders the reaction. A simple autocatalytic model is used to predict the conversion of the vinyl ester resin.

Recycled polyethylene terephthalate (RPET),recycled polypropylene (RPP) and CaCO3 were blendedand compatibilized with SEBS copolymer. The effects of compatibilization on morphological, thermal and mechanical properties were investigated. The results indicated that the dispersed phase in compatibilized blends is significantly smaller in size as compared to uncompatibilized blends. The crystallization temperature and crystallinity of the blends were affected by the incorporation of compatibilizers while tensile and impactproperties depended on the content of CaCO3 and compatibilizer.

Recycled polyethylene terephthalate (RPET) recycled polypropylene (RPP) and CaCO3 were blended and compatibilized with SEBS copolymer. The effects of compatibilization on morphological thermal and mechanical properties were investigated. The results indicated that the dispersed phase in compatibilized blends is significantly smaller in size as compared to uncompatibilized blends. The crystallization temperature and crystallinity of the blends were affected by the incorporation of compatibilizers while tensile and impact properties depended on the content of CaCO3 and compatibilizer.

Due to the recent demand for environmentally friendly polymers and the duty to take advantage of renewable natural resources when possible, biopolymers have become an important alternative to synthetic polymers. Starch when using glycerol as a plasticizer has proven to be a processable ƒ??greenƒ? polymer additive when compounded with maleated polypropylene. In this study, material was characterized based on its ability to perform over five months of exposure to natural conditions. The effects on modulus and elongation with the addition of plasticized starch, in a polypropylene matrix, were evaluated and are presented.

Due to the recent demand for environmentally friendly polymers and the duty to take advantage of renewable natural resources when possible biopolymers have become an important alternative to synthetic polymers. Starch when using glycerol as a plasticizer has proven to be a processable “green” polymer additive when compounded with maleated polypropylene. In this study material was characterized based on its ability to perform over five months of exposure to natural conditions. The effects on modulus and elongation with the addition of plasticized starch in a polypropylene matrix were evaluated and are presented.

The effect of notches was investigated by introducing single-edge hairline cracks and V-shaped notches of different depths on dumbbell samples to ascertain the fracture behavior at the skin and core parts of virgin and recycled poly(ethylene terephthalate), (V-PET/R-PET), injection-moldings. Investigation shows that the fracture behavior of the materials responded differently to both hairline crack and V-shaped notch. Results revealed that amere 5?¬m deep critical hairline crack caused a drasticchange in the fracture behavior of the materials. In contrast, a standard V-shaped notch would only cause drastic change in toughness at a much higher critical notch depth of 600?¬m. V-shaped notch also provided a gradual transition in fracture behavior from the skin to the core regions, which suggests that the fracture behavior can be dependent on the skin and core sizes of PET injection moldings.

The effect of notches was investigated by introducing single-edge hairline cracks and V-shaped notches of different depths on dumbbell samples to ascertain the fracture behavior at the skin and core parts of virgin and recycled poly(ethylene terephthalate) (V-PET/R-PET) injection-moldings. Investigation shows that the fracture behavior of the materials responded differently to both hairline crack and V-shaped notch. Results revealed that a mere 5?m deep critical hairline crack caused a drastic change in the fracture behavior of the materials. In contrast a standard V-shaped notch would only cause drastic change in toughness at a much higher critical notch depth of 600?m. V-shaped notch also provided a gradual transition in fracture behavior from the skin to the core regions which suggests that the fracture behavior can be dependent on the skin and core sizes of PET injection moldings.

Due to the recent interest on citrates as a biodegradable plasticizer for Polylactic acid PLA, several PLA blends that were plasticized with tributyl citrate TBC were prepared in a co-rotating twin screw extruder. A range of 12.4 to 22.5% by weight was considered for the plasticizer content. The thermal, rheological and mechanical properties were correlated with the plasticizer content and compared with pure Polylactic acid. Additionally, the change of these properties as a function of postproduction time was studied and correlated with the plasticizer permanence.

Poly(ethylene terephthalate) (PET) is one of the most important fibers for industrial production due to its high performance,low cost, and recyclability. The amount of waste that arise from post-consumer PET especially in the beverage industry have made recycling of poly(ethylene terephthalate) (PET) a beneficial effort in reducing environmental pollution. Studies of blends and composites using recycled PET have been carried out with several polymeric materials, like polyethylene and polystyrene. In this work, recycled poly(ethylene terephthalate)/ recycled polypropylene (RPET/RPP) blends was subjected to injection molding and then subjected to hydrothermal treatment in water bath at below transition glass temperature to determine the amount of moisture absorption. As polypropylene tends to degrade at a faster rate than poly(ethylene terephthalate), the results show that defect of polypropylene effect the tensile strength and modulus of the RPET/RPP blends.

Poly(ethylene terephthalate) (PET) is one of the most important fibers for industrial production due to its high performance low cost and recyclability. The amount of waste that arise from post-consumer PET especially in the beverage industry have made recycling of poly(ethylene terephthalate) (PET) a beneficial effort in reducing environmental pollution. Studies of blends and composites using recycled PET have been carried out with several polymeric materials like polyethylene and polystyrene. In this work recycled poly(ethylene terephthalate)/ recycled polypropylene (RPET/RPP) blends was subjected to injection molding and then subjected to hydrothermal treatment in water bath at below transition glass temperature to determine the amount of moisture absorption. As polypropylene tends to degrade at a faster rate than poly(ethylene terephthalate) the results show that defect of polypropylene effect the tensile strength and modulus of the RPET/RPP blends.

There is a global interest in replacing petroleum based synthetic composites with biodegradable hybrid materials in order to use renewable resources and to reduce the amount of persistent non-biodegradable plastics waste. Fillers (or reinforcements) play an important role to improve various characteristics in biodegradable hybrid composites. Various types of inorganic fillers are used to modify the properties of biodegradable composites in industrial applications. This paper attempts to investigate the effects of inorganic fillers (such as halloysite nano clay and calcium carbonate (CaCO3)) on the mechanical properties (tensile testing) and microstructures of hybrid thermoplastic cornstarch (TPS) material systems.

The effect of the degree of substitution (DS) of carboxymethylated starch (CMS) as green corrosion inhibitor of carbon steel on 200 mgL-1 NaCl solution was investigated. Physical/chemical structure of CMS was studied by Fourier Transform Infrared Spectroscopy (FTIR) and Nuclear Magnetic Resonance (13C-NMR). DS of this bio-polymer was determined by back-titration. Its inhibitive properties were evaluated using polarization curves and electrochemical impedance spectroscopy. CMS acts as corrosion inhibitor and the protection level is highly dependent on the degree of substitution. The formation of a chelate between carboxylate groups and ferrous cations allows the inhibition mechanism of CMS to be explained.