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The SPE Library contains thousands of papers, presentations, journal briefs and recorded webinars from the best minds in the Plastics Industry. Spanning almost two decades, this collection of published research and development work in polymer science and plastics technology is a wealth of knowledge and information for anyone involved in plastics.
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Recycling
Various topics related to sustainability in plastics, including bio-related, environmental issues, green, recycling, renewal, re-use and sustainability.
EFFECT OF ENVIRONMENTAL EXPOSURE ON MATERIALS BASED ON BLENDS
OF PLASTICIZED STARCH AND POLYPROPYLENE
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.
EFFECT OF HAIRLINE CRACK ON THE TOUGHNESS OF POLYETHYLENE TEREPHTHALATE
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.
EFFECT OF HAIRLINE CRACK ON THE TOUGHNESS OF POLYETHYLENE
TEREPHTHALATE
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.
RELATIONSHIP BETWEEN PROPERTIES, CITRATE CONTENT AND POSTPRODUCTION TIME FOR A PLASTICIZED POLYLACTIC ACID
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.
EFFECT OF HYGROTHERMAL TREATMENT ON RHEOLOGICAL AND MECHANICAL PROPERTIES OF RECYCLED POLY(ETHYLENE TEREPHTHALATE)/ RECYCLED POLYPROPYLENE 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.
EFFECT OF HYGROTHERMAL TREATMENT ON RHEOLOGICAL AND
MECHANICAL PROPERTIES OF RECYCLED POLY(ETHYLENE
TEREPHTHALATE)/ RECYCLED POLYPROPYLENE 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.
EFFECT OF NANO FILLERS IN HYBRID BIO DEGRADABLE THERMOPLASTIC CORNSTARCH MATERIALS
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.
EFFECT OF THE DEGREE OF SUBSTITUTION OF CARBOXYMETHYLATED CASSAVA STARCH TESTED AS GREEN CORROSION INHIBITOR OF CARBON STEEL
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.
EFFECT OF TRIACETYL CELLULOSE FILM SURFACE HYDRATION ON THE ADHESION STRENGTH TO POLYVINYL ALCOHOL (PVA) FILM
Triacetyl cellulose (TAC) film has been used as a protective film for the polyvinyl alcohol (PVA) based polarization film in liquid crystal display (LCD). Adhesion strength between TAC and PVA films by PVA type adhesive must be maintained sufficiently to keep the dimensional stability of polarized PVA film under severe environmental conditions, such as high temperatures and high humidity. In this study, the surface hydration of TAC film and adhesion process between TAC and PVA films were investigated. The surface hydration of TAC enhanced the adhesion strength between TAC and PVA films. Consequently, this provides better dimensional stability of polarized PVA film protected by TAC film. In addition to adhesion strength, appropriate draw ratio and the crosslinking in PVA film were also required for better dimensional stability in polarized PVA film.
EFFECTIVENESS OF SUPERCRITICAL FLUID FOR FOAMING OF POLY(LACTIC ACID) DURING INJECTION MOLDING
Poly(lactic acid) (PLA) is one of the most favorable candidates to replace conventional packaging materials due to its biodegradability and sustainability. However, its high viscosity and density often poses a challenge to melt processing especially injection molding. In this study, PLA was injection molded and foamed by using supercritical N2. Injection molding parameters such as mold temperature and SCF content were varied in order to investigate their effects on foam cell size. The effects of nucleating agent on the foam structure and cell size distribution were also elucidated by image analysis. Impact and dynamic mechanical performance of the foams were also evaluated.
EFFECTIVENESS OF TALC AS REINFORCEMENT FOR RECYCLED-PET/PE-G-MA BLENDS
Recycling post-consumer PET bottles is an essential and practical solution to reduce the amount of waste discarded at the landfills. Several methods are
commonly used to recycle PET such as fiber making,
sheet extrusion and injection molding. However, PET
is known to exhibit low notched impact strength and
low heat distortion temperature. In this study, an
impact modifier was successfully used to enhance the
toughness of recycled RPET (RPET). Subsequently,
talc, which is typically used in polypropylene, was
introduced into RPET and its effectiveness as a
reinforcement was evaluated. It was noted that the
heat distortion temperature (HDT) of the composites
increased significantly with increasing talc content.
SINGLE SCREW EXTRUSION OF BIOBASED AND BIODEGRADABLE POLY (HYDROXY BUTANOIC ACID) COPOLYMERS
The complex time and temperature dependent melt rheology of Poly (Hydroxy Butanoic Acid) or PHB copolymers is an important consideration for their extrusion. In this effort, we report the influence of temperature profile and screw design on the process stability, melt temperature, melt pressure, output rate and molecular weight retention using highly-instrumented commercial-scale extruders with smooth-bore feed sections. One important outcome of this investigation is screw design guidelines for the extrusion of PHB copolymers.
ENVIRONMENTAL HEALTH AND SAFETY ISSUES AND APPROACHES FOR THE PROCESSING OF POLYMER NANOCOMPOSITES
In 2005 Environmental Defense and DuPont entered into a partnership to develop a framework that seeks to identify and address potential environmental health and safety (EH&S) risks of nano-scale materials. The Nano Risk Framework was published to establish a systematic and disciplined process to identify and reduce potential risks during nanomaterial development and meet continued product stewardship commitments [1]. This paper describes an approach developed for and the application of the Framework to the processing of polymer nanocomposites at laboratory and semi-works scales. Carbon nanotubes were melt-blended into a polymer matrix with a batch mixer to improve mechanical and electrical properties.Nano-TiO2 nanocomposites were made on laboratoryand semi-works extruders. These case studies exemplify DuPontƒ??s approach to handling nanomaterials in the product research and evaluation phase of development.Utilization of the Framework enabled further refinement of internal EH&S management procedures and to identify questions to be answered for such applications before they move to commercialization.
ENVIRONMENTAL AGEING OF MATERIALS USED FOR COLLAPSIBLE FUEL STORAGE TANKS
The purpose of this work was to perform a comparative analysis of various candidate nitrile coated fabric materials supplied by potential vendors to be used as fuel storage tanks and compare the results to the currently fielded polyurethane storage tanks. Our strategy is to utilize advanced environmental ageing methods to simulate extended weathering conditions.
Our results demonstrate that the nitrile coated fabrics performed well in our evaluation. Their breaking strengths are about equal to the currently fielded urethanes and they performed comparably when subjected to environmental ageing conditions.
SYNTHESIS AND PHYSICAL CHARACTERIZATION OF BIODEGRADABLE
PLA/PHBV FOAMS
This paper examines the effect that blending two
biodegradable polymers has on the thermal properties and
morphology of the resultant foams blown with carbon
dioxide (CO2). Polylactic acid (PLA)
Polyhydroxybutyrate-co-valerate (PHBV) and blends of
both were foamed and characterized in terms of thermal
characteristics relative density cell size and foam
morphology. The results indicate that although PLA and
PHBV are immiscible the presence of small quantities of
PHBV could lead to low density foams with finer more
uniform cells.
SYNTHESIS, CHARACTERIZATION, AND DEGRADATION OF BIOPLASTICS FROM RENEWABLE POLYFUNCTIONAL MONOMERS
Bioplastics were produced by the copolymerization of 1,3-propanediol (PDO) with malonic acid (MA) and with itaconic acid (IA). Effects of reaction temperature and time were examined on the yields and molecular weight (MW) distributions. The resultant bioplastics were characterized using FTIR and 1H NMR and were found to contain anhydride, ester, and ether backbone functional groups. Hydrolytic degradation of the PDO-MA copolymer was also studied as a function of time, temperature, and pH.
THE BUILDING BLOCKS OF INNOVATION: DELIVERING COMPETITIVE ADVANTAGE THROUGH CREATIVE PEOPLE
The goal of innovation should be to create sustainablecompetitive advantage'not just create inventions withlittle or no market value. In order to compete, the productof service being offered must provide value to theconsumer, be differentiated from competitors' offerings,and be protected from imitation. Frequently employeesand managers involved with product development are notaware of the broader picture and the essential elementsnecessary to create innovative products.
EVA CURING STUDY BY DSC FOR SOLAR APPLICATION
Ethylene vinyl acetate (EVA) has been used as encapsulant for solar cell application. the curing degree needs to be controlled to optimize the property. The traditional way to characterize the gel content (crosslinking degree) is by extraction using organic solvent. This method is time consuming and environmental unfriendly due to the toxic solvent. One new way to characterize gel content is by DSC. From the exothermic residue crosslink peak the gel content can be determined. The study indicates excellent correlation between these two methods. Compared with extraction method, DSC is easier and more cost efficient.
THE FOAMABILITY OF POLYPROPYLENE COPOLYMER BLOWN WITH ARGON NITROGEN AND HELIUM
Due to environmental concerns research has been carried out to investigate the feasibility of using inert gases as blowing agents in plastic foaming processes.However the foamability of polypropylene copolymer blown with argon nitrogen and helium has not been reported previously. This paper investigates the nucleating powers of these gases to foam polypropylene copolymer by studying the polymeric foaming processes in situ.
EVALUATION OF ENVIRONMENTAL STRESS CRACKING RESISTANCE IN POLYETHYLENES: BENT STRIP VS. CONSTANT-TENSILE-LOAD METHODS
For a group of 14 polyethylenes (PE) with different densities (0.924 to 0.966 g/cm3) and melt flow index, MFI (0.38 to 42 dg/min), the Environmental Stress Cracking Resistance (ESCR) of each PE was determined by the typical method of bent strip or ESCR at constant strain.The results were compared with those obtained by the evaluations of ESCR by constant-tensile-load method. For both methods the effects of the density and MFI on ESCR were similar and in agreement with those reported in the literature. However, the failure time spread measured in the ESCR at constant load is smaller, although both methods lead to high experimental errors, attributed to limitations or omissions in the experimental protocols described in the standards used for these measurements.
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