SPE Library
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 STRESS CRACKING AGENTS ON FATIGUE AND CREEP OF A MDPE PIPE
The effect of concentration of Igepal CO 630 on slow crack propagation in MDPE pipe was investigated. The kinetics and mechanism of crack propagation in fatigue at R=0.1 and creep at 50 ?øC were compared to those in air. The fatigue and creep behavior followed the same stepwise crack growth mechanism as in air at all the concentrations used. As the concentration increased to 0.01 vol. % the creep lifetime decreased significantly whereas the lifetime in fatigue gradually increased. At higher concentrations the lifetime was similar in creep and fatigue.
FAILURE ANALYSIS OF A PLASTIC SLIDE VALVE ASSEMBLY
Premature cracks were observed during service in the
slide valve assembly molded from an acrylonitilebutadiene-
styrene resin. The investigation focused on the
determination of nature and cause of the failure. The
results obtained during the evaluation indicated that the
failure was due to environmental stress cracking which
occurred as a consequence of the presence of the residual
stress and the stress cracking agent. This paper will focus
on the testing used to characterize the failure mode and
identify the cause of the cracking of the slide valve
assembly.
FAILURE ANALYSIS OF A PLASTIC SLIDE VALVE ASSEMBLY
Premature cracks were observed during service in the slide valve assembly molded from an acrylonitilebutadiene- styrene resin. The investigation focused on the determination of nature and cause of the failure. The results obtained during the evaluation indicated that the failure was due to environmental stress cracking, which occurred as a consequence of the presence of the residual stress and the stress cracking agent. This paper will focus on the testing used to characterize the failure mode and identify the cause of the cracking of the slide valve assembly.
CHARACTERISATION OF BIOACTIVE POLYCAPROLACTONE
The effects of a bioactive [Nalidixic Acid - NA] and copolymers [Poly L-Lactic Acid (PLLA) and Polyethylene Glycol (PEG)] on the drug release morphology and mechanical properties of Poly -caprolactone [PCL] were studied. Release of NA increased with the addition of copolymers in the PCL with a maximum release of 55% in a blend containing 5%w/w each of PLLA PEG and NA. The filler effect of the NA was illustrated by an increase in viscosity in the blends. FTIR spectrums showed the blending of the PCL and the NA. The carbonyl bond present in the biodegradable polymers PCL and PEG allowed for some degree of miscibility also confirmed by the decrease in thermal conductivity from 0.26 to 0.2 Wm'C. Mechanical properties were decreased by the copolymers with the Young's Modulus decreasing by 15%.
CHARACTERIZATION OF BIODEGRADABLE ACRYLIC ACID GRAFTED POLY(?-CAPROLACTONE)/CHITOSAN BLENDS
Blend films of acrylic acid grafted polycaprolactone
(PCLgAA) and chitosan (CS) with different
compositions were prepared from aqueous acetic acid
solution. DSC measurements showed that the melting
temperatures and enthalpies of the blends decreased
with increasing CS content. From FTIR results it can
be seen that the amino groups of CS form covalent
bonds with the carboxylic groups of PCLgAA in
addition to hydrogen bonds between these components
in the blends. Though the crystal structure of the
PCLgAA component was not changed as proved by
WAXD results blending CS suppressed the
crystallinity of the blends. Furthermore the ductility
of CS was increased during tensile testing in
PCLgAA/CS blends due to enhanced affinity between
the two components. However PCLgAA/CS blends
showed greater resistance than PCL/CS blends to
biodegradation in an enzymatic environment.
CHARACTERIZATION OF BIODEGRADABLE ACRYLIC ACID GRAFTED POLY(?-CAPROLACTONE)/CHITOSAN BLENDS
Blend films of acrylic acid grafted polycaprolactone (PCLgAA) and chitosan (CS) with different compositions were prepared from aqueous acetic acid solution. DSC measurements showed that the melting temperatures and enthalpies of the blends decreased with increasing CS content. From FTIR results it can be seen that the amino groups of CS form covalent bonds with the carboxylic groups of PCLgAA in addition to hydrogen bonds between these components in the blends. Though the crystal structure of the PCLgAA component was not changed, as proved by WAXD results, blending CS suppressed the crystallinity of the blends. Furthermore, the ductility of CS was increased during tensile testing in PCLgAA/CS blends due to enhanced affinity between the two components. However, PCLgAA/CS blends showed greater resistance than PCL/CS blends to biodegradation in an enzymatic environment.
DEVELOPMENT OF ANTIMICROBIAL PLA NANOCOMPOSITES WITH SILVER
CONTAINING LAYERED NANOCLAYS FOR PACKAGING AND COATING
APPLICATIONS
This paper presents the development and characterization
of the antimicrobial activity of a novel family of
commercial food contact compliant silver-modified
nanolayered clays and of their nanobiocomposites with
polylactic acid. The antimicrobial nanolayered clays
showed an antimicrobial effectiveness of 99.99% against
Gram-negative Salmonella spp. In addition the PLA-clay
nanocomposite also showed a significant antimicrobial
activity and a synergistic water vapour permeability
reduction of 32% with respect to neat PLA. The results
indicate that these novel active nanolayered fillers can
potentially exhibit numerous applications in plastic and
bioplastic packaging and coatings where simultaneous
barrier and antimicrobial performance are desirable.
DEVELOPMENT OF ANTIMICROBIAL PLA NANOCOMPOSITES WITH SILVER
CONTAINING LAYERED NANOCLAYS FOR PACKAGING AND COATING
APPLICATIONS
This paper presents the development and characterization of the antimicrobial activity of a novel family of commercial food contact compliant silver-modified nanolayered clays and of their nanobiocomposites with polylactic acid. The antimicrobial nanolayered clays showed an antimicrobial effectiveness of 99.99% against Gram-negative Salmonella spp. In addition, the PLA-clay nanocomposite also showed a significant antimicrobial activity and a synergistic water vapour permeability reduction of 32% with respect to neat PLA. The results indicate that these novel active nanolayered fillers can potentially exhibit numerous applications in plastic and bioplastic packaging and coatings where simultaneous barrier and antimicrobial performance are desirable.
PROCESSING AND BLENDS OF BIOPLASTICS
Biopolymers are generally defined as polymers that are found in nature derived from nature or utilized as medical implants. Polymeric biomaterials which are utilized as medical implants are typically characterized for enduse performance as well as processability. While lactic acid is found in the human body polylactic acid is derived from natural resources and utilized as medical implants. This paper will utilize poly(lactic acid) as an example of a bioplastic where the morphological and isomeric structure has an influence on end-use properties such as mechanical properties biodegradability and biocompatibility.
SCREW DESIGN CONSIDERATIONS FOR BIOBASED POLYMERS
The family of biobased polymers is ever growing in
number and in popularity and the extruder/screw
manufacturing businesses need to keep abreast of the
machinery requirements of these polymers to insure that
efficient processing is understood. This paper will look at
the extrusion parameters and logic that are important to
determining the most efficient screw designs and
extrusion operating conditions for processing
biopolymers. Vented and non-vented operation will be
discussed. PLA data will be used as the basis for the
conclusions.
SCREW DESIGN CONSIDERATIONS FOR BIOBASED POLYMERS
The family of biobased polymers is ever growing in number and in popularity and the extruder/screw manufacturing businesses need to keep abreast of the machinery requirements of these polymers to insure that efficient processing is understood. This paper will look at the extrusion parameters and logic that are important to determining the most efficient screw designs and extrusion operating conditions for processing biopolymers. Vented and non-vented operation will be discussed. PLA data will be used as the basis for the conclusions.
THERMAL DEGRADATION OF FIBER-REINFORCED BIO-BASED RIGID POLYURETHANE FOAMS
Rigid polyurethane (PU) foams were prepared by a multi- step procedure using a polyol blend of poly(ethylenglycol) PEG-200/pineapple molasses and 4 4'-diisophenylmethane diisocyanate (MDI) with a NCO/OH ratio of 1.2. Such material was reinforced with fibers from banana rachis with a fiber composition ranging from 18% to 40% wt.Thermal and themooxidative degradation properties of these composites were assessed. Thermal degradation of PU60 showed the highest polymer lifetime values.
TOWARDS QUALITY PRODUCTS FROM BIO-BASED PLASTICS
The importance of three inter-dependent factors, i.e., (1) materials, (2) manufacturing, and (3) design and engineering, is generally recognized. All factors are indispensable and equally important for product development. Manufacturing is often the least structured factor and many designers and materials experts do not consider themselves capable to deal with it. Fortunately, expertise is sufficiently available and the best professionals are able to utilize plastics expertise properly in collaborative product development.
FEASIBILITY STUDY OF THE USE OF DDGS PLASTIC COMPOSITES
Recently, an increase in the demand for ethanol as
a fuel additive has resulted in a dramatic increase in its coproducts
namely distiller’s dried grains with solubles
(DDGS).
This work studied a composite of DDGS and
conventional petrochemical plastics (polyvinyl chloride)
for applications in windows construction. The goal was to
characterize the composite and its processibility for
“green” plastics. The experiments showed that DDGS can
be effectively extruded with PVC; at low filler levels (5-
10%) of DDGs strengthening of the PVC was seen.
However, higher filler levels (>10%) of DDGS degraded
the mechanical properties of PVC/DDGS composites.
Also, ground DDGS perform better as reinforcement
agents compared to standard DDGS. Caustic pretreatment
was also studied and it was found not to effect the
mechanical properties significantly. Also, the addition of
PVA had little effect on the properties of the composite.
NEW LOW GLOSS POLYCARBONATE BLENDS FOR AUTOMOTIVE APPLICATIONS
Automotive original equipment manufacturers are consistently looking for low-gloss materials for interior applications that can stand up to years of wear and tear and environmental exposure yet maintain aesthetic quality without painting. Bayblend?? LGX 300 resin is specifically developed for automotive interior applications requiring a material that is inherently low in gloss with extra flowability, good weathering and good scratch and mar resistance. Another important attribute of Bayblend LGX 300 is its low-emission characteristic, which is particularly important as automotive manufacturers strive to reduce the levels of VOCs in their automobiles to improve the interior environment and meet federal regulations. Because LGX 300 resin is a low gloss, high-flow polycarbonate (PC) blend with good heat and impact performance; thin-wall part design can be achieved without painting.
NEW LOW GLOSS POLYCARBONATE BLENDS FOR AUTOMOTIVE
APPLICATIONS
Automotive original equipment manufacturers are
consistently looking for low-gloss materials for interior
applications that can stand up to years of wear and tear and
environmental exposure yet maintain aesthetic quality
without painting. Bayblend® LGX 300 resin is specifically
developed for automotive interior applications requiring a
material that is inherently low in gloss with extra
flowability good weathering and good scratch and mar
resistance. Another important attribute of Bayblend LGX
300 is its low-emission characteristic which is particularly
important as automotive manufacturers strive to reduce the
levels of VOCs in their automobiles to improve the interior
environment and meet federal regulations. Because LGX
300 resin is a low gloss high-flow polycarbonate (PC)
blend with good heat and impact performance; thin-wall
part design can be achieved without painting.
NOVEL NANOBIOCOMPOSITES WITH ANTIMICROBIAL AND BARRIER PROPERTIES OF INTEREST IN ACTIVE PACKAGING APPLICATIONS
It is well-known that the nanocomposites technology can significantly enhance among others the thermal mechanical and barrier properties of plastics. It is also known that most bioplastics including the thermoplastic biopolymers have lower than desired levels for certain properties which makes their use in certain packaging applications problematic. The combination of active technologies such as antimicrobials and nanotechnologies such as nanocomposites can synergistically lead to bioplastic formulations with balanced properties and functionalities for their implementation in packaging applications. The present work presents the development and characterization of novel nanocomposites of polycaprolactone (PCL) with enhanced barrier properties and with controlled-release of biocide natural extracts.The antimicrobial nanocomposites of biodegradable materials were prepared in solution by a casting method.The morphology of the biocomposites was visualized by transmission electron microscopy (TEM) and by Atomic Force microscopy (AFM) the thermal properties were investigated by differential scanning calorimetry (DSC) and the solubility and kinetics of released biocide were determined by Attenuated Total Reflection Fourier Transformed Infrared (ATR-FTIR) spectroscopy. Water and limonene barrier properties were also enhanced in the biocomposites.
RESPONSIVE STARCH-BASED MATERIALS
Starch a low-cost annually renewable resource is naturally hydrophilic and its properties change with relative humidity. Starchƒ??s hygroscopic nature can be used to develop materials which change shape or volume in response to environmental changes (eg humidity). For example starch-based graft copolymers have been produced using reactive extrusion for potential superabsorbent and hydrogel applications. Besides absorbing large quantities of water some of these copolymers display large volume changes in aqueous alcohol depending on solvent quality. Other examples include starch-poly(methyl acrylate) graft copolymer films which shrink at high humidities. Various levels of shrinkage can be triggered in response to changes in relative humidity. (AAm) and varying amounts of 2-acrylamido-2-methyl- 1-propane sulfonic acid (AMPS) display various degrees of swelling in aqueous solutions and approximately discontinuous volume changes in aqueous ethanol solutions over narrow ethanol concentrations. Blown films of starch-PMA graft copolymers display controlled shrinkage in response to increases in relative humidity.
SOLID STATE SHEAR PULVERIZATION AND CHEMICAL RECYCLING OF POLYMERS
Solid state shear pulverization is a novel technology in polymer processing for production of new polymeric materials. By implementation of this technology various processes such as polymer recycling compounding and improving of mechanical-chemical properties of polymers can be enhanced. This is a continuous and one-stage process with low energy consumption. During this process polymers are subject to high pressure and shear forces. In this paper this technology and its applications to polymer processing is perused. At the end recycling of PET wastes by this technology is presented that have higher efficiency in comparison with existing methods.
TOWARDS QUALITY PRODUCTS FROM BIO-BASED PLASTICS
The importance of three inter-dependent factors i.e.
(1) materials (2) manufacturing and (3) design and
engineering is generally recognized. All factors are
indispensable and equally important for product
development. Manufacturing is often the least structured
factor and many designers and materials experts do not
consider themselves capable to deal with it. Fortunately
expertise is sufficiently available and the best
professionals are able to utilize plastics expertise properly
in collaborative product development.
For bio-based plastics which are rapidly emerging in
some specific markets it is already clear that the relation
between the three factors is different and more varied than
for the currently well-known plastics. Critical factors for
increased successful application of bio-based plastics will
be product manufacturing and the expectations of
applicators and consumers. From interviewing a variety of
professionals it was found that clear true and complete
information is currently not accessible for most whereas
some assumptions are not realistic or not correct
particularly the ones related to degradability and to
environmental effects. Better and well-structured
information will be needed resulting in fulfillment of
elementary consumer expectations.
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