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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Ben Hadj Salah H., Ben Daly H., Cole K. C., Denault J., Perrin-Sarazin F., May 2010
Polypropylene clay nanocomposites were injection-molded using two different coupling agents based on maleic anhydride-grafted polypropylene (MAgPP) and two clay loadings. The morphological aspects of these materials were studied by depth profiling. Molecular chain and clay orientations were characterized using attenuated total reflectance-infrared analysis (ATR-FTIR) and transmission electron microscopy (TEM). Both clay platelets and PP molecular chain orientations were found to decrease from the surface toward the core of the injectionƒ??molded specimens. Clay intercalation, characterized by both complementary X-ray diffraction (XRD) and TEM, was found to be significantly influenced by the characteristics of the coupling agent used to optimize properties of the nanocomposites. The use of low molecular weight (Mw) maleic anhydride grafted PP (MAgPP) led to a uniform intercalation but with no further exfoliation. The use of higher Mw MAgPP led to a heterogeneous intercalation with some signs of exfoliation. The crystallization behavior of polypropylene (PP) clay nanocomposites studied by differential scanning calorimetry (DSC) showed an increase of the level of crystallinity from the surface to the core of the specimens; these results were also confirmed by scanning electron microscopy (SEM).
Poly ether-b-amide thermoplastic elastomers (Pebax? thermoplastic elastomer*) provide a unique combination of physical chemical and processing properties. This unique combination of properties can be attributed to their chemical structure which consists of rigid polyamide segments acting as physical crosslinks and flexible polyether segments having a glass transition temperature well below room temperature (-60?øC). By selectively altering the structure and molecular weight of the polyamide and polyether segments it is possible to achieve desired properties exclusive to its respective stoichiometry and block length. It is this relationship between the polyamide and polyether phases that give its elastomeric property yielding high extensibility and recovery.The desired properties which make Pebax?? thermoplastic elastomer so extraordinary include exceptionally low hysteresis which results in good fatigue resistance low heat build up and good retention of properties. Other properties exclusive to Pebax?? thermoplastic elastomer include a low density (1.01 g/cm3) hydrophobic / hydrophilic nature depending upon monomer composition no yellowing and excellent UV resistance. What makes Pebax?? thermoplastic elastomer so attractive is the fact that it can be applied to nearly all industries. Due to the versatility of the physical properties of Pebax?? thermoplastic elastomer it is no surprise that Peba?? thermoplastic elastomer is encountered in a number of applications. New technological developments with Pebax?? thermoplastic elastomer include breathable film applications for the housing and apparel industry due to excellent permeability to moisture vapor while remaining waterproof and offering an excellent barrier layer to bacteria. Additional technological developments include Pebax?? thermoplastic elastomer for durable nonwoven elastic applications due to its ability to be extruded by both melt blown and spunbond technologies. Impact modification of Pebax??
Of the many tools available to the professional failure analyst, ranging from compositional analysis to visual and microscopic examination, a commonly underutilized tool is examination of the failed part using stereomicroscopy of mounted cross sections. Although transmission light microscopy can be utilized for examination of the crystalline structure in thin specimens, this paper will instead focus on the use of cross sectional examination of entire parts and assemblies. This will include an overview of the sample preparation method and several examples of its use including: characterization of plating failures, detection and re-creation of leak paths, qualitative assessment of filler material distribution, and knit line integrity.
Dong Won Jung, Eung Kee Lee, Chul B. Park, Hani E. Naguib, May 2010
This paper deals with the basic principles and procedures of the steam chest molding process for expanded polypropylene (EPP) bead foam. Steam chest molding is an integral process for EPP technology. However, little research has been carried out regarding the processing condition of steam chest molding. The characteristics of EPP foam are energy absorption, multiple impact protection, lightweight, structural strength and durability. In this study, the steam pressure in the steam chest molding was varied to find the optimum condition for manufacturing EPP foam. Moreover, annealing after EPP foam molding was put into practice to prevent the shrinkage of the steam-molded product. It was possible to verify the mechanism of foam shrinkage by observing the weight change with time at different annealing temperatures. A tensile test and scanning electron microscopy (SEM) analysis were also executed to support these experimental results. The dimensional stability was investigated for each molded product from different steam pressures.
Hongtao Zhang, Changwei Zhu, Saleh Amani, Chul B. Park, Jing Wang, May 2010
This paper presents the effects of the blowing agent content on the volume expansion of extruded polystyrene foams blown with CO2. Both lab-scale and pilot-scale extrusion systems were used to investigate the effects of extrusion equipment scales on the expansion ratio. Experimental results reveal that there was no apparent relationship between the expansion ratio of the PS foam sheets and the scale of extrusion systems. It was established that the degree of foam expansion is strongly affected by certain processing conditions, including processing temperature, pressure-drop rate, and CO2 content.
Viscosity change in polymer and gas mixtures is important in designing dies or molds because of its impact on the quality of the microcellular foaming product. In developing a continuous process for microcellular foams, very little attention has been directed towards researching the viscosity change that occurs when gas is injected into the polymer and its effect on cell morphology despite its importance. The purpose of this paper is to provide the basic data required to determine the processing condition by measuring viscosity changes against the gas injection rates of the blowing agent, and to verify the influence of viscosity change on the cell morphology of the samples during the injection molding process.
Yongrak Moon , Peter U. Jung , C.B. Park, May 2010
Viscosity change in polymer and gas mixtures is
important in designing dies or molds because of its impact
on the quality of the microcellular foaming product. In
developing a continuous process for microcellular foams,
very little attention has been directed towards researching
the viscosity change that occurs when gas is injected into
the polymer and its effect on cell morphology despite its
importance. The purpose of this paper is to provide the
basic data required to determine the processing condition
by measuring viscosity changes against the gas injection
rates of the blowing agent, and to verify the influence of
viscosity change on the cell morphology of the samples
during the injection molding process.
Neelam Singh, Santanu Dutta, Abhijit Baruah, Priyanka Singh, Y. Vasudeo, May 2010
In this study, anionic nanoclays are functionalized with active pharmaceutical ingredients (APIs) which intercalate into the interspacing of the clays through ion exchange reactions and then melt mixed with appropriate polymer matrices. The intercalated API is further released upon demand by physiochemical changes in an appropriate environment. The aspects of drug release from different systems containing dispersed or dissolved APIs in polymeric matrices are compared with those of systems containing nanoclays functionalized with different APIs in attempts to develop novel drug delivery systems.
Neelam Singh , Santanu Dutta , Abhijit Baruah , Priyanka Singh , Y. Vasudeo, May 2010
This paper discusses how melt flow indices and flow behavior data can be used to predict polymer flow in real industrial processes. The ability to simulate flow behavior can help us establish a robust process that has a large processing window and which accommodates a natural variation. The effect of shear rate on viscosity is of far greater significance. It is therefore important to find the Newtonian region of the curve and set the process parameters in this region for a specified mould thickness. This paper also aims at modifying the flow behavior of polypropylene blends using various lubricants and flow promoters both low molecular weight and polymeric flow promoters
Priyanka Singh, Santanu Dutta, Abhijit Baruah, Neelam Singh, Y. Vasudeo, May 2010
Free quenching of three-layered slabs of PS-PC-PS and PC-PS-PC from various initial melt temperatures to below the glass transition temperature was carried out. The thermal residual stress and birefringence distributions along the thickness direction of the slabs were simulated and the birefringence was measured. Simulations were based on the linear viscoelastic and photoviscoelastic constitutive equations and the first-order rate equation for volume relaxation. The relaxation modulus and strain-optical coefficient functions of polymers as a function of time and temperature were used in the simulations. Comparisons indicated a reasonable agreement between the simulated and measured data.
Priyanka Singh , Santanu Dutta , Abhijit Baruah , Neelam Singh , Y. Vasudeo, May 2010
To make polypropylene automotive components with reduced wall thickness, there rises the need to maintain equivalent load bearing capacity. The paper aims at establishing the basic mechanical property requirements which influence the design of automotive components with reduced wall thickness. A set of elastomer modified polypropylene resins with different levels of reinforcement is investigated with respect to their physico-mechanical properties such as yield strength, yield energy, stiffness, stiffness impact balance and impact strength together with impact energy.
This study investigates the effect of crystallinity and nanoclay content on the barrier properties of polyamides of similar polarity, one amorphous the other semicrystalline. The polyamide resins were compounded with commercial alkylammonium montmorillonite nanoclay to achieve volume percent inorganic contents of 0.125%, 0.25%, 0.5%, and 1%, as confirmed by thermogravimetric analysis (TGA). All formulations were then extruded through a 6 inch cast film die to yield transparent sheets which were then tested for oxygen and water vapor permeability, with the crystallinity of the semi-crystalline materials measured via differential scanning calorimetry (DSC).
Long glass fiber reinforced thermoplastics are widely used in industry because of their low cost and high performances. During the injection molding process, the glass fibers initial length is reduced by breakage and this phenomenon strongly affects some mechanical properties of the components, e.g. their impact strength. The aim of this study is to minimize the fibers breakage in a hot runner channel by optimizing its geometry. Geometrical control parameters were selected to model different geometries using a 3D modeler, and fluid dynamic numerical simulations were conducted using ANSYS Polyflow. An SQP optimization algorithm, implemented in a multi-objective optimization software, was used to determine the values of geometrical control parameters that minimize the fibers breakage.
Priyanka Singh, Santanu Dutta, Abhijit Baruah, Neelam Singh, Y. Vasudeo, May 2010
Of the four pillars required for the successful
development of a plastic part; material selection, part
design, processing, and service environment, processing
is often assumed to be the most controllable. Even when
the service environment has been properly defined, the
best design principles implemented, and the appropriate
material selected, seemingly insignificant changes in
processing can grossly and adversely affect an otherwise
well developed product. This paper will explore case
studies where the failure of the part can be traced directly
back to improper processing and how shortcomings in
processing ultimately predisposed them to premature
failure.
Priyanka Singh , Santanu Dutta , Abhijit Baruah , Neelam Singh , Y. Vasudeo, May 2010
The purpose of this work is to compare the mechanical
properties of the different PP/ Filler composites. We
considered the effect of treatment of the filler on the
adhesion between the filler and the matrix .Modification of
polypropylene (PP) with different coated and uncoated
fillers is investigated in this paper. Six types of different
fillers are used for preparation of filled PP composites. The
composite samples were homogenized in a twin screw
extruder. The compatibility of PP and fillers focused in
this study and modified by using coupling agent.
The obtained values of composites were correlated with
mechanical properties.
Priyanka Singh , Santanu Dutta , Abhijit Baruah , Neelam Singh , Y. Vasudeo, May 2010
The purpose of this work is to compare the mechanical properties of the different PP/ Filler composites. We considered the effect of treatment of the filler on the adhesion between the filler and the matrix .Modification of polypropylene (PP) with different coated and uncoated fillers is investigated in this paper. Six types of different fillers are used for preparation of filled PP composites. The composite samples were homogenized in a twin screw extruder. The compatibility of PP and fillers focused in this study and modified by using coupling agent.The obtained values of composites were correlated with mechanical properties.
Sunny M. Ogbomo , Mickey C. Richardson , Paul S. Braterman , Zhi Ping Xu , Nandika A. D’Souza, May 2010
Zn-Al Layered Double Hydroxides (LDHs) containing nitrate as the interlayer anion was prepared by coprecipitation. The resulting suspension was treated with deprotonated stearic acid (octadecanoic acid) to give an organo-modified hydrotalcite compound (Zn-Al LDHStearate).The prepared LDH-stearate was successfully delaminated in hexadecane resulting in a Zn-Al LDH stearate/hexadecane. In situ intercalative polymerization of styrene with the delaminated LDH (with different ratios) resulted in the formation of partially exfoliated polystyrene-based LDH-stearate/hexadecane nanocomposites (polymer/clay nanocomposites). The delaminated LDH nanosheets before and after introduction into the polystyrene matrix were confirmed by elemental analysis Atomic Absorption Spectroscopy (AAS) X-ray Diffraction Spectroscopy (XRD) and Thermogravimetric Analysis (TGA). X-ray diffraction confirmed exfoliation of the LDH through the disappearance of the basal (003) reflection.
Bio-derived thermosets were cured from inexpensive,
low-toxicity precursors. Epoxidized linseed oil (ELO) and
epoxidized soybean oil (ESO) were crosslinked with a
range of crosslinking agents: branched polyethyleneimine
(PEI) and triethylenetetramine (TETA). Curing conditions
were optimized through solvent uptake and soluble
fraction analysis. Properties may be varied from
elastomeric to rigid. Rigid bioepoxies, while not as stiff as
conventional materials, are expected to display better
toughness and may be promising for coatings and as
binders in engineered wood products.
Divya Kosuri, Sunny M. Ogbomo, Nandika A. D’Souza, May 2010
Polycarbonates find applications in food
industries due to their clarity and ductility.
Sometimes failure of a polycarbonate part
occurs. In food blender jars molded from
polycarbonate, cracks were observed in the
sealed joint only a few days after assembly. The
root cause was investigated via microscopy,
FTIR and GC-MS analyses. It was determined
the cracks initiated and radially propagated from
the bottom raised lip of the part. The root cause
was a combination of a high stress in the lip
region due to molding and design, and
environmental chemical compounds, i.e., esters
from a melt nut used in the assembly. The
failure was typical environmental stress
cracking (ESC) problem.
Flame retardance, low smoke generation and low smoke toxicity (often referred to as the FST properties) are among the critical requirements for polymeric materials used in building and construction as well as mass transit interior applications. Polyphenylene ether (PPE) is wellknown for its high char formation and low smoke toxicity when burned. Addition of a proprietary smoke suppressant 'LS-1' to a flame-retarded PPE blend results in low smoke density without significantly affecting smoke toxicity and flame-retardance, possibly owing to the formation of intumescent char. In addition to improved FST performance, various PPE compositions exhibit low specific gravity, wide colorability and good mechanical, thermal and electrical properties.
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Brown, H. L. and Jones, D. H. 2016, May.
"Insert title of paper here in quotes,"
ANTEC 2016 - Indianapolis, Indiana, USA May 23-25, 2016. [On-line].
Society of Plastics Engineers
Available: www.4spe.org.
Note: if there are more than three authors you may use the first author's name and et al. EG Brown, H. L. et al.
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