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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Danielle Froio , Sarah Schirmer , Jo Ann Ratto , Matthew Bernasconi , Christopher Thellen , Scott Winroth, May 2008
Two grades of ethylene vinyl alcohol copolymer
(EVOH) were compounded with kaolinite nanoparticles at
a loading level of 5% and subsequently extruded into
blown and cast monolayer films. Films were analyzed for
oxygen and water vapor barrier mechanical performance
and thermal properties. The films showed slight changes
in thermal stability no significant improvement in barrier
properties a decrease in Young's modulus and no change
in thermal properties such as melt and glass transition
temperature.
Multilayer nanocomposite films containing nylon
MXD6 as a barrier layer were produced through coextrusion
and stored at elevated temperatures for various
periods of time. Dramatic changes in the mechanical
properties and moisture content of these films were
observed after storage for 3 days at 140°F. Glasstransition
temperature increases of 20-40°C were
observed in the films after storage and mechanical testing
revealed a shift from ductile to brittle failure as storage
time and nanocomposite layer thickness increased.
Multilayer nanocomposite films containing nylon MXD6 as a barrier layer were produced through coextrusion and stored at elevated temperatures for various periods of time. Dramatic changes in the mechanical properties and moisture content of these films were observed after storage for 3 days at 140?øF. Glasstransition temperature increases of 20-40?øC were observed in the films after storage, and mechanical testing revealed a shift from ductile to brittle failure as storage time and nanocomposite layer thickness increased.
S.L. Villarroel , R.A. Morales , A. Gordillo , M. Sánchez-Soto, May 2008
The microstructure of an injection moulding polypropylene part has been varied through systematic changes on the process conditions. The specimens were mouldedmodifying the holding pressure mass caudaland gate design. The skin-core structure was characterized by polarized light microscopy. The thermo mechanical environment imposed during processing was characterized using simulation commercial software.From the mould filling stage two thermo mechanical indices were calculated. The results show the relationship between these indexes and the micro structural features obtained in the moulded specimens
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.
Injection-molded lenses have been widely employed for portable consumer products nowadays. A 3D CAE flow analysis program coupled with Generalized Newtonian Fluid (GNF) models based upon polymer melts and measurements of residual birefringence have been conducted for investigation on effects of prominent processing conditions. Furthermore experimental verifications of the predictions on residual stresses are investigated with two example cases of plastic lenses molded by cyclic-olefin-copolymers. Final results have shown that frozen-in shear stresses in terms of residual birefringence levels are mainly contributed by melt temperature and injection speed during the filling stage.The predictions agree well to the experimental measurements.
We present a nonisothermal multifilament spinning model applied to a variety of polymer and process conditions.The model combines the flow-enhanced crystallization fiber spinning model of McHugh et al. with a generalization of Dutta's multifilament model. The model predicts fiber and quench air properties throughout the fiber bundle. The McHugh FEC model for a single fiber which includes effects of viscoelastic flow and crystallization has been experimentally validated. We compare the multifilament simulation results to experimental measurements. A secondary goal of the current effort is to develop a model which can be executed on a desktop in 2 to 3 hours or lesscontinuing work.
The melt quality and its effect on the final
product quality is one of the least studied
subjects in the process of injection molding.
Consequently the present study is aimed at
investigating the plastification stage in injection
molding. A general-purpose screw and a barrier
type screw were studied with respect to the effect
of melt temperature back pressure and screw
rotation speed on product quality. Results
indicated that the melt temperature and the back
pressure are the decisive factor in the case of the
general-purpose screw and the barrier screw
respectively. Due to the longer residence times in
barrier type screws lower temperatures should
be used to avoid melt degradation and inferior
mechanical properties.
The melt quality and its effect on the final product quality is one of the least studied subjects in the process of injection molding. Consequently, the present study is aimed at investigating the plastification stage in injection molding. A general-purpose screw and a barrier type screw were studied with respect to the effect of melt temperature, back pressure and screw rotation speed on product quality. Results indicated that the melt temperature and the back pressure are the decisive factor in the case of the general-purpose screw and the barrier screw, respectively. Due to the longer residence times in barrier type screws, lower temperatures should be used to avoid melt degradation and inferior mechanical properties.
Luke M. Miller , Walter S. Smith , Timothy W. Womer, May 2008
Improved color mixing for injection molding can be
improved by different variables. Screw speed melt
temperature back pressure barrel temperature profiles
screw design dispersion discs etc. can all influence color
dispersion. The mixing ability of an injection molding
screw is an important element in the finished part quality
of a part which is why screw design is the focus of this
study. An I.M.C will allow examination of the molten
melt stream prior to exiting the die to give a quantitative
comparison of different injection molding screw designs.
A new method concerning with the simultaneous
reinforcing and toughening of polypropylene (PP)
was reported. Dynamical cure of the epoxy resin
was successfully applied in the PP/maleic
anhydride-grafted styrene-ethylene
butylenes-styrene (MAH-g-SEBS) triblock
copolymer and the obtained blends named as
dynamically cured PP/MAH-g-SEBS/epoxy blends.
The stiffness and toughness of the blends are in a
good balance and MAH-g-SEBS was acted as not
only an impact modifier but also a compatibilizer.
The structure of the dynamically cured
PP/MAH-g-SEBS/epoxy blends is the embedding
of the epoxy particles by the MAH-g-SEBS.
A new method concerning with the simultaneous reinforcing and toughening of polypropylene (PP) was reported. Dynamical cure of the epoxy resin was successfully applied in the PP/maleic anhydride-grafted styrene-ethylene butylenes-styrene (MAH-g-SEBS) triblock copolymer, and the obtained blends named as dynamically cured PP/MAH-g-SEBS/epoxy blends.The stiffness and toughness of the blends are in a good balance, and MAH-g-SEBS was acted as not only an impact modifier but also a compatibilizer.The structure of the dynamically cured PP/MAH-g-SEBS/epoxy blends is the embedding of the epoxy particles by the MAH-g-SEBS.
Shia-Chung Chen , Jeng-Sheng Huang , Ping-Shun Hsu , Jui-Pin Yang , Ho-Hsiang Wang, May 2008
In this study a variable mold temperature method via induction heating combined with water cooling was used to improve surface quality of microcellular parts. It was found that the surface roughness can decreases from 25?¬m to 6.5?¬m when mold surface temperature increases from 100?øC to 160?øC. The flow marks of gas bubbles on the part surface can be removed completely at mold temperature of 160?øC. When the mold temperature over a critical value about 180?øC the surface roughness can reach a saturated value about 5?¬m. Compared to conventional water heating with initial In 60?øC mold temperature surface roughness can be greatly improved by about 80% without a significant increase in cycle time.
Molecular orientation in injection molded polystyrene was investigated by polarized laser-Raman spectroscopy. The relative intensity ratio of two specific peaks in a spectrum was determined as Orientation Index Ior in accordance with an earlier report. Two kinds of orientation peak along the depthwise direction were found in a section of the molded specimen. This result is qualitatively consistent with the orientation model presented by Tadmor. Polarized laser-Raman spectroscopy was applied to a weldline region in which molecular orientation is supposed to be one of main factors to reduce its mechanical properties. The degree of molecular orientation increased along the flow direction in the case of adjacent flow weldline occurring behind an obstructive pin in the flow channel. This means that the orientation along the weldline in the area near the pin is relatively low. The tensile strength of the area nearest to the pin was higher than that of the downstream area despite the fact that the surface V-notch was deepest. This fact insists that the molecular orientation affects significantly to the mechanical properties of weldline in injection moldings.
Myoungbae Lee , Ozma Lane , James E. McGrath , Donald G. Baird, May 2008
Disulfonated poly(arylene ether sulfone) (BPSH) copolymers have been shown to be potentially useful in the generation of polymer electrolyte membranes (PEMs) in fuel cells. In our work we find that solvent-casting conditions such as solvent type drying temperature and initial polymer concentration significantly affects the morphology and properties of PEMs produced by means of film casting. The design of the solvent removal process requires a knowledge of the kinetics of phase separation which occurs during the drying process. Block copolymers are found to be much more sensitive to drying conditions than the random copolymers.
Ming Yi Wang , Nan Qiao Zhou , Gang Jin , Sheng Ping Wen, May 2008
The purpose of this research is to investigate the
effect of vibration on cell morphology of PC foam. In this
study foamed PC was produced using a dynamic
simulation foaming setup designed by ourselves with
supercritical CO2 as foaming agent. Cell morphology was
compared as vibration frequency varied from 2.5Hz to
10Hz and vibration amplitude varied from 25? m to 100
? m respectively under the same condition. The cell
morphology of foamed samples was characterized by
using SEM. It was found that foamed samples with better
cell morphology could be obtained as vibration frequency
increased?foamed samples with better cell morphology
could be obtained as vibration amplitude increased to 75
? m then cell morphology became worse with further
increase of vibration amplitude.
Ming Yi Wang , Nan Qiao Zhou , Gang Jin , Sheng Ping Wen, May 2008
The purpose of this research is to investigate the effect of vibration on cell morphology of PC foam. In this study, foamed PC was produced using a dynamic simulation foaming setup designed by ourselves, with supercritical CO2 as foaming agent. Cell morphology was compared as vibration frequency varied from 2.5Hz to 10Hz and vibration amplitude varied from 25?¬ m to 100 ?¬ m respectively under the same condition. The cell morphology of foamed samples was characterized by using SEM. It was found that foamed samples with better cell morphology could be obtained as vibration frequency increased‹¬?foamed samples with better cell morphology could be obtained as vibration amplitude increased to 75 ?¬ m, then cell morphology became worse with further increase of vibration amplitude.
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.
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.
Shia-Chung Chen , Chia-Yen Tseng , Chien-Chia Su, May 2008
This study investigates the surface quality of parts molded by external gas assisted injection. A flat ABS part was constructed 100 mm long 50 mm wide and 1.5 mm thick (designated T) with four different thicknesses of rib: 0.6T 0.8T 1T and 1.2T. Under external gas assisted molding process the sink mark for 1.2T rib design can be reduced from 26.88?¬m under conventional injection molding to 3.47?¬m. Combined with process condition optimization of parameters such as mold temperature gas pressure and packing time the sink mark can be further reduced (below 1?¬m). Increased cavity surface smoothness created by various polishing techniques also improves sink marks.
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Any article that is cited in another manuscript or other work is required to use the correct reference style. Below is an example of the reference style for SPE articles:
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.
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