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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María del Pilar Noriega , Juan Diego Sierra, May 2008
A prospective study on flexible plastic packaging was carried out in Andean Countries with the participation of two plastic research institutes and 20 companies including raw material manufacturers processors converters and end users.The inputs of this prospective study were a review of the state of the art on flexible packaging a benchmarking study considering the 10 most important companies a study using the Delphi method with national and international experts who identified the key variables to the development and progress of the flexible packaging in the region and workshops.This study generated new projects and products on the field of barrier smart and active packaging biodegradable materials among others; it shows that the Andean region is applying R&D and technological alliances in its industrial processes.
Tritan™ copolyesters are tough transparent
copolyesters recently developed by Eastman Chemical
Company. These new copolyesters have higher glass
transition temperatures than Eastman’s heritage
copolyesters of PETG PCTG and PCTA. The properties
of Tritan™ copolyesters allow it to be used in applications
in a variety of markets from housewares to signs. The
unique properties of Tritan™ copolyesters are achieved by
modifying poly(1 4-cyclohexylenedimethylene
terephthalate) or PCT with 2 2 4 4-tetramethyl-1 3-
cyclobutanediol (TMCD) . The properties of Tritan™
copolyesters can be tuned to meet the demands of
applications by changing the level of TMCD modification.
This paper describes the basic chemistry and structureproperty
relationships of Tritan™ copolyesters. In
addition this paper describes the properties for some of
the commercial Tritan™ copolyesters grades available.
Tritan copolyesters are tough, transparent copolyesters recently developed by Eastman Chemical Company. These new copolyesters have higher glass transition temperatures than Eastmanƒ??s heritage copolyesters of PETG, PCTG, and PCTA. The properties of Tritanƒ?› copolyesters allow it to be used in applications in a variety of markets from housewares to signs. The unique properties of Tritanƒ?› copolyesters are achieved by modifying poly(1,4-cyclohexylenedimethylene terephthalate), or PCT, with 2,2,4,4-tetramethyl-1,3- cyclobutanediol (TMCD) . The properties of Tritanƒ?› copolyesters can be tuned to meet the demands of applications by changing the level of TMCD modification.This paper describes the basic chemistry and structure-property relationships of Tritanƒ?› copolyesters. In addition, this paper describes the properties for some of the commercial Tritanƒ?› copolyesters grades available.
Molecular orientation in weldline region of
injection molded polypropylene was investigated by polarized
laser-Raman spectroscopy. The intensity ratio of two intrinsic
peaks in a Raman spectrum of weldline was considered to be a
molecular orientation index. By setting the angle of incident
laser beam in two ways so as to be parallel and perpendicular
to the weldline the molecular orientation around the weldline
was able to be clarified in detail. It was found that the
molecules in weldline region oriented along the interface of
the weldline even inside the moldings. Moreover the
orientation degree of the area 0.3 mm away from the interface
was higher than that of the interface itself. These findings are
much different from our expectation obtained from the former
experiments using polystyrene moldings in a similar method
which suggests that the orientation parallel to the weldline is
limited to the area beneath the surface. Although the cause of
this difference has yet to be identified there is little doubt that
crystallinity of polypropylene deeply plays an important role
on it.
Koji Yamada , Kiyotaka Tomari , Hiroyuki Hamada, May 2008
Molecular orientation in weldline region of injection molded polypropylene was investigated by polarized laser-Raman spectroscopy. The intensity ratio of two intrinsic peaks in a Raman spectrum of weldline was considered to be a molecular orientation index. By setting the angle of incident laser beam in two ways so as to be parallel and perpendicular to the weldline, the molecular orientation around the weldline was able to be clarified in detail. It was found that the molecules in weldline region oriented along the interface of the weldline even inside the moldings. Moreover, the orientation degree of the area 0.3 mm away from the interface was higher than that of the interface itself. These findings are much different from our expectation obtained from the former experiments using polystyrene moldings in a similar method which suggests that the orientation parallel to the weldline is limited to the area beneath the surface. Although the cause of this difference has yet to be identified, there is little doubt that crystallinity of polypropylene deeply plays an important role on it.
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.
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.
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.
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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