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Conference Proceedings
THE EFFECT OF POST DIE PROCESSING TIME ON ADHESION IN COEXTRUSION BLOWN AND CAST FILM
Peel strength between layers in coextruded cast film is found to increase with increasing post die process time.The results suggest that adhesion is limited by the time and temperature available for bonding after new interfacial area is created during drawing. This contrasts with previous work in blown film where increases in peel strength with process time were attributed primarily to stress effects.The results from both processes, however, were found to collapse onto a single master curve by multiplying the peel strength by the modulus of the tie resin and dividing the process time by the relaxation time of the tie resin.
RELATIONSHIP BETWEEN STRUCTURE AND RHEOLOGICAL
PROPERTIES IN POLYMER/LAYERED SILICATE
NANOCOMPOSITES
Poly[butylenes succinate-co-adipate] (PBSA)
layered silicate nanocomposite was prepared by
melt extrusion of PBSA and organically
modified montmorillonite (OMMT).
Nanocomposites were prepared at a single clay
loading. Before taking rheological
measurements the nanocomposites were
characterized by X-ray diffraction (XRD) and
transmission electron microscopy (TEM). Stress
growth experiments were performed for both
pure polymer and nanocomposite. Flow reversal
experiments were conducted for
nanocomposites at different predetermined rest
time after cessation of forward flow. The
orientation state of silicate layers were also
investigated by cooling down the sample in the
rheometer before and after the forward flow and
then by performing X-ray in the transmission
mode.
RELATIONSHIP BETWEEN STRUCTURE AND RHEOLOGICAL PROPERTIES IN POLYMER/LAYERED SILICATE NANOCOMPOSITES
Poly[butylenes succinate-co-adipate] (PBSA) layered silicate nanocomposite was prepared by melt extrusion of PBSA and organically modified montmorillonite (OMMT). Nanocomposites were prepared at a single clay loading. Before taking rheological measurements, the nanocomposites were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Stress growth experiments were performed for both pure polymer and nanocomposite. Flow reversal experiments were conducted for nanocomposites at different predetermined rest time after cessation of forward flow. The orientation state of silicate layers were also investigated by cooling down the sample in the rheometer before and after the forward flow and then by performing X-ray in the transmission mode.
POLYLACTIC ACID COMPOSITES BASED ON IONIC LIQUID MODIFIED
CATIONIC AND ANIONIC CLAYS
Hydrotalcite anionic clays were reacted with
phosphonium ionic liquids containing different
anions. Montmorillonite cationic clays were also
reacted with the residual cation of the ILs after
modification of the anionic clay. The clays were
analyzed by FTIR thermal analysis EDX and X-ray
diffraction in order to determine the extent and type
of intercalation of the IL anions/cations at the clay
interlayers. The modified cationic and anionic clays
and their mixtures were then melt compounded with
polylactic acid and their effects on the thermal and
mechanical properties of the resulting micro- and
nano-composites were investigated.
POLYLACTIC ACID COMPOSITES BASED ON IONIC LIQUID MODIFIED CATIONIC AND ANIONIC CLAYS
Hydrotalcite anionic clays were reacted with phosphonium ionic liquids containing different anions. Montmorillonite cationic clays were also reacted with the residual cation of the ILs after modification of the anionic clay. The clays were analyzed by FTIR, thermal analysis, EDX and X-ray diffraction in order to determine the extent and type of intercalation of the IL anions/cations at the clay interlayers. The modified cationic and anionic clays and their mixtures were then melt compounded with polylactic acid and their effects on the thermal and mechanical properties of the resulting micro- and nano-composites were investigated.
EFFECTS OF PROPERTY MODIFIERS ON THE DEGRADATION
CHARACTERISTICS OF POLYLACTIC ACID
The properties of polylactic acid (PLA) may be modified
by the addition of clays or the incorporation of ionic
liquids (IL). The effects of clays depend on degree of
polymer intercalation and the presence of clay
organomodifiers. Some ionic liquids act as plasticizers
and lubricants reducing glass transition temperature (Tg)
and melt viscosity the effects depending on the IL
structure and its polymer miscibility. This article
compares the effects of different cationic or anionic clays
and different ILs on the thermal hydrolytic and soil
degradation of PLA as measured by molecular weight
(MW) changes and relates to the structure of the additives
and their degree of dispersion/dissolution in the polymer
melt.
EFFECTS OF PROPERTY MODIFIERS ON THE DEGRADATION CHARACTERISTICS OF POLYLACTIC ACID
The properties of polylactic acid (PLA) may be modified by the addition of clays or the incorporation of ionic liquids (IL). The effects of clays depend on degree of polymer intercalation and the presence of clay organomodifiers. Some ionic liquids act as plasticizers and lubricants reducing glass transition temperature (Tg) and melt viscosity, the effects depending on the IL structure and its polymer miscibility. This article compares the effects of different cationic or anionic clays and different ILs on the thermal, hydrolytic and soil degradation of PLA as measured by molecular weight (MW) changes and relates to the structure of the additives and their degree of dispersion/dissolution in the polymer melt.
DEVELOPMENT OF AN AUTOMATED RUNNER-VALVE SYSTEM FOR THE FILLING BALANCE IN MULTI-CAVITY MOLDS
Since the runner-valve system (RVS) was proposed
by the authors for the filling balance in multi-cavity
molds its balancing capability has been proved in many
experiments. However it is not practical to adjust the
valve manually during the molding process. Therefore
authors developed an automated RVS. A motorized
actuator with a small installation area was designed and
built. An experimental mold with 4 cavities was machined
and the actuators were installed. In order to reliably
determine the resin-arrival-time in the automated RVS a
new method based on the sigmoid function approximation
was developed and optimum sampling range was obtained
in terms of a characteristic time. The data processing
program for the approximation was designed by the
LabVIEW. This work is ongoing project so that
experiment using the automated RVS is going to be done.
DEVELOPMENT OF AN AUTOMATED RUNNER-VALVE SYSTEM FOR THE FILLING BALANCE IN MULTI-CAVITY MOLDS
Since the runner-valve system (RVS) was proposed by the authors for the filling balance in multi-cavity molds, its balancing capability has been proved in many experiments. However, it is not practical to adjust the valve manually during the molding process. Therefore, authors developed an automated RVS. A motorized actuator with a small installation area was designed and built. An experimental mold with 4 cavities was machined and the actuators were installed. In order to reliably determine the resin-arrival-time in the automated RVS, a new method based on the sigmoid function approximation was developed, and optimum sampling range was obtained in terms of a characteristic time. The data processing program for the approximation was designed by the LabVIEW. This work is ongoing project so that experiment using the automated RVS is going to be done.
EFFECT OF POLYDIMETHYLSILOXANE ON COPOLYMER-POLYPROPYLENE FOAMS IN BATCH AND EXTRUSION PROCESSING
Both batch and continuous foaming processes were
employed to prepare plastic foams from polypropylene
(PP) / polydimethylsiloxane (PDMS) blends. The
blends were batch foamed at different saturation
pressures using carbon dioxide (CO2) as the blowing
agent. Ultimately the blend foams exhibited better cell
morphologies and higher cell densities in comparison to
those prepared from PP alone. The increased solubility
of CO2 in PDMS made it as a CO2 reservoir to induce
more nucleation. It was also noted that the addition of
PDMS to the PP matrix generated a bi-cellular structure
i.e. very small cells in the larger cell walls. In the case
of extrusion foaming the addition of PDMS had a
pronounced effect on both the expansion ratio and the
cell density. At 5% CO2 content the maximum
expansion ratio of the blend foams increased to as much
as twenty-five-fold whereas the maximum expansion
ratio of neat PP was below 10-fold with the same die.
EFFECT OF POLYDIMETHYLSILOXANE ON COPOLYMER-POLYPROPYLENE FOAMS IN
BATCH AND EXTRUSION PROCESSING
Both batch and continuous foaming processes were employed to prepare plastic foams from polypropylene (PP) / polydimethylsiloxane (PDMS) blends. The blends were batch foamed at different saturation pressures using carbon dioxide (CO2) as the blowing agent. Ultimately, the blend foams exhibited better cell morphologies and higher cell densities in comparison to those prepared from PP alone. The increased solubility of CO2 in PDMS made it as a CO2 reservoir to induce more nucleation. It was also noted that the addition of PDMS to the PP matrix generated a bi-cellular structure, i.e., very small cells in the larger cell walls. In the case of extrusion foaming, the addition of PDMS had a pronounced effect on both the expansion ratio and the cell density. At 5% CO2 content, the maximum expansion ratio of the blend foams increased to as much as twenty-five-fold whereas the maximum expansion ratio of neat PP was below 10-fold with the same die.
HIGH-PERFORMANCE-TIE-LAYER RESINS IN FLEXIBLE PACKAGING APPLICATIONS: STRUCTURE–PERFORMANCE RELATIONSHIPS
Interlayer adhesion between tie and barrier layers in
blown and cast film plays a major role in determining the
performance of tie layer resins in barrier applications. In
general tie-layer adhesion increases and film clarity
decreases with increased maleic anhydride functionality
(MAF). The tie resin employed for this investigation
showed reduced adhesion to EVOH even with increased
MAF. Understanding such unusual behavior is an
important aspect of the structure of tie-layer resins to be
used in industrial barrier packaging applications. We
investigated structural factors of the tie resins using
rheological measurements. It was found that dynamic
shear rheological data does not provide useful information
to understand tie layer performance. However extensional
rheological data showed useful information to understand
tie resin performance. The strain-hardening behavior of
the tie-layer resin during the melt extensional process
plays a major role in determining the interfacial adhesion
between tie and EVOH layers and clarity regardless of a
given range of MAF levels.
HIGH-PERFORMANCE TIE LAYER RESINS IN FLEXIBLE PACKAGING APPLICATIONS: STRUCTURE-PEROFRMANCE RELATIONSHIPS
Interlayer adhesion between tie and barrier layers in blown and cast film plays a major role in determining the performance of tie layer resins in barrier applications. In general, tie-layer adhesion increases and film clarity decreases with increased maleic anhydride functionality (MAF). The tie resin employed for this investigation showed reduced adhesion to EVOH even with increased MAF. Understanding such unusual behavior is an important aspect of the structure of tie-layer resins to be used in industrial barrier packaging applications. We investigated structural factors of the tie resins using rheological measurements. It was found that dynamic shear rheological data does not provide useful information to understand tie layer performance. However, extensional rheological data showed useful information to understand tie resin performance. The strain-hardening behavior of the tie-layer resin during the melt extensional process plays a major role in determining the interfacial adhesion between tie and EVOH layers and clarity, regardless of a given range of MAF levels.
DESIGN AND PERFORMANCE CRITERIA FOR MULTI-FUNCTIONAL SHAPE
MEMORY POLYMER NANOCOMPOSITES
Design and performance criteria for multifunctional
shape memory polymer (SMP) nanocomposites
were studied. A comparative analysis of nanocomposites
with augmented recovery stress and ability to respond to
the application of electrical voltage and light were
investigated. The role of filler type filler-matrix
interactions synthesis/processing conditions and thermal
expansion were investigated. It was found that the presence
of exfoliated organoclay significantly augmented the
recovery stress. The presence of carbonaceous fillers such
as carbon nanofiber and carbon black in SMP composites
was used to generate shape memory response from the
application of electrical voltage and light.
DESIGN AND PERFORMANCE CRITERIA FOR MULTI-FUNCTIONAL SHAPE MEMORY POLYMER NANOCOMPOSITES
Design and performance criteria for multifunctional shape memory polymer (SMP) nanocomposites were studied. A comparative analysis of nanocomposites with augmented recovery stress and ability to respond to the application of electrical voltage and light were investigated. The role of filler type, filler-matrix interactions, synthesis/processing conditions, and thermal expansion were investigated. It was found that the presence of exfoliated organoclay significantly augmented the recovery stress. The presence of carbonaceous fillers, such as carbon nanofiber and carbon black in SMP composites was used to generate shape memory response from the application of electrical voltage and light.
A NEW CLASS OF POLYVINYLCLORIDE NANOCOMPOSITE BASED ON
MAGNETIC NANOFILLERS AND PLASTISOLS
Two different magnetic nanocomposites of plasticized
poly(vinylchoride) (PVC) were prepared using ? Fe2O3
(magnetite). In one case the PVC was uncrosslinked; in
the second case the magnetite particles were modified with
3-aminopropyl-trietoxysilane (ATES) which successfully
induced crosslinking. Plastisols of both systems were
prepared by mixing DOP PVC and nanoparticles. Films
were prepared by static casting and gelling of the
plastisols at 180°C. The nanocomposite films thus
obtained were characterized by vibrating sample
magnetometry. Both samples showed superparamagnetic
behavior at room temperature with an expected decrease
in saturation magnetization due to surface effects. Stress
strain curves were obtained with the crosslinked system
showing a higher modulus. Dynamic mechanical analysis
(DMA) was used to characterize the viscoelastic behavior
of both systems. The crosslinked system showed an
extension of the elastic region. After Soxhlet extraction
the crosslinked system showed 5 to 7% gel as insoluble
material further supporting the effective crosslinking.
A NEW CLASS OF POLYVINYLCLORIDE NANOCOMPOSITE BASED ON MAGNETIC NANOFILLERS AND PLASTISOLS
Two different magnetic nanocomposites of plasticizedpoly(vinylchoride) (PVC) were prepared using ?? Fe2O3(magnetite). In one case the PVC was uncrosslinked; in the second case the magnetite particles were modified with 3-aminopropyl-trietoxysilane (ATES), which successfully induced crosslinking. Plastisols of both systems were prepared by mixing DOP, PVC and nanoparticles. Films were prepared by static casting and gelling of the plastisols at 180?øC. The nanocomposite films thus obtained were characterized by vibrating sample magnetometry. Both samples showed superparamagnetic behavior at room temperature with an expected decrease in saturation magnetization due to surface effects. Stress strain curves were obtained with the crosslinked system showing a higher modulus. Dynamic mechanical analysis (DMA) was used to characterize the viscoelastic behavior of both systems. The crosslinked system showed an extension of the elastic region. After Soxhlet extraction, the crosslinked system showed 5 to 7% gel as insolublematerial further supporting the effective crosslinking.
TOUGHENING OF EPOXY USING PEP-PEO BLOCK COPOLYMER NANOPARTICLES
A block copolymer (BCP) toughening agent which
forms self-assembled spherical micelle particles (15 nm)
was utilized to toughen epoxy. The nano-sized BCP at 5
wt% concentration can significantly improve the fracture
toughness of epoxy without deterioration in modulus and
with only a slight reduction in glass transition temperature
(Tg). The major toughening mechanisms are found to be
BCP nanoparticle cavitation-induced matrix shear
banding. Possible reasons responsible for the remarkable
mechanical property improvements due to the BCP
modification are discussed.
TOUGHENING OF EPOXY USING PEP-PEO BLOCK COPOLYMER NANOPARTICLES
A block copolymer (BCP) toughening agent, which forms self-assembled spherical micelle particles (15 nm), was utilized to toughen epoxy. The nano-sized BCP at 5 wt% concentration can significantly improve the fracture toughness of epoxy without deterioration in modulus and with only a slight reduction in glass transition temperature (Tg). The major toughening mechanisms are found to be BCP nanoparticle cavitation-induced matrix shear banding. Possible reasons responsible for the remarkable mechanical property improvements due to the BCP modification are discussed.
CHARACTERIZATION OF PROCESSING EFFECTS IN HIPS-CNF COMPOSITES USING THERMOGRAVIMETRIC ANALYSIS
Using thermogravimetric analysis (TGA) the effectof solvent processing and twin-screw extrusion (TSE) onthe weight loss rates and the corresponding temperatureswas investigated. Extruded composites exhibited higherthermal stability than the solvent processing ones. Highershear rates in extrusion also led to higher thermalstability. Furthermore it was observed that thenormalized weight loss of CNFs can provide a means ofcharacterizing the degree of dispersion resulting from theprocessing of the composites that complementsconventional microscopy techniques.
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