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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ULTRASONICALLY-AIDED EXTRUSION OF PEN/LCP BLENDS
Ultrasonic extrusion of polyethylene naphthalate (PEN), LCP and their blends was studied. Rheological, morphological, thermal and mechanical properties of the samples were investigated. Viscosity of PEN decreased with ultrasonic treatment, while that of the blends decreased at an amplitude of 10 ?¬m. Viscosity of LCP was unaffected by ultrasound. Blends treated at an amplitude of 10 ?¬m had larger LCP particles in moldings, leading to reduced mechanical properties in the blends. The results indicated that ultrasound had the predominant effect of degrading the PEN matrix and hindering LCP fibrillation in the blends, thereby masking possible compatibilization effects introduced by ultrasound.
PERFORMANCE OF HYBRID TOOLING IN MICRO INJECTION MOLDING
Previously, metal-polymer hybrid tooling improved the replication quality of microscale features due to the insulating effect of the polycarbonate in the tooling. In this research, hybrid tooling fabricated with a higher temperature polymer was evaluated for its resistance to deformation and ability to consistently reproduce parts over thousands of molding cycles. The polyimide-based hybrid tooling produced polystyrene and polycarbonate parts with consistently good depth ratios and no loss in feature definition over 1000 molding cycles. Although the new hybrid tooling exhibited no deformation, the metal coating peeled off the polyimide substrate. The new hybrid tooling cooled about six times more slowly than steel and nickel tooling, a characteristic that enhanced replication with relatively low mold temperatures.
ENHANCED COPOLYMERIZATION OF PEN/PET BLENDS DURING ULTRASONICALLY-AIDED EXTRUSION
PEN, PET, and their 50/50 blend were ultrasonically extruded at various amplitudes.Rheological, thermal, mechanical, morphological and spectroscopic characterizations of the untreated and ultrasonically treated samples were carried out. Fast homopolymerization during extrusion of PET was foundto occur at an ultrasonic amplitude of 7.5 ?¬m. In contrast,degradation of PEN was observed with ultrasonic treatment. Ultrasonic treatment at short residence time led to the enhancement of transesterification reaction in the PEN/PET blend, indicating that more copolymerization occurred during ultrasonic treatment.
UNEXPECTED RHEOLOGICAL BEHAVIOR OF NOVEL LOW-Tg TIN FLUOROPHOSPHATE GLASS/POLYAMIDE 6 HYBRIDS WITH ENHANCED BENEFITS
By incorporating special low glass transition inorganic tin fluorophosphates glass (Pglass) into polyamide 6, the latter exhibits unprecedented non-Einstein-like viscosity decrease in the liquid state and an increase in Young's modulus in the solid state. This behavior makes the hybrid Pglass/polymer solid material stronger yet easier to process in the liquid state. The linear rheological behavior is discussed in terms of the hybrid components rheology. The results should beneficially impact our ability to prepare lower viscosity, highly filled polymers using already existing polymer processing methods, making the simple strategy potentially widely applicable in a number of applications such as barrier resistant thin films and flame-retardant polymer composites.
HOT MELT EXTRUSION TECHNOLOGY FOR THE MANUFACTURE OF POORLY SOLUBLE DRUGS WITH CONTROLLED RELEASE DISSOLUTION PROFILES
Hot melt extrusion (HME) is an emerging technology in the Pharmaceutical industry. The primary driver for utilization of HME is bioavailability improvement of poorly soluble drugs (PSD). Previous research showed HME of PSD with water insoluble polymeric excipients tended to yield amorphous solid dispersions . Unfortunately, these compositions tended to have very poor aqueous drug solubility. It has now been demonstrated that the addition of a third component to the formulation (dissolution promoter) can be used to produce controlled release (CR) formulations of nearly unlimited profiles. The net result is an amorphous solid dispersion which exhibits controlled release properties. Further, formulations were observed which enhanced the overall solubility of the PSD compared to non-extruded analogs.
SENSITIVITY OF MECHANICAL PROPERTIES OF POLYAMIDE-IMIDE TO LOT-TO-LOT VARIABILITY
PAI (Torlon) is used in aerospace applications requiring excellent mechanical properties at high temperature, fluid resistance, and thermal stability. PAI is a delayed cure thermoset that reaches its ultimate properties and maximum Tg only with an extended postcure. This work examined the correlation of Tg and properties of four injection molded lots of PAI. Testing consisted of impact strength measurement, tensile and flexural strength and modulus testing at various temperatures and after different environmental conditioning. CTE in three orthogonal directions were measured and creep testing was run on samples after different environmental exposures, including long-term aging in turbine oil.
ULTRASONICALLY-AIDED EXTRUSION OF BLENDS OF TWO THERMOTROPIC ULTRASONICALLY-AIDED EXTRUSION OF BLENDS OF TWO THERMOTROPIC LCPS
Ultrasonically-aided extrusion of two thermotropic LCPs based on 6-oxy-2-napththoyl and p-oxybenzoyl moieties (LCP1), and p-oxybenzoyl, terephthaloyl and hydroquinone moieties (LCP2) and their blends were investigated. Miscibility of the blends was improved with ultrasonic treatment. Although LCP1 and LCP2 behaved differently under ultrasonic treatment, synergistic effects on fibrillation and mechanical properties of blends were observed in injection moldings. Ultrasonic treatment induced structural changes in the components, leading to improved mechanical properties of LCP1 moldings, and degradation of LCP2. Mechanical properties of melt spun fibers of the blends lied between those of components.
MESH PARTITIONING TECHNIQUE FOR THREE-DIMENSIONAL SIMULATION OF COEXTRUSION
A new algorithm for simulation of polymer coextrusion is introduced. In the new algorithm the finite element mesh of tetrahedral elements remains unaltered as the interface shape between adjacent polymer layers is developed during the simulation. The use of a fixed finite element mesh for coextrusion simulation is possible because in the new algorithm the interface between the two polymers is not required to match with an interelement boundary of the tetrahedral elements in the mesh.Instead by partitioning the tetrahedral elements intersected by the interface into two tetrahedral pyramidal or prismatic finite elements in the new algorithm the interface is allowed to pass through the interior of the tetrahedral elements in the original finite element mesh.
INVESTIGATION OF PROCESSABILITY OF ZEIN BASED PLASTICS AND COMPOSITES
The current market viability of petroleum based plastics is strong but may drop in the future due to international oil crisis accompanied by issues associated with disposal. This has already led to a thrust to develop bio-renewable and biodegradable plastics. One of the emerging contenders are plant based protein polymers such as soy protein and zein (corn protein).The paper reports on the extrusion molding and mechanical performance of zein based plastics and natural fiber composites. Different formulations of zein plastics with plasticizers and crosslinking agents were extruded and both injection and compression molded. Samples exhibited strengths of up to 12.7 MPa and a crosshead displacement extension value of 61% for different formulations respectively. In addition zein formulations were compounded with coconut and corn-cob fibers in various filler levels via extrusion. The injection molded composite samples had strengths upto 20 MPa.
INVESTIGATION OF PROCESSABILITY OF ZEIN BASED PLASTICS AND COMPOSITES
The current market viability of petroleum based plastics is strong, but may drop in the future due to international oil crisis accompanied by issues associated with disposal. This has already led to a thrust to develop bio-renewable and biodegradable plastics. One of the emerging contenders are plant based protein polymers such as soy protein and zein (corn protein).The paper reports on the extrusion, molding and mechanical performance of zein based plastics and natural fiber composites. Different formulations of zein plastics with plasticizers and crosslinking agents were extruded and both injection and compression molded. Samples exhibited strengths of up to 12.7 MPa and a crosshead displacement extension value of 61% for different formulations respectively. In addition zein formulations were compounded with coconut and corn-cob fibers in various filler levels via extrusion. The injection molded composite samples had strengths upto 20 MPa.
THIRTY YEARS OF PC/ABS BLENDS IN THE PLASTICS INDUSTRY
Innovative development has made blends of polycarbonate and ABS (PC/ABS) the largest selling polycarbonate-based blends in the world. The inherent cost/performance advantages of PC/ABS blends especially excellent processability and low temperature ductility have made PC/ABS a material of choice in automotive interiors and housings for business machines.Much of this growth has come about due to improvements in ABS and flame retardant technology. Development efforts continue to push PC/ABS blends into new nontraditional areas such as extrusion where its ability to thermoform like ABS makes PC/ABS an exciting candidate to replace FRP in large part applications.
POLYMER CARBON NANOTUBE NANOCOMPOSITE FOAMS: SYNTHESIS, PROCESSING AND PROPERTIES
Polymeric foams are one of the most widely used materials. Incorporating nanoparticles in polymeric foams offers several distinct benefits including morphological manipulation and nanoscale reinforcement. This work focuses on poly (methyl methacrylate) (PMMA) multiwalled carbon nanotubes (MWCNTs) nanocomposite foams prepared by using carbon dioxide as the foaming agent. PMMA CNTs nanocomposites were synthesized using anti-solvent process. In combination with surface functionalization, uniform dispersion of CNTs in the polymer matrix was achieved. The CNTs profoundly influenced the foam cell morphology and mechanical properties. In the presence of 1% carbon nanotubes, microcellular nanocomposite foam was prepared under moderate temperature and pressure (120 x C and 20.68 MPa). The microcellular foam exhibited exceptionally high cell density of 3.9 x 1010 cells / cm3 , an increase of over two orders of magnitude than the pure PMMA foam under the same foaming conditions. The cell size was reduced by ~85% to 2.7 ?¬m. The microcellular nanocomposite foam showed a synergistic increase in compressive modulus (>20%), strength (>70%) and strain at yield (>300%) over the pure PMMA foams prepared under the same foaming conditions.
PIEZORESISTIVE BEHAVIOR OF POLY (HYDROXYBUTYRATE VALERATE)/MULTI-WALLED CARBON NANOTUBES CONDUCTIVE COMPOSITE
In this study, piezoresistive behavior of poly(hydroxybutyrate valerate) (PHBV)/multi-walled carbon nanotoubes (MWCNTs) composite has been discussed. Melt mixing technique was used to achieve maximum possible dispersion of CNTs in polymer matrix, as this process involves very high shear forces during mixing. The prepared composite shows gauge factor value of three which is very close to gauge factor value of conductive metals like copper and aluminum. Quasi-static and time dependent piezoresistance was investigated for the prepared composite. Environmental scanning electron microscopy was performed to observe dispersion of CNT in PHBV matrix.
MECHANICAL PROPERTIES OF MODIFIED STARCH FILLED POLY(L-LACTIC ACID)
Starch with surface modification by grafting with polyethylene glycol (PEG) of different molecular weight (Starch-g-PEG) was developed and blended with poly(L-lactic acid) (PLA). Tolylene diisocyanate (TDI) was used as a coupling agent. The properties of PLA/Starch-g-PEG were investigated by tensile and impact testing, Differential Scanning Calorimetry (DSC) and Scanning Electron Microscopy (SEM). Significant increase in the elongation at break and impact strength of PLA/Starch-g- PEG blends without sacrificing the tensile modulus and strength at optimum PEG molecular weight range was obtained compared to those of PLA.
STERILE BARRIERS FOR MEDICAL DEVICES: FAILURE MODES AND MITIGATION
From sterilization to use, medical device packaging must provide a microbial barrier for the devices they protect. Reliability of this packaging is of the utmost importance since packaging materials must endure folding, rubbing, and a host of other mechanical and environmental stresses that can challenge the barriersƒ?? integrity. Pouches consist of flashspun high-density polyethylene (FS-HDPE) sheeting and laminates films composed of polyolefins and nylons. Case studies regarding sterile pouch failures that occurred at various stages of qualification testing and solutions for mitigating failures are presented. Common failure modes and mechanisms are discussed in detail.
AMT INVESTMENTS: MEASURING AND STRENGTHENING OF THEIR INFLUENCE ON COMPANYƒ??S PERFORMANCE
Paper discusses research in progress which is focused on performance management and measurement with regard on Advanced Manufacturing Technologies (AMT) investments. The aim of the paper is to show new combinations perspectives and potentials how to see the impact of AMT in the chain of performance effects.Based on critical literature review and experience from different performance management cases we determined several ƒ??toolsƒ? - EVA BSC ABC/M and EFQM Excellence Model as a suitable and powerful concepts which can be used mutually for measurement and management of the companyƒ??s performance. The synergic effects of the above mentioned concepts are discussed and the influence of AMT investments on companyƒ??s performance is analyzed.
COLOR MATCHING OF WEATHERABLE CO-EXTRUDED FILMS
Color matching of two-layer co-extruded films was performed by color compensation in either the top layer or bottom layer. With the former approach, excellent initial color match (??E<1.0) and weathering performance ??E~2.3 at 6,000kJ/m2 exposure) were achieved; however, a large color shift due to thickness variation (??E>3.0 at 50% thickness reduction) was observed. On the contrary, with the latter approach, poor initial color match (??E>4.0) and weathering performance (??E>3.0 at 6,000kJ/m2 exposure) were experienced; nonetheless, a very small color shift due to thickness variation (??E<1.0 at 50% thickness reduction) was produced.
BIREFRINGENCE IN GAS-ASSISTED INJECTION MOLDINGS: CONTRIBUTION OF THERMAL BIREFRINGENCE
Various components of birefringence in polystyrene (PS) tubular moldings obtained by gas-assisted injection molding (GAIM) were simulated considering both flowand thermally-induced stresses using linear and nonlinear viscoelastic theories respectively. Flow birefringence components were calculated using the stress optical rule while thermal birefringence components were simulated using a photoviscoelastic model. Free quenching experiments in tubular and rod samples were performed and various components of birefringence were measured. The measured values were found to be in fair agreement with predicted results. Considering thermal and flow birefringence in simulations provides a better description of experimental results indicating that in GAIM moldings the birefringence near the mold wall and inner wall were caused mainly by flow and thermal stresses respectively.
BIREFRINGENCE IN GAS-ASSISTED INJECTION MOLDINGS: CONTRIBUTION OF THERMAL BIREFRINGENCE
Various components of birefringence in polystyrene(PS) tubular moldings, obtained by gas-assisted injectionmolding (GAIM), were simulated considering both flowandthermally-induced stresses using linear and nonlinearviscoelastic theories, respectively. Flow birefringencecomponents were calculated using the stress optical rule,while thermal birefringence components were simulatedusing a photoviscoelastic model. Free quenchingexperiments in tubular and rod samples were performedand various components of birefringence were measured.The measured values were found to be in fair agreementwith predicted results. Considering thermal and flowbirefringence in simulations provides a better descriptionof experimental results indicating that, in GAIM moldings,the birefringence near the mold wall and inner wall werecaused mainly by flow and thermal stresses, respectively.
OPTIMIZATION OF MATERIAL FORMULATION AND PROCESSING PARAMETERS FOR WOOD PLASTIC COMPOSITE EXTRUSION
The development of wood plastic composite (WPC) has facilitated the economical extrusion of profiles for various applications. The extrusion processing can be optimized by regulating the process temperatures, use of compatibilizer, lubricants and melt flow index of polymers. In this study, a rectangular WPC profile was produced from high density polyethylene (HDPE) and wood fiber (WF) with different extrusion conditions and material formulations using lab scale twin-screw extruder profile line. The influence of HDPE melt index, lubricant contents and processing parameters on extrudate quality and mechanical properties are discussed.
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