SPE Library

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.

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.

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.

By combining ultrasonic energy which can cause chain scission of polymer molecules and a multifunctional agent (MFA) having double bonds at its ends we were able to modify the molecular structure of polystyrene (PS) from linear to a branched structure during melt processing. The three double bonds in chain ends of MFA were expected to act as sites for trapping macroradicals of PS during the course of ultrasound- assisted mixing process. The transformation of molecular structure of PS was confirmed by the measurements of rheological properties of the modified PS. After the ultrasonic irradiation of PS together with MFA increase in complex viscosities and shear-thinning behavior were observed. The Cole-Cole plot revealed the characteristic features of branched structure.

Various factors that might interfere with reaction stoichiometry and result in physical gumminess of the cured mass were investigated for a medical grade epoxy-amine adhesive system. Dynamic rheometry was used to probe the evolution of dynamic mechanical properties in the adhesive during isothermal curing and a Fourier-transform infrared spectrometer (FT-IR) was utilized to measure the degree of chemical conversion after curing. It has been found that physical gumminess of the adhesive cured under a selected normal curing condition was primarily due to the presences of excessive hardener and also liquid residuals of an industrial cleaner containing hydroxyl and amine functional groups while the presence of excessive epoxy resin at a moderate level arising from non-stoichiometric mixing is unlikely to cause physical gumminess of the cured adhesive mass. Accordingly it is considered that the selection of a proper cleaner and improvement of stoichiometric adhesive mixing prior to adhesive dispensing is of vital importance to developing reliable and strong adhesive bondlines.

Various factors that might interfere with reaction stoichiometry and result in physical gumminess of the cured mass were investigated for a medical grade epoxy-amine adhesive system. Dynamic rheometry was used to probe the evolution of dynamic mechanical properties in the adhesive during isothermal curing, and a Fourier-transform infrared spectrometer (FT-IR) was utilized to measure the degree of chemical conversion after curing. It has been found that physical gumminess of the adhesive cured under a selected, normal curing condition was primarily due to the presences of excessive hardener and also liquid residuals of an industrial cleaner containing hydroxyl and amine functional groups, while the presence of excessive epoxy resin at a moderate level arising from non-stoichiometric mixing is unlikely to cause physical gumminess of the cured adhesive mass. Accordingly, it is considered that the selection of a proper cleaner and improvement of stoichiometric adhesive mixing prior to adhesive dispensing is of vital importance to developing reliable and strong adhesive bondlines.

The luxury impression of a vehicle’s interior is strongly determined by the surface quality of the plastic interior trim parts. In higher level vehicles this is achieved by covering the plastic surfaces with Polyvinyl Chloride (PVC) or Thermoplastic Olefin (TPO) skins fabrics or paint. However in the majority of cases cost constraints dictate the use of unpainted molded-in-color plastic parts. The critical factors that determine the quality of unpainted interior part surfaces are low gloss appearance along with good scratch and abrasion resistance. The typical materials currently in use for molded-in-color parts are Polypropylene talc-filled Polypropylene (TF-PP) talcfilled Thermoplastic Olefin (TF-TPO) Acrylonitrile Butadiene Styrene (ABS) Polyamide/ABS (PA/ABS) and Polycarbonate/ABS (PC/ABS). Through extensive development efforts over the past several years the performance of these materials has significantly improved with respect to scratch resistance and low gloss aesthetic appearance. However a significant gap in surface quality and robustness in comparison to the painted solution is still present. A development project aiming to reduce these specific deficiencies resulted in new innovative material formulations which provide breakthrough improvements in low gloss appearance with excellent scratch and mar resistance. The resulting new material family makes use of the latest advancements in elastomer technologies from Dow Automotive. Velvex™ an Advanced Reinforced Elastomer will enable the automotive OEM to realize significant cost savings through the elimination of paint in higher segment vehicle interiors or with aesthetically more demanding applications.

The luxury impression of a vehicleƒ??s interior is strongly determined by the surface quality of the plastic interior trim parts. In higher level vehicles, this is achieved by covering the plastic surfaces with Polyvinyl Chloride (PVC) or Thermoplastic Olefin (TPO) skins, fabrics, or paint. However, in the majority of cases, cost constraints dictate the use of unpainted, molded-in-color plastic parts.The critical factors that determine the quality of unpainted interior part surfaces are low gloss appearance along with good scratch and abrasion resistance. The typical materials currently in use for molded-in-color parts are Polypropylene, talc-filled Polypropylene (TF-PP), talcfilled Thermoplastic Olefin (TF-TPO), Acrylonitrile Butadiene Styrene (ABS), Polyamide/ABS (PA/ABS), and Polycarbonate/ABS (PC/ABS). Through extensive development efforts over the past several years, the performance of these materials has significantly improved with respect to scratch resistance and low gloss aesthetic appearance. However, a significant gap in surface quality and robustness in comparison to the painted solution is still present. A development project aiming to reduce these specific deficiencies resulted in new innovative material formulations, which provide breakthrough improvements in low gloss appearance with excellent scratch and mar resistance. The resulting new material family makes use of the latest advancements in elastomer technologies from Dow Automotive. Velvexƒ?›, an Advanced Reinforced Elastomer, will enable the automotive OEM to realize significant cost savings through the elimination of paint in higher segment vehicle interiors, or with aesthetically more demanding applications.

In this study a light guide plate was designed using different micro features on a three-sided surface.Simulation software was applied to analyze the luminance of brightness and uniformity under various micro pattern designs so that a fair optical performance can be achieved.Then a micro-patterned mold was made for molding. The effect of replication accuracy on the brightness and the luminance uniformity resulting from molding was investigated. It was found the replication accuracy is increased with increasing mold temperature and melt temperature. When the replication accuracies of the Vgroove at three-side surface were improved the resulting luminance was also increased by 17.96 %.

Poly(ethylene terephthalate) (PET) nanocomposites and two organoclays with different content of the same surfactant were blended in a twin screw extruder. The effect of the amount of surfactant on the microstructure and isothermal crystallization kinetics of the filled and unfilled systems was studied. The isothermal data from differential scanning calorimetry was analyzed using the Avrami equation. The spherulitic structure was observed using scanning electron microscope. It was found that the amount of the surfactant significantly affected the crystallization and microstructure of PET/organoclay nanocomposite.

The effects of the mechanical properties on the scratch resistance are investigated by using Ball-type Scratch Profile (BSP) test developed by Cheil Industries Inc. BSP test method is designed for evaluating the scratch resistance by quantifying the amounts of created scratch to scratch width depth range and area. To investigate the relation between scratch behavior and mechanical property the measured scratch width is compared with the mechanical properties such as tensile strength tensile elongation flexural strength and flexural modules. The Rockwell hardness and pencil hardness results are also compared with the measured scratch width and their relations are studies.

Fiber-reinforced engineering materials are widely used for their superior mechanical properties in lots of plastic parts. And it is truly believed that in the injection molding process the fiber orientation and anisotropy shrinkage are very complex 3D phenomena which may influence the product properties deeply. In this research the fiber orientation is considered both in filling and packing process numerically. The result of fiber orientation shows a good agreement with experimental data. Moreover the investigation illustrates the strength of fiber orientation in filling and packing phases.

Structure and mechanical properties are studied for extruded sheets of isotactic polypropylene (PP) containing a small amount of N N’-dicyclohexyl-2 6-naphthalenedicarboxamide as a ?-form nucleating agent. It is found that the ? trigonal crystals are predominantly formed in the extruded samples containing the nucleating agent. Since the ?-form crystals are responsible for the marked mechanical toughness the impact strength of the sheet sample containing the nucleating agent is higher than that of the pure PP. Further PP molecules in the extruded sheet are found to orient perpendicular to the applied flow direction. As a result the sheet shows anomalous mechanical anisotropy.

Structure and mechanical properties are studied for extruded sheets of isotactic polypropylene (PP) containing a small amount of N,Nƒ??-dicyclohexyl-2,6-naphthalenedicarboxamide, as a ?ý-form nucleating agent. It is found that the ?ý trigonal crystals are predominantly formed in the extruded samples containing the nucleating agent.Since the ?ý-form crystals are responsible for the marked mechanical toughness, the impact strength of the sheet sample containing the nucleating agent is higher than that of the pure PP. Further, PP molecules in the extruded sheet are found to orient perpendicular to the applied flow direction.As a result, the sheet shows anomalous mechanical anisotropy.

E-Learning is now a popular learning method and it is a certain relation between e-Learning and Virtual Manufacturing‹¬?VM‹¬?. In the context it designed two experiments to prove the learning efficiency of using the VM technology in e-Learning. Two experiments were carried out including the learning efficiency test (LET) and the reliability test (RT). LET aims to prove whether the learning system provides learning efficiency; and RT aims to test the stability of the operating system. The results of experiments evidence that operation system provides the learner with learning efficiency 30% and reliability value( for operating time) is 0.835 . This hence concludes the usability of this way.

Anhydrous calcium sulfate is manufactured from high purity naturally occurring gypsum deposits in Oklahoma USA. The final product is a white fine grind powder which is suitable to extend and replace TiO2 in white color concentrate master batches. The material is heat stable in the realm of plastics processing temperatures and it is compatible with the various resins typically used in this application. Due to its low Mohs hardness calcium sulfate is easily processed while providing opacity by acting as an efficient and cost effective TiO2 spacer in the concentrate.

On-line gauging Systems with advanced Full Spectrum InfraRed sensor technologies and control strategies improve quality of multilayer high barrier films and coatings increase productivity of the manufacturing process and provide timely and valuable insights into the Biax Film and Extrusion Coating manufacturing processes with Process Analytical tools and Process Diagnostics Visualization tools. Diagnostic tools such as FFT Contourview Die mapping Process variables trending etc. pinpoint the process problems in a timely manner. The resultant Process Optimization contributes significantly to improved product quality increased productivity scrap reduction and high material yield.

On-line gauging Systems with advanced Full Spectrum InfraRed sensor technologies and control strategies improve quality of multilayer high barrier films and coatings, increase productivity of the manufacturing process, and provide timely and valuable insights into the Biax Film and Extrusion Coating manufacturing processes with Process Analytical tools and Process Diagnostics Visualization tools. Diagnostic tools such as FFT, Contourview, Die mapping, Process variables trending etc. pinpoint the process problems in a timely manner. The resultant Process Optimization contributes significantly to improved product quality, increased productivity, scrap reduction and high material yield.