SPE Library

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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Conference Proceedings

Chemical Imaging with near Filled Scanning Optical Microscopy

Stephan J. Stranick, D. Bruce Chase, Chris A. Michaels, May 2001

The ability to measure chemical bond changes on the nanometer scale is of critical importance for the characterization of catalytic processes, catalytic materials, and surfaces relevant to materials and biological problems. Our goal has been to develop a technique for in-situ, non-destructive measurements of site-specific chemistry on the nanometer scale. The strategy for realizing this goal involves coupling the high spatial resolution of near-field scanning optical microscopy (NSOM) with the chemical specificity of vibrational spectroscopy.

In-Mold Decorating of Plastic Parts

Jordan I. Rotheiser, May 2001

In-mold decorating is a technique with a long history. However, recent developments have created new opportunities for designers. This paper discusses these techniques and how they are applied to plastics.

Comparison of Conventional High-Flow HDPE and Single-Site High-Flow HDPE Blends

T.J. Schwab, W.G. Todd, May 2001

Polyethylene (PE) injection molded rigid containers are widely used for food packaging, especially for frozen and refrigerated food applications. Due to the cold end-use environment, molders of these containers are constantly looking to improve impact performance while maintaining other physical properties. This work compares molded part physical properties of conventional high-flow HDPE products to those obtained with single-site HDPE products and blends of conventional high-flow HDPE with single-site HDPE or metallocene PE.

COF of LLDPE Film at Low Loadings of Erucamide

María X. Ramírez, Douglas E. Hirt, Nate Miranda, May 2001

The relationship between surface concentration and COF of LLDPE films has been studied for the slip agent erucamide [1]. This research continues this study, relating the film's additive surface concentration to its bulk loading. Low bulk loadings ranging from 100 ppm to 1000 ppm were investigated. The surface concentration was measured using surface washing and the bulk loading was quantified using microwave extraction. Results indicate the COF at a given surface concentration to be path-independent, as was hypothesized in our previous study [1].

Migration of Fluorinated Additives to HDPE Film Surfaces

Keisha B. Walters, Douglas E. Hirt, May 2001

The surface concentration of fluorinated additives has been investigated in high density polyethylene (HDPE) films. These additives have been used as processing aids and are presently being studied as surface-property modifiers to lower the surface energy for applications where hydrophobicity is important. We have used ATR-FTIR and ESCA to characterize the composition of these modified film surfaces. Results indicate the extent of surface segregation as a function of additive molecular weight and bulk loading.

Measurement of Microstructural Variation in Blown Films

S. Cherukupalli, R. Jelen, A.A. Ogale, May 2001

A real-time study on the evolution of molecular structure in an isotactic polypropylene blown film (i-PP) is reported. The structural variation along the machine direction of the film has been observed with online Raman spectroscopy. Preliminary measurements indicate a variation in the intensity of 809 cm-1 peak relative to the 841 cm-1 peak as the state of the polymer changes from a melt to solid at the freeze line. This change is related to the development of crystallinity along the film line.

On the Use of Rotational Rheometry for Quality Control

Nafaa Mekhilef, David S.C. Lee, Florence Dion, May 2001

The aim of this work is to evaluate if rotational rheometry provides a more useful measurement of viscosity than capillary rheometry and melt flow index measurements in production environments. To achieve this, we compared the sensitivity of these methods for quality control in the batch production of a commercial fluorinated polymer by using statistical analysis and the ease-of-implementation criterion of each method. The utility of rotational rheometry to develop flow curves to assist blending in a batch process was also investigated.

Status of Research on Design for Mechanical Reliability of Injection Molded Plastics Products

Rolf Koster, May 2001

Various injection molded specimens and specimens from injection molded products have been tensile and tensile-impact tested to develop manufacturing-related design guidelines. Tensile strength of PS perpendicular to flow was affected by both filling-induced and packing-induced phenomena. For a nylon block copolymer the influence of test speed was shown. Cold weld line strength in PS was reduced by increased temperatures in the skins during molding. For polyester-amide and PHB the amorphous structure fraction contributed to reduced weld line strength.

Process Dynamics in Sequential Valve Gate Injection Molding - Processing Strategy and Process Control

Suk-young Shin, Nick Schott, Stephen McCarthy, May 2001

The process dynamics of sequential valve gate injection molding were investigated using multiple pressure transducers in a single cavity. System response is analyzed based on the servo valve signals and the cavity pressure profiles. The optimum process control and part quality control settings of the Sequential Valve Gate system were determined. Also, the experimental results were compared with the predicted results obtained from a simulation program.

Fracture Toughness of Co-Continuous Polycarbonate/ABS Blends

J.P.F. Inberg, L.C.E. Struik, R.J. Gaymans, May 2001

Polycarbonate/ABS blends are industrially important however very little reported on in literature. Co-continuous PC/ABS (50/50) blends were made on a twin-screw extruder and tested in notched Izod at different temperatures and different rubber content in the ABS. Ductility improved strongly with increasing rubber content in the ABS (Tbd lowered to about -40°C) with little decrease in modulus.

Numerical Simulation of Injection Molding of Semicrystalline Thermoplasti

Jianxin Guo, Kwabena A. Narh, May 2001

Injection molding process of semicrystalline plastics was simulated with a stress-induced crystallization model. Pseudo-concentration method was used to track the melt front advancement. The stress relaxation was incorporated into the model using the WFL model. Simulations were carried out under different processing condition to investigate the effect of processing parameters on the crystallinity of the final part. The simulation results reproduced most of the features reported in the literature.

Process Fingerprints for Compounding of Polymer Blends – An Industrial Prospective

Chi-Kai Shih, May 2001

A process fingerprint measurable by on-line monitoring of common process variables could aid immensely the ability of a process engineer to control the process output. The torque curve of a Brabender batch internal mixer offered many fingerprints related to the fundamental behavior the raw ingredients experienced during the mixing process. Suggestions were made how to derive fingerprints from the fundamental functions of twin screw extrusion processes.

Rheological Behavior of Modified Polypropylene (PP) with Nitrile Rubber (NBR)

M. Hernández, J. González, C. Albano, M. Ichazo, D. Lovera, May 2001

The rheological behavior of polypropylene (PP) modified with nitrile rubber (NBR), within the composition range of 10-30 wt% NBR content, was studied based on the blend ratio, dynamic vulcanization and additives blending effects. Results indicate all systems show a pseudoplastic behavior with an increasing melt viscosity on NBR content. Dynamically vulcanized blends present similar melt viscosity and lower die swell values than corresponding unvulcanized blends. The rheological behavior was correlated with blend morphology.

Interaction between PVA and Starch System Plasticized with Different Moisture Content

Yi-Fan Wu, Mei-Jan Chu, Chi-Hwa Chen, Ming-Shien Shung, Wen-Chi Hsie, Hsiao-Fu Shen, May 2001

We investigated the interaction between PVA and starch blended series plasticized with different moisture content. Brabender plasticoder was applied to research the effect of gelatinization of water plasticized starch on the processability of this series. The moisture content of this series was furthermore found increasing with the increase of relative humility in different ambient condition.

Morphology Distribution of Injection Molded Polypropylene

Peng Wei Zhu, Graham Edward, May 2001

The morphology distribution of injection-molded polypropylene (PP) was quantitatively studied using synchrotron radiation. Samples were taken from a PP plate at different positions from the gate. X-ray measurements were performed with the beam normal to the flow direction. The evaluation of x-ray data allows determination of distributions of the crystallinity, the imperfection factor, the á-phase orientation, and the â-phase concentration. Different distributions are observed at different distances from the gate.

Documenting Flow Segregation in Geometrically Balanced Runners

Louis G. Reifschneider, May 2001

The flow distribution through a geometrically balanced runner is not evenly balanced due to the melt temperature segregation that occurs at each branch point in the runner. A test mold is built and molding trials are conducted to document the flow segregation in a four cavity mold containing a geometrically balanced runner. The extent of the flow segregation is seen to be a function of the resin type, the flow rate, and the extent of the filling.

The Effect of Blending on the Viscosity Reduction of Recycled Milk Bottle Grade HDPE

Natalia Kukaleva, George Simon, Edward Kosior, May 2001

Post-consumer plastic waste in Australia contains over 50,000 tonnes p.a. of HDPE blow moulded bottles, with half still ending up in landfill. Recycled milk-bottle grade HDPE is known to be too high in molecular weight for processing by injection molding. In this study, the target was to make injection-molded compositions with a content of the recycled material of 75% or higher by blending with commodity plastics. The results of rheological, thermal and mechanical studies of the blends are presented.

Rheology and Processing of TPV's

Wim Zoetelief, May 2001

The rheological behavior of TPV in shear and extensional is studied to help understanding the flow behavior in various processing operations. The TPV's, which are dynamically vulcanized PP/EPDM blends show in shear flow a typical rheological behavior with an apparent yield stress at low shear rates and a shear-thinning viscosity at high(er) shear rates. In extension the TPV melts appeared not to show strain-hardening. This study discusses the observed behavior in terms of composition.

Impact Modification of Poly(Ethylene Terephthalate)

N. Chapleau, M.A. Huneault, May 2001

Many polar thermoplastics, such as poly(ethylene terephthalate), tend to be notch sensitive and can exhibit a sharp ductile-to-brittle transition. Many studies focusing on the improvement of toughness using elastomeric particles have demonstrated that the increase in toughness is related to the ability of the rubber particles to cavitate and to morphological parameters. In this work, the mechanical properties of a poly(ethylene terephthalate) matrix containing several impact modifiers are investigated.

Processing-Structure-Properties Relationships in Multilayer Films

Xiaomin Zhang, Verilhac Jean-Marie, Abdellah Ajji, May 2001

LDPE/PET multilayer films with and without a reactive tie layer were prepared by extrusion blowing process. PET layer showed a negligible orientation and an almost zero crystallinity. For PE layer, the crystalline a-axis was oriented along machine direction and the b-axis mainly tended to the transverse-normal plane, no orientation for amorphous phases was found. A morphological model for the different processing conditions was proposed. The shrinkage and tear strength correlated well with the orientation structure of the LDPE layer in the films.